Modification Research Of Nano-composite Gel Eelectrolytes

Compared with traditional liquid electrolytes,gel polymer electrolytes have the advantages of environmentally friendly,non-toxic and free of risk of leakage,and have better ionic conductivity,easy processing and flexibility than solid electrolytes,which bring the gel polymer electrolytes a wider application ranges.In order to prepare a gel polymer electrolyte with excellent performance,a self-made inorganic particle SiO₂ with didfferent diameters were compounded into a PMMA gel electrolyte to prepare a nano-composite PMMA gel electrolyte and the nano effect was discussed.In addition,PVDF and PMMA were combined to prepare PVDF/PMMA composite gel electrolyte.The study results are listed as the following:1.The monodisperse SiO₂ microspheres were synthesized by St?ber method.The the volume ratio of ethyl orthosilicate to ethanol would affect the particle size of SiO₂.The larger the volume ratio of ethanol is,the smaller the diameter of prepared SiO₂ is.When ethyl orthosilicate:ethanol=3:60?V/V?,the diameter of SiO₂ is about 150 nm.The surface modification of SiO₂ was carried out by KH-570.When the amount of KH-570 is 37.5 wt%,the modification effect is better.2.The effects of amount of PMMA and LiClO₄ and both particle size and amount of SiO₂on the nano-composite PMMA electrolyte were investigated by single factor experiments.In the composite electrolyte,when the amount of SiO₂ is the same,the electrochemical window of the electrolyte increases first and then decreases with the decrease of the particle size of SiO₂,and the ionic conductivity increases with the decrease of the particle size.The electrochemical window reaches the maximum when diameter of SiO₂ is 150 nm.When the amount of PMMA,LiClO₄ and SiO₂ are respectively 32 wt%,1.0 mol/L,7 wt%and the diameter of SiO₂ is 150 nm,the electrochemical window and the conductivity the nano-composite PMMA electrolyte are 4.8 V and 1.13 mS/cm,respectively.Moreover,the nano-composite electrolyte can be applied to the electrochromic device,and the color changes obviously,and the device has good stability.3.By adjusting the blend ratio of PVDF to PMMA,the ratio effect of the two polymers on properties of PVDF/PMMA composite gel electrolyte was investigated.The electrolyte crystallinity after compounding is significantly decreased than that of pure PVDF;the polymer with a mass ratio of PVDF:PMMA of 8:2 has a conductivity of 6.88×10^-4S/cm and an electrochemical window of 4.6V.The polymer with a mass ratio of PVDF:PMMA of 9:1 has the largest electrochemical window of 5.4V and a conductivity of 5.64×10^-4S/cm.Both of the two composite gel electrolytes have certain application properties.