Bimetallic synergy and interlayer π-π modulation in nickel-cobalt metal-organic frameworks enhance the performance of nickel-zinc batteries

This study developed a nickel-cobalt bimetallic metal-organic framework material (NiCo-MOF) with a layered porous structure through a solvothermal synthesis strategy that synergistically regulates the function of organic ligands and solvent ratio. This study used Co2+ doping to induce electronic structure reconstruction of Ni (reduce binding energy) and adjust interlayer π-π stacking (reduce interlayer spacing). The experimental results indicate that, at a Ni/Co molar ratio of 2:1, the NiCo-MOF-4 electrode prepared through the bimetallic synergistic effect achieved performance optimization. The fabricated NiCo-MOF-4//Zn cell exhibits a high areal capacity of 0.44 mAh cm−2 at 3 mA cm−2, with 70% capacity retention after 800 cycles. A high energy density of 3.65 mWh cm−2 with a power density of 645.4 mW cm−2 was achieved. The flexible solid-state NiCo-MOF-4//Zn battery assembled here maintains 60% capacity retention after 100 cycles at a stable open circuit voltage of 1.31 V. The three-dimensional pore channel optimization strategy provides new insights into wearable energy storage devices. By establishing a multidimensional “morphology-composition-interface” regulation mechanism, this work elucidates the structure-property relationships in bimetallic MOFs, advancing the design and application of high-stability nickel-zinc battery systems.