Coaxial Electrospun Tai Chi-Inspired Lithium-Ion Battery Separator with High Performance and Fireproofing Capacity
Ziyue Zeng, Zungui Shao, Ruimin Shen, Haonan Li, Jiaxin Jiang, Xiang Wang, Wenwang Li, Shumin Guo, Yifang Liu, Gaofeng Zheng
Abstract
Organic flame-retardant-loaded battery separator offers a new opportunity for battery safety. However, its poor thermal stability still poses serious safety issues. Inspired by Tai Chi, an “internal-cultivating and external-practicing” core–shell nanofibrous membrane was prepared by coaxial electrospinning, wherein the shell layer was a mixture of polyvinylidene fluoride, silicon dioxide (SiO 2 ), and graphene oxide (GO) and the core layer contained triphenyl phosphate (TPP). SiO 2 and GO enhanced the thermal stability and electrochemical performance. The encapsulated TPP prevented heat transfer and the degradation of electrochemical performance caused by its direct dissolution. This separator exhibited outstanding thermal stability and flame retardancy: it did not burn and remained relatively intact (91.2%) in an open flame for 15 s. The battery assembled with a composite separator showed excellent performance: the initial capacity reached 164 mA h/g and maintained 95% after 100 charge–discharge cycles. This novel strategy endows high-performance lithium batteries with relatively higher safety.