Activated Carbon Nanotube Fiber Fabric as a High-Performance Flexible Electrode for Solid-State Supercapacitors

Owing to their features of excellent mechanical flexibility, high conductivity, and light weight, carbon-based fiber fabrics (CBFFs) are highly attractive as flexible electrodes for flexible solid-state supercapacitors (SCs). However, the achieved areal capacitance of most CBFFs is still unsatisfactory. Carbon nanotube fiber fabric (CNTFF) is a new kind of CBFF and could provide a potential alternative to high-performance flexible electrodes. Herein, we report the activation of CNTFF using a facile thermal oxidation and acid treatment process. The activated CNTFF shows an exceptional combination of large areal capacitance (1988 mF cm–2 at 2 mA cm–2), excellent rate performance (45% capacitance reservation at 100 mA cm–2), and outstanding cycle life (only 3% capacitance decay after 10,000 cycles). The constructed solid-state SC reaches a maximum energy density of 143 μWh cm–2 at 1000 μW cm–2 and a maximum power density of 30,600 μW cm–2 at 82 μWh cm–2. Additionally, this device possesses good rate performance along with superb cycle stability and excellent mechanical flexibility under various bending conditions. Our present work therefore offers a new opportunity in developing high-performance flexible electrodes for flexible energy storage.