In situ fabrication of nitrogen-doped carbon nanosheet/wood-derived carbon composites and their energy storage performance

Aiming to address limited vertical channel utilization, scarce active sites, sluggish ion migration and inferior rate capability of wood-derived carbon electrodes, nitrogen-doped carbon nanosheets/wood-derived carbon composites (NCS/WC-T) were fabricated by employing basswood processing residues as the carbon framework. A urea-assisted Fe-catalyzed in-situ chemical vapor deposition strategy was adopted to controllably grow nitrogen-doped secondary carbon nanosheets on the inner and outer surfaces of the wood-derived carbon framework, thereby forming hierarchically porous architecture. The results showed that the NCS/WC-800 composite prepared at 800℃ perfectly retained the vertically-aligned through-pore structure of natural wood, and uniformly dense and interwoven feather-like two-dimensional nanocarbon sheets were in-situ grown. The composite possessed a specific surface area (912 m²·g⁻¹), high pore volume (0.78 cm³·g⁻¹) and moderate N and O contents (8.0at% and 8.1at%, respectively). At a high mass loading of 56 mg·cm⁻², the NCS/WC-800 composite delivered an areal specific capacitance of 11504 mF·cm⁻² in a three-electrode system, and remained 6715 mF·cm⁻² at 300 mA·cm⁻². The assembled symmetric supercapacitor achieved an areal energy density of 0.8 mWh·cm⁻² at a power density of 2 mW·cm⁻². The constructed zinc-ion hybrid capacitor exhibited an areal specific capacity of 2.2 mAh·cm⁻², with a capacity retention of 81.3% after 20,000 cycles. This work verifies that the developed strategy enables the synergistic integration of oriented wood scaffold, two-dimensional active nano-interfaces and heteroatom-modified carbon structure, offering a promising route for designing advanced biomass-based electrode materials toward high-mass-loading energy storage devices.