Ionogel hybrid polymer electrolytes encompassing room-temperature ionic liquids for 4V-class Li-metal batteries operating at ambient temperature

In this study, we prepare ionogels composed of bisphenol A ethoxylate dimethacrylate, poly(ethylene glycol) methyl ether methacrylate, lithium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide or 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide ionic liquids via rapid, scalable, solvent-free UV-induced polymerization.The various hybrid polymer electrolyte formulations are thoroughly characterized using acomprehensive set of physico-chemical and electrochemical methods, including gel content,FTIR, rheology, DTMA, TGA, SEM, cycling voltammetry, impedance spectroscopy, andgalvanostatic cycling in laboratory-scale Li-metal cells. We particularly focus on the influence ofusing two different ionic liquids as reaction medium on the properties of the resulting materialsand their electrochemical behaviors. Our results indicate that viscosity affects thepolymerization kinetics of the ionogels, which in turn might affect their thermal stability andgalvanostatic cycling behavior. In the purpose of promoting overall performance of solid-statebatteries, we also present the results of composite electrolytes obtained by introducingLi7La3Zr2O12(LLZO) into ionogels and followingin-situUV-polymerisation. The addition of LLZOceramic results in more porous solid networks, leading to enhanced charge/discharge stabilityat ambient temperature and higher C-rates featuring 4V-class NMC cathodes, enlightening thepromising prospects of the developed materials to be successfully implemented as stable,durable, and efficient electrolytes in next-generation Li-metal cells.