A novel process for improving the pore structure and electrochemical performance of wood-derived carbon/MnO composites

Water has different forms of existence in wood (free water and bound water), which can generate different effects on the microstructure of wood. Compared to other methods, the freeze-thawing method is equipped with simple, environmentally friendly, and low-cost features. In this paper, the permeability of wood with different ratios of free water to bound water (water content), as well as the pore structure characteristics and electrochemical properties after carbonization, were investigated by the freeze–thaw method. The results show that dry samples of poplar chips with a moisture content of 15–17% after KMnO₄ and freeze–thaw cycle treatment and carbonization (PC@15%-MnO) have a specific surface area of 936.94 m²/g. The areal specific capacitance is 4784 mF/cm² at a current density of 12 mA/cm², which is 3.3 and 22 times higher than those of wood-derived carbon without freeze–thaw treatment, respectively. Additionally, PC@15%-MnO maintains 80% of its specific capacitance after 2000 testing cycles, indicating that the freeze–thaw method effectively enhances the permeability, pore structure, and electrochemical properties of wood-derived carbon materials. This strategy offers new avenues for the research and application of wood in electrode materials.