1,1‐Diethoxyethane as an interfacial‐stabilizing solvent for lithium–sulfur batteries

Lithium–sulfur batteries (LSBs) have gained remarkable attention over the past several years, however, their inherent limitations, such as the poor interfacial stability of their Li anodes and the severe dissolution of polysulfide, are regarded as bottlenecks that prevent these batteries from entering commercial markets. In this study, a 1,1‐diethoxyethane (DEE), which has been functionalized with acetal groups, is proposed as an electrolyte cosolvent to complement the limitations of the electrode materials of LSBs. In Li/Li symmetric cells, the DEE cosolvent exhibited stable cycling behavior, whereas the cell with the baseline electrolyte exhibited rapidly increasing polarization, even after 650 h. In LSB cells, the electrolyte that contains 50% DEE exhibits the highest cycling retention (65.0%) compared to the baseline electrolyte (49.8%) because it effectively protects the interface of the Li anode, but also suppresses the dissolution of polysulfide species. The DEE is proposed as a surface‐stabilizing cosolvent for lithium–sulfur batteries (LSBs). The electrochemical reduction of DEE affords organic/inorganic‐based solid‐electrolyte interphases at the Li anode by participating in the electrochemical reactions. The DEE protects the Li anode and inhibits the dissolution of polysulfide, leading to improved cycling retention of LSBs.