Sol - Gel Lithium And Polystyrene Degradation Catalyst And Lithium Ion Polymer Solid Electrolyte Applications

Through a series of experiments,it has been found that thermal degradation temperature of polystyrene could be greatly reduced by using lithim intercalation (lithiated) boric acid prepared through sol-gel method.The lithiated boric acid was characterized by X-ray diffraction(XRD) and Raman spectroscopy.Results from XRD indicated that the product is boric acid,while Raman spectroscopy showed that Li⁺ ions were accumulated on the surface of H₃BO₃,or associated with O in B-O bond. In addition,thermal degradation temperature(T_d) of polystyrene with different lithiated boric acid was measured using thermalgravimetric analysis(TGA),and highest decrease of Td is about 70℃.To explain why thermal degradation temperature of polystyrene was reduced,a study was made on the chemical process of lithiated boric acid in high temperature.It has been found that the reduction of thermal degradation temperature arose from H⁺ produced by reaction of Li⁺ with H₃BO₃.It has been shown that concentrations of Li⁺ or Li-O complex greatly influenced T_d.Lithiated(lithium insertion) polyborosiloxane was successfully synthesized through sol-gel process in the presence of LiClO4.The lithium batteries solid polymer electrolytes(SPE) poly(ethylene oxide)/polyborosiloxane/LiClO4 were obtained through coating the mixed solution of lithiated polyborosiloxane and poly(ethylene oxide) on the nickel flake.The relatively low Tg of the SPE in high lithium salt concentration ascribed to our in-situ polymerization strategy,because the presence of large size ClO4- anions and inferior segmental motion enable the polymer chain to create extra free volume.The lewis-acid-base interaction was introduced by incorporation lewis acid boron into polysiloxane backbone,which decreased the interaction between the Li+ ion and host polymer.The maximum ion conductivity of polymer electrolyte at room temperature(30℃) was measured to be 0.64×10-3 S·cm-1,which is very close to the ideal ion conductivity of SPE in lithium batteries(1.0×10-3S·cm-1).In this paper,the environment of experiments is briefly described,and experimental results,as well as analysis of these results,are discussed in detail.