Enhancing the Stability of Sulfur Cathodes in Li–S Cells via in Situ Formation of a Solid Electrolyte Layer

Enhancing the performance of rechargeable lithium (Li)–sulfur (S) batteries is one of most popular topics in a battery field because of their low cost and high specific energy. However, S experiences dissolution during its electrochemical reactions; hence, maintaining its initial capacity is challenging. Protecting the S cathode with a Li ion conducting layer that acts as a barrier for polysulfide transport is an attractive strategy, but formation of such protective layers typically involves significant effort and cost. Here, we report a facile route to form a conformal solid electrolyte layer on S cathodes in situ using a carbonate solvent. The chemically and mechanically stable and Li ion conducting protective layer is formed by inducing electrolyte reduction and polymerization reactions on the cathode surface. The layer serves as a polysulfide’s barrier, successfully helping to retain S active material in the carbon pores. In addition, it helps to improve the performance of Li anodes.