离子液体EmimAc中聚偏氟乙烯改性纤维素/尼龙6锂电池隔膜的研究

摘要

为提高锂电池隔膜的热安全性能,以实验室合成的离子液体([Emim] Ac)作为溶剂,以聚乙烯吡咯烷酮(PVP K30)作为添加剂,通过聚偏氟乙烯(PVDF)对纤维素/尼龙6(PA6)锂电池隔膜进行改性,讨论了PVDF含量对隔膜的机械性能、吸液率、保液率、孔隙率及热稳定性能的影响,并进行了SEM形貌结构和接触角测试表征.结果表明,在铸膜液中保持纤维素质量分数为4％,PA6质量分数为3％的基础上,当PVDF质量分数为1.5％时,隔膜的综合性能最佳,抗张强度达到65.26 MPa,热收缩率、吸液率、保液率和孔隙率分别达到2.1％、230％、67.2％和53.3％,经PVDF改性后隔膜的机械性能和热安全稳定性显著提高.%In order to improve thermal safety performance of lithium battery separator,the celluloseylon 6 (PA6) lithium battery separator was modified by the addition of polyvinylidene fluoride (PVDF) with PVP K30 as additive and using ionic liquid [Emim]Ac as solvent.The effects of PVDF content on the mechanical properties,liquid absorption,liquid retention,porosity and thermal stability were studied.The characteristics of modified separator were investigated through the methods of SEM and contact angle measurements.The results showed that the optimum comprehensive properties of separator were obtained when the content of PVDF in the casting solution is 1.5％,based on the casting solution consisted of 4％ cellulose and 3％ PA6.The mechanical strength of separator could reach 65.26 MPa,the heat shrinkage rate,absorption rate,liquid retention rate and porosity could reach 2.1％ 、230％ 、67.2％ and 53.3％,respectively.The mechanical properties and thermal safety stability of the modified separator were improved greatly.