静电纺丝法制备POSS-(C₃H₆Cl)₈复合聚偏氟乙烯聚合物隔膜的结构与性能

To improve the safety of Li-ion batteries, the polyvinylidene fluoride (PVDF) membrane containing octa chloropropyl polyhedral oligomeric silsesquioxane (POSS-(C₃H₆Cl)₈) was prepared by electrospinning technique. The morphology and mechanical property of electrospun polymer separators (EPSs) were analyzed at first, then the electrochemical window and the charge/discharge cycle stability of Li/LiFePO₄ cells were tested. Results show that the electrospun polymer separators have the preferable performance when the content of POSS-(C₃H₆Cl)₈ is 10%. Under this condition, the fibers are very uniform and have better morphology. The tensile strength and broken elongation are increased by 106.4% and 27.2%, respectively. The ionic conductivity is 3.8×10^-3 S/cm at room temperature, which is improved by 97.4% than that of pure PVDF separator. The electrochemical stability window of polymer film is 5.7 V. The Li-ion batteries assembled with EPSs have superior cycle stability and rate capability.