Poly(poly(ethylene glycol) methyl ether methacrylate-co-acrylonitrile) gel polymer electrolytes for high performance lithium ion batteries: Comparing controlled and conventional radical polymerization

In this work, a series of crosslinked poly(poly(ethylene glycol) methyl ether methacrylate-co-acrylonitrile) [P(PEGMA-co-ACN)] copolymers has been designed as gel polymer electrolytes (GPEs) for high-safety and high voltage lithium ion batteries. Two approaches including conventional free radical polymerization (FRP) and control radical polymerization (CRP) through one-step reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of 2-cyano-2-propyl dodecyl trithiocarbonate (CPDT) were used to synthesize GPEs with different molar ratios of ACN and PEGMA. Although there was not observed remarkable advantage of polymerization method in different monomer compositions, P(PEGMA-co-ACN) by 50 mol.% ACN and PEGMA prepared via FRP exhibited the maximum ionic conductivity of 5.1 * 10−3 S cm−1, transference number (t+) of 0.55, and exceptional swelling ratio value of 150% in 30 min. Interestingly, it affords a supreme electrochemical stability window up to 5.13 V vs. Li/Li+, the charge capacity of 205 mAh g−1 at 0.1 C, and capacity retention of 89% after 100 cycles.