High-energy lithium-sulfur batteries

December 7, 2012

Topics:

A: Cycling performance of a Li-S battery with and without P2S5. B: Photograph of insoluble Li2S in tetraglyme, the common organic liquid electrolyte for Li-S batteries. Addition of P2S5. (right vial) results in fully dissolved complexes. C: SEM image of a solid-electrolyte interphase (SEI) layer peeled off from the Li anode.

Functional Materials for Energy
High-energy lithium-sulfur batteries.

Phosphorous pentasulfide (P₂S₅) was discovered to be a novel electrolyte additive that can prolong the cycle-life of high-energy lithium-sulfur (Li-S) batteries. With a theoretical energy density of 2600 Wh/kg, which is about 3-5 times higher than that of the lithium-ion batteries, Li_S batteries are the most promising next generation of high-energy batteries for large scale energy storage. The deployment of Li-S batteries is hampered by their poor cyclability due to the so-called polysulfide shuttle phenomenon: The migration of soluble sulfur species in the liquid electrolyte causes undesirable self-discharge, precipitation of lithium sulfide, corrosion of the lithium anode, and a low coulombic efficiency. Here we found that P₂S₅ is able to form complexes with lithium sulfide and lithium polysulfide. These complexes prevent the precipitation of lithium sulfide and passivate the surface of the lithium metal anode to reduce the polysulfide shuttle phenomenon. Li-S batteries with the P₂S₅ additive showed a dramatic increase in cyclability.

For more information, please contact Chengdu Liang, liangcn@ornl.gov

Z. Lin, Z. Liu, W. Fu, N. J. Dudney, and C. Liang, "Phosphorous pentasulfide as a novel additive for high-performance lithium-sulfur batteries," Adv. Funct. Mater. DOI: 10.1002/adfm.201200696, published on-line June 14, 2012.