Open AccessReview

Engineering LiBH₄-Based Materials for Advanced Hydrogen Storage: A Critical Review of Catalysis, Nanoconfinement, and Composite Design

Yaohui Xu

^1,3,

Yang Zhou

^2,*,

Yuting Li

⁴,

Maziar Ashuri

^5,*

and

Zhao Ding

^4,*

Laboratory for Functional Materials, School of New Energy Materials and Chemistry, Leshan Normal University, Leshan 614000, China

State Key Laboratory of New Textile Materials and Advanced Processing Technology, School of Textile Science and Engineering, Wuhan Textile University, Wuhan 430200, China

Leshan West Silicon Materials Photovoltaic New Energy Industry Technology Research Institute, Leshan 614000, China

⁴

College of Materials Science and Engineering, National Engineering Research Center for Magnesium Alloys, National Innovation Center for Industry-Education Integration of Energy Storage Technology, Chongqing University, Chongqing 400044, China

⁵

Department of Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, Chicago, IL 60616, USA

Authors to whom correspondence should be addressed.

Molecules 2024, 29(23), 5774; https://doi.org/10.3390/molecules29235774

Submission received: 15 November 2024 / Revised: 4 December 2024 / Accepted: 5 December 2024 / Published: 6 December 2024

(This article belongs to the Collection Green Energy and Environmental Materials)

Download

Browse Figures

Versions Notes

Abstract

Lithium borohydride (LiBH₄) has emerged as a promising hydrogen storage material due to its exceptional theoretical hydrogen capacity (18.5 wt.%). However, its practical application is hindered by high dehydrogenation temperature (>400 °C), sluggish kinetics, and limited reversibility due to stable intermediate formation. This review critically analyzes recent advances in LiBH₄ modification through three primary strategies: catalytic enhancement, nanostructure engineering, and reactive composite design. Advanced carbon architectures and metal oxide catalysts demonstrate significant improvements in reaction kinetics and cycling stability through interface engineering and electronic modification. Sophisticated nanostructuring approaches, including mechanochemical processing and infiltration techniques, enable precise control over material architecture and phase distribution, effectively modifying thermodynamic and kinetic properties. The development of reactive hydride composites, particularly LiBH₄-MgH₂ systems, provides promising pathways for thermodynamic destabilization while maintaining high capacity. Despite these advances, challenges persist in maintaining engineered structures and suppressing intermediate phases during cycling. Future developments require integrated approaches combining multiple modification strategies while addressing practical implementation requirements.

Keywords:

lithium borohydride; hydrogen storage; catalysis; nanoconfinement; reactive composites; thermodynamic destabilization

Graphical Abstract

1. Introduction

The global imperative to transition toward sustainable energy systems has positioned hydrogen as a pivotal energy carrier for the 21st century. With its exceptional gravimetric energy density (142 MJ/kg), clean combustion characteristics, and versatility across various applications, hydrogen presents a promising pathway for decarbonizing multiple sectors, including transportation, industrial processes, and power generation [1,2,3,4,5]. However, the widespread adoption of hydrogen-based technologies faces a fundamental challenge: the development of efficient, safe, and economically viable hydrogen storage systems [6,7,8,9]. To guide research and development efforts in this critical area, the U.S. Department of Energy has established specific technical targets for onboard hydrogen storage systems, as shown in Table 1. These ambitious targets underscore the significant technical challenges that must be overcome to enable practical hydrogen storage solutions. Conventional storage methods—compressed gas and cryogenic liquefaction—present significant limitations for practical applications [10,11,12]. Compressed hydrogen storage requires extremely high pressures (350–700 bar), necessitating expensive composite tanks and raising safety concerns, while cryogenic storage, despite achieving higher volumetric densities, demands considerable energy for liquefaction (−253 °C) and suffers from continuous boil-off losses. These challenges have catalyzed intensive research into solid-state hydrogen storage materials as alternative solutions [13,14,15,16,17].

Among the diverse array of solid-state hydrogen storage candidates, complex hydrides have emerged as particularly promising materials due to their exceptional gravimetric and volumetric hydrogen densities. Within this class, lithium borohydride (LiBH₄) stands out as a remarkable candidate, offering one of the highest theoretical hydrogen storage capacities (18.5 wt.%) among known materials [18,19]. Table 2 summarizes the key advantages and challenges associated with LiBH₄ as a hydrogen storage material. Despite its promising characteristics, the practical implementation of LiBH₄-based storage systems faces several critical challenges [20,21,22]. The material exhibits high thermodynamic stability, requiring temperatures exceeding 400 °C for hydrogen desorption—far beyond the operational range of most applications, particularly proton exchange membrane fuel cells (PEMFCs) that operate optimally below 100 °C. Furthermore, the dehydrogenation process is complicated by the formation of stable intermediate species, notably Li₂B₁₂H₁₂, which impedes complete hydrogen release and system reversibility. The rehydrogenation process demands severe conditions (typically > 600 °C and >150 bar H₂), presenting additional engineering challenges for practical applications.

Recent years have witnessed significant advances in addressing these limitations through various materials engineering strategies, which can be broadly categorized into three main directions: catalyst doping to reduce kinetic barriers and modify reaction pathways; nanostructuring and confinement to enhance surface reactivity and alter thermodynamic properties; and the formation of reactive hydride composites to modify the overall reaction energetics [23,24,25,26]. Each strategy has demonstrated promising results while also revealing new challenges and opportunities for further optimization. These advances have been supported by the development of advanced characterization techniques and mechanistic studies, enabling a deeper understanding of the fundamental processes governing hydrogen storage in LiBH₄-based systems.

While several comprehensive reviews have previously examined LiBH4-based systems, the rapid evolution of this field necessitates an updated perspective that integrates recent breakthroughs. This review uniquely synthesizes the latest advances (2019–2024) in catalyst design, nanostructuring, and composite development, with a particular emphasis on the fundamental mechanisms governing performance enhancement. By focusing on the critical role of interface engineering and phase evolution during cycling, along with the synergistic effects of combined modification strategies, we provide deeper insights into practical system development than previously available in the literature. This comprehensive review provides a critical analysis of the current state of LiBH₄-based hydrogen storage systems, examining both fundamental aspects and practical considerations. Following a detailed exploration of the structural and thermodynamic properties of LiBH₄, we systematically evaluate various modification strategies, including mechanistic studies of catalyst effects, nanoconfinement approaches, and reactive hydride composite systems. Special attention is devoted to emerging trends and innovative approaches in LiBH₄ modification, including the development of multifunctional catalysts, advanced nanostructuring techniques, and novel composite systems. Throughout this review, we emphasize the interplay between material properties, processing conditions, and system performance, providing insights for future research directions.

This review concludes with a comprehensive assessment of the remaining challenges and future opportunities in LiBH₄-based hydrogen storage research. By analyzing the critical developments needed to bridge the gap between current capabilities and practical requirements for commercial applications, this review serves as a valuable resource for researchers, engineers, and decision-makers working toward the realization of efficient hydrogen storage systems based on LiBH₄ and related materials. The systematic examination of recent advances, coupled with a critical analysis of persistent challenges, provides a foundation for future research efforts aimed at developing practically viable LiBH₄-based hydrogen storage systems.

2. Structural Chemistry and Reaction Mechanisms of LiBH₄

The fundamental behavior of LiBH₄ as a hydrogen storage material is governed by its unique structural chemistry and complex reaction mechanisms. At room temperature, LiBH₄ crystallizes in an orthorhombic structure (Figure 1a,b), characterized by a highly ordered network where each [BH₄]⁻ anion is tetrahedrally coordinated by four lithium cations [27]. This distinctive arrangement creates a dual bonding environment: strong covalent B-H bonds within the [BH₄]⁻ tetrahedra and ionic interactions between Li⁺ and [BH₄]⁻ units [28,29]. The interplay between these bonding types not only contributes to the material’s exceptional hydrogen storage capacity of 18.5 wt.% but also significantly influences its thermal stability and hydrogen release characteristics [30,31,32].

The structural evolution of LiBH₄ during heating reveals complex phase behavior that directly impacts its hydrogen storage properties. Upon heating, LiBH₄ undergoes a first-order phase transition from its low-temperature orthorhombic phase to a high-temperature hexagonal phase at approximately 380 °C [33,34]. This phase transformation is accompanied by dramatic changes in the material’s physical properties, including a significant increase in ionic conductivity and enhanced hydrogen mobility within the crystal lattice. The heightened atomic and ionic mobility in the high-temperature phase facilitate the initial stages of hydrogen release, though the temperature requirement remains substantially above the practical operating range for most applications.

The dehydrogenation of LiBH₄ proceeds through a complex, multi-step pathway that involves the formation of several intermediate phases [33,35,36,37]. The process begins at temperatures above 400 °C, following the sequence below.

Step 1: LiBH₄ → 1/12 Li₂B₁₂H₁₂ + 5/6 LiH + 13/12 H₂ (T > 400 °C)
Step 2: 1/12 Li₂B₁₂H₁₂ → 1/10 Li₂B₁₀H₁₀ + 1/15 LiH + 1/30 H₂ (T > 450 °C)
Step 3: 1/10 Li₂B₁₀H₁₀ + 9/10 LiH → LiBH + 9/20 H₂ (T > 500 °C)
Step 4: LiBH → LiH + B + 1/2 H₂ (T > 550 °C)

Among these steps, the formation of Li₂B₁₂H₁₂ (Figure 1c) represents a critical turning point in the dehydrogenation process [38]. This intermediate compound exhibits remarkable stability due to its unique icosahedral structure (space group: P21/n, Z = 2; a = 7.358 Å, b = 9.556 Å, c = 6.768 Å, β = 92.26°) and extensive electron delocalization within its closed-cage architecture. The extraordinary stability of Li₂B₁₂H₁₂ stems from its highly symmetric structure, where 12 (BH) units form a nearly perfect icosahedron, creating a network of strong B-B bonds that resist further decomposition. This structural characteristic presents a significant kinetic barrier to both complete dehydrogenation and subsequent rehydrogenation processes.

Figure 1. The LiBH4 structure at room temperature (a) Boron (top) and (b) lithium (bottom) [27]. (c) Atomistic structure model of the monoclinic Li₂B₁₂H₁₂ space group: P21/n, Z = 2; a = 7.358 Å, b = 9.556 Å, c = 6.768 Å, and β = 92.26°. The large, middle, and small spheres denote Li, B, and H atoms, respectively [38].

The thermodynamic landscape of LiBH₄ decomposition is equally complex. The standard enthalpy of dehydrogenation (ΔH ≈ 74 kJ/mol H₂) reflects the considerable energy requirement for breaking B-H bonds and rearranging the crystal structure [37,39,40,41]. This high enthalpic barrier, combined with the formation of stable intermediates, necessitates temperatures well above 400 °C for appreciable hydrogen release [42,43]. The situation becomes even more challenging during rehydrogenation, which typically requires hydrogen pressures exceeding 100 bar and temperatures above 400 °C. The rehydrogenation pathway can be represented as follows:

LiH + B + 3/2 H₂ → LiBH + 1/2 H₂ → 1/10 Li₂B₁₀H₁₀ + 9/10 LiH → 1/12 Li₂B₁₂H₁₂ + 5/6 LiH + 1/12 H₂ → LiBH₄

The severity of these rehydrogenation conditions stems from multiple factors, including the thermodynamic stability of the dehydrogenated products (LiH and B), the kinetic barriers associated with B-H bond formation, and the necessity of decomposing stable intermediate phases. The reformation of the original LiBH₄ structure requires precise control over reaction conditions to promote the complete reversal of the dehydrogenation pathway while minimizing the formation of persistent intermediate phases.

The structural evolution during cycling between hydrogenated and dehydrogenated states introduces additional complexity. Repeated hydrogen cycling can lead to structural deterioration, phase segregation, and the accumulation of stable intermediates, particularly Li₂B₁₂H₁₂ and Li₂B₁₀H₁₀. These changes often result in capacity degradation and slower kinetics in subsequent cycles. Understanding these structural and mechanistic aspects is crucial for developing effective strategies to enhance the hydrogen storage performance of LiBH₄. The challenges posed by the formation of stable intermediates and the high thermodynamic barriers have motivated extensive research into various modification approaches, including catalyst incorporation, nanostructuring, and the development of reactive hydride composites, which will be examined in detail in subsequent sections.

3. Catalytic Enhancement Strategies

Catalyst doping is a widely researched approach aimed at enhancing the dehydrogenation and rehydrogenation kinetics of LiBH₄ as well as lowering its dehydrogenation temperature. Studies have shown that introducing catalysts into LiBH4 can facilitate the breaking and reformation of B-H and Li-H bonds, thereby reducing activation energy and improving the kinetics of hydrogen absorption and desorption. Various catalysts, including carbon materials and metal oxides, have been explored for their effects on the hydrogen storage properties of LiBH₄ [44]. The catalytic effects are attributed to several key mechanisms. First, catalysts can act as nucleation sites for the formation of intermediate compounds, such as Li₂B₁₂H₁₂ and Li₂B₁₀H₁₀, reducing the activation energy required for the formation and decomposition of these compounds. Second, catalysts interact with B-H and Li-H bonds, weakening their bond strength and promoting bond dissociation during the dehydrogenation process. Finally, catalysts can facilitate the recombination of dehydrogenated products, such as LiH and B, during the rehydrogenation process, thus enhancing the reversibility of the hydrogen storage system. Although significant improvements in the hydrogen storage properties of LiBH₄ have been achieved through catalyst doping, challenges remain, such as the long-term stability and recyclability of catalysts during hydrogen absorption and desorption cycles [45]. Additionally, catalysts may sometimes promote the formation of stable intermediate compounds (e.g., Li₂B₁₂H₁₂), which hinder the complete dehydrogenation and rehydrogenation of LiBH₄ [46]. Therefore, the selection and optimization of catalysts for LiBH₄-based hydrogen storage systems require an in-depth understanding of catalytic mechanisms and the structure–property relationships involved. Table 3 summarizes the hydrogen storage performance of various composite materials under different temperatures and conditions, showing that the desorption capacity varies with the type of additive and experimental parameters. Overall, higher temperatures and vacuum conditions generally result in increased desorption capacities, with different additives demonstrating significant effects on performance modulation. These findings offer valuable insights for the optimization of hydrogen storage materials.

Table 3. Hydrogen storage and desorption capacities of LiBH₄-based composite materials under various conditions.

Materials	Adsorb Temperature	Adsorb Condition	Adsorb Capacities (ad)	Desorb Temperature	Desorb Condition	Desorb Capacities	Refs.
LiBH₄-30 wt.% SWNTs	-	-	-	550 °C	Vacuum	12.3 wt.%	[47]
LiBH₄-30 wt.% G	\	\	\	450 °C	Vacuum	6.8 wt.%	[48]
LiBH₄-30 wt.% AC	\	\	\	450 °C	Vacuum	10 wt.%
LiBH₄-30 wt.% SWNTs	\	\	\	450 °C	Vacuum	11 wt.%
LiBH₄-D-carbon	\	\	\	380 °C	Vacuum	7.4 wt.%	[49]
LiBH₄-AC-carbon	\	\	\	380 °C	Vacuum	7.6 wt.%	[50]
LiBH₄-20 wt.% Grapene	\	\	\	700 °C	Vacuum	11.4 wt.%	[51]
LiBH₄@NiO_Ar	150 °C	10 bar	2.13 wt.%	450 °C	Vacuum	6.32 wt.%	[52]
LiBH₄-0.06TiO	500 °C	50 bar/100 min	9 wt.%	400 °C	Vacuum/10 min	9 wt.%	[53]
LiBH₄-Fe₃O₄	450 °C	10 MPa/60 min	6.7 wt.%	400 °C	Vacuum	8.1 wt.%	[54]
LiBH₄-30% Fe₃O₄	450 °C	10 MPa/60 min	8.1 wt.%	350 °C	Vacuum/30 min	7.8 wt.%	[55]
LiBH₄-SrF₂	450 °C	8 MPa	5.2 wt.%	550 °C	Vacuum	5.3 wt.%	[56]
LiBH₄-20 wt.% Ce₂S₃	\	\	\	400 °C	Vacuum/50 min	4 wt.%	[57]

3.1. Carbon-Based Architectures

Carbon-based materials have emerged as exceptional catalytic platforms for LiBH₄ modification, offering unique advantages through their tunable structure, high surface area, and versatile surface chemistry. Beyond their traditional role as supports, carbon materials demonstrate intrinsic catalytic activity through electronic interactions and the creation of specialized reactive sites for hydrogen storage processes.

The pioneering work by Fang et al. [47] revealed the remarkable potential of single-walled carbon nanotubes (SWNTs) in enhancing LiBH₄ performance. Through systematic ball milling studies, they demonstrated that SWNTs significantly improve dehydrogenation/re-hydrogenation kinetics, enabling reversible hydrogen storage under milder conditions. Subsequent comparative analyses of various carbon architectures, including graphite (G), purified SWNTs, and activated carbon (AC), established a clear structure–performance relationship [48]. Both SWNTs and AC exhibited superior catalytic effects compared to graphite, highlighting the importance of surface accessibility and nanoscale architecture in catalytic efficiency. Further advancement in carbon-based catalysis was achieved through the strategic incorporation of multi-walled carbon nanotubes (MWCNTs). Weng et al. demonstrated that optimized MWCNT content (>7 wt.%) prevents agglomeration and facilitates approximately 7.5 wt.% hydrogen release. The enhanced performance was attributed to the creation of efficient gas diffusion channels and increased contact area between LiBH₄ and H₂, illustrating the critical role of architectural design in catalyst optimization [49].

A significant breakthrough in carbon catalyst design was achieved by Zhao et al. [50] through the development of nitrogen-doped hierarchical porous carbon (NHPC) materials using a zeolitic imidazolate framework (ZIF-8) as a sacrificial template. This innovative approach yielded a three-dimensional carbon framework with exceptional characteristics: high nitrogen content (11.22%), large surface area (2477 m²·g⁻¹), and hierarchical porosity. As shown in Figure 2a, the overlap of N signals with the main C signals confirms the presence of nitrogen doping. Ball-milled composites of LiBH4 with these carbon materials demonstrated remarkable hydrogen release properties, achieving approximately 6.13 wt.% H₂ release within 100 min at 320 °C (Figure 2b). The detailed structural characterization through XRD and FT-IR spectroscopy (Figure 2c,d) revealed that the carbon framework not only catalyzes hydrogen release but also stabilizes the dehydrogenated state while maintaining system reversibility.

The integration of graphene into LiBH₄ systems has opened new avenues for performance enhancement. Xu et al. [51] achieved a significant reduction in initial hydrogen release temperature to 230 °C by incorporating 20 wt.% graphene, resulting in a total weight loss of 11.4 wt.% below 700 °C. The graphene modification led to a remarkable decrease in dehydrogenation enthalpy from 74 kJ mol⁻¹ H₂ to 40 kJ mol⁻¹ H₂, demonstrating the profound impact of two-dimensional carbon architectures on the thermodynamics of hydrogen storage. Under hydrogen pressure of 3 MPa, the composite maintained a capacity of approximately 4.0 wt.% over 10 cycles at 400 °C, though the formation of Li₂B₁₀H₁₀ during rehydrogenation highlighted ongoing challenges in achieving complete reversibility.

The exceptional performance enhancements achieved through carbon-based catalytic systems stem from a sophisticated interplay of multiple mechanisms. The hierarchical architecture of carbon materials creates an intricate network of active sites and diffusion pathways, while their tunable surface chemistry enables precise control over hydrogen dissociation and recombination processes. Surface functionalization, particularly nitrogen doping, introduces additional electronic modification effects that can significantly alter local reaction energetics. Furthermore, the thermal conductivity of carbon frameworks facilitates efficient heat distribution during cycling, promoting uniform reaction progression. However, maintaining architectural integrity during extended cycling remains challenging, particularly regarding the stability of engineered interfaces and pore structures. The complex balance between maximizing catalytic activity through increased surface area and maintaining structural stability during repeated hydrogen cycling necessitates the careful optimization of carbon architecture design. Understanding and controlling these structure–property relationships is crucial for developing next-generation carbon-based catalytic systems that can maintain their enhancement effects throughout the material’s operational lifetime.

3.2. Metal Oxide Catalysis

Metal oxide catalysts have emerged as powerful modifiers for LiBH₄ systems, offering unique advantages through their diverse crystal structures, tunable surface chemistry, and versatile redox properties [17,58]. The incorporation of metal oxides can significantly alter the thermodynamics and kinetics of hydrogen storage processes through multiple mechanisms, including surface activation, electronic modification, and the creation of reactive interfaces [58,59]. The rational design of oxide catalysts, particularly through morphological control and interface engineering, has led to remarkable improvements in LiBH₄ performance.

The development of nickel oxide-based catalysts exemplifies the importance of morphological control in oxide catalyst design. Kaliyaperumal et al. [52] demonstrated the exceptional potential of flower-like NiO structures synthesized through a controlled hydrothermal process. When combined with LiBH₄ via wet sonication, these architecturally designed catalysts enabled hydrogen release initiation at temperatures as low as 250 °C. The composite system achieved an impressive two-stage hydrogen release: 2.13 wt.% H₂ between 50–250 °C, followed by an additional 6.32 wt.% H₂ in the range of 275–450 °C. This stratified release pattern, significantly superior to unmodified LiBH₄’s performance, highlights the profound impact of catalyst morphology on hydrogen storage behavior.

Titanium-based oxide systems have demonstrated particularly promising results through precise compositional and structural control. Li et al. [53] developed an innovative LiBH₄-0.06TiO composite system that showcases the complex interplay between catalyst structure and performance. An X-ray diffraction analysis post-ball milling revealed the preservation of the LiBH₄ phase, while FTIR spectroscopy (Figure 3a,b) identified characteristic absorption peaks at 2975, 2930, and 1050 cm⁻¹ corresponding to the -CH₃, -CH₂, and C-O groups from the titanium precursor. Upon thermal treatment, the emergence of TiO peaks coincided with the disappearance of organic functional groups, indicating successful structural transformation. The modified system demonstrated remarkable performance improvements, with hydrogen desorption initiating at 240 °C and reaching its peak at 340 °C—a substantial 140 °C reduction compared to pristine LiBH₄. Under isothermal conditions at 400 °C, the composite rapidly released 9 wt.% H₂ within 10 min. The system’s rehydrogenation capability was equally impressive, initiating hydrogen uptake at 150 °C and achieving a 9 wt.% capacity after 100 min at 500 °C under 50 bar H₂. An XPS analysis (Figure 3c) confirmed the presence of TiO through characteristic spin-orbit splitting peaks at 455.0 and 460.5 eV, providing valuable insights into the catalyst’s electronic state.

Iron oxide-based catalysts have revealed fascinating mechanistic insights through both theoretical and experimental investigations. Liu et al. [60] employed first-principles calculations to elucidate the fundamental role of Fe₂O₃ clusters in modifying the LiBH₄ (001) surface. Their computational studies unveiled the critical coupling effect between spin-up Fe-d orbitals and the hybridization of H-s, B-p, and Fe-d orbitals, establishing Fe₂O₃ clusters as effective nucleation sites for surface activation. These theoretical insights have guided the development of advanced iron oxide architectures. Wang et al. [54] successfully synthesized myrica-like hierarchical iron oxide-graphene nanospheres that enabled hydrogen release below 100 °C and achieved an impressive total capacity of 8.1 wt.% H₂ at 400 °C, maintaining 70% capacity after 10 cycles.

Further advancement in iron oxide catalyst design was achieved through the development of passionfruit-like porous hybrid materials (p-Fe₃O₄@C) by Wang et al. [55]. This innovative architecture, featuring ultrafine Fe₃O₄ particles encapsulated within carbon shells, demonstrated the power of synergistic effects combining nano-confinement, catalysis, and surface instability. With optimized LiBH₄ loading at 60 wt.%, the system achieved a remarkably low dehydrogenation onset temperature of 175 °C and released 4.9 wt.% H₂ by 350 °C. The composite demonstrated exceptional kinetics, reaching 7.8 wt.% capacity within 20 min and maintaining stability through extended isothermal operation. A detailed kinetic analysis revealed a significant reduction in dehydrogenation activation energy to 108.1 kJ mol⁻¹, substantially lower than the 179.1 kJ mol⁻¹ of unmodified LiBH₄. The system’s cycling stability was particularly noteworthy, retaining 93% capacity after 20 cycles at 300 °C (Figure 3e–g).

The remarkable effectiveness of metal oxide catalysts in enhancing LiBH4’s hydrogen storage performance arises from their multifaceted influence on both reaction thermodynamics and kinetics. The formation of reactive metal–oxygen interfaces creates localized electronic environments that facilitate hydrogen dissociation and recombination, while the potential for oxygen ion mobility enables the dynamic modification of local bonding environments. The observed synergistic effects between different oxide phases, particularly in hierarchical architectures combining multiple metal species, demonstrate the potential for further performance optimization through careful catalyst design. The formation of oxygen-containing intermediates during cycling can modify reaction pathways and influence the stability of various phases, though controlling these processes to maintain consistent performance remains challenging. The development of oxide catalysts that can simultaneously address multiple performance limitations while maintaining structural and chemical stability under cycling conditions represents a critical direction for future research in this field.

3.3. Alternative Catalyst Systems

Beyond traditional carbon and oxide catalysts, a diverse array of alternative materials including borides, fluorides, and sulfides has demonstrated remarkable potential in modifying LiBH₄’s hydrogen storage properties [61,62]. These compounds offer unique advantages through their distinctive chemical bonding, electronic structures, and surface properties, enabling novel pathways for performance enhancement. The systematic investigation of these alternative catalyst systems has revealed innovative strategies for overcoming the limitations of conventional approaches while providing deeper insights into catalyst design principles [63].

Boride-based catalysts have emerged as particularly effective modifiers due to their chemical compatibility and unique electronic properties. Cai et al. [64] conducted a comprehensive investigation of SiB₄/FeB/TiB₂ additives, revealing their profound impact on LiBH₄’s reversible hydrogenation behavior. An infrared spectroscopic analysis (Figure 4) demonstrated the formation of characteristic B-H bonds in the 2200–2500 cm⁻¹ region for SiB₄/FeB/TiB₂-LiH systems. The SiB₄-LiH combination proved especially effective, exhibiting distinctive B-H stretching vibrations at 2382, 2291, and 2223 cm⁻¹, along with a characteristic bending mode at 1125 cm⁻¹. These spectral features, displaying notably higher intensities than conventional systems, indicated enhanced LiBH4 formation kinetics. While the presence of a B-H vibration at 2480 cm⁻¹ signaled the formation of the intermediate Li₁₂B₁₂H₁₂ phase, its relative concentration remained manageable. The composite demonstrated complex thermal behavior, with both LiBH₄ and Li₁₂B₁₂H₁₂ phases exhibiting dehydrogenation at reduced temperatures, as shown in Figure 4b. However, the system’s overall hydrogen release capacity at 400 °C was limited to 1.8 wt.%, corresponding to approximately 19.6 wt.% LiBH₄ formation during hydrogenation (Figure 4c).

Fluoride-based systems have introduced novel approaches to the thermodynamic modification of LiBH₄. Zhao et al. [56] investigated the 6LiBH₄/SrF₂ system and revealed distinctive plateau regions in the pressure–composition isotherms at approximately 0.35, 0.70, and 1.15 MPa for temperatures of 400, 450, and 500 °C, respectively (Figure 4d). A detailed thermodynamic analysis determined enthalpy and entropy changes for dehydrogenation at 52 kJ/mol H₂ and 87 J/(mol·K) H₂, respectively, representing a significant reduction in LiBH₄’s thermal stability. The system demonstrated practical reversibility, achieving LiBH₄ and SrF₂ regeneration alongside LiSrH3 formation at 450 °C under 8 MPa hydrogen pressure, with approximately 5.2 wt.% hydrogen release capacity maintained in the second dehydrogenation cycle. Mechanistic studies using XRD and FTIR techniques revealed complex phase evolution during ball milling and thermal treatment. The process was initiated with anion substitution between reactants at ambient temperature, followed by the sequential formation of SrH₂, LiH (LiF), and SrB₆ phases upon heating. The reaction pathway culminated in the conversion to SrF₂ and LiH (LiF) at 500 °C, proceeding through the following reaction: 6LiBH₄ + SrF₂ → SrB₆ + 2LiF + 4LiH + 10H₂ (Figure 4e).

Sulfide catalysts have demonstrated unique capabilities in enhancing LiBH₄’s performance through distinct mechanistic pathways. Wang et al. [57] developed Ce₂S₃ particles with controlled dimensions of 100–200 nm using a sophisticated solvothermal approach. The interaction between Ce₂S₃ and LiBH₄ generated Li₂S and CeB₆ as dehydrogenation products, which functioned as active species during rehydrogenation, significantly enhancing the system’s reversibility. At an optimal Ce₂S₃ loading of 20 wt.%, the composite maintained a hydrogen absorption capacity of 3.6 wt.% even after four cycles. The modification reduced the initial dehydrogenation temperature to 250 °C, representing an 80 °C improvement over pristine LiBH₄. Under isothermal conditions at 400 °C, the composite released approximately 4.0 wt.% hydrogen within 3000 s, representing a 67% improvement over the unmodified system. The activation energy for dehydrogenation decreased from 181.80 kJ/mol to 157.82 kJ/mol, confirming the catalytic effectiveness of the sulfide system.

The investigation of alternative catalyst systems, encompassing borides, fluorides, and sulfides, has revealed sophisticated mechanisms for performance enhancement that complement traditional approaches. These materials demonstrate unique capabilities in modifying both the thermodynamic landscape and reaction pathways of LiBH₄ through distinct chemical interactions and interface effects. The formation of intermediate phases during cycling can create self-sustaining catalytic effects, while careful control over composition and structure enables the targeted modification of specific reaction steps. However, the complexity of these systems, particularly regarding phase evolution and interface stability during extended cycling, presents ongoing challenges for practical implementation. The continued development of these alternative catalysts requires careful consideration of the balance between catalytic effectiveness, system complexity, and long-term stability. Understanding the fundamental mechanisms of catalyst–LiBH₄ interactions at the atomic and molecular levels will be crucial for optimizing these systems for practical hydrogen storage applications.

4. Nanostructure Engineering

The development of nanostructured LiBH₄ represents a transformative approach to addressing the fundamental limitations of bulk material systems. Through precise control of material architecture at the nanoscale, significant modifications to thermodynamic stability, reaction kinetics, and mass transport characteristics can be achieved. Nanostructuring strategies operate through multiple synergistic mechanisms: increased surface-to-volume ratio facilitating enhanced hydrogen molecule interactions; shortened diffusion pathways for hydrogen atoms and ions; modified local chemical environments affecting bond strengths and reaction energetics; and controlled interface engineering for improved reaction kinetics. The successful implementation of nanostructuring approaches requires careful consideration of synthesis methods, stability under cycling conditions, and the preservation of effective hydrogen storage capacity. Table 4 summarizes the hydrogen storage performance of various composite materials prepared using different synthesis methods during adsorption and desorption processes. The results indicate that the choice of preparation method and experimental conditions significantly influences material performance. Notably, there is a marked variation in capacities under high-pressure adsorption and vacuum desorption conditions, with certain materials demonstrating superior adsorption or desorption efficiency. These findings provide a foundational reference for the optimization of hydrogen storage materials.

Table 4. Hydrogen storage performance of LiBH₄-based composites prepared by different methods under various conditions.

Materials	Method	Absorb Temperature	Absorb Condition	Absorb Capacities	Desorb Temperature	Desorb Condition	Desorb Capacities	Refs.
LiBH₄-30 wt.% FL-Grs	Ball Milling	350 °C	100 bar/60 min	7 wt.%	350 °C	Vacuum/100 min	7.8 wt.%	[65]
LiBH₄@CNCs	Melt	400 °C	50 bar/30 min	4 wt.%	400 °C	Vacuum/60 min	4.8 wt.%	[66]
LiBH₄@NPC	Melt	\	\	\	350 °C	Vacuum/120 min	6.5 wt.%	[67]
LiBH₄/AC	Melt	350 °C	6 MPa	6 wt.%	400 °C	Vacuum	13.6 wt.%	[68]
50LBH4@NC-NbF₅	Melt	300 °C	12 MPa/100 min	6.2 wt.%	320 °C	Vacuum/39 min	7.55 wt.%	[69]
LiBH₄/carbon	Solution	\	\	\	300 °C	Vacuum/90 min	3.4 wt.%	[70]
LiBH₄@2TiO₂	Solution	\	\	\	310 °C	Vacuum/120 min	2.5 wt.%	[71]
LiBH₄@NiMnO₃	Solution	\	\	\	300 °C	Vacuum/60 min	2.8 wt.%	[72]
Nano-LiBH₄	Solution	400 °C	100 bar/25 min	12 wt.%	450 °C	Vacuum/100 min	13 wt.%	[73]

4.1. Mechanochemical Processing

High-energy ball milling has emerged as a sophisticated mechanochemical technique for engineering nanostructured LiBH₄ systems [74]. Beyond simple particle size reduction, this approach enables precise control over defect chemistry, interface formation, and local structural modifications. Through careful optimization of processing parameters, ball milling can induce fundamental changes in material properties while maintaining high hydrogen storage capacity.

The mechanistic complexity of ball milling processes is illustrated through the multi-dimensional forces applied during processing. As shown in Figure 5a, the controlled manipulation of rotation speed, ball-to-powder ratio, and milling atmosphere enables the tailored modification of LiBH₄ structure and properties [75]. The process involves repeated cycles of particle deformation, fracture, and cold welding under high-energy impacts (Figure 5b), leading to the creation of high-energy surfaces and defect-rich regions that enhance hydrogen storage kinetics [76]. Agresti et al. [77] demonstrated the remarkable potential of mechanochemical processing through their investigation of LiBH₄ synthesis directly from LiH and B precursors. Their innovative approach utilized high-energy ball milling under a hydrogen atmosphere, revealing a direct correlation between milling duration and hydrogen release capacity. The process effectiveness was further enhanced through careful optimization of hydrogen pressure within the milling vial and the strategic substitution of WC balls for conventional stainless steel media. This methodology resulted in the successful synthesis of phase-pure LiBH₄, which was confirmed through a detailed X-ray diffraction analysis of the separated crystalline product.

Complementary studies by Çakanyıldırım et al. [78] advanced the understanding of mechanochemical processing through the systematic investigation of different milling media and environments. Utilizing an SPX-type mill with various container materials (WC, stainless steel, and zirconia), they examined the impact of Li and B mixing ratios under a controlled argon atmosphere. An initial XRD analysis confirmed the formation of LiB intermediates, leading to the development of a specialized hydrogenation system operating at 60 bar pressure to facilitate hydrogen incorporation into the LiB structure. Optimization of the B/Li molar ratio to 0.214 resulted in successful LiBH₄ formation, which was verified through comprehensive FTIR spectroscopic analysis. The hydrogen-rich nature of the resulting structure was further confirmed through simultaneous thermal analysis combining DSC and TGA techniques, demonstrating enhanced mass loss characteristics.

The incorporation of support materials during ball milling has proven crucial for controlling nanostructure evolution and preventing agglomeration. Zhang et al. [65] made significant advances in this area through the strategic use of few-layer graphene (FL-Grs) supports to modify LiBH₄ morphology. Their work demonstrated a remarkable transformation from nanorods to nanoparticles in the presence of FL-Grs, with the resulting particles exhibiting controlled dimensions of 20–50 nm. This architectural modification enabled impressive performance metrics: hydrogen desorption initiated at 230 °C with absorption possible at 190 °C, accompanied by excellent cycling stability. Detailed mechanistic studies identified the growth and cyclic separation of B and LiH particles as key factors influencing the gradual evolution of desorption and absorption kinetics.

The optimization of ball milling processes for LiBH₄ nanostructuring continues to face several technical challenges. Extended milling can lead to particle reagglomeration, necessitating careful process optimization. Wear from milling media and potential atmospheric exposure requires stringent control measures. The translation of laboratory-scale processes to industrial production presents significant engineering challenges, while maintaining nanostructured features during hydrogen cycling requires careful material design and processing control. Ongoing research is focused on developing advanced characterization techniques to monitor structural evolution during milling and optimizing processing parameters for enhanced performance and scalability.

4.2. Melt Infiltration Design

Melt infiltration has emerged as a sophisticated approach for engineering nanoconfined LiBH₄ systems, offering precise control over material distribution and interface formation [79,80]. This technique exploits the melting behavior of LiBH₄ to achieve intimate contact with host materials, enabling the creation of well-defined nanostructures with enhanced hydrogen storage properties. The strategic selection of porous support materials and careful control of processing conditions allow for the development of architectures that fundamentally alter the thermodynamic and kinetic landscape of hydrogen storage reactions.

Carbon-based materials have demonstrated exceptional promise as hosts for melt-infiltrated LiBH₄ due to their thermal stability, tunable porosity, and surface chemistry. Guo et al. [66] achieved significant breakthroughs using carbon nanocages (CNCs) as host structures. Their LiBH₄@CNCs composites exhibited dramatically reduced hydrogen release temperatures, initiating desorption at 200 °C with peak activity around 320 °C—representing a remarkable 180 °C reduction compared to bulk LiBH₄. The system achieved a substantial hydrogen desorption capacity of 7.5 wt.%, maintaining 78% of initial capacity after five cycles at 400 °C. The enhanced performance stemmed from a complex interplay between nanoconfinement effects and chemical interactions. During infiltration, LiBH₄ reacted with oxygen-containing functional groups on the CNC surface, forming LiBO₂ and subsequently Li₃BO₃. These oxide species participated in additional reactions with LiBH₄, generating supplementary hydrogen release pathways and enhancing the system’s reversible storage capacity. Surrey et al. [28] advanced the field through innovative template design, employing salt-templating methods to create precisely engineered carbon scaffolds. This sustainable approach to producing micro- and mesoporous carbon architectures enabled high LiBH₄ loading capacities up to 40 wt.%. The nanoconfined system demonstrated hydrogen desorption initiation at 200 °C, with primary release occurring at 310 °C. While partial rehydrogenation was achieved under moderate conditions (100 bar, 300 °C), NMR investigations revealed the presence of amorphous and partially oxidized boron species in dehydrogenated samples, highlighting the complex relationship between host structure and reversibility. Liu et al. [67] conducted a systematic investigation into the fundamental effects of pore size on LiBH₄ behavior within porous hard carbon templates. Their work revealed profound size-dependent effects on structural phase transitions and melting thermodynamics. In confined systems with pore dimensions below approximately 4 nm, conventional phase transitions and melting phenomena were progressively suppressed and ultimately eliminated. The desorption characteristics showed systematic improvement with decreasing pore size, accompanied by a notable reduction in B₂H₆ evolution. This suppression of borane formation indicated that spatial confinement could effectively block undesired reaction pathways, potentially improving the reversible storage capacity of the composites. Zhou et al. [68] demonstrated the effectiveness of activated carbon (AC) as a host material through careful melt infiltration studies. Their LiBH₄/AC composites initiated hydrogen release at the remarkably low temperature of 190 °C—a 160 °C improvement over bulk LiBH₄. The system achieved an impressive total hydrogen release of 13.6 wt.% upon heating to 400 °C. Under moderate rehydrogenation conditions (6 MPa H₂, 350 °C), the composite maintained a reversible capacity of 6 wt.%, while unmodified LiBH₄ showed negligible reversibility. The apparent activation energy for dehydrogenation decreased substantially from 156.0 kJ/mol to 121.1 kJ/mol, reflecting significant kinetic enhancement through nanoconfinement.

Further performance improvements have been realized through the strategic modification of carbon host materials. Gasnier et al. [81] investigated the effects of nitrogen doping in graphene-based hosts, infiltrating LiBH₄ at various volume fractions (30%, 50%, and 70%). The N-doped system demonstrated a 10 °C reduction in release temperature accompanied by a 1 wt.% increase in hydrogen release at 325 °C. This enhancement proved more significant than geometric effects achieved by reducing pore dimensions from 10 nm to 5 nm, highlighting the importance of chemical modification in host design. Jia et al. [69] achieved remarkable results through the development of sophisticated N-doped carbon nanocages containing NbB₂. Their systematic investigation of the xLBH@NC-NbF₅ system revealed critical loading-dependent behavior. An SEM analysis (Figure 6a–c) demonstrated the preservation of the cage structure at 40 wt.% loading, with minor nanosheet fracturing occurring at 50 wt.%. At 60 wt.% loading, excess LiBH₄ (26.8 wt.%) led to intersheet agglomeration. The optimized 50LBH@NC-NbF₅ system achieved exceptionally low dehydrogenation temperatures and reduced activation energies (82.51 ± 6.46 kJ/mol), releasing 7.55 wt.% H₂ within 39 min at 320 °C. Most impressively, the system retained 93% capacity through 20 cycles at 300 °C, demonstrating exceptional stability and reversibility.

The remarkable success of melt infiltration techniques in enhancing LiBH₄ performance stems from multiple synergistic effects. The confined geometry restricts particle growth and agglomeration during cycling, while the intimate contact between LiBH₄ and host materials facilitates heat and mass transfer. Additionally, the modified surface chemistry of host materials can influence local bonding environments and reaction pathways, potentially suppressing the formation of stable intermediates. These combined effects enable significant improvements in both the thermodynamic and kinetic aspects of hydrogen storage, though challenges remain in optimizing loading levels, preventing structural degradation during cycling, and maintaining long-term stability of the confined systems.

4.3. Solution-Based Synthesis

While melt infiltration has demonstrated considerable success in creating nanostructured LiBH₄ systems, the high processing temperatures required can potentially compromise host material integrity and limit architectural control [82,83]. Solution-based impregnation methods have emerged as a sophisticated alternative, offering precise control over material distribution and morphology under mild conditions. This approach enables both the uniform incorporation of LiBH₄ within porous frameworks and the synthesis of unsupported nanostructures through carefully controlled solution chemistry.

The versatility of wet chemical methods in modifying carbon-based host materials has been extensively demonstrated through systematic studies. Liu et al. [67] conducted pioneering work examining the confinement effects of porous hard carbon templates with varying pore architectures. Their research revealed that the phase behavior of confined LiBH₄ underwent dramatic modifications compared to the bulk material. The characteristic phase transitions and melting phenomena of LiBH₄ exhibited systematic shifts toward lower temperatures as pore dimensions decreased, eventually disappearing completely in pores smaller than approximately 4 nm. This geometric control extended beyond simple phase behavior, affecting the fundamental desorption characteristics. Notably, the evolution of B₂H₆, a problematic byproduct in LiBH₄ decomposition, showed progressive suppression with decreasing pore size, indicating that spatial confinement could effectively modify reaction pathways and potentially enhance system reversibility. Eymery et al. [70] advanced the field through precise control of mesoporous carbon template architecture, developing host materials with optimized 4 nm pore dimensions and substantial pore volume (1.1 cm³ g⁻¹). This careful structural design led to remarkable improvements in hydrogen desorption kinetics, with confined systems achieving 3.4 wt.% release within 90 min at 300 °C—conditions under which unmodified LiBH₄ showed negligible decomposition. Their work with LiBH₄/carbon composites at a 33:67 ratio revealed a simplified dehydrogenation pathway occurring above the LiBH₄ melting point (280 °C), notably avoiding the formation of problematic intermediates such as dodecaborane. This streamlined decomposition route offered valuable insights into the relationship between confinement architecture and reaction mechanisms.

The application of wet chemical methods to oxide-based hosts has opened new avenues for performance enhancement. Liu et al. [71] developed an innovative approach using solvothermally synthesized porous TiO₂ microtubes as host structures. The successful embedding of LiBH₄ nanoparticles within the TiO₂ framework through chemical impregnation demonstrated the synergistic benefits of nanoscale confinement and oxide catalysis. The LiBH₄@2TiO₂ system, optimized at a 1:2 mass ratio, achieved hydrogen release initiation at 180 °C, with the apparent activation energy reduced significantly from 146 kJ mol⁻¹ to 121.9 kJ mol⁻¹. Xu et al. [72] further expanded the potential of oxide hosts through their investigation of LiBH₄ confined within porous NiMnO₃ microspheres. The wet impregnation approach enabled the uniform distribution of LiBH₄ within the NiMnO₃ pore network, resulting in substantial improvements in dehydrogenation behavior. The composite system demonstrated impressive low-temperature performance, initiating hydrogen release at 150 °C and achieving a release capacity of 2.8 wt.% within 1 hour at 300 °C.

Perhaps the most significant advancement in wet chemical processing has been the development of unsupported LiBH₄ nanostructures. Zhang et al. [73] pioneered an innovative synthesis approach utilizing n-BuLi and Et₃N·BH₃ precursors in the n-hexane medium. Their sophisticated protocol, involving controlled sonication and thermal treatment under 50 bar H₂ pressure at 100 °C, yielded hierarchically porous LiBH₄ nanostructures composed of primary particles in the 50–60 nm range. This architectural design enabled remarkable performance improvements, with hydrogen desorption initiating at just 165 °C and achieving approximately 12 wt.% H₂ release upon heating to 400 °C (Figure 7b). The engineered nanostructure demonstrated superior cycling stability compared to conventional LiBH₄, exhibiting significantly reduced capacity decay over multiple cycles (Figure 7c).

The enhanced performance characteristics achieved through wet chemical processing stem from several key advantages of the approach. The low-temperature conditions preserve the structural integrity of both host materials and the resulting nanostructures. Solution-phase processing enables precise control over particle size and morphology while also facilitating uniform distribution within host frameworks. The technique allows for the incorporation of surface modifiers and stabilizers that can influence interfacial properties and stability. However, the method requires careful control of processing parameters to ensure complete solvent removal and prevent oxidation or degradation during synthesis. The relationship among processing conditions, resulting architecture, and hydrogen storage performance continues to be an active area of investigation, with particular emphasis on optimizing structure stability and cycling behavior.

5. Reactive Composite Systems

Reactive hydride composites (RHCs) represent an advanced strategy for fundamentally altering the thermodynamic and kinetic landscape of LiBH₄-based hydrogen storage systems. This approach strategically combines LiBH₄ with secondary hydrides to establish alternative reaction pathways through the formation of thermodynamically favorable compounds during dehydrogenation [37,84,85]. The underlying principle relies on the creation of more stable dehydrogenated products (such as MgB₂, CaB₆, or AlB₂) compared to elemental boron, effectively reducing the overall reaction enthalpy and lowering hydrogen release temperatures. These newly formed phases not only modify the system’s thermodynamics but also create dynamic interfaces that enhance hydrogen diffusion and mass transfer. The presence of multiple hydride phases generates additional active sites for hydrogen interactions, while the structural evolution during cycling introduces beneficial defects and high-energy interfaces, collectively contributing to improved kinetics and reversibility while maintaining high storage capacity.

5.1. LiBH₄-MgH₂ Composites

The combination of LiBH₄ with MgH₂ has emerged as a particularly promising RHC system, offering significant advantages through cooperative dehydrogenation processes and the formation of stable reaction products. Systematic investigations have revealed complex reaction mechanisms that can be strategically manipulated to enhance system performance. Bösenberg et al. [86] conducted pioneering studies on the decomposition pathways of LiBH₄-MgH₂ composites under varying pressure and temperature conditions, revealing distinct reaction regimes: at 450 °C and 3 bar, MgH₂ and LiBH₄ underwent separate decomposition, while at 400 °C and 5 bar, simultaneous hydrogen release from LiBH₄ occurred alongside MgB₂ formation. In situ X-ray diffraction and infrared spectroscopy demonstrated the presence of both crystalline and amorphous phases during reaction progression, notably without detecting intermediate metallic Mg phases during hydrogen evolution.

The development of advanced processing techniques has led to significant breakthroughs in system performance. Crosby et al. [87] demonstrated remarkable improvements through low-temperature graphite addition during high-energy ball milling of 2LiBH₄ + MgH₂ mixtures, achieving a fivefold increase in hydrogen release at 265 °C compared to conventionally milled systems. Both hydride components contributed to solid-state hydrogen release, with rehydrogenation kinetics primarily controlled by Mg reformation. These enhancements were attributed to the formation of nanocrystalline and amorphous phases, increased defect concentrations, and potential catalytic effects of the various system components. Building on these advances, Ding et al. developed the innovative Ball Milling Aerosol Spraying (BMAS) technique, illustrated in Figure 8a, which integrates aerosol generation with ball milling to enable precise control over particle formation in the 0.02–0.30 mm range [88]. This process facilitates the room-temperature formation of Li₂B₁₂H₁₂ through aerosolized LiBH₄/THF solution decomposition, followed by the reaction with in situ formed MgH₂ to produce MgB₂ and LiH [89].

The BMAS-processed LiBH₄ + MgH₂ nanocomposite demonstrated exceptional performance through a complex network of parallel hydrogen release mechanisms, involving the decomposition of nano-LiBH₄, nano-Mg(BH₄)₂, and nano-MgH₂ [90]. This sophisticated reaction architecture enabled the solid-state hydrogen release of 4.11 wt.% at ≤265 °C, maintaining 2.87 wt.% capacity after eight cycles [91]. The detailed kinetic analysis, illustrated in Figure 8c,d, revealed a fascinating evolution in the rate-limiting step from nucleation/growth to moving phase boundary control and eventually to diffusion control with increased cycling [92]. The formation of a continuous Mg shell around the shrinking MgH₂ core during dehydrogenation emerged as a critical architectural feature, controlling hydrogen diffusion rates and directly impacting system performance through the modulation of the interfacial area between MgH₂ and LiBH₄.

Figure 8. (a) Schematic of the device for the ball milling with aerosol spraying (BMAS) process in making nano-particles with reactants LiBH₄ and MgH₂ mixing at the nanometer scale [88]. (b) Hydrogen amount of desorption and absorption as a function of dehydrogenation and re-hydrogenation cycles [90]. Schematic of the dehydrogenation via the LiBH₄-Li₂B₁₂H₁₂ pathway: (c) the (Li₂B₁₂H₁₂ + 10 LiH) products form a continuous shell outside the LiBH₄ shrinking core, leading to a reaction rate controlled by H₂ gas desorption at the surface of the (Li₂B₁₂H₁₂ + 10 LiH) product layer, and (d) takes place at the Li₂B₁₂H₁₂/MgH₂ interface, leading to the nucleation and growth of MgB₂ + LiH products (shown inside the dashed box) accompanied by H₂ release [92].

The remarkable success of the LiBH₄-MgH₂ system stems from the synergistic combination of thermodynamically favorable MgB₂ formation during dehydrogenation, the creation of active interfaces that facilitate mass transport, and the stabilization of reaction intermediates through controlled phase evolution. These fundamental advances in understanding and controlling the complex interplay between processing, structure, and performance have established a robust foundation for the continued development of practical hydrogen storage systems based on reactive hydride composites.

5.2. Complex Hydride Combinations

The development of alternative reactive hydride composites beyond MgH₂-based systems has revealed promising pathways for enhancing the hydrogen storage performance of LiBH₄. Complex hydrides such as NaAlH₄ and LiAlH₄ offer unique advantages through their relatively low dehydrogenation temperatures, favorable thermodynamics, and ability to form stable intermediates that promote reversible hydrogen storage. These systems demonstrate distinct reaction mechanisms and synergistic effects that contribute to improved overall performance characteristics.

NaAlH₄-based systems have demonstrated particularly promising results through carefully designed compositional control. Yap et al. [93] conducted comprehensive investigations of Na₃AlH₆-LiBH₄ composites with varying stoichiometric ratios, revealing unexpected reaction pathways that surpassed conventional double decomposition mechanisms. Their systematic study of 1:3 and 1:4 molar ratio composites demonstrated the formation of Li₃AlH₆ and NaBH₄ phases, with the 1:4 ratio exhibiting superior hydrogenation performance. The system’s dehydrogenation proceeds through a sophisticated three-stage mechanism: initial hydrogen release begins at 180 °C with Li₃AlH₆ decomposition to LiH and Al; subsequently, NaBH₄ decomposition occurs around 380 °C, coupled with an Al reaction to form AlB₂ at a temperature approximately 100 °C lower than isolated NaBH₄; the final stage involves catalytic decomposition of residual NaBH₄ with AlB₂ at 430 °C. Under moderate conditions (320 °C, 33 atm H₂), the composite demonstrates rapid hydrogen absorption, achieving 3.0 wt.% within 60 min, with capacity increasing to 6.0 wt.% when heated to 420 °C.

The incorporation of advanced nanostructuring strategies has further enhanced the performance of NaAlH₄-based composites. Javadian et al. [94] achieved significant improvements by confining 2LiBH₄-NaAlH₄ within a mesoporous carbon aerogel framework (pore size: 30 nm, BET surface area: 689 m²/g, total pore volume: 1.21 mL/g). This architectural modification reduced the hydrogen release temperature by 132 °C compared to bulk material, enabling hydrogen evolution below 100 °C. The confined system undergoes a complex reaction sequence involving LiAlH₄ and NaBH₄ formation, ultimately producing LiH, LiAl, AlB₂, and Al as dehydrogenation products. Rehydrogenation studies at 400 °C and 126 bar demonstrated the recovery of amorphous NaBH₄ alongside unreacted species, identifying NaBH₄ as a crucial component for reversible hydrogen storage. The nanoconfined system maintained 83% of initial hydrogen content after three cycles, substantially outperforming the bulk material’s 47% retention.

LiAlH₄-based systems offer complementary advantages through their structural similarity to LiBH₄ and distinct reaction characteristics. Li et al. [95] demonstrated the effective destabilization of LiBH₄ using both LiAlH₄ and Li₃AlH₆, with 2LiBH₄-Li₃AlH₆ and 2LiBH₄-LiAlH₄ systems achieving dehydrogenation at 416 °C and 435 °C respectively—significantly below pure LiBH₄’s 469 °C. The composites released substantial hydrogen quantities, with 2LiBH₄-Li₃AlH₆ achieving a 9.1 wt.% H₂ release within 150 min, demonstrating superior kinetic performance. Meethom et al. [96] further enhanced reaction kinetics through an innovative approach combining dehydrogenated composite quenching and re-milling. This process promoted reactions between Al and both LiBH₄ and LiH, yielding AlB₂ and LiAl phases that significantly improved system performance—tripling kinetic rates and reducing the initial temperature by 120 °C while maintaining reversibility.

The incorporation of catalytic additives has proven effective in further optimizing LiAlH₄-LiBH₄ systems. Mao et al. [97] demonstrated remarkable improvements through TiF₃ addition, achieving reductions in initial dehydrogenation temperatures of 64 °C and 150 °C for the first two stages respectively, compared to the undoped system. The catalyst facilitated Al-B reactions to form AlB₂, providing additional active sites and reducing the decomposition enthalpy from 74 kJ/mol H₂ to 60.4 kJ/mol H₂. Under optimized conditions (600 °C, 4 MPa H₂), the system achieved hydrogen absorption capacities of 3.76 wt.% within 1 h and 4.78 wt.% after 14 h, demonstrating practical rehydrogenation capabilities.

The diverse performance characteristics of these alternative reactive hydride composites highlight the potential for tailored system design through the careful selection of constituent hydrides and processing conditions. The formation of intermediate phases, coupled with strategic architectural control and catalyst incorporation, enables the development of systems with improved thermodynamics, enhanced kinetics, and maintained reversibility. These advances in complex hydride combinations continue to expand the possibilities for practical hydrogen storage applications based on LiBH₄ systems.

6. Research Gaps and Conclusion Remarks

Although significant advances have been achieved in LiBH4-based systems, several critical research gaps persist that hinder their practical implementation. At the fundamental level, the interface dynamics during hydrogen cycling remain incompletely understood, particularly regarding the stability and evolution of catalytic interfaces over extended cycling periods. The complex interactions between catalysts and the host material, especially under dynamic cycling conditions, require deeper investigation. While the formation of Li₂B₁₂H₁₂ and other intermediates has been widely observed, the precise mechanisms controlling their formation, stability, and decomposition pathways are not fully understood, making it challenging to develop effective strategies for enhancing system reversibility. The role of local chemical environments and defect structures in influencing intermediate phase formation needs systematic study.

From a materials engineering perspective, significant challenges remain in optimizing the synergistic effects between different modification strategies. The interaction between catalytic additives and nanoconfinement effects, for instance, requires further investigation to maximize their combined benefits. Most reported advances focus on laboratory-scale demonstrations, leaving significant knowledge gaps in scaling up these improvements to practically viable systems. Critical questions remain regarding heat management in larger systems, pressure distribution in scaled-up configurations, and material containment strategies for practical applications. Current characterization methods primarily rely on ex-situ analysis, limiting our understanding of real-time material evolution during hydrogen cycling. The development of advanced in operando characterization techniques is essential for understanding the dynamic processes occurring during hydrogen storage and release.

Additionally, the long-term stability and degradation mechanisms of modified LiBH₄ systems under realistic operating conditions remain inadequately explored. The impact of thermal cycling, mechanical stress, and environmental factors on system performance needs systematic investigation. The development of standardized testing protocols and performance metrics that accurately reflect real-world application requirements represents another critical research gap.

The systematic investigation of LiBH₄-based hydrogen storage materials has demonstrated that rational material design and optimization can substantially enhance system performance through three distinct modification strategies: catalytic incorporation, nanostructure engineering, and reactive composite development.

Catalytic modification strategies have evolved from simple dopant addition to sophisticated interface and electronic structure engineering. Early studies focusing on transition metal catalysts have expanded to include advanced carbon architectures and metal oxide systems, revealing the critical role of surface chemistry and interface dynamics. The most significant advances have emerged from understanding the mechanistic aspects of catalytic enhancement, particularly how different catalyst types influence specific reaction steps. Advanced carbon frameworks demonstrate exceptional performance through their tunable surface properties and high active site density, while metal oxide systems excel in stabilizing reaction intermediates and modifying local electronic environments. The development of hybrid catalytic systems has further revealed synergistic effects that can simultaneously address multiple performance limitations.

Nanostructure engineering has progressed from basic size reduction to precise architectural control, fundamentally altering the thermodynamic and kinetic landscape of LiBH₄ systems. The field has witnessed a transition from conventional ball milling to sophisticated templating and infiltration techniques, enabling unprecedented control over material architecture across multiple length scales. Critical insights have emerged regarding the relationship between structural features and system performance, particularly how confined geometries and engineered interfaces influence hydrogen storage behavior. The development of hierarchical architectures combining multiple structural features has proven especially effective in optimizing overall system performance, though maintaining structural integrity during cycling remains challenging.

Reactive composite development has evolved from simple mixture studies to carefully designed multi-component systems that achieve fundamental modifications of reaction thermodynamics. The success of LiBH₄-MgH₂ systems has demonstrated how strategic phase formation can enhance reversibility while maintaining high capacity, while investigations of complex hydride combinations have revealed complementary approaches to thermodynamic destabilization. The field has progressed toward understanding the complex interplay among phase evolution, interface formation, and reaction kinetics, enabling more rational design of composite systems.

The advancement of these modification strategies has been significantly enhanced by the development of advanced characterization techniques and improved theoretical understanding. The integration of multiple approaches has revealed promising synergistic effects, while the systematic investigation of structure–property relationships has enabled more rational material design. As summarized in Table 5, each strategy has undergone significant evolution, achieved specific breakthroughs, and faced distinct challenges. The accumulated knowledge and understanding provide a strong foundation for the future development of practical LiBH4-based hydrogen storage systems.

Rather than operating independently, these three strategies increasingly demonstrate complementary effects when appropriately combined. The future advancement of LiBH₄-based systems will likely depend on the strategic integration of multiple modification approaches while addressing their respective limitations. The progress achieved thus far, while substantial, also highlights the importance of continued fundamental research alongside practical engineering solutions.

7. Future Perspectives

The transition toward practical applications of LiBH₄-based hydrogen storage systems faces multiple fundamental challenges requiring systematic investigation and innovative solutions. From an economic perspective, the scaled production of engineered materials, particularly nanostructured composites and advanced catalysts, must achieve cost-effectiveness while maintaining critical performance characteristics. The optimization of synthesis routes and material selection needs to balance enhanced storage properties with manufacturing feasibility and material costs.

Technical barriers present significant challenges for practical implementation. Current operating temperatures exceeding 300 °C remain substantially higher than the target range below 100 °C required for most applications. Kinetic limitations during both hydrogen absorption and desorption processes impact system response times and cycling efficiency. The development of efficient heat management strategies during operation is crucial, as thermal effects significantly influence both performance and system stability. Additionally, maintaining long-term stability under practical operating conditions requires careful consideration of material degradation mechanisms and their mitigation.

The scale-up of laboratory processes to industrial production presents complex engineering challenges. Maintaining critical material features during large-scale synthesis while ensuring reproducibility and quality control requires sophisticated process optimization. The integration of storage systems with fuel cell technologies demands careful consideration of interface management and system compatibility. The development of standardized testing protocols for practical evaluation becomes increasingly important for reliable performance assessment.

Looking forward, several promising research directions emerge for addressing these challenges. Advanced material design strategies focus on developing novel multi-functional catalysts and engineered interfaces that can enhance kinetics while maintaining stability. The implementation of in situ and operando characterization techniques provides deeper insights into material evolution during cycling, enabling more effective system optimization. Computational modeling approaches offer powerful tools for material screening and mechanism investigation under practical conditions.

System integration represents a critical area for future development. The optimization of heat exchange systems and pressure management strategies must address both performance and safety considerations. Modular design approaches offer flexibility for various applications while maintaining system efficiency. The successful development of practical LiBH₄-based storage systems ultimately requires coordinated efforts across multiple research domains, combining fundamental understanding with engineering solutions while maintaining economic viability.

Author Contributions

Conceptualization, Y.X. and Z.D.; validation, Y.Z. and Y.L.; formal analysis, M.A.; data curation, Y.X. and Y.L.; writing—original draft preparation, Y.X., Y.L. and M.A.; writing—review and editing, Y.Z. and Z.D.; supervision, M.A. and Z.D.; project administration, Y.Z. and Z.D.; funding acquisition, Y.X. and Z.D. All authors have read and agreed to the published version of the manuscript.

Funding

This study was financially supported by the Leshan West Silicon Materials Photovoltaic New Energy Industry Technology Research Institute (2023GY8), Fundamental Research Funds for the Central Universities (2023CDJXY-019), Opening Project of Crystalline Silicon Photovoltaic New Energy Research Institute (2022CHXK002), and Leshan Normal University Research Program (KYPY2023-0001).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

References

Huang, Z.; Wang, Y.; Wang, D.; Yang, F.; Wu, Z.; Zheng, L.; Han, X.; Wu, L.; Zhang, Z. Synergistic Effects of Mg and N Cosubstitution on Enhanced Dehydrogenation Properties of LiBH₄: A First-Principles Study. J. Phys. Chem. C 2019, 123, 1550–1558. [Google Scholar] [CrossRef]
Yang, H.; Ding, Z.; Li, Y.-T.; Li, S.-Y.; Wu, P.-K.; Hou, Q.-H.; Zheng, Y.; Gao, B.; Huo, K.-F.; Du, W.-J.; et al. Recent advances in kinetic and thermodynamic regulation of magnesium hydride for hydrogen storage. Rare Met. 2023, 42, 2906–2927. [Google Scholar] [CrossRef]
Guan, H.; Lu, Y.; Liu, J.; Ye, Y.; Li, Q.; Pan, F. Microscopic Scaling Relation of Ti-Based Catalysts in De/Hydrogenation Reactions of Mg/MgH₂. ACS Catal. 2024, 14, 17159–17170. [Google Scholar] [CrossRef]
Wan, H.; Zhou, S.; Wei, D.; Qiu, J.; Ding, Z.; Chen, Y.a.; Wang, J.; Pan, F. Enhancing hydrogen storage properties of MgH₂ via reaction-induced construction of Ti/Co/Mn-based multiphase catalytic system. Sep. Purif. Technol. 2025, 355, 129776. [Google Scholar] [CrossRef]
Wan, H.; Qiu, J.; Guan, H.; Ding, Z.; Lu, Y.; Chen, Y.a.; Wang, J.; Pan, F. FCC/α-Fe biphasic nano-sites synergize with CNTs to enhance reversible hydrogen storage of MgH₂. Inorg. Chem. Front. 2024, 11, 4197–4206. [Google Scholar] [CrossRef]
Wan, H.; Ran, L.; Lu, H.; Qiu, J.; Zhang, H.; Yang, Y.; Chen, Y.a.; Wang, J.; Pan, F. Optimizing microstructure and enhancing hydrogen storage properties in Mg alloy via tailoring Ni and Si element. J. Magnes. Alloys 2024, in press. [CrossRef]
Benzidi, H.; Garara, M.; Lakhal, M.; Abdalaoui, M.; Benyoussef, A.; El kenz, A.; Louilidi, M.; Hamedoun, M.; Mounkachi, O. Vibrational and thermodynamic properties of LiBH₄ polymorphs from first-principles calculations. Int. J. Hydrogen Energy 2018, 43, 6625–6631. [Google Scholar] [CrossRef]
Feng, L.; Liu, Y.; Jiang, Y.; Guo, Y.; Sun, Y.; Wang, Y. Light-driven rapid dehydrogenation of LiBH₄-TiF₃-TiO₂ hydrogen storage composite. J. Alloys Compd. 2025, 1010, 176848. [Google Scholar] [CrossRef]
Ding, Z.; Li, Y.; Jiang, H.; Zhou, Y.; Wan, H.; Qiu, J.; Jiang, F.; Tan, J.; Du, W.; Chen, Y.a.; et al. The integral role of high-entropy alloys in advancing solid-state hydrogen storage. Interdiscip. Mater. 2024, 1–34. [Google Scholar] [CrossRef]
Qiu, J.; Wan, H.; Ding, Z.; Chen, Y.; Pan, F. Tailoring hydrogen diffusion pathways in Mg-Ni alloys through Gd addition: A combined experimental and computational study. Chem. Eng. J. 2024, 502, 157767. [Google Scholar] [CrossRef]
Blaha, P.; Schwarz, K.; Sorantin, P.; Trickey, S.B. Full-potential, linearized augmented plane wave programs for crystalline systems. Comput. Phys. Commun. 1990, 59, 399–415. [Google Scholar] [CrossRef]
Bouaricha, S.; Dodelet, J.P.; Guay, D.; Huot, J.; Schulz, R. Activation characteristics of graphite modified hydrogen absorbing materials. J. Alloys Compd. 2001, 325, 245–251. [Google Scholar] [CrossRef]
Nie, K.; Li, J.; Lu, H.; Zhang, R.; Chen, Y.A.; Pan, F. Enhanced hydrogen storage properties of MgH₂ with alkalized Nb₂CT_x MXene: The role of enlarged interlayer spacing and optimized surface. Sep. Purif. Technol. 2025, 354, 129069. [Google Scholar] [CrossRef]
Wan, H.; Yang, X.; Zhou, S.; Ran, L.; Lu, Y.; Chen, Y.a.; Wang, J.; Pan, F. Enhancing hydrogen storage properties of MgH₂ using FeCoNiCrMn high entropy alloy catalysts. J. Mater. Sci. Technol. 2023, 149, 88–98. [Google Scholar] [CrossRef]
Li, Y.; Guo, Q.; Ding, Z.; Jiang, H.; Yang, H.; Du, W.; Zheng, Y.; Huo, K.; Shaw, L.L. MOFs-Based Materials for Solid-State Hydrogen Storage: Strategies and Perspectives. Chem. Eng. J. 2024, 485, 149665. [Google Scholar] [CrossRef]
Zang, L.; Sun, W.; Liu, S.; Huang, Y.; Yuan, H.; Tao, Z.; Wang, Y. Enhanced Hydrogen Storage Properties and Reversibility of LiBH₄ Confined in Two-Dimensional Ti₃C₂. ACS Appl. Mater. Interfaces 2018, 10, 19598–19604. [Google Scholar] [CrossRef]
Zhu, Y.; Zeng, L.; Wu, D.; Tang, R.; Zhou, Q. Coupling rare-earth metal introduction and alkali oxide addition to achieve efficient regeneration of LiBH₄ by reacting hydrous LiBO₂ with Al. Chem. Eng. J. 2024, 499, 156057. [Google Scholar] [CrossRef]
Avrami, M. Kinetics of Phase Change. I General Theory. J. Chem. Phys. 1939, 7, 1103–1112. [Google Scholar] [CrossRef]
Pistorius, C.W.F.T. Melting and Polymorphism of LiBH₄ to 45 kbar. Z. Für Phys. Chem. 1974, 88, 253–263. [Google Scholar] [CrossRef]
Deprez, E.; Muñoz-Márquez, M.Á.; Roldán, M.A.; Prestipino, C.; Palomares, F.J.; Minella, C.B.; Bösenberg, U.; Dornheim, M.; Bormann, R.; Fernández-Camacho, A. Oxidation state and local structure of Ti-based additives in the reactive hydride composite 2LiBH₄ + MgH₂. J. Phys. Chem. C Am. Chem. Soc. 2010, 114, 3309–3317. [Google Scholar] [CrossRef]
Hu, J.Z.; Kwak, J.H.; Yang, Z.; Wan, X.; Shaw, L.L. Detailed investigation of ion exchange in ball-milled LiH + MgB₂ system using ultra-high field nuclear magnetic resonance spectroscopy. J. Power Sources 2010, 195, 3645–3648. [Google Scholar] [CrossRef]
Cai, W.; Yang, Y.; Tao, P.; Ouyang, L.; Wang, H.; Yang, X. A fleeting glimpse of the dual roles of SiB(4) in promoting the hydrogen storage performance of LiBH(4). Dalton Trans. 2019, 48, 1314–1321. [Google Scholar] [CrossRef] [PubMed]
Pal, P.; Kumari, P.; Wang, Y.; Isobe, S.; Kumar, M.; Ichikawa, T.; Jain, A. Destabilization of LiBH₄ by the infusion of Bi₂X₃ (X = S, Se, Te): An in situ TEM investigation. J. Mater. Chem. A 2020, 8, 25706–25715. [Google Scholar] [CrossRef]
Ding, Y.; Li, C.; Zhang, X.; Chen, W.; Yu, X.; Xia, G. Spatial Confinement of Lithium Borohydride in Bimetallic CoNi-Doped Hollow Carbon Frameworks for Stable Hydrogen Storage. ACS Appl. Mater. Interfaces 2024, 16, 50717–50725. [Google Scholar] [CrossRef] [PubMed]
Li, Y.; Chung, J.S.; Kang, S.G. First-principles rational design of M-doped LiBH4(010) surface for hydrogen release: Role of strain and dopants (M = Na, K, Al, F, or Cl). Int. J. Hydrogen Energy 2019, 44, 6065–6073. [Google Scholar] [CrossRef]
Zhu, J.; Mao, Y.; Wang, H.; Liu, J.; Ouyang, L.; Zhu, M. Reaction Route Optimized LiBH4 for High Reversible Capacity Hydrogen Storage by Tunable Surface-Modified AlN. ACS Appl. Energy Mater. 2020, 3, 11964–11973. [Google Scholar] [CrossRef]
Soulié, J.P.; Renaudin, G.; Černý, R.; Yvon, K. Lithium boro-hydride LiBH₄. J. Alloys Compd. 2002, 346, 200–205. [Google Scholar] [CrossRef]
Surrey, A.; Bonatto Minella, C.; Fechler, N.; Antonietti, M.; Grafe, H.-J.; Schultz, L.; Rellinghaus, B. Improved hydrogen storage properties of LiBH₄ via nanoconfinement in micro- and mesoporous aerogel-like carbon. Int. J. Hydrogen Energy 2016, 41, 5540–5548. [Google Scholar] [CrossRef]
Halim Yap, F.A.; Ismail, M. Functions of MgH2 in the Hydrogen Storage Properties of a Na₃AlH₆–LiBH₄ Composite. J. Phys. Chem. C 2018, 122, 23959–23967. [Google Scholar] [CrossRef]
Ding, Z.; Yang, W.; Huo, K.; Shaw, L. Thermodynamics and Kinetics Tuning of LiBH₄ for Hydrogen Storage. Prog. Chem. 2021, 33, 1586–1597. [Google Scholar] [CrossRef]
Zaluska, A.; Zaluski, L.; Ström-Olsen, J.O. Structure, catalysis and atomic reactions on the nano-scale: A systematic approach to metal hydrides for hydrogen storage. Appl. Phys. A 2001, 72, 157–165. [Google Scholar] [CrossRef]
Gomes, S.; Hagemann, H.; Yvon, K. Lithium boro-hydride LiBH₄: II. Raman spectroscopy. J. Alloys Compd. 2002, 346, 206–210. [Google Scholar] [CrossRef]
Vajo, J.J.; Salguero, T.T.; Gross, A.F.; Skeith, S.L.; Olson, G.L. Thermodynamic destabilization and reaction kinetics in light metal hydride systems. J. Alloys Compd. 2007, 446–447, 409–414. [Google Scholar] [CrossRef]
Her, J.H.; Yousufuddin, M.; Zhou, W.; Jalisatgi, S.S.; Kulleck, J.G.; Zan, J.A.; Hwang, S.J.; Bowman, R.C., Jr.; Udovic, T.J. Crystal structure of Li₂B₁₂H₁₂: A possible intermediate species in the decomposition of LiBH₄. Inorg Chem 2008, 47, 9757–9759. [Google Scholar] [CrossRef]
Tanniru, M.; Ebrahimi, F. Effect of Al on the hydrogenation characteristics of nanocrystalline Mg powder. Int. J. Hydrogen Energy 2009, 34, 7714–7723. [Google Scholar] [CrossRef]
Vajo, J.J.; Skeith, S.L.; Mertens, F. Reversible Storage of Hydrogen in Destabilized LiBH₄. J. Phys. Chem. B 2005, 109, 3719–3722. [Google Scholar] [CrossRef]
Pinkerton, F.E.; Meyer, M.S.; Meisner, G.P.; Balogh, M.P.; Vajo, J.J. Phase Boundaries and Reversibility of LiBH₄/MgH₂ Hydrogen Storage Material. J. Phys. Chem. C 2007, 111, 12881–12885. [Google Scholar] [CrossRef]
Orimo, S.-I.; Nakamori, Y.; Ohba, N.; Miwa, K.; Aoki, M.; Towata, S.-i.; Züttel, A. Experimental studies on intermediate compound of LiBH₄. Appl. Phys. Lett. 2006, 89, 021920. [Google Scholar] [CrossRef]
Rosi, N.L.; Eckert, J.; Eddaoudi, M.; Vodak, D.T.; Kim, J.; O’Keeffe, M.; Yaghi, O.M. Hydrogen storage in microporous metal-organic frameworks. Science 2003, 300, 1127–1129. [Google Scholar] [CrossRef]
Züttel, A.; Rentsch, S.; Fischer, P.; Wenger, P.; Sudan, P.; Mauron, P.; Emmenegger, C. Hydrogen storage properties of LiBH₄. J. Alloys Compd. 2003, 356–357, 515–520. [Google Scholar] [CrossRef]
Yu, X.B.; Grant, D.M.; Walker, G.S. A new dehydrogenation mechanism for reversible multicomponent borohydride systems—The role of Li–Mg alloys. Chem. Commun. 2006, 37, 3906–3908. [Google Scholar] [CrossRef] [PubMed]
Bösenberg, U.; Kim, J.W.; Gosslar, D.; Eigen, N.; Jensen, T.R.; von Colbe, J.M.B.; Zhou, Y.; Dahms, M.; Kim, D.H.; Günther, R.; et al. Role of additives in LiBH₄–MgH₂ reactive hydride composites for sorption kinetics. Acta Mater. 2010, 58, 3381–3389. [Google Scholar] [CrossRef]
Ouyang, L.Z.; Cao, Z.J.; Wang, H.; Liu, J.W.; Sun, D.L.; Zhang, Q.A.; Zhu, M. Dual-tuning effect of In on the thermodynamic and kinetic properties of Mg₂Ni dehydrogenation. Int. J. Hydrogen Energy 2013, 38, 8881–8887. [Google Scholar] [CrossRef]
Yang, J.; Sudik; Andrea; Wolverton, C. Destabilizing LiBH4 with a metal (M = Mg, Al, Ti, V, Cr, or Sc) or metal hydride (MH₂, MgH₂, TiH₂, or CaH₂). J. Phys. Chem. C 2007, 111, 19134–19140. [Google Scholar] [CrossRef]
Ding, Z.; Li, H.; Yan, G.; Yang, W.; Gao, Z.; Ma, W.; Shaw, L. Mechanism of hydrogen storage on Fe₃B. Chem. Commun. 2020, 56, 14235–14238. [Google Scholar] [CrossRef]
Ding, Z.; Chen, Z.; Ma, T.; Lu, C.-T.; Ma, W.; Shaw, L. Predicting the hydrogen release ability of LiBH₄-based mixtures by ensemble machine learning. Energy Storage Mater. 2020, 27, 466–477. [Google Scholar] [CrossRef]
Fang, Z.Z.; Kang, X.D.; Dai, H.B.; Zhang, M.J.; Wang, P.; Cheng, H.M. Reversible dehydrogenation of LiBH₄ catalyzed by as-prepared single-walled carbon nanotubes. Scr. Mater. 2008, 58, 922–925. [Google Scholar] [CrossRef]
Fang, Z.-Z.; Kang, X.-D.; Wang, P. Improved hydrogen storage properties of LiBH4 by mechanical milling with various carbon additives. Int. J. Hydrogen Energy 2010, 35, 8247–8252. [Google Scholar] [CrossRef]
Weng, B.; Wu, Z.; Li, Z.; Yang, H.; Leng, H. Enhanced hydrogen generation by hydrolysis of LiBH₄ doped with multiwalled carbon nanotubes for micro proton exchange membrane fuel cell application. J. Power Sources 2011, 196, 5095–5101. [Google Scholar] [CrossRef]
Zhao, Y.; Liu, Y.; Kang, H.; Cao, K.; Wang, Y.; Jiao, L. Nitrogen-doped hierarchically porous carbon derived from ZIF-8 and its improved effect on the dehydrogenation of LiBH4. Int. J. Hydrogen Energy 2016, 41, 17175–17182. [Google Scholar] [CrossRef]
Xu, J.; Meng, R.; Cao, J.; Gu, X.; Qi, Z.; Wang, W.; Chen, Z. Enhanced dehydrogenation and rehydrogenation properties of LiBH₄ catalyzed by graphene. Int. J. Hydrogen Energy 2013, 38, 2796–2803. [Google Scholar] [CrossRef]
Kaliyaperumal, A.; Vellingiri, L.; Periyasamy, G.; Annamalai, K. Improved dehydrogenation properties of surface-oxidized LiBH₄@NiO nanostructure. J. Mater. Sci. Mater. Electron. 2021, 33, 9144–9154. [Google Scholar] [CrossRef]
Li, Z.; Gao, M.; Wang, S.; Zhang, X.; Gao, P.; Yang, Y.; Sun, W.; Liu, Y.; Pan, H. In-situ introduction of highly active TiO for enhancing hydrogen storage performance of LiBH₄. Chem. Eng. J. 2022, 433, 134485. [Google Scholar] [CrossRef]
Wang, S.; Wu, M.H.; Zhu, Y.Y.; Li, Z.L.; Yang, Y.X.; Li, Y.Z.; Liu, H.F.; Gao, M.X. Reactive destabilization and bidirectional catalyzation for reversible hydrogen storage of LiBH₄ by novel waxberry-like nano-additive assembled from ultrafine Fe₃O₄ particles. J. Mater. Sci. Technol. 2024, 173, 63–71. [Google Scholar] [CrossRef]
Wang, S.; Gao, M.; Yao, Z.; Liu, Y.; Wu, M.; Li, Z.; Liu, Y.; Sun, W.; Pan, H. A nanoconfined-LiBH₄ system using a unique multifunctional porous scaffold of carbon wrapped ultrafine Fe₃O₄ skeleton for reversible hydrogen storage with high capacity. Chem. Eng. J. 2022, 428, 131056. [Google Scholar] [CrossRef]
Zhao, S.X.; Wang, C.Y.; Liu, D.M.; Tan, Q.J.; Li, Y.T.; Si, T.Z. Destabilization of LiBH₄ by SrF₂ for reversible hydrogen storage. Int. J. Hydrogen Energy 2018, 43, 5098–5103. [Google Scholar] [CrossRef]
Wang, J.; Wang, Z.; Li, Y.; Ke, D.; Lin, X.; Han, S.; Ma, M. Effect of nano-sized Ce₂S₃ on reversible hydrogen storage properties of LiBH₄. Int. J. Hydrogen Energy 2016, 41, 13156–13162. [Google Scholar] [CrossRef]
Kumari, P.; Sharma, K.; Agarwal, S.; Awasthi, K.; Ichikawa, T.; Kumar, M.; Jain, A. The destabilization of LiBH₄ through the addition of Bi₂Se₃ nanosheets. Int. J. Hydrogen Energy 2020, 45, 23947–23953. [Google Scholar] [CrossRef]
Fan, Y.; Chen, D.; Liu, X.; Fan, G.; Liu, B. Improving the hydrogen storage performance of lithium borohydride by Ti₃C₂ MXene. Int. J. Hydrogen Energy 2019, 44, 29297–29303. [Google Scholar] [CrossRef]
Liu, C.; Huang, S. A first-principles study of the tuning effect of a Fe₂O₃ cluster on the dehydrogenation properties of a LiBH₄ (001) surface. Dalton Trans 2016, 45, 10954–10959. [Google Scholar] [CrossRef]
de Kort, L.M.; Harmel, J.; de Jongh, P.E.; Ngene, P. The effect of nanoscaffold porosity and surface chemistry on the Li-ion conductivity of LiBH₄–LiNH₂/metal oxide nanocomposites. J. Mater. Chem. A 2020, 8, 20687–20697. [Google Scholar] [CrossRef]
Tena-García, J.R.; Osorio-García, M.; Suárez-Alcántara, K. LiBH₄–VCl₃ and LiAlH₄–VCl₃ mixtures prepared in soft milling conditions for hydrogen release at low temperature. Int. J. Hydrogen Energy 2022, 47, 28046–28060. [Google Scholar] [CrossRef]
Oguchi, H.; Kim, S.; Maruyama, S.; Horisawa, Y.; Takagi, S.; Sato, T.; Shimizu, R.; Matsumoto, Y.; Hitosugi, T.; Orimo, S.-i. Epitaxial Film Growth of LiBH₄ via Molecular Unit Evaporation. ACS Appl. Electron. Mater. 2019, 1, 1792–1796. [Google Scholar] [CrossRef]
Cai, W.; Hou, J.; Huang, S.; Chen, J.; Yang, Y.; Tao, P.; Ouyang, L.; Wang, H.; Yang, X. Altering the chemical state of boron towards the facile synthesis of LiBH₄ via hydrogenating lithium compound-metal boride mixture. Renew. Energy 2019, 134, 235–240. [Google Scholar] [CrossRef]
Zhang, W.; Zhou, L.; Zhang, X.; Zhang, L.; Lou, Z.; Guo, B.; Hong, Z.; Gao, M.; Sun, W.; Liu, Y.; et al. From nanorods to nanoparticles: Morphological engineering enables remarkable hydrogen storage by lithium borohydride. Nano Energy 2024, 130, 110128. [Google Scholar] [CrossRef]
Guo, L.; Li, Y.; Ma, Y.; Liu, Y.; Peng, D.; Zhang, L.; Han, S. Enhanced hydrogen storage capacity and reversibility of LiBH₄ encapsulated in carbon nanocages. Int. J. Hydrogen Energy 2017, 42, 2215–2222. [Google Scholar] [CrossRef]
Liu, X.; Peaslee, D.; Jost, C.Z.; Baumann, T.F.; Majzoub, E.H. Systematic Pore-Size Effects of Nanoconfinement of LiBH4: Elimination of Diborane Release and Tunable Behavior for Hydrogen Storage Applications. Chem. Mater. 2011, 23, 1331–1336. [Google Scholar] [CrossRef]
Zhou, H.; Liu, H.-Z.; Gao, S.-C.; Wang, X.-H. Enhanced dehydrogenation kinetic properties and hydrogen storage reversibility of LiBH₄ confined in activated charcoal. Trans. Nonferrous Met. Soc. China 2018, 28, 1618–1625. [Google Scholar] [CrossRef]
Jia, Y.; Zhou, P.; Xiao, X.; Wang, X.; Han, B.; Wang, J.; Xu, F.; Sun, L.; Chen, L. Synergetic action of 0D/2D/3D N-doped carbon nanocages and NbB₂ nanocatalyst on reversible hydrogen storage performance of lithium borohydride. Chem. Eng. J. 2024, 485, 150090. [Google Scholar] [CrossRef]
Cahen, S.; Eymery, J.B.; Janot, R.; Tarascon, J.M. Improvement of the LiBH₄ hydrogen desorption by inclusion into mesoporous carbons. J. Power Sources 2009, 189, 902–908. [Google Scholar] [CrossRef]
Liu, H.; Jiao, L.; Zhao, Y.; Cao, K.; Liu, Y.; Wang, Y.; Yuan, H. Improved dehydrogenation performance of LiBH₄ by confinement into porous TiO₂ micro-tubes. J. Mater. Chem. A 2014, 2, 9244–9250. [Google Scholar] [CrossRef]
Xu, X.; Zang, L.; Zhao, Y.; Liu, Y.; Wang, Y.; Jiao, L. Enhanced dehydrogenation performance of LiBH₄ by confinement in porous NiMnO₃ microspheres. Int. J. Hydrogen Energy 2017, 42, 25824–25830. [Google Scholar] [CrossRef]
Zhang, X.; Zhang, W.; Zhang, L.; Huang, Z.; Hu, J.; Gao, M.; Pan, H.; Liu, Y. Single-pot solvothermal strategy toward support-free nanostructured LiBH₄ featuring 12 wt% reversible hydrogen storage at 400 °C. Chem. Eng. J. 2022, 428, 132566. [Google Scholar] [CrossRef]
Zhang, X.; Zhang, L.; Zhang, W.; Ren, Z.; Huang, Z.; Hu, J.; Gao, M.; Pan, H.; Liu, Y. Nano-synergy enables highly reversible storage of 9.2 wt% hydrogen at mild conditions with lithium borohydride. Nano Energy 2021, 83, 105839. [Google Scholar] [CrossRef]
Yuan, Z.; Li, X.; Li, T.; Zhai, T.; Lin, Y.; Feng, D.; Zhang, Y. Improved hydrogen storage performances of nanocrystalline RE5Mg41-type alloy synthesized by ball milling. J. Energy Storage 2022, 46, 103702. [Google Scholar] [CrossRef]
Révész, Á.; Gajdics, M. Improved H-Storage Performance of Novel Mg-Based Nanocomposites Prepared by High-Energy Ball Milling: A Review. Energies 2021, 14, 6400. [Google Scholar] [CrossRef]
Agresti, F.; Khandelwal, A. Evidence of formation of LiBH4 by high-energy ball milling of LiH and B in a hydrogen atmosphere. Scr. Mater. 2009, 60, 753–755. [Google Scholar] [CrossRef]
Çakanyıldırım, Ç.; Gürü, M. Processing of LiBH4 from its elements by ball milling method. Renew. Energy 2008, 33, 2388–2392. [Google Scholar] [CrossRef]
Zhu, Y.; Liu, M.; Li, J.; Zeng, W.; Zeng, L.; Wu, D.; Zhou, Q.; Tang, R.; Xiao, F. Facile regeneration of lithium borohydride from anhydrous lithium metaborate using magnesium hydride. Inorg. Chem. Front. 2022, 9, 5161–5168. [Google Scholar] [CrossRef]
Guo, R.F.; Hsu, C.Y.; Kostoglou, N.; Hinder, S.; Baker, M.; Mitterer, C.; Rebholz, C.; Wang, C.Y. Improved thermolytic dehydrogenation of LiBH₄ nanoconfined in few-layer graphene with different functionalities. Mater. Today Sustain. 2023, 24, 100486. [Google Scholar] [CrossRef]
Gasnier, A.; Luguet, M.; Pereira, A.G.; Troiani, H.; Zampieri, G.; Gennari, F.C. Entanglement of N-doped graphene in resorcinol-formaldehyde: Effect over nanoconfined LiBH₄ for hydrogen storage. Carbon 2019, 147, 284–294. [Google Scholar] [CrossRef]
Li, Z.; Wang, S.; Gao, M.; Xian, K.; Shen, Y.; Yang, Y.; Gao, P.; Sun, W.; Liu, Y.; Pan, H. Catalyzed LiBH₄ Hydrogen Storage System with In Situ Introduced Li₃BO₃ and V for Enhanced Dehydrogenation and Hydrogenation Kinetics as Well as High Cycling Stability. ACS Appl. Energy Mater. 2022, 5, 1226–1234. [Google Scholar] [CrossRef]
Huang, Y.; Mo, X.; Hu, C.; Ma, Y.; Zuo, X.; Zhou, R.; Jiang, W. Enhanced dehydrogenation of LiBH₄ with Ti or/and F additives: Insight from first-principles calculations. Int. J. Hydrogen Energy 2024, 50, 148–159. [Google Scholar] [CrossRef]
Nakagawa, T.; Ichikawa, T.; Hanada, N.; Kojima, Y.; Fujii, H. Thermal analysis on the Li–Mg–B–H systems. J. Alloys Compd. 2007, 446–447, 306–309. [Google Scholar] [CrossRef]
Talyzin, A.V.; Andersson, O.; Sundqvist, B.; Kurnosov, A.; Dubrovinsky, L. High-pressure phase transition in LiBH₄. J. Solid State Chem. 2007, 180, 510–517. [Google Scholar] [CrossRef]
Bösenberg, U.; Ravnsbæk, D.B.; Hagemann, H.; D’Anna, V.; Minella, C.B.; Pistidda, C.; van Beek, W.; Jensen, T.R.; Bormann, R.; Dornheim, M. Pressure and Temperature Influence on the Desorption Pathway of the LiBH₄−MgH₂ Composite System. J. Phys. Chem. C 2010, 114, 15212–15217. [Google Scholar] [CrossRef]
Crosby, K.; Shaw, L.L. Dehydriding and re-hydriding properties of high-energy ball milled LiBH₄ + MgH₂ mixtures. Int. J. Hydrogen Energy 2010, 35, 7519–7529. [Google Scholar] [CrossRef]
Ding, Z.; Zhao, X.; Shaw, L.L. Reaction between LiBH₄ and MgH₂ induced by high-energy ball milling. J. Power Sources 2015, 293, 236–245. [Google Scholar] [CrossRef]
Ding, Z.; Lu, Y.; Li, L.; Shaw, L. High reversible capacity hydrogen storage through Nano-LiBH₄ + Nano-MgH₂ system. Energy Storage Mater. 2019, 20, 24–35. [Google Scholar] [CrossRef]
Ding, Z.; Li, H.; Shaw, L. New insights into the solid-state hydrogen storage of nanostructured LiBH₄-MgH₂ system. Chem. Eng. J. 2020, 385, 123856. [Google Scholar] [CrossRef]
Ding, Z.; Shaw, L. Enhancement of Hydrogen Desorption from Nanocomposite Prepared by Ball Milling MgH₂ with In Situ Aerosol Spraying LiBH₄. ACS Sustain. Chem. Eng. 2019, 7, 15064–15072. [Google Scholar] [CrossRef]
Ding, Z.; Wu, P.; Shaw, L. Solid-state hydrogen desorption of 2 MgH₂ + LiBH₄ nano-mixture: A kinetics mechanism study. J. Alloys Compd. 2019, 806, 350–360. [Google Scholar] [CrossRef]
Halim Yap, F.A.; Mustafa, N.S.; Yahya, M.S.; Mohamad, A.A.; Ismail, M. A study on the hydrogen storage properties and reaction mechanism of Na₃AlH₆LiBH₄ composite system. Int. J. Hydrogen Energy 2018, 43, 8365–8374. [Google Scholar] [CrossRef]
Javadian, P.; Sheppard, D.; Buckley, C.; Jensen, T. Hydrogen Desorption Properties of Bulk and Nanoconfined LiBH₄-NaAlH₄. Crystals 2016, 6, 70. [Google Scholar] [CrossRef]
Li, Y.; Wu, S.; Zhu, D.; He, J.; Xiao, X.; Chen, L. Dehydrogenation Performances of Different Al Source Composite Systems of 2LiBH(4) + M (M = Al, LiAlH(4), Li(3)AlH(6)). Front Chem 2020, 8, 227. [Google Scholar] [CrossRef]
Meethom, S.; Kaewsuwan, D.; Chanlek, N.; Utke, O.; Utke, R. Enhanced hydrogen sorption of LiBH₄–LiAlH₄ by quenching dehydrogenation, ball milling, and doping with MWCNTs. J. Phys. Chem. Solids 2020, 136, 109202. [Google Scholar] [CrossRef]
Mao, J.F.; Guo, Z.P.; Liu, H.K.; Yu, X.B. Reversible hydrogen storage in titanium-catalyzed LiAlH₄–LiBH₄ system. J. Alloys Compd. 2009, 487, 434–438. [Google Scholar] [CrossRef]

Figure 2. (a) TEM image and the corresponding C- and N-elemental mappings of D-carbon. (b) Isothermal hydrogen desorption curves at 320 °C of LiBH₄-(D-carbon), LiBH4-(Ac-carbon), and bulk LiBH₄. (c) XRD patterns of dehydrogenated LiBH4-(Ac-carbon) at 250 °C, 320 °C, and 380 °C for 5 h. (d) FT-IR spectra of the dehydrogenated products of LiBH₄-(Ac-carbon) at 250 °C, 320 °C and 380 °C for 5 h; pure LiBH₄ is also included for comparison [50].

Figure 3. (a) XRD patterns and (b) FTIR spectra of the heat-treated LiBH4 + 0.06Ti(OEt)₄ mixture at 230 °C for 30 min as well as ball-milled mixture and ball-milled LiBH₄. (c) XPS spectrum of Ti 2p of the heat-treated LiBH₄ + 0.06Ti(OEt)₄ mixture. (d) Schematic illustration of the preparation process of the passionfruit-like p-Fe₃O₄@C hybrid. (e) Isothermal dehydrogenation curves of the 6LiBH₄@4p-Fe₃O₄@C system at 300 °C, 325 °C, and 350 °C and that of the pristine LiBH₄ at 350 °C. (f) Kissinger’s plot of the 6LiBH₄@4p-Fe₃O₄@C system, where the inset is the TPD-MS curves measured at different heating rates. (g) Cyclic curves of the 6LiBH4@4p-Fe₃O₄@C system with a regime of dehydrogenation at 350 °C for 200 min and hydrogenation at 450 °C under 10 MPa H₂ for 100 min [55].

Figure 4. (a) FTIR spectra of SiB₄/FeB/TiB₂LiH after hydrogenation at different conditions. The right part is the enlargement of the dashed region in left FTIR, TPD-MS, (b) and isothermal dehydrogenation curve at 400 °C (c) of SiB₄-LiH samples after hydrogenation at different conditions [64]. (d) Dehydrogenation of PeC isotherms of the 6LiBH₄/SrF₂ system at 400, 450, and 500 °C. (e) FTIR spectra of the 6LiBH₄/SrF₂ system. (f) XRD patterns of different samples [56].

Figure 5. (a) The flowchart for the preparation method of the as-milled Sm₅Mg₄₁ alloy [75]. (b) Illustration of the deformation of powder agglomerate during the impact process [76].

Figure 6. SEM of (a) 40LBH@NC-NbF₅, (b) 50LBH@NC-NbF₅, and (c) 60LBH@NC-NbF₅ in the same magnification. (d) Theoretical and experimental dehydrogenation capacities of _xLBH@hNCNC and xLBH@NC-NbF₅ and their differences. (e) Cyclic performance with a regime of dehydrogenation at 300 °C in vacuum and rehydrogenation at 300 °C under 12 MPa H₂ [69].

Figure 7. (a) Schematic of the preparation. (b) Non-isothermal hydrogenation curves of nano-LiBH₄. (c) Comparison of dehydrogenation capacity of pristine LiBH₄ (500 °C), nano-LiBH₄ (400 °C), and nano-LiBH₄/LiH (400 °C) with cycling [73].

Table 1. US DOE technical targets for onboard hydrogen storage systems.

Storage System Targets	Gravimetric Density (kg H₂/kg System)	Volumetric Density (kg H₂/L System)	Cost $/kWh ($/kg H₂)
2020	1.5	1	$10
2020	−0.045	−0.03	($333)
Ultimate	2.2	1.7	$8
Ultimate	−0.065	−0.05	($266)

Table 2. Properties of LiBH₄ as hydrogen storage material.

Advantages	Disadvantages
High theoretical capacity (18.5 wt.%)	High dehydrogenation temperature (>400 °C)
Abundant constituent elements	Slow kinetics for H₂ release/uptake
Good theoretical volumetric density	Formation of stable intermediates (Li₂B₁₂H₁₂)
Relatively low material cost	Poor reversibility
Good stability at room temperature	Complex multi-step reaction pathway
High volumetric density	Severe rehydrogenation conditions (>600 °C, >150 bar)

Table 5. Comprehensive analysis of LiBH₄ modification strategies from fundamental mechanisms to system performance.

Strategy	Scientific Foundation	Design Evolution	Key Breakthroughs	System Impact	Current Limitations
Catalytic modification	Surface chemistry and electronic modification	Single dopant to multi-functional catalysts	Hybrid catalyst systems; interface engineering	Temperature reduction: 100–150 °C; enhanced kinetics	Long-term stability; Cost-effectiveness
Nanostructure engineering	Size effects and interface physics	Mechanical processing to templated synthesis	Hierarchical architectures; confined geometries	Onset temperature: ~200 °C; modified thermodynamics	Structure preservation; scale-up challenges
Reactive composites	Thermodynamic destabilization	Binary mixtures to multi-component systems	Strategic phase formation; synergistic effects	High capacity (8–11 wt.%); enhanced reversibility	Complex phase evolution; heat management

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

Share and Cite

MDPI and ACS Style

Xu, Y.; Zhou, Y.; Li, Y.; Ashuri, M.; Ding, Z. Engineering LiBH₄-Based Materials for Advanced Hydrogen Storage: A Critical Review of Catalysis, Nanoconfinement, and Composite Design. Molecules 2024, 29, 5774. https://doi.org/10.3390/molecules29235774

AMA Style

Xu Y, Zhou Y, Li Y, Ashuri M, Ding Z. Engineering LiBH₄-Based Materials for Advanced Hydrogen Storage: A Critical Review of Catalysis, Nanoconfinement, and Composite Design. Molecules. 2024; 29(23):5774. https://doi.org/10.3390/molecules29235774

Chicago/Turabian Style

Xu, Yaohui, Yang Zhou, Yuting Li, Maziar Ashuri, and Zhao Ding. 2024. "Engineering LiBH₄-Based Materials for Advanced Hydrogen Storage: A Critical Review of Catalysis, Nanoconfinement, and Composite Design" Molecules 29, no. 23: 5774. https://doi.org/10.3390/molecules29235774

APA Style

Xu, Y., Zhou, Y., Li, Y., Ashuri, M., & Ding, Z. (2024). Engineering LiBH₄-Based Materials for Advanced Hydrogen Storage: A Critical Review of Catalysis, Nanoconfinement, and Composite Design. Molecules, 29(23), 5774. https://doi.org/10.3390/molecules29235774

Article Menu

Engineering LiBH₄-Based Materials for Advanced Hydrogen Storage: A Critical Review of Catalysis, Nanoconfinement, and Composite Design

Abstract

1. Introduction

2. Structural Chemistry and Reaction Mechanisms of LiBH₄