芳纶纳米纤维增强纸基锂离子电池隔膜的制备及性能研究

Study on Preparation and Performance of Aramid Nanofiber-reinforced Paper-based Lithium-ion Battery Separators

中文关键词:  纸基锂离子电池隔膜  芳纶纳米纤维  耐高温

Key Words:paper-based separator  aramid nanofibers  high-temperature-resistant

中文摘要:

      为提高锂离子电池隔膜的电解液润湿性能和热尺寸稳定性，以漂白硫酸盐阔叶木浆（LBKP）和芳纶纳米纤维（ANFs）为原料，采用造纸工艺制备得到耐高温的LBKP/ANFs纸基锂离子电池隔膜。通过微观形貌表征、拉伸试验、接触角测试等分析手段，重点探究了ANFs质量分数对LBKP/ANFs纸基锂离子电池隔膜的孔隙结构、机械性能、热尺寸稳定性、电解液润湿性能等特性的影响。结果表明，当LBKP打浆度80 °SR、ANFs质量分数20%时，制备得到的LBKP/ANFs-20纸基锂离子电池隔膜性能最佳，孔隙率达55.5%，吸液率达145.9%，抗张强度达58.9 MPa，在180 ℃下基本无尺寸收缩。经LBKP/ANFs-20纸基锂离子电池隔膜组装得到的钴酸锂/锂（LiCoO₂/Li）电池在0.2 C倍率下具有较高的初始放电比容量（168.07 mAh/g），50次充放电循环后容量保持率（91.7%）高于由商业聚烯烃隔膜Celgard 2325（68.2%）组装的锂离子电池，具有良好的倍率性能和充放电循环性能。

Abstract:

      In order to improve the electrolyte wettability and thermal dimensional stability of lithium-ion battery separators， high-temperature-resistant bleached sulphate-flour broadleaf wood pulp （LBKP）/aramid nanofibers （ANFs） paper-based lithium-ion battery separators were obtained via papermaking process， which were prepared by using LBKP and ANFs as raw materials. The effects of the mass fraction of ANFs on the pore structure， mechanical properties， thermal dimensional stability， and electrolyte wettability of the LBKP/ANFs paper-based lithium-ion battery separators were mainly investigated by micro-morphological characterization， tensile test， contact angle test and other analytical means. The results showed that when the LBKP beating degree was 80 °SR and the mass fraction of ANFs was 20%， the prepared LBKP/ANFs-20 paper-based lithium-ion battery separator had the best performance， with a porosity of 55.5%， a liquid absorption rate of 145.9%， a tensile strength of 58.9 MPa， and basically no dimensional shrinkage at 180 ℃. The lithium cobaltate/lithium （LiCoO₂/Li） battery assembled with LBKP/ANFs-20 paper-based lithium-ion battery separator had a higher initial discharge specific capacity （168.07 mAh/g） at 0.2 C rate， and the capacity retention rate after 50 charge/discharge cycles was 91.7%， higher than that of the lithium-ion battery assembled with the commercial polyolefin diaphragm Celgard 2325 （68.2%）， which exhibited good rate performance and charge/discharge cycle performance.