Synthesis And Application Of Glyceryl Ester Modified Acylate Polymers

In this thesis,two types of glyceride modified acrylic ester derivatives-poly(2-oxo-1,3-dioxolan-4-yl)methyl acrylate(PDOMA)and poly(2-oxo-1,3-dioxolan-4-yl)methyl methacrylate(PDOMMA)were designed and synthesized successfully.The molecular structure of two polymers was characterized by FT-IR and 1H NMR.Their thermal stability was investigated by thermogravimetric analysis(TG).And the surface morphology of the polymer electrolyte was observed by scanning electron microscope(SEM).Then the room-temperature conductivity of these gel polymer electrolytes was measured by electrochemical impedance spectroscope(EIS).Finally,these porous films with PE,as gel polymer electrolyte,were applied to lithium ion battery for studying their effects on the electrochemical performance of lithium-ion batteries:cyclic performance,rate capability,impedance and other electrochemical tests.The results were listed as follows:1H NMR and FT-IR showed that the target products-poly(2-oxo-1,3-dioxolan-4-yl)-methyl acrylate and poly(2-oxo-1,3-dioxolan-4-yl)methyl methacrylate were obtained.The thermogravimetric analysis implied that the decomposition temperatures of two polymers were both above 243?,and thus they could be applied as gel polymer electrolyte.Gel polymer porous membrane of two polymers was measured for the absorption rate and the data showed that the absorbance of PE-PDOMA and PE-PDOMMA were higher than 300%.The conductivity of polymer electrolyte with different molecular weight was determined by AC impedance.And their room-temperature conductivity reached 10-3 S/cm,which means these gel polymer electrolyte can be applied to lithium ion battery.Compared with PE membrane,the electrochemical performance of Li/MCMB half-cells with PE-PDOMA and PE-PDOMMA polymer electrolyte indicated that the PE-PDOMA and PE-PDOMMA polymer electrolytes with different molecular weights could improve the cycling performance of lithium-ion half-cell,but made the cell's discharge capacity lower at high rate of discharge current.The impedance value of the PE-PDOMA polymer electrolyte with a molecular weight of 100,000 and 340,000 after 20 cycles significantly decreased after 2 cycles.And the same phenomenon was observed in the PE-PDOMMA polymer electrolyte.The above results suggested that these gel electrolytes could be very useful for stable SEI film and can improve the interface properties of the electrode/electrolyte.