In addition to the traditional LAGP solid electrolyte, composite systems such as LAGP/(PVDF-HFP) have been fabricated by the CSP process at 120 °C with water as the solvent (as shown in Fig.4 b–d) [74].Due to the low ionic conductivity of the PVDF-HFP polymer, the conductivity of the composite electrolyte was found to decrease with an increase of polymer content.