Low‐Curvature Wood‐Derived Thick Electrodes with High Capacity via In Situ Grown Nanoflower‐Like Ni/Co Bimetallic MOFs for Aqueous Nickel–Zinc Battery

Abstract

Nickel–Zinc Battery (NZB) faces a dual bottleneck: limited mass loading capacity stemming from its electrode structure and capacity degradation caused by Ni lattice rotation during charging and discharging. Herein, this study develops a porous carbon current collector with low curvature based on natural wood to optimize the electrode structure, thereby increasing the loading of active substances and significantly accelerating the ion transport kinetics in thick electrodes. Meanwhile, Nickel/Cobal bimetallic metal‐organic framework (Ni/Co‐MOF), serving as active materials, is in situ grown on carbonized wood (CW), which modulates the electronic structure and coordination environment, thereby stabilizing the M‐H2‐H3 phase transition and mitigating stress and lattice degradation. The constructed self‐supported Ni/Co‐MOF@CW (N4C1M@CW‐N2) electrode exhibits a high areal capacity of 1.71 mAh cm−2 at a current density of 5 mA cm−2, with a high active substance loading of 12.3 mg cm−2. In addition, the assembled Ni/Co‐MOF@CW//Zn (N4C1M@CW‐N2//Zn) battery demonstrates excellent electrochemical performance with an energy density of 3.54 mWh cm−2 at a power density of 70.34 mW cm−2. And after 8000 cycles, the capacity retention rate is as high as 88.9%. The synthetic strategy combining a self‐supported wood‐derived electrode with Ni/Co‐MOF provides new directions for the next generation of high‐performance electrochemical energy storage devices.