Design of Flexible Films Based on Kinked Carbon Nanofibers for High Rate and Stable Potassium?Ion Storage

• 作者: Qiaotian Xiong Hongcheng He Ming Zhang
• 来源期刊: 纳微快报（英文版）
• 年，卷（期）: 2022,（3）
• 页码范围: 184-200
• 页数: 17页
• 语种: 英文

摘要

With the emer-gence of wearable electronics, flexible energy storage materials have been extensively studied in recent years. However, most stud-ies focus on improving the electro-chemical properties, ignoring the flexible mechanism and structure design for flexible electrode mate-rials with high rate capacities and long-time stability. In this study, porous, kinked, and entangled net-work structures are designed for highly flexible fiber films. Based on theoretical analysis and finite element simulation, the bending degree of the porous structure (30％ porosity) increased by 192％ at the micro-level. An appropriate increase in kinking degree at the meso-level and contact points in entanglement network at the macro-level are beneficial for the flexibility of fiber films. Therefore, a porous and entan-gled network of sulfur-/nitrogen-co-doped kinked carbon nanofibers (S/N-KCNFs) is synthesized. The nanofiber films synthesized from melamine as nitrogen sources and segmented vulcanization exhibited a porous, kinked, and entangled network structure, and the stretching degree increased several times. The flexible S/N-KCNFs anode delivered a higher rate performance of 270 mAh -g?1 at a current density of 2000 mA -g?1 and a higher capacity retention rate of 93.3％ after 2000 cycles. Moreover, the foldable pouch cell assembled by potassium-ion hybrid supercapacitor operated safely at large-angle bending and showed long-time stability of 88％ capacity retention after 4000 cycles. This study provides a new idea and strategy for the flexible structure design of high-performance potassium-ion storage materials.