High-Performance PVDF-HFP Based Gel Polymer Electrolyte Modified by Core-Shell SiO2-PMMA for Electrochromic Devices

Abstract

The aim of the study was to determine the effect of inorganic core-shell SiO2 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 SiO2 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 SiO2 nanoparticles before and after modification were characterized by XRD, FTIR and SEM analysis. Then the modified SiO2 nanoparticles were used to prepare the composite GPE, composed of chemically modified core-shell structured SiO2-PMMA and PVDF-HFP polymer matrix. The transformation of nano-silica to SiO2-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 SiO2-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.