Roles of Polymerized Anionic Clusters Stimulating for Hydrolysis Deterioration in Li7P3S11

Abstract

The atmospheric hydrolysis reaction in sulfide solid electrolytes (SEs) is destructive to their Li-ion conducting behavior, but a comprehensive understanding of their reaction steps is still lacking. Therefore, here, we studied the atmospheric deterioration of a well-known sulfide SE, Li7P3S11, based on the analogies between the hydrolysis and electrochemical reactions. Through analyzing the change in the S2p binding energy, we found that the anionic structures of both air-exposed and delithiated sulfides were altered owing to Li-ion loss. Considering the high diffusivity and massive hydrate formation ability of Li ions, we found that the anionic structures of both air-exposed and delithiated sulfides were altered. We showed that the hydrolysis of sulfide SEs with anionic polymerization has a thermodynamically favorable final state energy of −3.85 eV because S ions offer high degrees of freedom in their charge states ranging from −0.89 to −0.31e.