Wood derived carbon electrodes containing carbonized wood fibers with high specific surface area for high-areal-performance supercapacitors

The unique hierarchical porous structure and components of wood enable the direct utilization of carbonized wood as both the active substance and self-supporting electrodes in supercapacitors, eliminating the need for additional conductive agents and binders. Nonetheless, the directly carbonized wood electrode exhibits a limited specific capacity due to its inherently low specific surface area. Therefore, in this study, wood derived carbon electrode CW-0 had been successfully produced by making full use of wood components and structures, which is enriched with carbonized wood fibers at the top and bottom layers of carbonized wood, and significantly enhanced the electrochemical performance of the wood-derived carbon electrode without adding other pseudocapacitive materials or carbon materials. The prepared CW-0 electrode demonstrated a significantly higher specific surface area and enhanced porosity, contributing to its excellent electrochemical performance primarily attributed to its abundant carbonized wood fiber structure. The areal capacitance of the CW-0 electrode was up to 9578.9 mF cm−2 at 5 mA cm−2, with a retention rate of 99.4 % after 15,000 cycles. The CW-0//CW-0 symmetric supercapacitor assembled under alkaline electrolyte exhibited an energy density of 0.467 mWh cm−2 at a power density of 1.68 mW cm−2, maintaining 97.4 % capacitance retention after 20,000 cycles. In Na2SO4 pollution-free neutral electrolyte, CW-0//CW-0 symmetric supercapacitors still exhibited good electrochemical performance and excellent stability, with a wide 1.8 V voltage window and a high energy density of 0.5 mWh cm−2 at a power density of 2.46 mW cm−2. © 2024 Elsevier B.V.