Glyoxylic‐Acetal‐Based Gel‐Polymer Electrolytes for Lithium‐Ion Batteries

Abstract This work focuses on the combination of two strategies to improve the safety of lithium‐ion batteries: The use of a glyoxylic‐acetal, 1,1,2,2‐tetraethoxyethane, in the solvent blend to reduce the flammability of the liquid electrolyte and further its confinement inside of a methacrylate‐based polymer matrix, to prevent electrolyte leakage from the battery cells. Physicochemical characterizations of this novel gel‐polymer electrolyte (GPE) confirm its improved thermal properties and suitable ionic conductivity, as well as electrochemical stability window. Tests in LFP and hard carbon half‐cells vs. lithium metal show that the combination of glyoxylic‐acetal‐based electrolyte and the methacrylate‐based polymer matrix can promote lithium‐ion intercalation and deintercalation with stable capacity values. The application in lithium‐ion battery full cells furthermore shows that the GPE can promote a similar performance compared to the respective liquid electrolyte and can therefore make possible the realization of energy storage devices with improved safety characteristics.