PVDF-HFP接枝PEG聚合物电解质的制备和性能研究

Preparation and properties of the polymer electrolyte of PVDF-HFP grafted with PEG

以聚偏二氟乙烯-六氟丙烯(PVDF-HFP)接枝聚乙二醇(PEG)为基质,用萃取法制备了均相结构的微孔型聚合物电解质。对此共聚物电解质和纯PVDF-HFP电解质进行比较表征,并以接枝共聚物电解质组装扣式电池进行了性能检测。结果表明,PVDF-HFP接枝PEG后可提高吸液率、保液能力和电导率。20℃时PVDF-HFP和PVDF-HFP-g-PEG的电导率分别为2.60×10-3S/cm和3.28×10-3S/cm。0.2 C充放电时,电池首次放电比容量为119.3 mAh/g。50次充放电循环过程中,充放电效率为99%,初始放电比容量为120.7 mAh/g,终止放电容量为115.9 mAh/g。0.5、12、C的放电比容量分别为0.2 C放电容量的96.2%、94.5%和81.3%。

A homogeneous micmporous polymer electrolyte of poly（ vinylidene fluoride-co-hexafluompropylene）（ PVDF- HFP） grafted with polyethylene glycol（PEG） is prepared by extraction. The prepared polymer electrolyte is characterized, and button cells with the grafting copolymer electrolyte are assembled and tested. The results show that PVDF-HFP grafted with PEG has higher liquid absorption, liquid electrolyte retention and conductivity in contrast with the pure PVDF-HFP. The conductivity （at 20℃） of PVDF-HFP and PVDF-HFP-g-PEG is 2.60 × 10^-3 S/cm and 3.28 × 10^-3 S/cm, respectively. The initial discharge capacity of the cell is 119.3 mAh/g at 0.2 C. During the 50 cycles the charge-discharge efi%iency is about 99% with the initial discharge capacity of 120.7 mAh/g and the terminal discharge capacity of 115.9 mAh/g. While the discharge capacity at 0.5 C, 1 C and 2 C is 96.2% ,94.5% and 81.3% ,respectively,of the discharge capacity at 0.2 C.