Novel Solid Electrolyte Based Lithium-Sulfur Batteries

Abstract

This project aims to develop safe, reliable, and low-cost Li-S batteries with high energy density and long cycle life. Two approaches have been used to realize this purpose. One is the adaptation of extremely high-surface-area carbon substrates to confine sulfur in their optimal nano-pores. A superionic conductor has also been developed to further improve the cycle life of the Li-S batteries. The developed Li-S cells demonstrated significantly improved energy density and cycle life. The composite cathodes effectively inhibited the polysulfide shuttle mechanism and provided appropriate elasticity for sulfur lithiation, enabling Li-S cells to retain more than 70% of initial discharge capacity after 300 cycles. Moreover, These cathodes proved to have confined an extremely high loading of sulfur, significantly improving specific energy to more than 300 Wh/kg (on a basis of active cell components). In addition, the Li-S cells are able to operate at high charge/discharge rate (1 C), directly promoting their power density. The proposed project has led to great improvements in energy/power density and cycle life of Li-S batteries. Meanwhile, the low prices of Li-S batteries make them more commercially viable in comparison to lithium ion batteries. This is significant because high energy density, long cycle life and low cost will enable Li-S batteries to power automotive vehicles and public transit systems.