纳米芳纶纤维/纳米氧化铝涂覆改性锂电池用聚丙烯微孔膜的性能

Properties of Nano-Aramid Fiber/Nano-Alumina Coating Modified Polypropylene Microporous Membrane for Lithium Battery

通过纳米芳纶纤维/纳米氧化铝对锂电池用聚丙烯(PP)微孔膜进行涂覆改性,以提高微孔膜亲电解液性能及耐热性能。将芳纶短纤在碱性二甲基亚砜溶液中分散制备纳米芳纶纤维分散液,加入纳米氧化铝涂覆在PP微孔膜表面获得改性微孔膜。通过扫描电镜对微孔膜表面微观形貌进行观察,结果表明,纳米氧化铝的加入改善了纳米芳纶纤维层的孔结构,提高了改性微孔膜的透气性能。接触角测试表明,改性微孔膜电解液接触角从未改性聚丙烯微孔膜的87°降低到0°,改性后微孔膜对电解液有更好的浸润效果。耐热测试结果证实,改性微孔膜的热收缩程度显著降低,在170℃放置30min,未改性微孔膜热收缩率为37.3%,改性微孔膜降低至13.4%,耐热性能明显提高。电池性能测试结果表明,改性涂层提升了锂电池的电池容量及容量稳定性。

Polypropylene(PP)microporous membranes for lithium batteries were coated and modified by nano-aramid fiber/nano-alumina to improve the electrophilic performance and heat resistance of the microporous membranes.The aramid staple fibers were dispersed in an alkaline dimethyl sulfoxide solution to prepare a nano-aramid fiber dispersion,and then nano-alumina was added to obtain a slurry,which was coated on the surface of the PP microporous membranes to obtain modified microporous membranes.The microscopic morphologies of the microporous membrane surface were observed by scanning electron microscope.The results show that the addition of nano-alumina improves the pore structure of the nano-aramid fiber layer and the air permeability of the modified microporous membranes.The contact angle test shows that the electrolyte contact angle of the modified microporous membranes is reduced from 87°of the PP microporous membrane to 0°,and the modified microporous membranes have the better infiltration effect on the electrolyte.The heat resistance test results confirm that the thermal shrinkage of the modified microporous films is significantly reduced.When placed at 170℃for 30 min,the thermal shrinkage of the unmodified microporous membrane is 37.3%,and that of the modified microporous membrane decreases to 13.4%,indicating that the heat resistance of the microporous membrane is successfully improved.The battery performance test results show that the modified coating improves the battery capacity and capacity stability of the lithium battery.