A cross-linked gel polymer electrolyte employing cellulose acetate matrix and layered boron nitride filler prepared via in situ thermal polymerization

The cross-linked gel polymer electrolyte (GPE) with cellulose acetate (CA) as matrix, poly (ethylene glycol) diacrylate (PEGDA) as cross-linking agent, and layered boron nitride (BN) as reinforcement is prepared for lithium-ion batteries (LIBs). Different from reported CA based polymer electrolytes, we adopt a simple in situ thermal polymerization method in the battery to prepare the GPE and polymer LIBs simultaneously. BN filler is uniformly dispersed in the cross-linked GPE and it interacts with not only the polymer matrix but also the anion in liquid electrolyte. Therefore, BN filler facilitates the transport of Li+ ions and delays the oxidative decomposition of the GPE. BN filler inhibits the evaporation of organic solvents at the low temperature, whereas it accelerates their decomposition at the high temperature. Due to the synergistic effect of CA matrix and BN filler, the obtained GPE exhibits a high ionic conductivity of 8.9 × 10−3 S cm−1 at 30 °C, an excellent electrochemical stability up to 5.5 V, and a good thermal stability. This work sheds light on the interaction between GPEs and the inorganic fillers, which is crucial for designing new polymer electrolyte systems.