Construction of N, O Codoped Petal-like Hierarchical Porous Carbon with an Ultrahigh Specific Surface from Waste Bamboo for High-Performance Supercapacitors

Considering the problems of environmental pollution and treatment costs generated by renewable waste biomass on a global scale, the development of high-performance electrodes utilizing plentiful natural waste biomass as sustainable precursors is essential to facilitate the practical application of supercapacitors. Hence, we develop a facile and efficient method to construct waste bamboo shavings into petal-like hierarchical porous carbon electrode materials with an ultrahigh specific surface area and N, O codoped interfaces through H3PO4-catalyzed hydrothermal pretreatment combined with coactivation by KOH/melamine. The effects of optimal regulation of pore structure and surface modification (heteroatom doping) on the superior electrochemical properties of carbon materials are investigated in depth. The derived carbon materials presenting an excellent potential for practical applications of supercapacitors are mainly attributed to their large specific surface area (3392 m2 g–1), prominent pore volume (2.081 m3 g–1), and petal-like hierarchical porous structure with abundant N, O content, which results in rapid ion diffusion and adequate electrical charge storage as well as contributed pseudocapacitance. 5-BHPC-700-4 exhibits attractive electrochemical properties in a 6.0 M KOH electrolyte, including a delightful capacitance (501.6 F g–1 at 0.5 A g–1 in a three-electrode system) and superior cycling stability (94.2% capacitance retention after 10,000 cycles at 5.0 A g–1). The assembled symmetrical supercapacitor device achieves an impressive energy density of 15.3 Wh kg–1 at a power density of 290 W kg–1. This work provides a valuable reference for the design and preparation of biomass-based hierarchical porous carbon with outstanding supercapacitor performance and low cost.