Modification Of PMMA Gel Polymer Electrolyte With Organic Rectorite

The natural rectorite(REC) was modified with dodecyl benzyl dimethyl ammonium chloride (1227) , then a kind of organic-modified rectorite was obtained, termed as OREC which was studied at its structure and surface property. Then OREC was used as modification additive to modify gel electrolytes in which Poly methyl-methacrylate was used as the main polymer system, propylene carbonate (PC) as plasticizer to increase flexibility of electrolyte, and LiClO₄ as salt to provide Li ion. The microcosmic structure and interaction of modified gel polymer electrolyte were analysed, and the property of liquid kept, ionic conductivity and thermal property were also studied.By Fourier transform infrared(FTIR), X-ray diffraction(XRD), transmission electron microscope(TEM) and polarized light microscope(PLM) analysis, it were found that the distance of layer of OREC is 3.00nm which was increased than that of REC which was 2.22nm, and that OREC present club in organic solvent, the length was much bigger than span and possess nicer microcosmic structure. By expand property and wetting property of OREC, the surface property was changed from hydrophilicity to hydrophobe, which resulted in well compatibility between OREC and polymer.The preparation process of modified gel electrolyte was confirmed. The microcosmic structure of GPE/OREC was studied by scanning electron microscope (SEM), XRD and Molau experiment, and it was found that when the adding amount of OREC was 2 or 5phr, OREC was separated well in electrolyte, but when the adding amount was 8phr, congeries in electrolyte was appeared, which led to precipitate OREC in Molau experiment. Through viscosity and FTIR study, it was found that there was strong hydrogenolysis between OREC and PC, and static action between Li⁺ and PC.PC was used as floating phase and PMMA , PMMA+OREC and PMMA+ OREC + Li⁺was respectively used as immovable phase in the inverse gas chromatogram (IGC) experiment from which the adsorption free energy was obtained. The adsorption free energy of PMMA+OREC was the biggest, which demonstrated there was very strong reaction between OREC and PC. This kind of reaction was very useful to increase the solvent kept ability of electrolyte. It was found that the solventcept ability of modified electrolyte vas greatly increase, ind when the adding amount of OREC was 5 phr, the best result was obtained.The effect of temperature on ionic conductivity of modified electrolyte was studied. It was found that the relation between ionic conductivity and temperature greatly accorded with VTF equation. Under the temperature of 20 °C, when the adding amount of OREC was 5phr, the ionic conductivity increased from 2.17 to 4.67 mS-cm"1. Through thermal property analysis, it was found that when the adding amount of OREC was 2, 5 or 8phr, the glass translation temperature(Tg) was respectively increased to -91.6, -90.8 and -88.9°C, while Tg of non-mondified electrolyte was -93.6°C;when the mass loss percent was 5.0%, the temperature of modified electrolyte was respectively 105.5, 108.8, 111.2°C which greatly increased, and the temperature of non-mondified system was 90.5 °C.