Quasi-Solid-State Electrolytes of Polyethylene Oxide-Based Composite Electrolyte with Liquid Electrolytes

A thin film of PEO18Li(CF3SO2)2N(LiTFSI)-tetraethylene glycol dimethyl ether (G4)-Li1.4Al0.4Ge0.2Ti1.4(PO4)3-LiCl·H2O (LAGTP·LiCl) was prepared by addition of 1,2-dimethoxyethane (DME). The grain boundary resistance of PEO18LiTFSI-LAGTP·LiCl was considerably reduced by the addition of G4, and a large-sized thin film of the composite polymer electrolyte was prepared easily by the addition of 10 wt.% DME. The electrical conductivity of [(PEO18LiTFSI-2G4)-5 wt.% LAGTP·LiCl]-10 wt.% DME was 1.2 × 10-4 S cm-1 at 25°C, and the tensile strength of the composite was 0.4 M Pa with an elongation at break of 27% at room temperature. The Li/[(PEO18LiTFSI-2G4)-5 wt.% LAGTP·LiCl]-10 wt.% DME/Li cell was constructed, which showed an excellent cyclic performance at 0.2 mA cm-2 and 0.2 m Ah cm-2 and 25°C for more than 800 h.