Preparation of all-solid-state polymer electrolyte by ultraviolet cross-linking method

In the application of all-solid-state polymer electrolyte (SPE), the bottleneck is how to meet the requirements of ion conductivity and mechanical strength simultaneously. Aiming at the above problem, this paper adopts the reversible addition fragmentation chain transfer (RAFT) solution polymerization technology to synthesize SPEs with different chain structures. The SPEs apply the cyclohex-3-enylmethyl acrylate (CEA) as post-crosslinking monomer and the poly(ethylene glycol) methyl ether acrylate (PEGMA) as ion-conducting monomer. A chemically cross-linked network structure was formed by the "click chemistry" reaction between the double bond on the cyclohexene in CEA and the mercaptan. The prepared triblock copolymer electrolyte has independent ion-conducting blocks while the crosslinking monomers concentrating at both ends of the molecular chain, thus meeting the demands of mechanical strength and ionic conductivity simultaneously. The prepared triblock copolymer electrolyte presented ionic conductivity of 6.13×10-5 S/cm at 60℃. The lithium iron phosphate/lithium (LiFePO4/Li) all-solid-state battery using the prepared triblock copolymer electrolyte presented specific discharge capacity of 139.1 mAh/g after 130 cycles at 0.5 C. The retention rate was 97.8% while the coulombic efficiency remained above 99.0%, showing good electrochemical performance. © 2022, Editorial Board of CIESC Journal. All right reserved.