WO2018062770A1 - Lithium-rich antiperovskite compound, lithium secondary battery electrolyte comprising same, and lithium secondary battery comprising same - Google Patents

Abstract

The present invention relates to a lithium-rich antiperovskite compound and a use thereof, and to: a lithium-rich antiperovskite compound having a novel structure in which a dopant is substituted in a Li₃OCl compound, wherein the dopant is substituted at a position of O instead of that of an anion Cl as in a conventional lithium-rich antiperovskite compound; and an electrolyte using the same. The lithium-rich antiperovskite compound has high lithium ion conductivity and excellent thermal stability, and thus can be applied as an electrolyte of a lithium secondary battery driven at a high temperature.

Description

Lithium rich antiperovskite compound, electrolyte for lithium secondary battery comprising same and lithium secondary battery comprising same

This application claims the benefit of priority based on Korean Patent Application No. 10-2016-0126258 filed on September 30, 2016 and Korean Patent Application No. 10-2017-0118438 filed on September 15, 2017. All content described in the literature is included as part of this specification.

The present invention relates to a novel Li-rich antiperovskite compound having an antiperovskite crystal structure, an electrolyte for a lithium secondary battery comprising the same, and a lithium secondary battery comprising the same.

Recently, as interest in environmental problems increases, researches on electric vehicles and hybrid electric vehicles that can replace vehicles using fossil fuel, such as gasoline and diesel vehicles, which are one of the main causes of air pollution, are being conducted. As a power source of such electric vehicles and hybrid electric vehicles, nickel-metal hydride secondary batteries are mainly used. However, researches using lithium secondary batteries with high energy density and discharge voltage and long cycle life and low self-discharge rate have been actively conducted. And is in some stages of commercialization.

As a negative electrode active material of such a lithium secondary battery, a carbon material is mainly used, and the use of lithium metal, a sulfur compound, etc. is also considered. In addition, lithium-containing cobalt oxide (LiCoO ₂ ) is mainly used as a positive electrode active material, and lithium-containing manganese oxides such as LiMnO _{2 having a} layered crystal structure and LiMn ₂ O _{4 having a} spinel crystal structure, and lithium-containing nickel oxide (LiNiO _2). ) Is also being considered. In addition, various materials such as a liquid electrolyte, a solid electrolyte, and a polymer electrolyte are used as the electrolyte.

 The lithium secondary battery has low thermal stability at high temperatures (eg, 90 ° C. or higher), causing internal short circuits, and the battery swells and explodes. In particular, when a liquid electrolyte is used, leakage of the electrolyte occurs, and a solid electrolyte or a polymer electrolyte has been proposed as an alternative, but satisfactory lithium ion conductivity cannot be obtained.

Recently, compounds having a lithium rich antiperovskite crystal structure (hereinafter referred to as 'LiRAP') having a chemical structure such as Li ₃ OBr or Li ₃ OCl have been proposed, and these compounds have a lithium ion conductivity. Not only is it excellent, it is safe at high temperatures, and research is being conducted as an alternative to the next-generation electrolyte.

Antiperovskite crystal structure (Antiperovskite crystal structure) is a structure similar to perovskite, means a structure in which the position between the cation and other constituent elements in the crystal structure. The perovskite structure is usually represented by ABX _3, where A is a monovalent cation, B is a divalent cation, and X is a monovalent anion. The antiperovskite structure is, in ABX ₃ , X is a cation such as an alkali metal, and A and B mean anions. There are hundreds of known perovskite and antiperovskite crystal structures depending on which atoms (or functional groups) are present in A, B, and X. Electrical properties vary from conductors to semiconductors and insulators.

Xujie Lu et al. Present Li ₃ OCl as LiRAP, and the material exhibits a high level of ionic conductivity of 0.85 × 10 ⁻³ S / cm at room temperature, and orthorhombic crystals having tetragonal phases It has been suggested that it can be used as an electrolyte because of its excellent stability at high temperatures due to its structure [Yusheng Zhao et al ., Superionic Conductivity in Lithium-Rich Anti-Perovskites , J. Am. Chem . Soc ., 2012, 134 (36), pp 15042-15047; US 2013-0202971].

Crystal structures such as LiRAP add dopants, which are intentional impurities, to increase ion conductivity. In this regard, Yusheng Zhao et al. Reported that the ion conductivity of Br ₃ doped Li ₃ O (Cl _0.5 , Br _0.5 ) is 10 ⁻² S / cm, which is better than the 10 ⁻³ value of Li ₃ OCl, which is a solid electrolyte. It is suggested that it can be used as [Yusheng Zhao et al ., Superionic Conductivity in Lithium-Rich Anti-Perovskites , J. Am. Chem. Soc ., 2012, 134 (36), pp 15042-15047].

Similarly, Yusheng Zhao and MH Braga et al. Proposed a compound of (Ba, Li) ₃ OCl structure in which lithium ions were substituted with other metals, which could increase the ionic conductivity at room temperature and non-combustible at high temperature. It has been disclosed that the present invention can be used in a battery that requires high-temperature operation, such as a metal-air battery or an all-solid-state battery.

[Patent Documents]

(Patent Document 1) US 2013-0202971 (Aug. 8, 2013), Anti-Perovskite Solid Electrolyte Compositions

[Non-Patent Documents]

(Non-Patent Document 1) Xujie Lu et al., Li-rich anti-perovskite Li 3 OCl films with enhanced ionic conductivity, Chem. Commun., 2014, 50, 11520

(Non-Patent Document 2) Yusheng Zhao et al., Superionic Conductivity in Lithium-Rich Anti-Perovskites, J. Am. Chem. Soc., 2012, 134 (36), pp 15042 ~ 15047

(Non-Patent Document 3) M. H. Braga et al., Novel Li 3 ClO based glasses with superionic properties for lithium batteries, J. Mater. Chem. A, 2014, 2, 5470-5480

Therefore, as a result of the research of LiRAP compounds such as Li ₃ OCl, the applicant has designed a structure in which a dopant for substitution is substituted in place of oxygen (O) rather than in place of Cl, and this novel structure is The present invention was completed by predicting that the compound having excellent stability at high temperature with high ionic conductivity.

Accordingly, an object of the present invention is to provide a LiRAP compound having a novel structure.

Another object of the present invention is to provide a use of the LiRAP compound in a lithium secondary battery.

In order to achieve the above object, the present invention provides a compound having a lithium rich antiperovskites (LiRAP) crystal structure represented by the following formula (1), (2) or (3).

[Formula 1]

Li _{3 - x} ClO _{1 - x} Hal _x

(In Formula 1, Hal is F, Cl, Br or I, 0 <x <1).

[Formula 2]

Li _3-yx M _y O _1-x Hal _x Cl

(In Formula 2, M is Na, K, Rb or Cs, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <2).

[Formula 3]

Li _3-2y-x M _y O _1-x Hal _x Cl

(In Formula 3, M is Mg, Ca, Sr or Ba, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <1).

In addition, the present invention provides an electrolyte for a lithium secondary battery comprising a compound having a lithium rich antiperovskites (Liithium Rich Antiperovskites, LiRAP) crystal structure represented by the following formula (1), (2) or (3).

[Formula 1]

Li _3-x ClO _1-x Hal _x

(In Formula 1, Hal is F, Cl, Br or I, 0 <x <1).

[Formula 2]

Li _3-yx M _y O _1-x Hal _x Cl

(In Formula 2, M is Na, K, Rb or Cs, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <2).

[Formula 3]

Li _3-2y-x M _y O _1-x Hal _x Cl

(In Formula 3, M is Mg, Ca, Sr or Ba, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <1).

In addition, the present invention provides a lithium secondary battery comprising the electrolyte for a lithium secondary battery.

The lithium compound having a novel crystal structure according to the present invention has high ionic conductivity as the dopant is formed by replacing oxygen rather than lithium cations. This lithium compound is used as a solid electrolyte of a lithium secondary battery, and maintains high ionic conductivity even when the battery is driven at a high temperature, and satisfies all characteristics such as an electrochemically stable potential window, low electrical conductivity, high temperature stability, and low toxicity. .

In particular, the lithium compound may be used as an electrolyte in various secondary battery fields such as a solid oxide battery, an all-solid-state battery, and a lithium-sulfur battery that operate at a high temperature.

1 is a schematic diagram showing the crystal structure of Li ₃ OCl.

2 is a schematic diagram showing a crystal structure in which Li is substituted with a Ba cation.

3 is a schematic diagram showing a crystal structure in which O is substituted with an F anion.

4 is a schematic diagram showing a crystal structure in which Li is substituted with Na cation and O is substituted with F anion.

5 is a schematic diagram showing a crystal structure in which Li is replaced with a Ba cation and O is substituted with an F anion.

6 is a graph comparing bandgap change results of LiRAP compounds according to dopants.

7 is a graph comparing the change of activation energy for lithium ion migration of LiRAP compounds according to dopants.

8 is an XRD spectra of Li ₃ ClO according to an embodiment of the present invention.

9 is an XRD spectra of Li _2.963 ClO _0.963 F _0.037 according to an embodiment of the present invention.

10 is Li ₂ according to an embodiment of the present invention _{. 926} Na _{0 . 037} is a ClO _{0 .963 0.037} F of the XRD spectra.

11 is Li ₁ according to an embodiment of the present invention _{. 889} Ba _{0 . 037} is a ClO _{0 .963 0.037} F of the XRD spectra.

Hereinafter, the present invention will be described in detail.

LiRAP Compound

The LiRAP ((Lithium Rich Antiperovskites) compound of the present invention is a compound having a lithium rich antiperovskite crystal structure. Specifically, the LiRAP compound is formed of a dopant on the basic crystal structure of Li ₃ OCl to improve ion conductivity. Substituted as a structure in which a dopant is substituted for O, not Cl, as in the prior art, and preferably has a chemical structure represented by the following Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3.

[Formula 1]

Li _3-x ClO _1-x Hal _x

(In Formula 1, Hal is F, Cl, Br or I, 0 <x <1).

[Formula 2]

Li _3-yx M _y O _1-x Hal _x Cl

(In Formula 2, M is Na, K, Rb or Cs, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <2).

[Formula 3]

Li _3-2y-x M _y O _1-x Hal _x Cl

(In Formula 3, M is Mg, Ca, Sr or Ba, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <1).

LiRAP compounds of Formulas 2 and 3 are compounds in which a cation of Li is further substituted.

The compounds of Formulas 1, 2 and 3 have an ionic conductivity (25 ° C.) of 10 to 10 ⁻¹⁰ S / cm, and are excellent in thermal stability to almost maintain the ionic conductivity at high temperature.

LiRAP compounds of Formulas 1, 2, and 3 have a structure in which a halogen element of F, Cl, Br, or I as a dopant is partially substituted in place of O, and has a ionic conductivity equal to or higher than that of LiOCl without a conventional dopant substituted And thermal stability.

In this case, the type of dopant and the molar ratios represented by x and y directly affect the activation energy together with the bandgap described later, and the molar ratio (i.e., the content of the dopant) consequently affects the ionic conductivity. It is desirable to control the content.

Preferably, if the molar ratio of the halogen element, which is a dopant of O, is small, the synergistic effect of the ion conductivity cannot be secured. On the contrary, if the amount is too large, the band gap is reduced and the active energy increases, resulting in a decrease in the ion conductivity. Therefore, it uses suitably in the said range. This tendency applies equally to the metal represented by M, which is a substituted metal of Li.

Diffusion mechanisms of doping by dopants include substitutional diffusion and interstitial diffusion. The substitutional diffusion is diffusion through a vacancy on the lattice, and means a diffusion in which a valence is pushed out of a substitutional site to a niche location and a dopant enters the position. In addition, interstitial diffusion is where the lattice jumps and spreads through interstitial sites, which diffuses and diffuses much faster than alternative diffusions to form deep levels in the semiconductor.

The dopants presented in the present invention are doped by a crevice diffusion mechanism. In the case of gap diffusion, energy must be moved from the gap position to another gap position, and thus, energy of heat treatment is required for such atomic movement. The addition of the dopant results in a change in the electronic state, ie the crystal structure, and consequently the bandgap and activation energy of the material are converted.

That is, LiRAP according to the present invention has a certain level of energy level before doping with a dopant, and there is an energy gap (Eg), that is, a bandgap, depending on the interaction and active state of atoms constituting LiRAP. The numerical value of the band gap is changed by the change of the energy level of LiRAP due to the doping of the dopant. The change in the band gap is usually greatly influenced by the type and concentration of the dopant. In general, when the band gap is 3.0 eV or more, the insulator has a very low electrical conductivity, and about 5 eV in the case of LiRAP, and the band gap is converted according to the type of dopant.

When Li or O is substituted with another element, the bandgap tends to be smaller than that of LiRAP, and a smaller tendency of reduction may be considered as a candidate group of the preferred dopant.

When using a specific dopant, such as the halogen element as shown in the formula (1), (2) and (3), the band gap change is small, and when Li is substituted in another metal, the band gap change in Na and Ba There was a small tendency.

The band gap of the LiRAP compounds of Formula 1, Formula 2, and Formula 3 may be predicted through the following calculation.

FIG. 1 is a schematic diagram showing the crystal structure of Li ₃ OCl. FIG. 1 is a schematic diagram showing the crystal structure of Li ₈₁ Cl ₇ O ₂₇ in a 3 * 3 * 3 supercell crystal structure consisting of 135 atoms. This crystal structure has a large cation (A) at the vertex of the cube unit lattice (8 × 1/8), and a small cation (B) among them, and an anion (X) at the center of each plane (6 × 1/2). It's a rescue.

2 is a schematic diagram which shows the crystal structure which substituted Li by Ba cation.

Li ₃ OCl having a crystal structure of FIG. 1 and a (Li, M) ₃ OCl compound having a crystal structure of FIG. 2 are substituted with a cation shown below and doped with an anion, and the band gap change is compared with that of Li ₃ OCl. The calculation is shown in FIG. 3.

Cation:

+1 is: Na, K, Rb, Cs

+2 is: Mg, Ca, Sr, Ba

+3: B, Al, Ga, In, Sc, Y, La

+4 is: Si, Ge, Ti, Zr, Hf

Negative ion:

O position: F, Cl, Br, I

In the candidate, the cation is an element substituted with Li and the anion is an element substituted with O.

We used VASP (version 5.3.5), a density functional theory (DFT) code based on PAW (projector augmented wave) to calculate the bandgap, and the kinetic energy cutoff of the electron was 500 eV, and the exchange-correlation function was GGA (PBE). )

The k-point mesh for the supercell calculation was considered only the gamma point and the atomic structure optimization was performed until the interatomic force was ± 0.1 eV / ÅA by the conjugate gradient method. The energy gap between the conduction band minimum (CBM) and the valence band maximum (VBM) at the gamma point of the optimized structure corresponds to the band gap.

6 is a graph comparing bandgap results of LiRAP compounds according to dopants. In this case, the GGA-PBE bandgap tends to be underestimated than the actual bandgap. In FIG. 6, since the value is slightly different from the actual case, only the relative comparison with Li ₃ OCl is significant rather than a quantitative change. At this time, when the GGA-PBE bandgap is 3.0 eV or more, it is determined that the insulator has very low electrical conductivity.

Referring to FIG. 6, when the Li was substituted with another element, the band gaps were all smaller than those of the Li ₃ ClO. In addition, Na, K, Rb, Al, B, La, Ba, Ca, Sr, Mg, F (O substitution), Cl (O substitution), Br (O substitution), I (O substitution ) May be the preferred dopant. In addition, when the tetravalent cation was substituted, the concentration of Li vacancy was high, but the band gap showed a tendency to decrease significantly.

Activation energy (Eg) for lithium ion migration is calculated for the change of lithium ion conductivity with the above band gap change.

Activation energy was calculated by calculation of judged elastic band (NEB) and between the initial structure before the movement of Li + ion and the final structure after movement to model the movement of Li + ion in the [110] crystal direction. Five images divided by equal intervals were used. NEB calculation was performed using VASP (version 5.3.5), which is a PAW-based DFT calculation code.

The activation energy is moved to the interstitial site of Li-O by the dopant, and the required activation energy can be measured by using VASP, which is a code based on density functional theory.

7 is a graph comparing the change of activation energy for lithium ion migration of LiRAP compounds according to dopants.

Referring to FIG. 7, Li ₃ ClO showed Ea = 0.323 eV, which was similar to the experimental value reported in the existing literature, 0.36 eV. Only six cases of Ba, Na, F (Osubstituted), Cl (Osubstituted), Br (Osubstituted) and I (Osubstituted) showed lower energy than Li ₃ ClO.

In addition, when mono and divalent cations were substituted at Li sites or when monovalent anions were substituted at O sites, Ea for Li + migration tended to be similar or low.

Thus, Li _{3 which} is not doped with LiRAP compound doped or substituted with Na (Li substitution), Ba (Li substitution), F (oxygen substitution), Cl (oxygen substitution), Br (oxygen substitution), I (oxygen substitution) It may have a higher ion conductivity than ClO.

In summary, from the results of the bandgap and lithium ion transfer activation energy of FIGS. 6 and 7, a halogen element, i.e., at the O site of the anion represented by Formula 1, Formula 2 or Formula 3, which is not Cl in the prior art in LiRAP, It can be seen that when F, Cl, Br or I is substituted, it has a low band energy with a high band gap. In addition, it can be seen that even when a part of Li cation is replaced with a cation of Na or Ba, it has the following active energy before doping.

The preparation of the LiRAP compound of Formula 1, Formula 2 or Formula 3 according to the present invention is not particularly limited.

According to one embodiment, the lithium precursor ₍₃ LiNO), comprising: a mixture of Li Hal synthesize lithium oxyhalides (for example, Li _{1 963} O _{0 .963 0. 037 F.);} And a mixture of LiCl added to the lithium oxy halide through annealing at a high temperature of 180 to 900 ° C.

At this time, in the case of the compound represented by the formula (2) or formula (3), it is possible to manufacture by adding a precursor containing a metal to the first step. The precursor may be a chloride, nitride, hydroxide, oxyhydroxide, alkoxide, amidate, or the like of the metal, preferably an alkoxide.

In addition, the synthesis of formula (2) or formula (3) using a precursor containing a metal does not particularly limit the method of synthesis.

As an example, it is possible to carry out the synthesis of the formula (2) or (3) by adding the precursor containing the metal in the synthesis step of the lithium oxyhalide or in the step of high temperature annealing.

According to another embodiment of the present invention, by reacting Li ₃ OCl powder with HX (X = halide) to prepare a LiRAP compound of Formula 1, or by reacting the Li precursor and M precursor (Li, M) ₃ OCl Then, reacted with HX (X = halide) to prepare a LiRAP compound of Formula 2 or Formula 3.

Lithium secondary battery

LiRAP compound of Formula 1, Formula 2 or Formula 3 can be applied to a lithium secondary battery due to high ionic conductivity.

The lithium secondary battery includes a positive electrode, a negative electrode, and an electrolyte interposed therebetween, wherein a LiRAP compound of Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3 is used as the electrolyte.

LiRAP compounds exhibit high lithium ion conductivity compared to conventional Cl-substituted structures while satisfying all of the characteristics such as electrochemically stable potential window, low electrical conductivity, high temperature stability and low toxicity, and are preferably used as electrolytes for batteries. Improve battery performance and thermal stability.

When used as an electrolyte, the LiRAP compounds of Formula 1, Formula 2 or Formula 3 may be used alone or in combination, respectively, and may be mixed and used to have various combinations of M and X.

In addition, the electrolyte may further include a material used for this purpose in order to further increase the lithium ion conductivity.

In one example, LiCl, LiBr, LiI, LiClO ₄ , LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiSCN, LiC (CF ₃ SO ₂ ) ₃ , (CF ₃ SO ₂ ) ₂ NLi, (FSO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carbonate, lithium 4-phenylborate, lithiumimide Lithium salts, such as these may further be included.

In addition, it further comprises an inorganic solid electrolyte or an organic solid electrolyte. The inorganic solid electrolyte is a ceramic-based material, a crystalline or amorphous and crystalline materials can be _{used, Thio-LISICON (Li 3.} 25 Ge 0 .25 P 0. 75 S 4), Li 2 S-SiS 2, LiI -Li ₂ S-SiS ₂ , LiI-Li ₂ SP ₂ S ₅ , LiI-Li ₂ SP ₂ O ₅ , LiI-Li ₃ PO ₄ -P ₂ S ₅ , Li ₂ SP ₂ S ₅ , Li ₃ PS ₄ , Li ₇ P ₃ S ₁₁ , Li ₂ OB ₂ O ₃ , Li ₂ OB ₂ O ₃ -P ₂ O ₅ , Li ₂ OV ₂ O ₅ -SiO ₂ , Li ₂ OB ₂ O ₃ , Li ₃ PO ₄ , Li ₂ O-Li ₂ WO ₄ -B ₂ O ₃ , LiPON, LiBON, Li ₂ O-SiO ₂ , LiI, Li ₃ N, Li ₅ La ₃ Ta ₂ O12, Li ₇ La ₃ Zr ₂ O ₁₂ , Li ₆ BaLa ₂ Inorganic solid electrolytes such as Ta ₂ O ₁₂ , Li ₃ PO _{(4-3 / 2w)} Nw (w is w <1) and Li _3.6 Si _0.6 P _0.4 O ₄ are possible.

Examples of the organic solid electrolyte include polymer-based materials such as polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyedgetion lysine, polyester sulfides, polyvinyl alcohol, and polyvinylidene fluoride. What mixed lithium salt can be used. At this time, these may be used alone or in combination of at least one or more.

In addition, these LiRAP compounds may be applied as a solid electrolyte through preparation of pellets through compression after preparation in powder form, or may be mixed with known materials such as binders and applied in the form of a thick film through slurry coating. In addition, if necessary, it can be applied as an electrolyte in the form of a thin film through a deposition process such as sputtering.

The specific application method to the electrolyte is not particularly limited in the present invention, and may be selected or selected by a method known by those skilled in the art.

The lithium secondary battery to which the LiRAP compound of Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3 is applicable as an electrolyte is not limited to a positive electrode or a negative electrode, and particularly, a lithium-air battery, a lithium oxide battery, a lithium-sulfur battery, and a lithium metal that operate at a high temperature. It is applicable to a battery, an all-solid-state battery, and the like.

The positive electrode of a lithium secondary battery may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with one or more transition metals; Formula _{Li 1 + x Mn 2 - x} O 4 (0≤x≤0.33), LiMnO 3, the lithium manganese oxide such as LiMn ₂ O _3, LiMnO _2; Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ , Cu ₂ V ₂ O ₇ and the like; Ni-site type lithium nickel oxide represented by the formula LiNi _{1 - x} M _x O ₂ (M Co, Mn, Al, Cu, Fe, Mg, B or Ga; 0.01 ≦ x ≦ 0.3); With the formula LiMn _{2 - x} M _x O ₂ (M Co, Ni, Fe, Cr, Zn or Ta; 0.01≤x≤0.1) or Li ₂ Mn ₃ MO ₈ (which is M Fe, Co, Ni, Cu or Zn) Lithium manganese composite oxides represented; Spinel-structure lithium manganese composite oxides represented by LiNi _x Mn _{2 - x} O ₄ ; LiMn ₂ O _{4 in} which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe ₂ (MoO ₄ ) ₃ and the like may be included, but is not limited thereto.

Such a positive electrode active material may be formed on a positive electrode current collector. The positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, carbon, on the surface of aluminum or stainless steel, The surface-treated with nickel, titanium, silver, etc. can be used. In this case, the positive electrode current collector may use various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric having fine irregularities formed on a surface thereof so as to increase the adhesion with the positive electrode active material.

In addition, the negative electrode has a negative electrode mixture layer having a negative electrode active material formed on the negative electrode current collector, or uses a negative electrode mixture layer (for example, lithium foil) alone.

In this case, the type of the negative electrode current collector or the negative electrode mixture layer is not particularly limited in the present invention, and a known material may be used.

In addition, the negative electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and for example, carbon on the surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel , Surface-treated with nickel, titanium, silver, or the like, aluminum-cadmium alloy, or the like can be used. In addition, the negative electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric having fine irregularities formed on the surface, similar to the positive electrode current collector.

In addition, the negative electrode active material is one selected from the group consisting of crystalline artificial graphite, crystalline natural graphite, amorphous hard carbon, low crystalline soft carbon, carbon black, acetylene black, Ketjen black, super-P, graphene, fibrous carbon Carbon-based material, Si-based material, LixFe ₂ O ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), Sn _x Me _{1 - x} Me ' _y O _z (Me: Mn, Fe Me ': Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen; 0 <x≤1;1≤y≤3; 1≤z≤8) Metal composite oxides; Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , Metal oxides such as Bi ₂ O ₅ ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials; Titanium oxide; Lithium titanium oxide and the like may be included, but are not limited thereto.

In addition, the negative electrode active material is SnxMe _{1 - x} Me ' _y O _z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, group 1, group 2, group 3 elements of the periodic table, Metal composite oxides such as halogen, 0 <x ≦ 1, 1 ≦ y ≦ 3, 1 ≦ z ≦ 8); SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO _{2 2} , Bi ₂ O ₃ , Bi ₂ O ₄ and An oxide such as Bi ₂ O ₅ may be used, and a carbon-based negative active material such as crystalline carbon, amorphous carbon or a carbon composite may be used alone or in combination of two or more thereof.

In this case, the electrode mixture layer may further include a binder resin, a conductive material, a filler and other additives.

The binder resin is used for bonding the electrode active material and the conductive material and the current collector. Examples of such binder resins include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetra Fluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers thereof, and the like.

The said conductive material is used in order to improve the electroconductivity of an electrode active material further. Such a conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon blacks such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Polyphenylene derivatives and the like can be used.

The filler is optionally used as a component for inhibiting the expansion of the electrode, and is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.

The manufacturing of the electrode for lithium secondary batteries according to the present invention is not particularly limited, and a conventional battery manufacturing process is followed. For example, the electrode mixture layer and the electrode protective layer are sequentially stacked on an electrode current collector.

The shape of the lithium secondary battery is not particularly limited and may be in various shapes such as cylindrical, stacked, coin type.

In addition, the present invention provides a battery module including the lithium secondary battery as a unit cell, and provides a battery pack including the battery module.

The battery pack may be used as a power source for medium and large devices that require high temperature stability, long cycle characteristics, and high capacity characteristics.

Examples of the medium-to-large device include a power tool that is driven by an electric motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (Escooters); Electric golf carts; Power storage systems and the like, but is not limited thereto.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

EXAMPLE

Example 1: Preparation of Li _3-x ClO _1-x Hal _x (Li _2.963 ClO _0.963 F _0.037 )

6.528 g of LiNO ₃ powder and 0.048 g of LiF powder were dissolved in 100 ml HNO ₃ (0.1 M) in a reaction vessel and allowed to react at room temperature for 12 hours. After the reaction, it is dried using a rotary evaporator and an electric oven. The dried powder is fired at 900 ° C. for 3 days and then dropped to room temperature at a rate of 3 ° C./min. The synthesized powder is washed several times with distilled water to remove unreacted material, and then calcined in air at 600 ° C. for 1 hour. The synthesized material was ground mixed with 2.1 g of LiCl powder to prepare a ground mixed powder. 3 ml H ₂ O was added to the mixed powder to prepare a gel mixture. Subsequently, after annealing for 2 hours or more in an autoclave at 600 ° C. under an oxygen atmosphere, the resultant was dried under the same temperature for about 1 hour to prepare Li _2.963 ClO _0.963 F _0.037 .

Example 2: Li _x M _y O _{3 -y- 1 - x x} Hal Cl Preparation of _{(Li 2 926 Na 0 037 ClO} 0 .963 F 0.037..)

6.451 g of LiNO ₃ powder, 0.048 g of LiF powder, and 0.15 g of Na (CH ₃ COO) powder were dissolved in 100 ml HNO ₃ (0.1 M) in a reaction vessel and allowed to react at room temperature for 12 hours. After the reaction, it is dried using a rotary evaporator and an electric oven. The dried powder is fired at 900 ° C. for 3 days and then dropped to room temperature at a rate of 3 ° C./min. The synthesized powder is washed several times with distilled water to remove unreacted material, and then calcined in air at 600 ° C. for 1 hour. The synthesized material was ground mixed with 2.1 g of LiCl powder to prepare a ground mixed powder. 3 ml H ₂ O was added to the mixed powder to prepare a gel mixture. Subsequently, heat treatment was performed for 2 hours or more in an autoclave at 600 ° C. under an oxygen atmosphere, followed by drying under the same temperature for about 1 hour to prepare Li _2.926 Na _0.037 ClO _0.963 F _0.037 .

Example 3: Li _x M _y O _{3 -2y- 1 - x x} Hal Cl Preparation of _{(Li 1 889 Ba 0 037 ClO} 0 .6963 F 0.037..)

6.325 g of LiNO ₃ powder, 0.048 g of LiF powder, and 0.46 g of Ba (CH ₃ COO) ₂ powder were dissolved in 100 ml HNO ₃ (0.1 M) in a reaction vessel and allowed to react at room temperature for 12 hours. After the reaction, it is dried using a rotary evaporator and an electric oven. The dried powder is fired at 900 ° C. for 3 days and then dropped to room temperature at a rate of 3 ° C./min. The synthesized powder is washed several times with distilled water to remove unreacted material, and then calcined in air at 600 ° C. for 1 hour. The synthesized material was ground mixed with 2.1 g of LiCl powder to prepare a ground mixed powder. 3 ml H ₂ O was added to the mixed powder to prepare a gel mixture. Subsequently, after annealing for 2 hours or more in an autoclave at 600 ° C. under an oxygen atmosphere, the resultant was dried under the same temperature for about 1 hour to prepare Li _1.889 Ba _0.037 ClO _0.963 F _0.037 .

Experimental Example 1: X-ray peak simulation analysis

In order to calculate the optimal structure of F-substituted O-site, the first-order principle calculation based on density functional theory (DFT) was used. First, a 3x3x3 supercell is formed by increasing the unit cell of Li ₃ ClO three times in the x-axis, y-axis, and z-axis directions, respectively, and then at the (0.5, 0.5, 0.5) position. Oxygen was replaced with F. To charge balance, one of the lithium present around the substituted F was removed to create a lithium vacancy. The structure used in the calculation is shown below and has the chemical formula Li ₇₉ Cl ₂₇ O ₂₆ F ₁ . We used VASP, a planewave based density density method code for structural optimization, and the exchange correlation to simulate electron-electron interactions in the calculations is based on Perdew-Burke of Generalized Gradient Approximation (GGA). We used the Ernzerhor (PBE) function. The electron kinetic energy cutoff was 400 eV and the energy smearing was Gaussian. The k-point mesh in inverse lattice space for the calculation of the energy (eigenvalue) used a condition involving only gamma points and repeated calculations until the force between all atoms was less than 0.01 eV / Å. Based on this optimized structure, x-ray peak simulation was performed. 8, 9, 10, 11 is Li ₃ ClO, Li ₂ derived through the above method _{. 963} ClO _{0 .963} F _0.037 , Li _2.926 Na _0.037 ClO _0.963 F _0.037 , XRD peak spectra of Li _1.889 Ba _0.037 ClO _0.963 F _0.037 .

Claims (6)

1. A compound having a lithium rich antiperovskites (LiRAP) crystal structure represented by the following formula (1), (2) or (3):

   [Formula 1]

   Li _3-x ClO _1-x Hal _x

   (In Formula 1, Hal is F, Cl, Br or I, 0 <x <1).

   [Formula 2]

   Li _3-yx M _y O _1-x Hal _x Cl

   (In Formula 2, M is Na, K, Rb or Cs, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <2).

   [Formula 3]

   Li _3-2y-x M _y O _1-x Hal _x Cl

   (In Formula 3, M is Mg, Ca, Sr or Ba, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <1).
2. The method of claim 1,

   The compound is characterized in that it has an ionic conductivity of 10 to 10 ^-10 S / cm.
3. An electrolyte for a lithium secondary battery comprising a compound having a lithium rich antiperovskites (Liithium Rich Antiperovskites, LiRAP) crystal structure represented by the following formula (1), (2) or (3):

   [Formula 1]

   Li _3-x ClO _1-x Hal _x

   (In Formula 1, Hal is F, Cl, Br or I, 0 <x <1).

   [Formula 2]

   Li _3-yx M _y O _1-x Hal _x Cl

   (In Formula 2, M is Na, K, Rb or Cs, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <2).

   [Formula 3]

   Li _3-2y-x M _y O _1-x Hal _x Cl

   (In Formula 3, M is Mg, Ca, Sr or Ba, Hal is F, Cl, Br or I, 0 <x <1, 0 <y <1).
4. The method of claim 3,

   The compound is a lithium secondary battery electrolyte, characterized in that it has an ionic conductivity of 10 to 10 ^-10 S / cm.
5. A lithium secondary battery comprising the electrolyte for lithium secondary battery according to claim 3 or 4.
6. The method of claim 5,

   The lithium secondary battery is a lithium secondary battery, characterized in that one selected from lithium-air battery, lithium oxide battery, lithium-sulfur battery, lithium metal battery or all-solid-state battery.

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