Carbon Nanotubes Grown on Flax Fabric as Hierarchical All-Carbon Flexible Electrodes for Supercapacitors

Hierarchical all-carbon flexible electrodes based on natural fiber textiles have promising applications in flexible energy storage devices, due to their mechanical flexibility, large accessible surface area, and stable high-rate performance. Herein, a supercapacitor electrode based on carbonized natural flax fabric and in situ grown carbon nanotubes is developed. The carbonized flax fabric serves as 3D flexible scaffolds, carbon nanotubes uniformly grown on fabric surfaces provide a large accessible surface area with a tunable volume ratio between micropores and mesopores, and the in situ growth offers closely contacted interfaces. As a result, the optimal electrode exhibits a high surface area of 580 m² g⁻¹, an excellent specific capacitance of 191 F g⁻¹ at 0.1 A g⁻¹, a high cycling retention of 96% after 5000 cycles at 20 A g⁻¹, and a high power density of 3.3 kW kg⁻¹. Such a hierarchical all-carbon architecture provides new design opportunities for wearable electronics and stable energy storage applications.