Nitrogen-Doped Hierarchical Porous Carbon Films Derived from Metal–Organic Framework/Cotton Composite Fabrics as Freestanding Electrodes for Flexible Supercapacitors

Carbon-based materials are highly desirable for developing flexible supercapacitor electrodes. However, due to the limitations of the carbon electrode structure including the low accessible active surface area, inappropriate porous structure, nonoptimum surface chemical states, and low flexibility, their electrochemical performance is not always the same as expected in flexible supercapacitors. In this study, we develop a freestanding porous nitrogen-doped carbon textile electrode by carbonizing a ZIF-8/cotton composite fabric without involving chemical activation or etching processes. Benefiting from the hierarchical porosity, large specific surface area, nitrogen-doped surface, and robust electrode structure, the resulting electrode shows a high specific capacitance of 375.2 F g–1 (4034 mF cm–2) at 2 mV s–1, long cycling life, and good flexibility. Besides, the assembled symmetric all-solid-state supercapacitor delivers an energy density of 17.0 Wh kg–1 and has potential in powering flexible and wearable electronics.