Polymer-based solid-state electrolytes for lithium sulfur batteries

Abstract

Lithium-sulfur (Li-S) batteries offer substantial theoretical energy density gains over Li-ion bat-teries, a crucial factor for transportation electrification. In addition, sulfur is an earth-abundant, inexpensive material obtainable from multiple resources; thus, Li-S batteries are envisioned to provide environmentally sustainable solutions to the growing demand for energy storage. A crit-ical roadblock to the realization of commercial Li-S batteries is the formation of polysulfides and their secondary reactions with liquid organic electrolytes, resulting in low coulombic efficiency for charging and fast self-discharge rates. The realization of solid-state electrolytes for Li-S bat-teries provides potential pathways to address the safety concerns of liquid electrolytes and inhib-it the formation of polysulfides and/or prevent their diffusion into the anode electrode. However, current solid-state electrolytes are limited by low ionic conductivity, inadequate electrode inter-facial compatibility, and restricted electrochemical windows. This review discusses the status of polymer-based electrolytes for Li-S batteries, and outlines current methods for their fabrication, their transport characteristics and ongoing research aimed at overcoming material properties hindering the development of all-solid-state Li-S batteries.