Amide-Modulated Gel Electrolytes Enable Nickel-Rich Cathodes with Enhanced Interphase Stability at 90 °C

The safe and reliable operation of high-voltage lithium metal batteries (LMBs) at elevated temperatures is currently hindered by the lack of electrolyte designs that exhibit a high thermal safety and oxidation resistance. Here, an in situ gelation strategy, combining a thermally stable sulfone-based electrolyte with N,N-dimethylacrylamide monomer, is proposed to fabricate a wide-temperature gel electrolyte that is thermally stable up to 235 °C and maintains high-voltage stability above 4.3 V at 90 °C. An oxidation-resistant and thermally stable gel protective layer enables the conformal coating of LiNi_0.6Co_0.2Mn_0.2O₂ particles in the cathode, effectively preventing electrolyte decomposition during high-voltage operation at elevated temperatures. As a result, the Li/LiNi_0.6Co_0.2Mn_0.2O₂ batteries with the resulting in situ gel electrolyte demonstrate exceptional cycle life and safety at 90 °C, even under abusive conditions. This study paves a new pathway to the development of high-energy LMBs operating under extremely high-temperature conditions.