造纸法制备CNF/PMIA/PPTA锂电池隔膜

CNF/PMIA/PPTA Lithium-ion Battery Separator Prepared by Paper-making Process

中文关键词:  造纸法  隔膜  纳米纤维素  芳纶纤维  电化学

Key Words:paper-making  separator  nanocellulose  aramid fiber  electrochemistry

中文摘要:

      本研究以水溶性聚酰亚胺（PI）为增强剂，将纤维素纳米纤维（CNF）和芳纶纤维（PMIA/PPTA）悬浮液共混后，通过造纸法湿法成形制备CNF/PMIA/PPTA锂电池隔膜，并对隔膜性能进行了表征分析，探讨了各组分质量分数对隔膜机械性能及电化学性能的影响。研究结果表明，隔膜性能最佳的组分及用量（均相对于混合浆料总质量）为：CNF质量分数0.5%、PMIA/PPTA纤维质量分数0.5%（质量比5∶5）、硅藻土质量分数0.05%；PI水溶液喷涂量1.5%（相对于膜材料绝干质量）。此时，锂电池隔膜的拉伸强度为23.28 MPa，断裂伸长率为3.41%，吸液率、保液率和孔隙率分别为237.16%、152.88%和69.34%，热收缩率仅为0.31%，离子电导率可达1.041 mS/cm；由其组装的锂电池首次放电容量为158.2 mAh/g。CNF/PMIA/PPTA锂电池隔膜不仅具有优异的热稳定性和润湿性能，还具有较高离子电导率、较宽电化学稳定窗口、出色的倍率性能和循环性能，满足锂电池隔膜的技术安全要求。

Abstract:

      CNF/PMIA/PPTA lithium-ion battery separators were prepared by wet forming of paper-making method using water-soluble polyimide （PI） as reinforcing agent， and mixing cellulose nanofiber （CNF） and poly（ethylene oxide）‍-modified poly（aramid fiber） （PMIA/PPTA） suspension. After characterization and analysis of separator performance， the effects of dispersion and stability of CNF and PMIA/PPTA suspensions and the mass fraction of each component on the mechanical and electrochemical properties of the separator were investigated. The results showed that the composition and dosage for the optimum properties of separator was： CNF （mass fraction of 0.5%， relative to the mixed total pulp mass， the same below）， PMIA/PPTA fibers （mass fraction of 0.5%， mass ratio of 5：5）， diatomaceous earth （mass fraction of 0.05%）； and PI aqueous solution was sprayed （spraying quantity of 1.5%， relative to the absolate dry mass of the separator）. At this time， the tensile strength of the lithium-ion battery separator was 23.74 MPa， the elongation at break was 3.41%， the liquid absorption， liquid retention， and porosity were 237.16%， 152.88%， and 69.34%， respectively， and the thermal shrinkage was only 0.31%， with an ionic conductivity of up to 1.041 mS/cm； the first discharge capacity of the lithium-ion battery assembled by separator was 158.2 mAh/g. The CNF/PMIA/PPTA lithium-ion battery separator not only had excellent thermal stability， but also higher ionic conductivity， wider electrochemical stabilization window， excellent multiplicity and cycling performance， which met the technical safety requirements of lithium-ion battery separator.