Electrolytes for Lithium-Sulfur Batteries

Abstract

One idea is to replace the graphite electrode for the metallic lithium and metal-oxide cathode with a more capacious sulfur electrode. Because of the use of large-surface-area carbons as the host matrix in the cathode composite materials, liquid electrolytes with good wetting properties are required, characterized by low surface tensions and low viscosities. The major disadvantages of concentrated electrolytes are their increased viscosity and lower conductivity and lithium diffusion rate, which influence the battery performance at high current densities. The development of this technology needs to overcome the challenges such as low Li-ion conductivity, poor solid-solid contact, lack of in-depth understanding of sulfur redox chemistry in solid electrolytes, and the choice of techniques to probe in detail the interfacial properties. Starting from the first study on a poly(ethylene oxide) (PEO)-based electrolyte for Li-S cells, several types of solid electrolytes have been investigated.