Preparation and Characterization of Composite Microporous Gel Polymer Electrolytes Containing SiO2(Li+)

Abstract

In this paper, the single ionic conductor SiO2(Li+) was first synthesized from Tetraethylorthosilicate and γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560) by sol–gel hydrolysis and then neutralized by lithium hydroxide in methanol. The poly(vinylidene fluoride) based composite microporous gel polymer electrolytes (CMGPEs) doped with SiO2(Li+) was prepared by phase inversion method and the desirable CMGPEs was obtained after being activated in liquid electrolyte. The physicochemical properties of the CMGPEs were characterized by FT-IR, DSC, XRD, TG, stress–strain response and electrochemical measurements. It was found that with the addition of SiO2(Li+), the degree of crystallization of microporous polymer membrane was decreased while its porosity increased, which could promote the absorption and gelation of liquid electrolyte. In addition, due to vast amount of Li+ ions in the SiO2(Li+), it would promote ionic conductivity at room temperature for the CMGPEs. When the content of SiO2(Li+) reached 5 %wt, the ionic conductivity of the CMGPEs could reach 10−2S/cm order of magnitude at room temperature and the reciprocal temperature dependence of ionic conductivity of as-prepared CMGPEs follow arrhenius equation, in addition, its electrochemical stability window could reach 5.2 V.