聚偏氟乙烯电纺膜及其电化学性能的研究

用电纺的方法制备了聚偏氟乙烯纳米纤维膜,它们具有多微孔结构,能够作为锂电池聚合物电解质.电纺中聚合物溶液的浓度对制备的电纺膜的结构形态有很大的影响,低浓度(10 wt%)时得到珠丝结构的膜,浓度15 wt%时则为纤维结构,而高浓度(18 wt%)时,电纺膜为交联的网状结构.用电纺法制备的聚偏氟乙烯纳米纤维微孔膜具有较高的孔隙率,而且它们与锂金属电极具有良好的界面稳定性;在25℃时吸液率最高可达340%,以这种膜制备的聚合物电解质室温电导率可达到1.57×10-3S.cm-1;由该电解质组装的扣式电池以0.5 mA.cm-2恒流充放电,25℃时50次循环后几乎无容量损失,具有良好的循环性能;即使60℃时,电池仍能保持良好的工作稳定性.

PREPARATION AND ELECTROCHEMICAL PROPERTIES OF ELECTROSPUN POLY(VINYLIDENE FLUORIDE) MEMBRANES

Nanofibrous poly(vinylidene fluoride) membranes were produced by the electrospinning method.Since these electrospun membranes have microporous structure,they can be applied as polymer electrolyte for lithium ion battery.The morphology of electrospun membranes was strongly affected by the concentration of polymer solutions.It presents a usual web of fibers at a concentration of 15 wt%,a web of fibers with a few beads at a lower concentration(10 wt%) and a cross-linked web of fibers at a higher concentration(18 wt%) The electrospun PVDF membranes show a high uptake of liquid electrolyte and good compatibility with metal lithium.The electrospun PVDF-based electrolyte membranes exhibited the maxima of uptake(340%) and ion conductivity(1.57×10~(-3) S·cm~(-1)) at room temperature.At a 0.5 mA·cm~(-2) rate,the coin cell with the electrospun PVDF-based polymer electrolyte had good cycling performance with little capacity fade after 50 cycles at 25℃.Even at 60℃,the coin cells show a good stability.