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

Abstract

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.