高强度芳纶纳米纤维隔膜在高温锂电池中的研究

Study on High Strength Aramid Nano Fiber Separator in High Temperature Lithium Battery

锂离子电池作为新型储能器件在众多可移动设备中占据了主导地位,然而,动力电池在高功率下工作时,通常产生大量的热,严重影响了锂离子电池的安全性能。传统商业化的锂离子电池隔膜是聚烯烃材料经过拉伸造孔工艺制备,在高温时会发生闭孔。不仅如此,高温下的隔膜也容易收缩,引起电池的内短路,带来极大的安全隐患。本文借助相转移工艺,通过层-层构造技术,开发了一种阻燃耐高温的纳孔芳纶隔膜。研究表明芳纶隔膜具有优异的物理化学性质,其断裂强度高达127 MPa,能够避免锂枝晶的刺穿,提升锂金属电池的安全性能。尽管芳纶隔膜的离子电导率低于商业化的聚烯烃隔膜,其组装的电池在100℃下依然能够稳定工作。芳纶隔膜的提出,能够一定程度为下一代高安全性能锂(离子)电池提供参考。

As a new type of energy storage device,lithium-ion battery plays a dominant role in many mobile devices.However,when power batteries operate at high power,they usually generate a lot of heat,which seriously threatens the safety performance of lithium-ion battery.The traditional commercial lithium-ion battery separator is made of polyolefin material by stretching pore-making process,and the pore closure occurs at high temperature.In addition,polyolefin separator tends to shrink at high temperature,causing internal short circuit of the battery,and bringing great safety risks.In this paper,a kind of flame retardant and high-temperature resistant aramid nano fiber separator was developed by phase transfer process and layer-layer structure technology.Studies show that the aramid-based separator has excellent physical and chemical properties with a fracture strength up to 127 MPa,which can avoid the punctures of lithium dendrites and improve the safety performance of lithium metal batteries.Although the ionic conductivity of the aramid-based separator is lower than that of the commercially available polyolefin separator,the assembled battery can still operate stably at 100℃.The proposed aramid diaphragm can provide reference for the next generation lithium(ion)battery with high safety performance to a certain extent.