An In Situ Gelled Polymer Electrolyte to Stabilize Lithium–Air Batteries

Abstract

Gel polymer‐based lithium batteries exhibit a unique combination of advantageous properties, including the favorable interfacial contact characteristic of liquid‐state batteries and the inherent stability of solid‐state batteries. For Li–air batteries operated in the semi‐open atmosphere, implementing in situ synthesized gel polymer electrolytes (GPEs) is effective in mitigating the environment‐induced challenges. In this study, a dimethyl sulfoxide (DMSO)‐based GPE in situ initiated by the toluene‐2,4‐diisocyanate (TDI) and 1,4‐benzenediboronic acid (BDBA) is designed to enable the stable operation of lithium–air batteries. The integration of in situ polymerization and polyvinyl alcohol's functional group engineering not only brings benefits to the interfacial contact and electrochemical stability of the battery but also mitigates the moisture sensitivity and volatility of the DMSO electrolyte in the ambient environment. In addition, the GPE can promote the formation of a robust protection film on the lithium surface. As a result, the designed GPE makes the batteries fully leverage their outstanding cycling stability in the ambient environment (241 cycles at 500 mA g−1 and 1000 mAh g−1). Moreover, an optimized Li–air pouch cell structure incorporating the GPE achieves a boasted energy density of 757.5 Wh kg−1, providing a significant technical pathway to bring Li–O2 batteries to practical Li–air batteries.