Developing hierarchical supermacroporous wood-derived carbon structures for thick electrodes in high-energy storage devices

Abstract

The utilization of biomass energy, regarded as one of the most promising renewable energy sources, has emerged as current focal point in research for development of high-performance energy storage devices. Biomass-derived carbon electrodes possess the inherent porous structure of biomass, thereby endowing the electrode with abundant energy storage sites and exceptional conductivity. However, the current research on the porous structure of biomass-derived carbon primarily focuses on the development of micropores and mesopores, while neglecting the discussion on macropores and supermacroporous structures. Here, the surface of wood-derived carbon tracheids has been successfully coated with a highly structured supermacroporous layer through a straightforward filling process. The resulting supermacroporous wood-derived carbon (super-MWC-4) thick electrode preserves the micropore/mesopore structure and the wood tracheids architecture while significantly increasing its pore volume to 0.665 mL g⁻¹. Thanks to its unique structural features, the super-MWC-4 thick electrode exhibits excellent areal capacitance (6.4 F cm⁻²), remarkable energy density (0.48 mWh cm⁻²), superior rate performance, and long cycle stability when used in a symmetric supercapacitor configuration with another identical electrode. Our findings highlight the crucial role of macropore/supermacroporous in enhancing energy storage capabilities of thick electrodes derived from renewable biomass resources such as wood.