Cyclotriphosphazene-based flame-retardant polymer electrolytes for high performance sodium metal batteries

作者：Zhou, Binghua^*; Yang, Chaolong; Wu, Fengtian; Deng, Tingzhi; Guo, Shien; Zhu, Guozhen; Jiang, Yunliang^*; Wang, Zhipeng^*

来源：Chemical Engineering Journal, 2022, 450: 138385.

DOI：10.1016/j.cej.2022.138385

• Polymer electrolyte
• Fire-resistant
• Sodium metal batteries
• Boronic ester
• Photopolymerization

A flexible flame-retardant polymer electrolyte (FRPE) based on the cross-linked network containing cyclo-phosphazene groups in the presence of poly(ethylene glycol)-functionalized cyclotriphosphazene (PEG-CP) is fabricated via thiol-acrylate and radical photopolymerizations under UV irradiation for the application in sodium metal batteries (SMBs). The PEG-CP with star-shaped structure applied as the ionic conductor and flame-retardant reinforcer, improves simultaneously the flame retardancy and ionic conductivity of FRPEs. With the increase of PEG-CP content, the crystallinity and glass-transition temperature of FRPEs decrease significantly, which is beneficial to the improvement of ionic conductivity. More importantly, the introduction of cyclic boronic ester improves the sodium-ion transference number and interfacial stability owing to the interaction between anions of sodium salt and boronic ester. The Na/FRPE-40/Na3V2(PO4)3 cell exhibits high specific ca-pacity of 88.0 mAh/g at 0.1C, and retains 91.4 % of the initial capacity after 100 cycles. This work demonstrates that the FRPEs have the great potential for SMBs with high safety and excellent electrochemical performances.

• 单位
  南昌航空大学