锂聚合物电池PVdF电解质膜的研究

Research on PVdF Electrolyte Membranes in Lithium Polymer Battery

本文采用萃取-活化方法制备了由PVdF2801聚合物电解质膜,研究了聚合物电解质膜的机械强度、在 1M LiPF6-EC/DMC(质量比2:1)电解液中的吸液率、离子电导率、电化学稳定电位窗口等。结果表明30％ PVdF2801-20％发烟硅-50％DBP膜的吸液率、机械强度、离子电导率明显优于50％PVdF2801-50％DBP膜, 经过萃取浸电解液后30℃时其电导率为1．8×10-3S/cm,以不锈钢为工作电极时的电化学稳定电位窗口高达 5．1V,与高压阴极之间是相容的,能够满足实际应用的要求。

The paper introduces the preparation of polymer electrolyte membranes comprised of PVdF2801 by using extraction-activation method, and presents the researches on the properties of the polymer electrolyte membranes such as mechanical strength, electrolyte absorption ratio, ion conductivity and electrochemical stability window in 1M LiPF6-EC/DMC（W/W= 1：1 ）solution. The results show that electrolyte absorption ratio, mechanical strength and ion conductivity of the polymer electrolyte comprised of 30% PVdF2801-20% fumed silica -50% DBP are obviously higher than that comprised of 50% PVdF2801-50% DBP and its ion conductivity is 1.8 ×10^-3S/cm at 30℃ after extracted and activated. The result of potentiodynamic sweep experiment shows that electrochemical stability window is up to 5.1V on stainless steel working electrode, which proves that it is compatible with high voltage cathode and is suitable for practical use.