Alternative Energy - Material Matters v3n4
Alternative Energy - Material Matters v3n4
Alternative Energy - Material Matters v3n4
Vol. 3, No. 4
Alternative Energy
Generation and Storage
Light-Driven
Generation of Hydrogen
Polymer Electrolyte
Membrane Fuel Cells
Polymer-based Materials
Alternative Energy—the way to go
for Printed Electronics
Advanced
Lithium Ion Batteries
Introduction TM
Introduction
Joe Porwoll, President
Aldrich Chemical Co., Inc.
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A Biologically-Inspired Electrochemical Half-Cell
for Light-Driven Generation of Hydrogen
Emerging Technologies
Generation of Hydrogen
Light-Driven
78 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
In vitro systems that combine biological and/or non-biological Low
components in novel ways were the first attempt at a hybrid potential e–
approach for hydrogen production. These in vitro systems acceptors
utilize isolated proteins or proteins within chloroplasts in FB PsaC
conjunction with metal deposition and/or naturally occurring FA
H2ases. A PS I-H2ase construct has been created by fusing the stroma
Generation of Hydrogen
Light-Driven
gene encoding for the [NiFe]-H2ase from Ralstonia eutropha FX
H16 with the gene encoding the PsaE (PS I stromal) protein.
A1 A1
When the H2ase/PsaE fusion product is re-bound to a PsaE
deletion mutant of PS I, hydrogen is evolved, albeit at low rates
(0.2 μmol H2 mg Chl-1 h-1).9 Greenbaum and coworkers have A0 A0
pioneered the use of PS I/metal nanoparticle constructs for the
photocatalysis of H2. In this work, Pt and other metals have been PsaA P700 PsaB
directly photoprecipitated on the stromal side of both isolated lumen
High
PS I proteins and PS I contained within spinach chloroplasts.10,11 potential e–
Illumination of these platinized chloroplasts and PS I proteins donors
enables the production of H2, but again at low rates of 0.2 to
2.0 μmol H2 mg Chl-1 h-1. In a more recent study, the cross-linking Figure 1. This cartoon depicts Photosystem I within the thylakoid membrane.
of the naturally-occurring electron donor plastocyanin was shown PsaA and PsaB (light green) are an intramembrane protein heterodimer that
contain the core electron transfer cofactors within PS I—P700, A0, A1, and FX.
to double the rates of hydrogen production achieved from PsaC lays outside of the membrane on the stromal side of PS I and harbors
platinized PS I.12 the electron transfer cofactors FA and FB. Additional intramembrane proteins
(dark green) support antenna chlorophyll molecules that are responsible
Efficient Photon Capture and for light harvesting. High potential (low energy) electron donating proteins
(plastocyanin or cytochrome c6) provide electrons to P700. The light-driven
Energy Conversion by PS I electron transfer through the membrane is photocatalyzed by photons
absorbed by the antenna chlorophyll molecules. Electrons ultimately arrive on
PS I is a light harvesting complex that is located in the the stromal side of PS I at FB and can then transfer to soluble low potential
(high energy) electron accepting proteins (ferredoxin or flavodoxin).
photosynthetic membranes of plants and cyanobacteria,
a photosynthetically active bacteria. The major purpose of
PS I is to use the energy of light to transfer electrons from
high potential (i.e. low energy) redox proteins across the
membrane to low potential (i.e. high energy) redox proteins.13
Figure 1 depicts the arrangement of PS I proteins within
the membrane. Although PS I comprises 13 proteins, only
PsaA, PsaB, and PsaC are of interest for this article. PsaA and
PsaB are intramembrane proteins which support the core
electron transfer cofactors of PS I, while PsaC lies outside of
the membrane and acts as an interface to shuttle electrons
from within the membrane to soluble low potential electron
accepting proteins. Figure 2 affords a more detailed look
at the organization of PS I. Additional intramembrane Figure 2. a) The intramembrane α-helices of PS I (yellow tubes) act as
proteins surround the PsaA/PsaB heterodimer and support scaffolds for antenna Chl a molecules (green) and the core electron transfer
~100 antenna chlorophyll molecules that are active in light cofactors; the [4Fe-4S] clusters, FA and FB, are visible on the stromal side.
b) Rotating structure (a) 180° and removing the protein scaffold affords a
harvesting. 14 These antenna pigments in cyanobacterial
look (top down from the stromal side) at the organization of the antenna
PS I are chlorophyll a (Chl a) molecules that are capable of Chl a molecules around the core electron transfer cofactors (circled in grey).
absorbing photons with wavelengths shorter than 700 nm.
This absorbance corresponds to 43-46% of the total solar
radiation that reaches the surface of the earth. 15 When a
Chl a molecule absorbs a photon, an excited state is created;
the energy is ultimately transferred by resonance energy
transfer to the primary electron donor of PS I, a Chl a special
pair, termed P700. The arrangement of the core electron
transfer cofactors is shown in Figure 3. When the exciton
reaches P700, a charge-separated state occurs between P700
and the primary electron acceptor, A0, another Chl a molecule.
Ultimately, the electron is transferred through the other
electron transfer cofactors to FB, the terminal cofactor within
PS I. The FB cluster has a midpoint potential of -580 mV, which
is more than sufficient to reduce protons to H2.13 The quantum Figure 3. The core electron transfer cofactors are arranged to allow for
yield of PS I approaches 1.0 which means that nearly all of light-induced electron transfer to occur rapidly from P700, through the
cofactors, to FB. A charge-separated state is first established between P700
the photons that PS I absorbs are converted to the charge
and A0. The electron is then transferred to A1, a bound phyloquinone
separated state P700+/FB-. molecule, and then to three [4Fe-4S] clusters. The first of these, the
inter-polypeptide [4Fe-4S] cluster, FX, is ligated by cysteine residues provided
by both PsaA and PsaB. The stromal protein PsaC harbors the two terminal
[4Fe-4S] clusters, FA and FB.
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Electron transfer on the PS I acceptor side is thermodynamically In practice, a system could be set up in which PS I and Pt
favorable, as the midpoint potential of each of the subsequent nanoparticles are suspended in solution, however hydrogen
cofactors is more positive than the previous one. Figure 4 generation would most likely be of low yield due to the fact
shows the potentials of the electron transfer cofactors as that the interactions between nanoparticles and PS I would be
a function of their distance from P700 as well as forward controlled by slow diffusion chemistry. The speed of diffusion
electron transfer and charge-recombination times. The electron decreases as size of the body in motion increases. In this case,
Generation of Hydrogen
Light-Driven
transfer from P700 to FB is rapid (~200 ns) and the lifetime both the PS I and the Pt nanoparticles are large entities and
of the charge-separated state, P700+/FB-, is long (~65 ms).16 diffusion would likely be too slow to transfer the electron from
Provided the electron is transferred away from the FB cluster FB- to the nanoparticle surface before the charge recombination
within this lifetime, charge recombination will not occur and between P700+ and FB- would occur. In order to avoid this
electron can be harnessed for useful work. In the case of inevitable loss of energy, a direct link should be made between
normal photosynthesis, this work is the reduction of ferredoxin the PS I and the Pt nanoparticle.
or flavodoxin (and the subsequent production of NADPH), but
if the electron can be removed at FB- directly, it can be used to
reduce protons to H2.
Molecular Wires Form a
Covalent Pathway
–1400
Molecular wires are the answer to the diffusional limitation in
P700*
electron transfer. A molecular wire, in the form of an aliphatic
–1200 10-30 ps or aromatic hydrocarbon chain, can be used to connect PS I
A0 with the Pt nanoparticle. On one hand, the molecular wire
–1000 should be sufficiently long to shield the protein from the
50 ps
A1 nanoparticle surface to limit protein denaturation. On the
–800 FX other hand, the molecular wire should be sufficiently short
1-30 ns FB
enough to allow for efficient energy transfer between the two
FA
–600 200 ns modules. Because the charge-separated state P700+/FB- is stable
E, mV
H2
for ~65 ms, efficient electron transfer away from FB must occur
20 ms
–400 on the order of 1 ms. Marcus theory, which relates the rate
of electron transfer to the distance between the cofactors (as
65 ms
well as the Gibbs free energy change, reorganization energy,
–200
and temperature), governs the maximum distance between
PS I and the Pt nanoparticle for optimal electron transfer.
0 Under ideal conditions, for the electron to be transferred
on the microsecond timescale, the distance between the
200 cofactors should be shorter than 2.0 nm. Short aliphatic and
aromatic hydrocarbons with thiol moieties easily functionalize
400 P700 Pt nanoparticle surfaces and are commercially available (See
product table ‘Functionalized Nanoparticles’ on pg 82).
0 10 20 30 40 50
Unfortunately, a direct bond cannot be made to native PS I
without modification.
X-ray distance in the membrane
80 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
so-called rescue ligand for the FB cluster. The insertion process, While the initial rates for this system were already promising,
incidentally, is driven to completion by the entropic gain realized continued research has yielded better performance. Altering the
when seven 2-mercaptoethanol molecules are released into pH and the ionic strength of the solution, changing the length
solution during the insertion process. Thiol functionalities in and the aromaticity of the molecular wire, as well as cross-linking
the form of a molecular wire can then readily displace the cytochrome c6 to the rebuilt PS I promises to increase the rate of
single 2-mercaptoethanol ligand through facile sulfur-iron hydrogen generation by the PS I/molecular wire/Pt nanoparticle
Generation of Hydrogen
Light-Driven
displacement reactions.17,18 bioconjugate. The best rates of H2 generation to-date are at pH
7.0 in 10 mM MgCl2 and 10 mM NaCl using chemically-cross
Catalytic Hydrogen Production linked cytochrome c6.
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Gold and Silver Functionalized Nanoparticles
Name Structure Concentration Particle Size Cat. No.
1-Mercapto-(triethylene glycol) methyl 2 % (w/v) in absolute ethanol 3.5 - 5.5 nm (TEM) 694169-5ML
ether functionalized gold nanoparticles Au S OCH3
O
3
HS
p-Terphenyl-4,4′′-dithiol - 704709-100MG
HS SH
HO OH
82 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Selected Nanopowders for Energy Applications
For a complete list of nanopowder please visit sigma-aldrich.com/nano.
Generation of Hydrogen
Light-Driven
Silver <100 nm surface area 5.0 m2/g 99.5% trace metals basis 576832-5G
Titanium(IV) oxide, <100 nm (BET) spec. surface 15 m2/g 99.9% trace metals basis 634662-25G
mixture of rutile and anatase <50 nm (XRD) 634662-100G
Titanium(IV) oxide, ~21 nm (average particle size BET surf. area 50(±18) m2/g 99.9% trace metals basis, 53-57 wt. % in 700355-25G
mixture of rutile and anatase of starting nanopowder) (BET surface area of starting diethylene glycol monobutyl ether/ethylene glycol
<250 nm (DLS) nanopowder)
Titanium(IV) oxide, <150 nm (DLS) - 99.9% trace metals basis, 33-37 wt. % in H2O 700347-25G
mixture of rutile and anatase ~21 nm (average particle size 700347-100G
of starting nanopowder)
Titanium(IV) oxide, ~15 nm BET surf. area 102 m2/g 99.9% trace metals basis, 43-47 wt. % in xylene 700339-100G
mixture of rutile and anatase <150 nm (DLS) (BET surface area of starting
nanopowder)
Titanium(IV) oxide, anatase <25 nm spec. surface 200-220 m2/g 99.7% trace metals basis 637254-50G
637254-100G
637254-500G
Titanium(IV) oxide, rutile <100 nm spec. surface 130-190 m2/g 99.5% trace metals basis 637262-25G
637262-100G
637262-500G
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Hydrogen Storage Materials: New Additions
Storing hydrogen in solids—hydrides, organic or inorganic materials, and metal-organic frameworks—offers a unique
opportunity for its convenient and safe use in a broad variety of fuel cell applications. Aldrich’s products for hydrogen
storage are designed to satisfy the basic requirements for materials research. Information provided with our products
includes purity, hydrogen content, impurity profiles and x-ray powder differentiation dots.
For our complete product offer please visit sigma-aldrich.com/hydrogen
Organic Hydrogen Storage Media & Linkers for Metal Organic Frameworks (MOFs)
Product Name Prod. No.
1,3,5-Tris(4-carboxyphenyl)benzene ≥98%, ≤20 wt. % solvent 686859
Hexadecahydropyrene 95% 691704
4,4’-Bipiperidine 705845
Tetradecahydro-4,7-phenanthroline 705853
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Materials Issues in Polymer Electrolyte Membrane Fuel Cells
A catalyst is utilized at the anode to promote separation of the
hydrogen’s protons and electrons. The protons travel through a
membrane material to the cathode while the electrons travel via
Lemont, IL 60439
*E-mail: Nancy.Garland@ee.doe.gov Conventional anodes and cathodes are comprised of small
platinum (Pt) catalyst particles (2-5 nm) supported on porous
carbon (Aldrich Prod. No. 205923) as shown in Figure 1.1,2 Such
Introduction electrodes face a number of issues including Pt particle stability,
Fuel cells have the potential to reduce the nation’s energy use especially under automotive duty cycles; carbon support corrosion;
through increased energy conversion efficiency and dependence and insufficient catalytic activity to meet Pt content targets.
on imported petroleum by the use of hydrogen from renewable
resources. The US DOE Fuel Cell subprogram emphasizes
polymer electrolyte membrane (PEM) fuel cells as replacements
for internal combustion engines in light-duty vehicles to support
the goal of reducing oil use in the transportation sector. PEM
fuel cells are the focus for light-duty vehicles because they are
capable of rapid start-up, demonstrate high operating efficiency,
and can operate at low temperatures.
The program also supports fuel cells for stationary power,
portable power, and auxiliary power applications where earlier
market entry would assist in the development of a fuel cell
manufacturing and supplier base. The technical focus is on
developing materials and components that enable fuel cells to
achieve the fuel cell subprogram objectives, primarily related
to system cost and durability.
For transportation applications, the performance and cost
of a fuel cell vehicle must be comparable or superior to
today’s gasoline vehicles to achieve widespread penetration
into the market and achieve the desired reduction in Figure 1. Illustration of polymer electrolyte membrane fuel cell operating on
petroleum consumption. By translating vehicle performance hydrogen fuel and oxygen from air.
requirements into fuel cell system needs, DOE has defined
Most of the current research on catalysts for PEM fuel cells is
technical targets for 2010 and 2015. These targets are based
focused on the cathode. The general objectives are: to reduce
on competitiveness with current internal combustion engine
Pt content (and thereby cost); to obtain higher catalytic activity
vehicles in terms of vehicle performance and cost, while
than the standard carbon-supported platinum catalysts; and
providing improvements in efficiency of a factor of 2.5 to 3.
to increase the durability of the catalyst/support system,
The overall system targets are: a 60% peak-efficient, durable,
especially during transients and shutdown/startup cycles.3
direct hydrogen fuel cell power system for transportation at a
cost of $45/kW by 2010 and $30/kW by 2015. The state-of-the-art membrane material is based on
perfluorosulfonic acid that depends on the presence of water
DOE’s approach to achieving these technical and cost targets
in the membrane to conduct the protons. The primary deficits
is to improve existing materials and to identify and qualify
of this material are: loss of conductivity at temperatures above
new materials.
100°C and low humidity; insufficient conductivity at low
temperature (–20°C); insufficient mechanical integrity; during
Fuel Cell Description humidity cycles which cause swelling and shrinking; and
chemical stability. Most DOE membrane research is focused
A fuel cell electrocatalytically generates electricity in a manner
on durability and operation at temperatures above 100°C.
analogous to batteries. However, in a fuel cell the electrodes
Both mechanical and chemical durability are being addressed
are not consumed. Rather, a fuel cell consumes fuel (hydrogen
by physical reinforcement and by changes to the ionomer
for PEM fuel cells) at the anode and oxygen from the air at
chemistry and structure and its end groups, respectively.
the cathode.
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Fuel Cell Targets Table 2. Membrane Targets
To help achieve the high-level goals mentioned above and Characteristica Units 2010 2015
to guide component researchers, DOE has also developed Oxygen crossoverb mA/cm2 2 2
targets for individual PEM fuel cell components. Targets for the Hydrogen crossover b
mA/cm 2
2 2
electrocatalyst, membrane, and membrane electrode assembly
Polymer Electrolyte
Membrane Fuel Cells
86 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Technology Development demonstrated a Young’s modulus exceeding 500 MPa at 25°C
and 30%RH, compared to ~200 MPa for an unreinforced
Approach and Status membrane. Similarly, higher proportional limit stress and higher
break stress at all temperature and humidity levels, as well as
Electrocatalyst and Support Research (Figure 2) lower dimensional changes due to swelling were observed for
Research efforts here are centered on increasing cathode the reinforced membrane.16 Single cells containing a stabilized
Figure 2. TEM image of a Pt/C electrode. The smaller, darker particles are the Summary
Pt catalysts and the larger spherical particles are the carbon supports. Ionomer
surrounding the catalyst and support provides a pathway for proton transfer. Fuel cell systems are already being demonstrated in prototype
vehicles, consumer electronics devices, materials handling
An example of a non-carbon catalyst support is 3M’s equipment, and backup power and other stationary
nanostructured thin film polymer whisker concept7 as well applications. Finally, the performance of the fuel cell system
as titanium oxide (Aldrich Prod. No. 14021) and tungsten must be comparable in all respects to incumbent technologies,
carbide (Aldrich Prod. No. 241881).8,9 whether it is an internal combustion engine powering an
Non-PGM catalysts are based on metal porphyrins and other automobile, a diesel generator set providing distributed
metal-C-N heterocyclic ligand complexes, metal free C-N generation, or a lithium-ion battery powering a consumer
heterocyclic systems, nitrogen-doped carbon nanostructures electronics device. While many promising new approaches
and their composites, and metal chalcogenides.10-12 have been developed in the last two years, technical
challenges remain to achieve the upcoming 2010 and the
Major progress in the electrocatalyst and support area has
ultimate 2015 system targets.
been made. Several researchers have demonstrated Pt alloy
compositions with significantly higher performance and References:
durability than Pt alone.10,13,14 A total Pt loading of 0.4 mg (1) More, K. 2008 DOE Hydrogen Program Review, Washington, D.C., June 9-13,
Pt/cm2 has been demonstrated in a single cell for more 2008. (2) More, K. 2007 DOE Hydrogen Program Review, Washington, D.C., May
14-19, 2007. (3) Yu, P.T., Kocha, S., Paine, L., Gu, W, Wagner, F., AIChE Spring National
than 7,300 hours with voltage cycling, surpassing the 2015 Meeting: Conference Proceedings, April 25-29, 2004. Publication: New York, NY:
durability targets.14 Catalysts with the required activity and American Institute of Chemical Engineers, - Standard No: ISBN: 0816909423 (CD-ROM).
durability still need to be developed. (4) US Department of Energy. Information Resources. http://www.eere.energy.gov/
hydrogenandfuelcells/mypp (accessed Oct 24, 2008). (5) Motupally, S., International
Workshop on Degradation Issues of Fuel Cells, September 2007, Crete, Greece.
Membrane Research (6) Payne, T.L., Benjamin, T.G., Garland, N.L., Kopasz, J.P. ECS Trans., 2008, 16, in press.
There are two major areas of focus: durability and performance (7) Debe, M. 2007 DOE Hydrogen Program Review, Washington, D.C., May 14-18, 2007.
(8) Viswanathan, V. 2008 DOE Hydrogen Program Review, Washington, D.C., June 9-13,
over the entire range of automotive operating conditions. 2008. (9) Merzougui, B., Carpenter, M.K., Swathirajan, S., U.S. Patent 20060257719,
In traditional PFSA membranes, conductivity increases with 2006. (10) Protsailo, L. in DOE Hydrogen Program 2005 Annual Progress Report, p.
739, U.S. Department of Energy, Washington D.C., 2005. (11) Shao, Y., Sui, J., Yin, G.,
increasing sulfonic acid group concentration, however this and Gao, Y., Appl. Catal. B-Environ., 2008, 79, 89. (12) Zhang, L., Zhang, J., Wilkinson,
leads to increased swelling and decreases membrane stability. D.P., Wang, H., J. Power Sources, 2006, 156, 171. (13) Zelenay, P. 2008 DOE Hydrogen
Program Review, Washington, D.C., June 9-13, 2008. (14) Debe, M. 2008 DOE Hydrogen
Significant advances in membrane stability have been made Program Review, Washington, D.C., June 9-13, 2008. (15) Schwiebert, K.E., Raiford,
in the recent past. Chemical stability has been increased K.G., Escobedo, G., Nagarajan, G., ECS Trans., 2006, 1, 303. (16) Tang, Y., Kusoglu, A.,
by decreasing the number of carboxylic end groups in the Karlsson, A.M., Santare, M.H., Cleghorn, S., Johnson, W. B., J. Power Sources, 2008,
175, 817. (17) Mittelsteadt, C. 2008 DOE Hydrogen Program Review, Washington, D.C.,
polymer, while mechanical stability has been increased through June 9-13, 2008. (18) Escobedo, G., Barton, K., Choudhury, B., Curtin, D., Perry, R. 2007
use of inert support materials, such as PTFE (Aldrich Prod. Fuel Cell Seminar & Exposition, San Antonio, TX, p. 20, 2007. (19) Martin, K.E., Garland,
N.L., Kopasz, J.P., McMurphy, K.W. 236th ACS National Meeting, Philadelphia, PA,
Nos. 430935, 430943, 468096, 468118, 182478), polysulfone August 17-21, 2008. (20) Fenton, J. 2008 DOE Hydrogen Program Review, Washington,
(Aldrich Prod. Nos. 428302, 182443) or polyimide D.C., June 9-13, 2008.
(Aldrich Prod. No. 23817).15-17 Reinforced membranes have
For questions, product data, or new product suggestions, please contact Aldrich Materials Science at matsci@sial.com. 87
Catalyst Materials for PEM Fuel Cells
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Platinum on activated charcoal 10% Pt basis (based on dry substance) activated charcoal support, 80983-1G
moistened with water (H2O ~50%) 80983-5G
99.9+% trace metals basis, fuel cell grade powder, surface area 25-34 m2/g 520780-1G
520780-5G
99.9+% trace metals basis powder, surface area 27-36 m2/g 520799-1G
520799-5G
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Membrane Materials for PEM Fuel Cells
For a complete list of membrane materials including silica-composite membranes, please visit sigma-aldrich.com/membranes.
Membranes
Nafion perfluorinated membrane, reinforced with A ‘bimembrane’ with one layer having equivalent weight L × W 12 × 12 in. 565067-1EA
poly(tetrafluoroethylene) fiber 1,500 and thickness 0.001in., and the other layer having thickness 0.006 in.
equivalent weight 1,000 and thickness 0.005in.
Nafion perfluorinated membrane, reinforced with eq. wt. 1,100 L × W 12 × 12 in. 563994-1EA
poly(tetrafluoroethylene) fiber thickness 0.007 in.
Nafion perfluorinated membrane, reinforced with eq. wt. 1,050 L × W 12 × 12 in. 564664-1EA
poly(tetrafluoroethylene) fiber thickness 0.005 in.
Nafion perfluorinated resin 5 wt. % in mixture of lower aliphatic alcohols eq. wt. 1,000 527084-25ML
and water, water 45% 527084-100ML
Nafion perfluorinated resin 5 wt. % in mixture of lower aliphatic alcohols eq. wt. 1,100 510211-25ML
and water, water 45% 510211-100ML
Nafion perfluorinated resin 20 wt. % in lower aliphatic alcohols and water, - 663492-25ML
water 34% 663492-100ML
Nafion perfluorinated resin 20 wt. % in mixture of lower aliphatic alcohols eq. wt. 1,100 527122-25ML
and water, water 20% 527122-100ML
Nafion perfluorinated resin 5 wt. % in lower aliphatic alcohols and water, eq. wt. 1,100 274704-25ML
water 15-20% 274704-100ML
274704-500ML
Nafion perfluorinated resin, aqueous dispersion 10 wt. % in H2O eq. wt. 1,000 527114-25ML
527114-100ML
Nafion perfluorinated resin, aqueous dispersion 10 wt. % in H2O eq. wt. 1,100 527106-25ML
527106-100ML
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Electrode Materials for Solid Oxide Fuel Cells (SOFC)
For a complete list of electrode materials please visit sigma-aldrich.com/fuelcell.
Anode Materials
Polymer Electrolyte
Membrane Fuel Cells
Nickel oxide - Cerium samarium oxide NiO/SDC Cerium Samarium Oxide 40 wt. % 704210-10G
for coatings Nickel Oxide 60 wt. %
Cathode Materials
Name Description Composition Cat. No.
Cerium(IV) oxide-calcium doped calcium 10 mol % as dopant <100 nm surface area 100-120 m2/g 572403-25G
Cerium(IV) oxide-gadolinium doped gadolinium 20 mol % as dopant <100 nm surface area >100 m2/g 572357-25G
Cerium(IV) oxide-samaria doped samaria 15 mol % as dopant <100 nm surface area 100-120 m2/g 572365-25G
Cerium(IV) oxide-yttria doped yttria 15 mol % as dopant <100 nm surface area 100-120 m2/g 572381-25G
Zirconium(IV) oxide-yttria stabilized Y2O3 0-10% as stabilizer <100 nm (BET) BET surf. area 40-60 m2/g 544779-5G
544779-25G
90 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Interactive Periodic Table
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Polymer-based Materials for Printed Electronics:
Enabling High Efficiency Solar Power and Lighting
The display industry has already begun to employ OLED
for Printed Electronics
Polymer-based Materials
92 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Materials for Printed Electronics 30
Polymer Semiconductors 25
Plextronics’ Plexcore® technology platform is comprised of
semiconducting polymers and solution-processable inks that
2.0
1
80000 1.9 A B C D
1.8 Batch
70000
1.7 Figure 4. OPV efficency for P3HT:PCBM. Plexcore OS 2100 example batch
Avg. M n (GPC)
1.5
50000 1.4
Mn (GPC) 1.3
40000 PDI
1.2
30000 1.1
1.0
A B C D
Batch
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The PNJ solar cell consists of an active layer that is a composite highest occupied molecular orbital (HOMO) level of the p-type
of a p-type (electron donating) light harvesting polymer and an semiconductor. Jsc is a measure of the maximum current density
n-type (electron accepting) semiconductor. Figure 5 shows the that could, in practice, be produced by a cell. It is principally
basic device architecture for an OPV cell comprising a photoactive influenced by the band-gap of the light-harvesting organic
layer. For the purposes of this discussion, the photoactive layer is materials in an OPV device. Power In is typically defined as
based on a blend of Plexcore® OS 2100 (P3HT) and [6,6] phenyl 1000 W/m2, which is equivalent to 1 sun (AM 1.5G). Conjugated
for Printed Electronics
Polymer-based Materials
C61 butyric acid methyl ester (PCBM), deposited on top of an polymers have strong, broad light absorption and most are
organic hole transport layer (HTL), that planarizes the transparent semiconducting materials that exhibit a range of band gaps. FF is
anode, and also facilitates the collection of positive charge a figure of merit for how much power the cell can output versus
carriers (holes) from the light-harvesting layer. These the ideal power defined by the Jsc and Voc product. Many material
photo-generated charges migrate to the collecting electrodes properties, such as nanoscale morphology and charge carrier
through this intimately mixed interpenetrating network. Examples mobilities of the electrons and holes, affect the photophysical
of the best performing polymer organic cells have been based processes in an OPV cell. When optimized, this process leads to
on the P3HT:PCBM junction.12-15 The system is characterized by efficient charge separation and extraction; and FF is a composite
phase-separation of the p- and n-components of the composite parameter that includes contributions from all of these processes.
into discrete manifolds beneficial for charge transport and exciton Achieving > 7% cell efficiencies will require tailoring of all of
dissociation. The I-V data in Figure 6 represents a these properties in combination. In addition, advancements
single-junction OPV cell that was certified by the National in packaging, device architecture, and electrode engineering
Renewable Energy Laboratory (NREL) at 3.39% efficiency; a will contribute to the best performance of organic solar cells
typical performance in a P3HT:PCBM system. for commercial applications. Plextronics is actively pursuing
development of higher efficiencies with the Plexcore PV platform.
NREL-certified efficiencies in excess of 5% have already been
achieved with improvements in materials and morphology.16
Cathode ––Ca/Al
Cathode Ca/Al
η = VOC * JSC * FF / Power In
Photoactive
Photoactive Layer
Layer –– Plexcore
Plexcore OS
OS2100:
2100:PCBM
PCBM
Power
Output Hole
HoleTransport Layer(HTL)
Transport Layer (HTL) Table 1. Factors Influencing OPV Efficiency
TransparentAnode
Transparent Anode–-ITO
ITO Drivers of Efficiency Material and Ink Properties
VOC(V) • Molecular Energies
Transparent Substrate
Transparent Substrate Open Circuit Voltage • LUMOn-type–HOMOp-type
JSC(mA/cm2) • Eg (Band gap)
Short Circuit Current Density • α (Absorption coefficient)
Sunlight • Charge Extraction
Absorbed
FF • p/n charge carrier mobility balance
Figure 5. OPV device stack. Fill Factor • Bulk Heterojunction Morphology
ITO: Indium Tin Oxide
PCBM: [6,6] phenyl C61 butyric acid methyl ester
Ca/Al: Calcium/Aluminium Polymer Conductors
Regioselective polymerization techniques used for synthesizing
1.0
P3HT allow fine control of the absolute structure of the
polymeric materials which support a variety of functionalities,
0.8
thus enabling a greatly expanded platform for polymer design.17
For example, Plextronics has developed an inherently doped
0.6 VOC = 0.5956 V sulfonated solution of Poly(thiophene-3-[2-(2-methoxyethoxy)
ISC = 0.88871 mA
Current (mA)
JSC = 9.3460 mA/cm2 ethoxy]-2,5-diyl) (see Figure 7). When combined with a matrix
0.4
Fill Factor = 60.87 % polymer and other additives in a solvent system, this ink
formulation functions as an effective hole injection layer (HIL)
0.2 Imax = 0.75536 mA
for OLED devices18 and as a hole transport layer (HTL) for OPV
Vmax = 0.4265 V
Pmax = 0.32216 mW devices. Plextronics provides 2% concentration solutions for
0.0 application as an HIL - Plexcore OC 1100 (Aldrich Prod. No.
Efficiency = 3.39 %
699799) and Plexcore® OC 1200 (Aldrich Prod. No. 699780).
-0.2
-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6
OCH3
Voltage (V)
O
Figure 6. NREL certified I-V curve for Plexcore OS 2100:PCBM OPV cell. The HO O
S O
device temperature is 27.0 ± 3.0 °C, the device area is 0.095 cm2 and the
irradiance is 1000.0 W/m2. O
S
Several material parameters directly impact short circuit current S x y n
density (Jsc), open circuit voltage (Voc), fill factor (FF), and O O
ultimately the efficiency (η) of an OPV device, as depicted in OCH3
Table 1. Voc is a measure of cell potential and typically scales
Figure 7. Poly(thiophene-3-[2-(2-methoxyethoxy)ethoxy]-2,5-diyl),
with the difference between lowest unoccupied molecular sulfonated (Aldrich Prod. Nos. 699799, 699780)
orbital (LUMO) level of the n-type semiconductor and the
94 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Some of the performance benefits that Plexcore® OC offers as a) 103
an HIL include:
Reduced acidity, preventing anode degradation and ensuring
improved device lifetime. 101
2
Cathode –– Ca/Al
Cathode Ca/Al
0
Electron
ElectronTransport Layer(ETL)
Transport Layer (ETL) – Alq
– Alq3 3
10-2 10-1 100 101 102 103
Hole
HoleBlocking
Blocking Layer (HBL)– -BCP
Layer (HBL) BCP
Power Current Density (mA/cm ) 2
Emissive
EmissiveLayer
Layer(EML)
(EML) ––CBP:Ir(ppy)
CBP:Ir(ppy) 3
Input 3
Hole
HoleTransport
TransportLayer
Layer (HTL) - NPB
(HTL) -NPB Figure 9. (a) J-V curve; (b) efficiency vs. current density for a green PHOLED
with device architecture shown in Figure 8.
Hole
HoleInjection
InjectionLayer
Layer (HIL)
(HIL) – –Plexcore
PlexcoreOC
OC
Transparent Substrate
Transparent Substrate
Light Emission
Light Emission
For questions, product data, or new product suggestions, please contact Aldrich Materials Science at matsci@sial.com. 95
One of the critical aspects for a SSL luminaire is the ability to Conclusion
achieve high brightness at low operating voltage. Figure 10
shows the power efficiency of the device shown on the Printed Electronics could dictate the future of electronics and
previous page as a function of operating brightness. The the energy industry by employing OPV and OLED devices in
presence of the HIL reduces injection barriers leading to various applications, such as solar modules and luminaires
lower operating voltage and improved efficacy (Lumen/Watt) based on solid state lighting. In addition, applications that
for Printed Electronics
Polymer-based Materials
at higher brightness. Maintaining higher efficacy at higher integrate light and power may enable a new market segment
brightness ensures more light output for lower cost. It is for economical and environmentally friendly products.
expected that SSL products enabled by Plexcore® OC will help Plextronics’ polymer products such as Plexcore OS have the
realize the energy efficient lighting of the future. potential to yield high-efficiency OPV devices to serve the
renewable energy market. Also, Plexcore OC ink systems that
16 have already demonstrated exceptional performance in OLED
Power Efficacy vs Efficiency devices, can enable SSL products and help meet the low
14 energy consumption demands of the lighting market.
12 References:
10 (2) Navigant, DOE, Lighting Research & Development Report 2006. (3) Sony Corporation.
www.sonystyle.com (accessed Oct 24, 2008). (4) Gong, X. M. D., Moses, D., Heeger, A.
J., Liu, S., Jen, K. Appl. Phys. Lett. 2003, 83, 183. (5) Chen, S., Wang, C. Appl. Phys. Lett.
8 2005, 85, 765. (6) Kraft, A., Grimsdale, A. C., Holmes, A. B. Angew. Chem. Int. Ed. 1998,
37, 402. (7) Fthenakis, V. M. In European Materials Research Society Spring Meeting,
6 Nice, France, May 29-June 2. 2006. (8) McCullough, R. D., Lowe, R. S. J. Chem. Soc.,
Chem. Commun 1992, 70. (9) McCullough, R. D., Lowe, R. S., Jayaraman, M., Anderson,
D. L. J. Org. Chem. 1993, 58, 904. (10) McCullough, R. D., Lowe, R. S., Jayaraman, M.,
4 Ewbank, P. C., Anderson, D. L., Tristam-Nagle, S. Synth. Met. 1993, 55, 1198.
(11) McCullough, R. D., Williams, S. P., Tristam-Nagle, S., Jayaraman, M., Ewbank, P. C.,
Miller, L. Synth. Met. 1995, 67, 279. (12) Kazmerski, L. L. J. Electron Spectrosc. Relat.
2 Phenom. 2006, 150, 105. (13) Li, G., Shrotriya, V., Huang, J., Yao, Y.; Moriarty, T., Emery,
K., Yang, Y. Nature Materials 2005, 4, 864. (14) Ma, W.,Yang, C., Gong, X., Lee, K.;
0 Heeger, A. J. Adv. Funct. Mater. 2005, 15, 1617. (15) Reyes-Reyes, M., Kim, K., Carroll,
D. L. Appl. Phys. Lett. 2005, 87, 083506. (16) Green, M. A., Emery, K., Hishikawa, Y.,
0.1 1 10 100 1000 10000
Warta, W. Prog. Photovolt: Res. Appl. 2008, 16, 435. (17) Lowe, R. S., Khersonsky, S. M.,
McCullough, R. D. Adv. Mater. 1999, 11, 250. (18) Shao, Y., Sui, J., Yin, G., and Gao, Y.,
Efficiency (cd/m2) Appl. Catal. B-Environ., 2008, 79, 89.
Figure 10. Power efficiency of a PHOLED utilizing Plexcore OC as the hole
injection layer (HIL). As observed, the loss in power efficacy is minimized up
to 1,000 units of brightness.
High molecular weight; ultra-high purity P3HT CH2(CH2)4CH3 99.995% trace metals basis, >98% average Mn 45,000‑65,000 698997-250MG
optimized for use in organic photovoltaics (OPV) head-to-tail regioregular (HNMR) 698997-1G
research and devices. S regioregular
n
High purity P3HT for organic electronics research. CH2(CH2)4CH3 99.995% trace metals basis, >95% average Mn 25,000‑35,000 698989-250MG
Material optimized for use in active layers of OFETs head-to-tail regioregular (HNMR) 698989-1G
and other devices. S regioregular
n
O ≥99.99% trace metals basis 2% in ethylene glycol monobutyl ether/water, 3:2 699780-25ML
HO S O OCH3
O O ≥99.99% trace metals basis 2% in 1,2-propanediol/isopropanol 699799-25ML
S
S
x y
O
O OCH3
96 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Electron Acceptors
For a complete list of electron acceptors and to view the PCBM library, please visit sigma-aldrich.com/oel.
[6.6] Diphenyl C62 bis(butyric acid methyl ester)(mixture of isomers) 99.5% 704326-100MG
OCH3
N C C N
F F
N C C N
Tris[1-phenylisoquinoline-C ,N]iridium(III),
2
99% 324 / 615 nm in tetrahydrofuran 688118-250MG
sublimed grade
Ir
N
Tris[2-phenylpyridinato-C ,N]iridium(III),
2
- 305 / 507 nm in chloroform 694924-250MG
sublimed grade
Ir
N
For questions, product data, or new product suggestions, please contact Aldrich Materials Science at matsci@sial.com. 97
Organic Photovoltaic Materials: Indium Tin Oxide/Indium Oxide
For a complete list of ITOs please visit sigma-aldrich.com/oel.
Indium tin oxide coated aluminosilicate glass slide 5-15 Ω/sq 576360-10PAK
576360-25PAK
Indium(III) oxide particle size <100 nm (BET) 99.9% trace metals basis 632317-5G
632317-25G
Indium tin oxide −325 mesh 99.99+% trace metals basis 494682-25G
494682-100G
Indium tin oxide, dispersion particle size <100 nm (DLS) 30 wt. % in isopropanol 700460-25G
700460-100G
Light-Emitting Polymers
Sigma-Aldrich® offers a wide variety of products for use in organic
m
S S
n
light-emitting diodes. Our product offerings include, but are not limited to:
CH3(CH2)6CH2 CH2(CH2)6CH3
F8T2 (Aldrich Prod. No. 685070) • Electron Transport Materials • Light-Emitting Polymers
λem 497 nm in chloroform
• Hole Transport Materials • Polymer Hole and Transport Materials
• Hole Injection Materials
n
C8H17 C8H17 N
S
N
Make Sigma-Aldrich Materials Science your one-stop source for organic
F8BT (Aldrich Prod. No 698687) electronic materials. Visit sigma-aldrich.com/oel for a full listing of products
λem 515-535 nm in chloroform and literature pertaining to this field of study.
sigma-aldrich.com
98 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Ruthenium-Based Dyes for Dye Solar Cells
Dye solar cells (DSCs) are third generation solar cells
Ruthenium Dyes
with the promise of high efficiency combined with
low production costs. While present day DSCs provide O OH
HO N
further improvement is envisaged through optimized N NCS
Ru
materials and novel cell and module architectures. N NCS
HO N
The amphiphilic dyes display several advantages over the N-3 dye:
O O
O O
3) increased stability of solar cells towards water-induced dye desorption
Aldrich Prod. No. 703214
4) o
xidation potential of these complexes is cathodically shifted compared N-719 dye: Modification of N-3
to increase cell voltage and is the most
to that of the N-3 sensitizer, which increases the reversibility of the common high performance dye.
ruthenium III/II couple, leading to enhanced stability. Molecular Formula: C58H86N8O8RuS2,
Formula Weight: 1188.55
CH2(CH2)7CH3
CH3(CH2)7CH2
N
N NCS
Ru
N NCS
HO N
O OH
sigma-aldrich.com
U.S. Department of Energy’s Materials Research for
Advanced Lithium Ion Batteries
Development Goals and Approach
Lithium Ion Batteries
Advanced
100 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Scaled specific
energy (Wh/kg)
e– e–
200
BAlloy/
mmpz0
Anode Cathode
180 IHigh
jhi!VW !TMO
UN P
60
Li+
40
20
Figure 2. Schematic showing operation of Li ion cell
0
2008
2010
2012
2014
Anodes
2016
The most popular material used as a host for lithium in the
Figure 1. Energy gains from materials research anode is graphitic carbon, usually supported on a copper
substrate current collector. Other carbons, including both soft
and hard carbons, have been used but graphitic carbons offer
Materials Research the best balance of reversible capacity and cycle life. When
Background fully charged, all carbon materials approach to within 50 mV
of the reversible lithium potential.
Lithium metal is an attractive material for batteries due to
its lightweight, high voltage, high electrochemical capacity As an alternative to graphite, the DOE is investigating
per unit weight, and good conductivity (Aldrich Prod. Nos. lithium alloys, including Li-Si, Li-Sn, and Li-Sb systems, and
220914, 62360, 62361). Development of high-energy primary intermetallic electrodes, such as CuSn, Cu6Sn6, and CoCu5Sn5.
(non-rechargeable) batteries using lithium anodes started in These materials can provide an electrochemical potential
the 1960’s and these batteries were first used in the 1970’s for only a few hundred mV above that of metallic lithium and a
military applications. Today these batteries are used in a variety capacity of at least 400 mAh/g (>1500 mAh/ml).3 Alloys of
of applications, including calculators, watches, cameras, lithium with metals and/or intermetallic compounds, however,
memory backup circuits, etc. experience severe volume expansion/contraction during the
charging (alloying), and discharging (de-alloying processes).
Development of rechargeable batteries with lithium metal
When used in electrodes in Li-ion cells, these large volume
anodes started in the early 1980’s. A number of rechargeable
changes lead to mechanical pulverization, loss of electronic
battery chemistries were developed, but due to persistent life
contact between particles, and poor cycling. Approaches to
and safety problems none achieved commercial success. These
alleviating this problem include using nanosized particles
problems arise from lithium’s reactivity with the electrolyte and its
and/or including the alloying metal particles in a matrix phase
tendency to form mossy and sometimes dendritic deposits when
to buffer the volume changes. These approaches are showing
recharged. These deposits lead to cell failures when the dendrites
some improvements in experimental cells.
penetrate the separator and cause internal short circuits.
Metal oxides, such as lithium titanate (Aldrich Prod. No.
These problems were circumvented with the introduction
400939), that were previously investigated as positive electrode
of lithium-ion batteries (sometimes abbreviated Li-ion) in
materials, have recently attracted attention as negative
the early 1990’s. These batteries contain no metallic lithium
electrodes. The DOE program has studied the electrochemical
but instead rely on the transfer of lithium ions between the
and thermal properties of the Li4Ti5O12 spinel4 and is now
anode (negative electrode) and cathode (positive electrode),
focused on LiTiO2. These materials generally have high reversible
as illustrated in Figure 2. When the cell is charged, lithium
capacity (up to 600 mAh/g) and high lithium diffusion rates,
ions are inserted or intercalated into the interstitial space
though their potential against lithium is in the order of 1.0-1.5V.
between the atomic layers of the anode and during discharge
This results in a reduction of cell voltage and energy compared
the lithium is extracted from the anode and inserted into
to cells using a carbonaceous anode with the same cathode and
the cathode.2 The lithium ions are transported between
electrolyte. Moreover, these materials are extremely stable and
the electrodes in an electrolyte comprised of a lithium salt
can lead to battery systems that are inherently reliable and safe
dissolved in an aprotic organic solvent. A typical electrolyte,
compared to other Li-Ion battery technologies. A new stable,
widely used in the DOE programs, consists of LiPF6
nano-phase form of lithium titanate was developed that can
(Aldrich Prod. No. 450227) dissolved in a mixture of ethylene
provide an increase in the energy density of the cell and allow
carbonate (EC, Aldrich Prod. No. 676802) and ethyl methyl
for easier industrial processing.
carbonate (EMC). A separator layer, usually a microporous
polyolefin film, such as Celgard® 2500, a 25 µm polypropylene
membrane, is placed between the electrodes to prevent
electrical shorts while allowing flow of ionic current.
For questions, product data, or new product suggestions, please contact Aldrich Materials Science at matsci@sial.com. 101
Cathodes Research is also underway to understand the fundamental
The majority of Li-ion batteries on the market today utilize characteristics of Li+ transport to enable higher rate, more stable
lithium cobalt oxide (LiCoO2, Aldrich Prod. No. 442704) as electrodes and electrolytes to be developed. First principles
the positive electrode material. LiCoO2 offers good electrical quantum chemistry calculations are being used to develop
performance, is easily prepared, and is relatively insensitive to atomic force fields, which are then used in molecular dynamics
process variations and moisture. It may not, however, have simulations to investigate charge transport, bulk, and interfacial
Lithium Ion Batteries
Advanced
the balance of properties needed to meet the stringent life, resistance. Among other findings, it has been discovered that
abuse tolerance, and cost targets of vehicle applications. As a the predicted charge transfer resistance increased over one
consequence, DOE is evaluating several candidate lithiated metal order of magnitude when the temperature was decreased from
oxide cathode materials that offer improvements over LiCoO2. room temperature to below 0°C, as observed experimentally,
and that the main contribution to this increased resistance is the
Manganese oxides are inexpensive, environmentally benign, mean free energy associated with Li+ desolvation.
have excellent safety characteristics, and inherently high rate
capability making them ideal candidates for advanced cathodes. Research is also continuing to find an electrolyte that will permit
Work is underway to improve the performance of Mn-based the use of lithium metal as an anode since it offers the highest
electrodes by developing a firm scientific understanding of the theoretical energy density of any known form of lithium. One
factors that control or influence electrochemical performance and approach being investigated is the development of a composite
utilize this to design and develop improved compositions. One polymer electrolyte (with a hard non-conducting part that
approach being taken is cationic and anionic substitutions, e.g., inhibits dendrites and second highly conducting portion) that
substituting Li, Ni and/or Co for Mn and F for O. For example, mitigates the threat of dendritic growths that can short the
a substituted spinel, LiMn1.8Li0.1Ni0.1O3.8F0.2, exhibited improved cell. This concept, illustrated in Figure 3, holds the promise of
electrochemical performance compared to a conventional enabling lithium rechargeable cells with two to three times the
LiMn2O4 cathode (Aldrich Prod. No. 482277). Another approach energy density of current lithium ion cells.
is the development of high-voltage, high-capacity electrodes
with two-component integrated structures, e.g., ‘layered-layered’
xLi2M’O3•(1-x)LiMO2 and ‘layered-spinel’ xLi2M’O3•(1-x)LiM2O4
electrodes in which M’ is predominantly Mn and M is selected
mainly from Mn, Ni and Co. In these composite structures,
one layer is electrochemically active while the other is an
electrochemically inactive, stabilizing component.
DOE is also investigating ways to improve the performance
of LiFePO4 cathodes. This effort is focused on developing
composite cathodes with electrochemically-active polymers.
The purpose is to replace electrochemically inactive cathode
components, such as binders and conductive carbons, with
electroactive materials that will contribute to the cell’s energy Figure 3. Schematic of composite electrolyte
storage capacity. The investigations include fabricating and
evaluating carbon-coated LiFePO4/polymer composite cathodes
with polypyrrole (PPy, polymerized from a pyrrole monomer
Summary
with sodium p-toluenesulfonate dopant and (NH4)2S2O8 The materials research and development activities described
(Aldrich Prod. No. 215589) as oxidizer in deionized water), above are part of a comprehensive DOE effort to develop the
polyaniline (PAn, synthesized from aniline with (NH4)2S2O8 as advanced batteries needed to commercialize plug-in hybrid
oxidizer in water), and polytriphenylamine (PTPA, obtained by electric vehicles. The objective of this research is to give battery
polymerization of triphenylamine monomer with FeCl3 developers a range of materials for anodes, cathodes, and
(Aldrich Prod. No. 236489) as oxidizer in CHCl3 solution). electrolytes that they might choose to incorporate in the cells
Different methods are being used to make these composite and batteries that they are developing. The current battery
cathodes, including direct mixing of LiFePO4 with the polymer development efforts, sponsored by DOE in partnership with
and simultaneous chemical polymerization of PPy or PAn with the USABC, consist of four contracts to address critical issues
LiFePO4 in the precursor solution. of PHEV battery cost and life and incorporate many of the
materials and technologies described above. This wide range
Electrolytes and the Solid Electrolyte of technologies is being explored in order to reduce the
Interphase (SEI) uncertainty of whether cost-competitive batteries with adequate
Most practical electrolyte solvents are not thermodynamically performance and life can be commercialized by 2016.
stable at the low voltage of the negative electrode and a References:
layer of decomposition products form spontaneously on
(1) Ahmad A. Pesaran, et al, “Battery Requirements for Plug-In Hybrid Electric Vehicles -
the carbonaceous anode electrode surface during the first Analysis and Rationale,” Electric Vehicle Symposium 23, Anaheim CA., December 2-5, 2007.
charge. This solid electrolyte interphase (SEI) layer protects the (2) Linden, David and Thomas B. Reddy, Handbook of Batteries, Third Edition, McGraw Hill,
New York, 2002. (3) FY2007 Annual Progress Report for the DOE Energy Storage Research
electrolyte from further decomposition while being ionically and Development Program, January 2008, available at http://www1.eere.energy.gov/
conductive and allowing passage of Li+ ions and is the key to vehiclesandfuels/resources/fcvt_reports.html. (4) FY2005 Annual Progress Report for the DOE
stable battery performance. The dominant species in the SEI Energy Storage Research and Development Program, January 2006, available at
http://www1.eere.energy.gov/vehiclesandfuels/resources/fcvt_reports.html
layer have been identified as lithium alkyl carbonates (ROCO2Li)
and lithium alkoxides (ROLi), and include Li oxalate, Li ethylene
carbonate, and Li ethylene dicarbonate. Additional studies into
the characteristics of the SEI layer and how they are impacted
by cell fabrication and formation conditions are underway.
102 sigma-aldrich.com TO ORDER: Contact your local Sigma-Aldrich office (see back cover), or visit sigma-aldrich.com/matsci.
Select Materials for Battery Applications
For a complete list of battery related materials please visit sigma-aldrich.com/energy.
Electrode Materials
Name Description Cat. No.
99.99+% 496596-113.4G
Lithium, ribbon 99.9% trace metals basis, thickness × W 1.5 × 100 mm 266000-25G
266000-100G
Lithium, wire (in mineral oil) 99.9% trace metals basis, diam. 3.2 mm 220914-25G
220914-100G
Manganese(II) oxide, powder and chunks 99.99+% trace metals basis 431761-1G
431761-10G
For questions, product data, or new product suggestions, please contact Aldrich Materials Science at matsci@sial.com. 103
Electrolyte Materials
Name Formula Form Purity Cat. No.
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Solvents
Name Structure Description Cat. No.
≥99% B103608-25G
≥99% 256382-1L
256382-2L
≥99.5%, GC 38569-500ML-F
38569-1L-F
99% 184497-500ML
184497-1L
184497-4L
Mn ~19900 81628-100MG
Mp ~20900
Mw ~20500
Mn ~75500 81635-100MG
Mp ~79500
Mw ~79100
99.7% 414220-1L
414220-2L
≥99% 230464-5ML
230464-100ML
230464-1L
≥99% 320544-1L
320544-2.5L
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and its affiliate Sigma-Aldrich Biotechnology, L.P. Sigma brand products are sold through Sigma-Aldrich, Inc. Sigma-Aldrich, Inc. warrants that its products conform to the information
contained in this and other Sigma-Aldrich publications. Purchaser must determine the suitability of the product(s) for their particular use. Additional terms and conditions may apply.
Please see reverse side of the invoice or packing slip. Nafion is a registered trademark of E.I. du Pont de Nemours & Co., Inc. ESCAT is a trademark of Engelhard Corp. Eppendorf is a
registered trademark of Eppendorf-Netheler-Hinz GmbH. Sepharose is a registered trademark of GE Healthcare. Coomassie is a registered trademark of Imperial Chemical Industries LBE
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