State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, 200050, China.
State Key Laboratory of Materials Processing and Die and Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China.
Adv Mater. 2017 Nov;29(44). doi: 10.1002/adma.201703548. Epub 2017 Oct 16.
Separators play a pivotal role in the electrochemical performance and safety of lithium-ion batteries (LIBs). The commercial microporous polyolefin-based separators often suffer from inferior electrolyte wettability, low thermal stability, and severe safety concerns. Herein, a novel kind of highly flexible and porous separator based on hydroxyapatite nanowires (HAP NWs) with excellent thermal stability, fire resistance, and superior electrolyte wettability is reported. A hierarchical cross-linked network structure forms between HAP NWs and cellulose fibers (CFs) via hybridization, which endows the separator with high flexibility and robust mechanical strength. The high thermal stability of HAP NW networks enables the separator to preserve its structural integrity at temperatures as high as 700 °C, and the fire-resistant property of HAP NWs ensures high safety of the battery. In particular, benefiting from its unique composition and highly porous structure, the as-prepared HAP/CF separator exhibits near zero contact angle with the liquid electrolyte and high electrolyte uptake of 253%, indicating superior electrolyte wettability compared with the commercial polyolefin separator. The as-prepared HAP/CF separator has unique advantages of superior electrolyte wettability, mechanical robustness, high thermal stability, and fire resistance, thus, is promising as a new kind of separator for advanced LIBs with enhanced performance and high safety.
分离膜在锂离子电池（LIBs）的电化学性能和安全性方面起着关键作用。商业上使用的微孔聚烯烃基分离膜通常存在电解液润湿性差、热稳定性低和严重安全问题等缺点。本文报道了一种新型的基于羟基磷灰石纳米线（HAP NWs）的高度灵活和多孔分离膜，具有优异的热稳定性、阻燃性和卓越的电解液润湿性。通过杂交，HAP NWs 和纤维素纤维（CFs）之间形成了分级交联网络结构，赋予了分离膜高柔韧性和强大的机械强度。HAP NW 网络的高热稳定性使得分离膜在高达 700°C 的温度下仍能保持其结构完整性，HAP NWs 的阻燃性能确保了电池的高安全性。特别是，得益于其独特的组成和高度多孔的结构，所制备的 HAP/CF 分离膜与液体电解质的接触角接近零，电解液吸收率高达 253%，与商业聚烯烃分离膜相比，表现出卓越的电解液润湿性。所制备的 HAP/CF 分离膜具有卓越的电解液润湿性、机械坚固性、高热稳定性和阻燃性等独特优势，有望成为一种新型的高性能和高安全性先进 LIBs 用分离膜。
