CuCo‐Layered Double Hydroxide Nanosheets Grown on Hierarchical Carbonized Wood as Bifunctional Electrode for Supercapacitor and Hydrogen Evolution Reaction

Carbonized wood has great potential as a self‐supported electrode for energy storage/conversion applications. However, developing efficient and economical bifunctional electrodes by customizing the surface structure remains a challenge. This study proposes a novel multifunctional electrode design strategy, using N/P co‐doped carbonized wood (NPCW) as carriers and in situ grows copper nanoparticles (Cu NPs) as nucleation centers to induce vertical growth of CuCo‐layered double hydroxid (LDH) nanosheets along the substrate. This method avoids the disordered stacking of catalysts and forms the “carbon‐metal‐LDH” tertiary conductive network. Therefore, the hierarchical CuCo‐LDH@Cu/NPCW is successfully fabricated. Benefiting from the hierarchical ultrathin nanosheet arrays and the strong electronic interactions between CuCo‐LDH and Cu/NPCW substrates, CuCo‐LDH@Cu/NPCW exhibits a high specific capacitance of 26.24 F cm −2 at 2 mA cm −2 , with a capacitance retention of 96.70% after 10 000 cycling tests. The assembled symmetric supercapacitor (SSC) achieves a high energy density of 0.80 mWh cm −2 at 7.50 mW cm −2 . In addition, CuCo‐LDH@Cu/NPCW exhibits excellent HER performance with high activity (η 10 = 32 mV), low Tafel slope (78 mV dec −1 ), and excellent long‐term stability. This work realizes the controllable preparation of high‐performance bifunctional electrodes and provides new ideas for the application of biomass‐derived materials in energy storage and conversion.