Microstructural Limitations in Lithium-Sulfur Battery Performance

Wednesday, 4 October 2017: 16:30
Maryland A (Gaylord National Resort and Convention Center)
A. Mistry and P. P. Mukherjee (Texas A&M University)
Lithium-sulfur batteries present a lucrative option in the beyond lithium-ion chemistry category due to higher theoretical specific capacity (e.g. 1675 mAh/g of sulfur) compared to Li-ion batteries. However, experimental evidence suggests that typical Li-S cells exhibit reduced capacity even for the first discharge over a wide range of operating rates. The electrochemical operation of Li-S batteries is complex having its roots in both materials as well as electrode microstructural limitations. Transport in the liquid electrolyte progressively evolves during operation with disparate reduction speciation. The precipitating discharge products, such as Li2S, are electronically insulating, giving rise to local reaction shutdown and may even lead to partial pore blockage. Precipitation in the cathode may also lead to leakage of the electrolyte and equivalent loss of the sulfur active material. This work discusses the implications of the underlying microstructure-transport-electrochemical evolution coupling in the sulfur cathode and resulting influence on the cell performance.