Separators play a crucial role in inhibiting thermal runaway in lithium-ion batteries (LIBs). In this study, the doctor blade coating method and heavy-ion track etching technology were used to prepare a polyimide-based covalent organic framework (PI_COF) separator with excellent thermal stability and a long cycle life. Specifically, COF300 was simply coated on the surface of a polyimide-based track-etched membrane (PI_TEM) with straight through holes, which provided a rigid framework and high-temperature stability at 300 °C. These features were conducive to inhibiting thermal runaway, while porous COF300 with large holes increased the wettability of the electrolyte, facilitating lithium-ion migration and suppression of lithium dendrite growth; consequently, LIBs with an excellent cycling performance and a high rate capacity were obtained. The cell with the PI_COF separator delivered a high capacity of 90.0 mA h g^–1 after 1000 cycles. The PI_COF separator with high thermal stability exhibited a long cycle life in LIBs. These features are beneficial for improving the safety characteristics of LIBs as well as for accelerating the practical application process of the PI_COF separator.

中文翻译：

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具有高热稳定性的共价有机框架涂层聚酰亚胺离子径迹蚀刻隔膜，用于开发长寿命锂离子电池


隔膜在抑制锂离子电池（LIB）热失控方面发挥着至关重要的作用。本研究采用刮刀涂布法和重离子径迹刻蚀技术制备了具有优异热稳定性和长循环寿命的聚酰亚胺基共价有机骨架（PI_COF）隔膜。具体来说，将COF300简单地涂覆在具有直通孔的聚酰亚胺基径迹蚀刻膜（PI_TEM）的表面上，该膜提供了刚性框架和300℃的高温稳定性。这些特性有利于抑制热失控，而大孔的多孔COF300增加了电解质的润湿性，有利于锂离子迁移并抑制锂枝晶的生长；因此，获得了具有优异循环性能和高倍率容量的LIB。配备 PI_COF 隔膜的电池在 1000 次循环后可提供 90.0 mAh g ^–1 的高容量。具有高热稳定性的PI_COF隔膜在LIB中表现出较长的循环寿命。这些特性有利于提高LIB的安全特性以及加速PI_COF隔膜的实际应用进程。