Pore size distribution modulation of waste cotton-derived carbon materials via citrate activator to boost supercapacitive performance

Abstract

Structural engineering involving pore configuration tuning and specific surface area enhancement is an effective strategy to improve the electrochemical properties of carbon-based capacitors. Herein, the hierarchical porous carbons are extracted from natural waste cottons as advanced electrode materials for supercapacitors via facile carbonization and citrate modification processes. The optimal PC-K (porous carbon with potassium citrate as activator) sample is equipped with remarkable mesopore configuration (1292.9 m2 g−1), considerable specific surface area (1727.9 m2 g−1) and even premier heteroatom content (17.1 at%), owing to the well-designed structural engineering. Further, it displays superb electrochemical performances including high capacity of 273.7 F g−1 at 1.0 A g−1 (maintaining 203.8 F g−1 at 10 A g−1), and long cycling stability with 97.49% capacitance retention after 8000 charge/discharge cycles at 10 A g−1, indicating the significant application potential. Simultaneously, the maximum energy density reaches almost 9.93 Wh kg−1 at a power density of 350 W kg−1 in the two-electrode device. Extensive source, inexpensive cost, and superior electrochemical performances unambiguously suggest that the cotton-derived hierarchical porous carbon materials can be rendered great practical value and broad prospects for supercapacitors.