Mechanistic insights into electrolyte decomposition induced by polysulfide migration in large-scale Li–S battery cells

Abstract

Despite their high theoretical energy density, Li–S batteries suffer from polysulfide (PS) migration and electrolyte degradation. Here, we present one of the first integrated operando and ex situ studies in 18650-format Li–S cells, revealing that a sulfur@activated carbon cathode suppresses PS crossover, reduces gas evolution by 35.7-fold, and stabilizes the solid electrolyte interphase (SEI). Multi-technique analysis confirms that cathode architecture is crucial for enabling durable, and scalable Li–S batteries.