High-Performance PVDF-HFP Based Gel Polymer Electrolyte Modified by Core-Shell SiO 2 -PMMA for Electrochromic Devices

The aim of the study was to determine the effect of inorganic core-shell SiO 2 nanoparticles modified with polymethyl methacrylate (PMMA) layer, on the optical and electrochemical properties of poly vinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) gel polymer electrolyte (GPE). The core-shell SiO 2 nanoparticles were first modified with PMMA to improve its dispersibility and compatibility in the polymer matrix. The morphology and structural properties of the core-shell SiO 2 nanoparticles before and after modification were characterized by XRD, FTIR and SEM analysis. Then the modified SiO 2 nanoparticles were used to prepare the composite GPE, composed of chemically modified core-shell structured SiO 2 -PMMA and PVDF-HFP polymer matrix. The transformation of nano-silica to SiO 2 -PMMA nanoparticles shows the better compatibility of PMMA and PVDF-HFP that favours the silica to be well dispersed in the organic matrix and significantly improve the doping effect. Various concentrations of modified SiO 2 -PMMA were used to dope PVDF-HFP GPEs. The results indicate that the 10% doping shows the highest ionic conductivity i.e. 2.22 × 10 −3 s cm −1 . In addition, the composite GPEs show the high transmittance and good thermal stability; therefore it can add important insight into developing high-performance materials for electrochromic devices.