Highly loaded self-supported hollow urchin-like Metallic Organic Framework for high-performance nickel-zinc batteries

The rational design of the cathode featuring high mass loading and distinctive morphology constitutes a crucial stage in developing aqueous nickel-zinc batteries with high energy density and exceptional stability. In this study, a hollow urchin-like bimetallic organic framework (NiCoBTC-P) grown on nickel foam (NF) with a loading of approximately 10.0 mg cm- 2 is fabricated by a one-step hydrothermal approach and utilized as a cathode for high-performance alkaline nickel-zinc batteries. The introduction of the polyvinylpyrrolidone (PVP) morphology modifier triggers the formation of a distinctive hollow urchin-like structure. This three-dimensional open architecture benefits electrolyte penetration and OH- diffusion, leading to NiCoBTC-P/NF achieving a high area- specific capacitance of 28.6 F cm- 2 at 1 mA cm- 2 . The nickel-zinc battery assembled with NiCoBTC-P/NF as the cathode exhibits a high specific capacity of 2.4 mAh cm- 2 at 3 mA cm- 2 , and maintains capacity retention of 95 % after 1000 cycles. Furthermore, it exhibits a high areal energy density of 3.9 mWh cm- 2 and a peak power density of 32.6 mW cm- 2 . This work presents a novel approach to developing aqueous alkaline nickel-zinc batteries with enhanced energy and power densities and superior cycle stability.