P(VDF-HFP)-PMMA/CaCO3(SiO2)复合聚合物电解质的电化学性质

Electrochemical Behaviour of the Composite Polymer Electrolyte P(VDF-HFP)-PMMA/CaCO_3(SiO_2)

采用激光扫描共焦显微镜、X射线衍射、循环伏安和交流阻抗等方法对由聚(偏二氟乙烯-六氟丙烯)(P(VDF-HFP))、聚甲基丙烯酸甲酯(PMMA)以及纳米碳酸钙(二氧化硅)制备的几种复合聚合物电解质(CPE)膜P(VDF-HFP)-PMMA/CaCO3(SiO2)的性能进行了研究.结果表明,PMMA的加入能提高CPE的吸液率,从而增大其离子导电率.在P(VDF-HFP)与PMMA质量比为1∶1条件下制得的CPE性能最佳.用P(VDF-HFP)-PMMA为聚合物基体与纳米级SiO2、CaCO3进行复合制成的聚合物膜,无机粒子的加入没有破坏原来聚合物非晶结构;室温下CPE的电导率达到3.42 mS.cm-1;电化学稳定窗口为4.8 V.电池Li/CPE/GMS(石墨基材料)的测试证明,CPE与石墨负极有很好的相容性.聚合物电池Li/CPE(CaCO3)/LiCoO2比Li/CPE)(SiO2)/LiCoO2具有更优越的倍率放电性能.

Electrochemical behavior of the composite polymer electrolyte （CPE） prepared from polyvinylidene fluoride-co-hexafluoropropylene（P（VDF-HFP））, poly（methyl methacrylate） （PMMA）, and nanosized CaCO3（SiO2） particles was investigated by confocal laser scanning microscopy, X-ray diffraction （XRD）, cyclic voltammetry （CV）, and electrochemical impedance spectroscopy （EIS）. Results show that CPEs have many micropores, and that the addition of PMMA can increase the absorption potential of the liquid electrolyte and therefore improve ionic conductivity. The best performance of CPE was found at a P（VDF-HFP）/PMMA mass ratio of 1：1. The composite polymer electrolyte that was produced by adding nanosized CaCO3 and SiO2 to a P（VDF-HFP）-PMMA base keeps the amorphous structure of the original polymer base. The ionic conductivity of CPE can reach 3.42 mS·cm^-1 and the electrochemical window can be up to 4.8 V at room temperature. A test on Li/CPE/GMS cells showed that the composite polymer electrolyte was compatible with graphite anodes. The battery made from Li/CPE（CaCO3）/LiCoO2 was shown to have a superior rate discharging performance to Li/CPE（SiO2）/LiCoO2.