Notes

Lithium–sulfur battery
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Lithium–sulfur battery
specific energy
350 W h/kg demonstrated [1]
500–600 W h/kg achievable [2]
energy density 350 W h/l
Charge/discharge efficiency C/5 nominal; up to 2C
Cycle durability disputed
Nominal cell voltage cell voltage varies nonlinearly in the range 2.5–1.7 during discharge; batteries often packaged for 3V
The lithium–sulfur battery (Li–S battery) is a rechargeable battery with a very high energy density.[3] By virtue of the low atomic weight of lithium and moderate weight of sulfur, Li–S batteries are relatively light; about the density of water. They were demonstrated on the longest and highest-altitude solar-powered airplane flight in August, 2008.[4] Lithium–sulfur batteries may succeed lithium-ion cells because of their higher energy density and the low cost of sulfur.
Contents [hide]
1 Chemistry
1.1 Degradation
2 Safety
3 Recent advances
4 References
5 External links
[edit]Chemistry

The chemical processes in the Li–S cell include lithium dissolution from the anode surface (and incorporation into polysulfides) during discharge, and reverse lithium plating to the nominal anode while charging.[5] This contrasts with conventional lithium-ion cells, where the lithium ions are intercalated in the anode and cathodes, and consequently Li-S allows for a much higher lithium storage density. Polysulfides are reduced on the cathode surface in sequence while the cell is discharging:
S8 → Li2S8 → Li2S6 → Li2S4 → Li2S3
Across a porous diffusion separator, sulfur polymers form at the nominal cathode as the cell charges:
Li2S → Li2S2 → Li2S3 → Li2S4 → Li2S6 → Li2S8 → S8
These reactions are analogous to those in the sodium–sulfur battery.
For experimental purposes most batteries are constructed with a carbon and sulfur cathode and a lithium anode.[6] Sulfur as a raw material has the advantage for mass production that it is very cheap, but it lacks electroconductivity. Sulfur alone being at 5*10−30 S cm−1 at 25°C.[7] The carbon coating on the sulfur then provides the electroconductivity missing from pure sulfur. The solution to this problem is carbon nanofibers. The carbon materials provide an effective electron conduction path and structural integrity. The disadvantage of carbon nanofibres is the high cost.[8]
Each sulfur atom can host two lithium ions. Typically, in lithium-ion batteries, for every host atom, only 0.5–0.7 lithium ions can be accommodated.[9]
[edit]Degradation
One of the primary shortfalls of most Li–S cells is intermediary reactions with the electrolytes. While S and Li2S are relatively insoluble in most electrolytes, many of the intermediary polysulfides are not. The dissolving of LiSn into electrolytes causes irreversible loss of active sulfur material.[10] The majority of research on Lithium-sulfur batteries in 2010 is to improve the choice of electrolytes to minimize this side reaction.
[edit]Safety

Because of the high potential energy density and the nonlinear discharge and charging response of the cell, a microcontroller and other safety circuitry is sometimes used along with voltage regulators to control cell operation and prevent rapid discharge.[11]
[edit]Recent advances

Research conducted at the University of Waterloo has produced Li–S cells with 84% of the theoretical maximum energy density for Li–S that suffer minimal degradation during charge cycling, and thus potentially offering four times the gravimetric energy density of lithium-ion. The team accomplished this through use of a mesoporous carbon cathode, full of deep pits. Sulfur and carbon were milled and heated together, causing the low surface tension sulfur to seep into the pits, with just enough room to expand. The composite was then heated to bake off residual sulfur from the surface. To further trap the polysulfides in the cathode, the surface was functionalized and coated with polyethylene glycol to repel the hydrophobic polysulfides and keep them trapped in the pits. In a "worst case scenario" test using a glyme solvent known for its affinity for dissolving polysulfides, a traditional sulfur cathode lost 96% of its sulfur over 30 cycles, while the new cathode lost only 25%.[12] Researchers at Yi Cui's lab Stanford University in 2011 have also shown ways to improve the durability and capacity of sulfur based cathodes by coating only the insides of disordered carbon nanotubes with sulfur. This prevents lithium polysulfides from coming into contact with the electrolytes. They also used an electrolyte additive that boosted the coulomb efficiency from 85% to over 99%. A specific capacity of 730mAh/g was demonstrated after 150 cycles.[13] This may be combined with anodes based on silicon nanowires to produce batteries with very high energy storage capacity.[14]
[edit]References

^ Sion Power 2007. Power QinetiQ New Release Final Version.pdf. Retrieved 2010-03-24.
^ Kolosnitsyn, V.S.; E.V. Karaseva (2008). "Lithium-sulfur batteries: Problems and solutions". Russian Journal of Electrochemistry (Maik Nauka/Interperiodica/Springer) 44: 506–509. doi:10.1134/s1023193508050029.
^ Moore, Wm. (11 December 2004) "Sion Introduces a Lithium Sulfur Rechargeable Battery" EV World
^ Amos, J. (24 August 2008) "Solar plane makes record flight" BBC News
^ Tudron, F.B., Akridge, J.R., and Puglisi, V.J. (2004) "Lithium-Sulfur Rechargeable Batteries: Characteristics, State of Development, and Applicability to Powering Portable Electronics" (Tucson, AZ: Sion Power)
^ Choi, Y.J.; Kim, K.W. (2008). "Improvement of cycle property of sulfur electrode for lithium/sulfur battery". Journal of Alloys and Compounds (Elsevier Science Sa) 449: 313–316. doi:10.1016/j.jallcom.2006.02.098.
^ Lange's Handbook of Chemistry (third ed.), New York: McGraw-Hillrk |year=1985 |page=3-5 |editor=J.A. Dean
^ Choi, Y.J.; Ahn, J.H. (November 16–20), Effects of carbon coating on the electrochemical properties of sulfur cathode for lithium/sulfur cell, Elsevier Science Bv, pp. 548–552, doi:10.1016/j.jpowsour.2008.02.053
^ Bullis, Kevin (May 22, 2009). "Revisiting Lithium-Sulfur Batteries". Technology Review. Retrieved January 2010.
^ Jeong, S.S.; ect. (June 18–23). "Electrochemical properties of lithium sulfur cells using PEO polymer electrolytes prepared under three different mixing conditions". Journal of Power Sources (Elsevier Science Bv) 174: 745–750. doi:10.1016/j.jpowsour.2007.06.108.
^ Akridge, J.R. (October 2001) "Lithium Sulfur Rechargeable Battery Safety" Battery Power Products & Technology
^ Xiulei Ji, Kyu Tae Lee, and Linda F. Nazar. (17 May 2009) "A highly ordered nanostructured carbon-sulphur cathode for lithium-sulphur batteries." Nature Materials
^ Guangyuan, Zheng; Yuan Yang, Judy J. Cha, Seung Sae Hong, Yi Cui (14 September 2011). Nano Letters: 4462–4467. Bibcode 2011NanoL..11.4462Z. doi:10.1021/nl2027684. http://pubs.acs.org/doi/abs/10.1021/nl2027684.
^ Keller, Sarah Jane (October 4, 2011). "Sulfur in hollow nanofibers overcomes challenges of lithium-ion battery design". Stanford News (Stanford, CA, USA: Stanford University). Retrieved February 18, 2012.
[edit]External links

Energy portal
http://sionpower.com/
http://polyplus.com/lisulfur.html
http://www.oxisenergy.com/
http://en.winston-battery.com/index.php/products/power-battery/category/lsp-battery
[hide] v t e
Galvanic cells
Non-rechargeable:
primary cells
Alkaline battery Aluminium battery Bunsen cell Chromic acid cell Clark cell Daniell cell Dry cell Grove cell Leclanché cell Lithium battery Mercury battery Nickel oxyhydroxide battery Silicon–air battery Silver-oxide battery Weston cell Zamboni pile Zinc–air battery Zinc–carbon battery Zinc–chloride battery

Rechargeable:
secondary cells
Automotive battery Lead–acid battery Lead–acid battery (gel) Lithium–air battery Lithium-ion battery Lithium-ion polymer battery Lithium iron phosphate battery Lithium–sulfur battery Lithium–titanate battery Nanowire battery Nickel–cadmium battery Nickel–hydrogen battery Nickel–iron battery Nickel–lithium battery Nickel–metal hydride battery Low self-discharge NiMH battery Nickel–zinc battery Polysulfide bromide battery Potassium-ion battery Rechargeable alkaline battery Sodium-ion battery Sodium–sulfur battery Vanadium redox battery Zinc–bromine battery Zinc–cerium battery
Kinds of cells
Battery Wet cell Dry cell Concentration cell Flow battery Fuel cell Trough battery Voltaic pile
Parts of cells
Anode Catalyst Cathode Electrolyte Half-cell Ions Salt bridge Semipermeable membrane
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