聚酰亚胺静电纺隔膜的电化学性能

Electrochemical properties of electrospun polyimide membrane for lithium ion battery

通过静电纺丝和热亚胺化处理制备热固性聚酰亚胺（PI）纳米纤维膜，并研究隔膜的力学性能及在2种充电截止电压（常用的4.2 V和高电压4.4 V）下的电化学循环性能.结果表明：PI纳米纤维的平均直径为276 nm，作为隔膜的孔隙率高达92%，且其吸液率远远高于商业用Celgard2400隔膜；0.2C/0.2C速率50次充放电循环下，2种电压范围下的容量保持率均在80%以上，且在2.8～4.4 V高电压下的容量保持率高达91.6%，明显优于Celgard2400；在2种电压范围内，随着放电倍率的增大，其比容量衰减较Celgard2400隔膜缓慢，PI膜表现出更优异的倍率性能.

The thermosetting polyimide （PI） nano-fibers based nonwoven membrane is prepared by electrospinning technique and followed by thermal imidization. The physical and mechanical properties of PI nano-fibers based nonwoven separators are tested and the electrochemical performance of the PI membrane for lithium ion battery at different charge cut-off voltage （herein, common voltage 4.2 V and higher 4.4 V） is investigated. The results show that the average diameter of PI nano-fibers is as fine as 276 nm; the porosity of PI nano-fibers based nonwoven separators is up to 92% and they exhibit better wettability for the polar electrolyte compared to the commercial Celgard 2400 membrane; After 50 cycles at 0.2C/0.2C charge and discharge rate, the capacity retention ratio of the cell assembled with PI nano-fibers based nonwoven separators at both voltage range is higher than 80%, especially that of 4.4 V charge is up to 91.6%, which are obviously superior to commercial Celgard 2400 membrane; moreover, the special capacity of PI separators fades slower than Celgard 2400 membrane with the increase of discharge rate at both situation.