A nanocomposite cross-linked polyethylene glycol-based gel electrolyte and its preparation method

Abstract

This invention discloses a nanocomposite cross-linked polyethylene glycol (PEG)-based gel electrolyte and its preparation method. The method includes the following steps: a nucleophilic addition reaction is performed between the isocyanate group at one end of a silane coupling agent and the hydroxyl groups at both ends of polyethylene glycol to form PEG polymer segments containing urethane groups; a silane coupling reaction is carried out between lithium diatomaceous earth and the PEG polymer segments containing urethane groups to obtain a viscous slurry; the viscous slurry is coated onto both sides of a cellulose membrane and dried to obtain a nanocomposite cross-linked PEG-based thin film; the nanocomposite cross-linked PEG-based thin film is wetted with an electrolyte to obtain the nanocomposite cross-linked PEG-based gel electrolyte. This invention significantly improves the high-voltage electrochemical stability of the PEG-based electrolyte while also optimizing its key electrochemical properties such as ionic conductivity, lithium-ion transference number, interfacial compatibility with lithium metal anodes, and charge-discharge cycle stability.

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