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

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 <i>operando</i> and <i>ex situ</i> 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.