Effects of structure of PMMA-b-PS and nano-organic rectorite on the gel polymer electrolytes

Polymethylmethacrylate (PMMA)-based gel polymer electrolytes (GPE) have excellent compatibility with electrodes and ion transport property, but the low thermal stability and mechanical strength are still open to improvement. Novel polymer matrixes was compounded and organic rectorite was added to enhance the properties of PMMA-based GPE, with block polymer PMMA-b-PS as the matrixes, propylene carbonate (PC) as the plasticizer and lithium perchlorate (LiClO₄) as the electrolyte salt. Three kinds of block polymer, PMMA-b-1PS, PMMA-b-2PS and PMMA-b-3PS were synthesized by atom transfer radical polymerization (ATRP) with different mole ratio of MMA and St varying from 1:1 to 1:3. The ion conductivity of GPE membranes was characterized by AC impedance. It was found that all the three types of PMMA-b-PS based GPE have higher conductivity than PMMA-based GPE, in which PMMA-b-1PS based GPE was the best one with the ion conductivity of 5.99×10^-5 S/cm. A series of PMMA-b-1PS based NGPE membranes were prepared. The microstructure of NGPE was characterized by X-ray diffraction (XRD). The results of AC impedance indicate that the conductivity of all NGPE are superior to the conductivity of PMMA-b-1PS based GPE without nano-organic rectorite. Typically, the conductivity of NGPE with 3wt% nano-organic rectorite was 3.11×10^-4 S/cm at room temperature. TGA curves display that the thermal decomposition temperature of PMMA-b-1PS based GPE was 66.1°C higher than PMMA based GPE when it lost 5% in weight, and the addition of nano-organic rectorite improve the thermal stability of PMMA-based GPE further.