LLZTO涂覆天丝无纺布锂离子电池隔膜的制备

Preparation of LLZTO-coated Lyocell fibers as non-woven separator for lithium-ion battery

针对锂离子电池用无纺布隔膜孔径分布不均的问题,采用原纤化天丝纤维制备湿法无纺布基材,结合氧化物固态电解质涂层,在收窄孔径尺寸及区间分布的同时,降低电池内阻,提升电化学性能。固态电解质涂层搭配低转数无纺布隔膜会导致基材侧渗出大量陶瓷,但对于组装后电池循环及倍率测试无影响。涂覆之后的无纺布隔膜(LC10)组装钴酸锂全电池循环后拥有较低的极化电压,且由于拥有较高的离子迁移数及更低的欧姆电阻和电荷转移电阻,其在3C高倍率循环下的容量保持率可达85.93%。未涂覆固态电解质涂层的无纺布隔膜低温性能差于商品样,低温镀锂情况较商品样更加严重,而LC10低温下的初始比容量可达124.9 mAh/g,容量保留率为94.23%。

In order to solve the problem of uneven pore size distribution existed in non-woven separators in lithium-ion batteries,the wet-laid non-woven substrate was prepared by fibrillated Lyocell fibers and combined with Li6.4La3Zr1.4Ta0.6 O12(LLZTO)oxide solid electrolyte coating,which narrowed the pore size and distribution.As a result,the internal resistance of the battery was reduced,and the electrochemical performance was improved.Combined with the solid electrolyte coating,the nonwoven substrates prepared by Lyocell fibrillated fibers with low beating revolutions caused a large amount of the ceramics to permeate through the substrate side,but it had no effect on the battery cycle and rate performance after assembly.The coated non-woven membrane(LC10)assembled with the lithium cobalt oxide full battery had a low polarization voltage after cycling,and its capacity retention reached 85.93%under 3C high rate cycles due to its high ion transference number,low ohmic resistance and charge transfer resistance.The low temperature performance of the non-woven separator without solid electrolyte coating was worse than that of the commercial sample,and lithium plating was more serious than that of the commercial sample.The initial capacity of LC10 at low temperature reached 124.9 mAh/g,and the capacity retention was 94.23%.