Using Organosulfur Materials to Solve Critical Challenges Facing Lithium-Sulfur Batteries

Abstract

The high abundance and environmental benignity of sulfur coupled with its high energy density of nearly 2,500 Wh kg-1 render the lithium-sulfur (Li-S) battery technology a sustainable energy storage solution for the future. Unfortunately, in Li-S batteries, the sulfur cathode suffers from poor electronic and ionic conductivity and the notorious polysulfide shuttle effect. Meanwhile, the anode suffers from continuous degradation owing to the high reactivity of Li metal. Organosulfur materials may present a way to overcome these limitations. Organic functional groups bound to sulfur could enhance electronic and ionic conductivity. Limiting the polysulfide order in an organosulfur material can minimize the shuttle effect. Furthermore, organic groups could stabilize the electrolyte-anode interface.Two studies on using organosulfur materials to overcome the challenges of Li-S will be presented. The first study shows a method to rationally design organosulfide polymers that can provide inherent Li-ion conductivity. The enhancement in ionic conductivity results in an improvement in performance under high-rate and high-loading conditions. The application of such materials in flexible Li-S batteries will be showcased. In the second study, a mechanistic understanding of how organosulfide-rich interphase at the Li-metal anode improves the stripping/plating efficiency will be elucidated. By understanding the effect of different functional groups on the efficiency of the anode, a set of design rules for developing organosulfide molecules that generate a stable interface will be proposed.