Electrodeposited Zeolitic Imidazolate Framework-8 Modified Zinc Anode Supported Over Porous Copper Structure for Rechargeable Aqueous Zinc-Ion Batteries

Abstract

Electrodeposition technique is used to create a protective layer of zeolitic imidazolate framework-8 (ZIF-8), a metal-organic framework (MOF), over the zinc-copper (Zn-Cu) structure, forming an efficient anode (ZIF-8/Zn-Cu) for aqueous zinc-ion battery (ZIB). The utilization of ZIF-8 layer extends battery life in symmetric cell configurations to 1000 hours at 0.5 mA.cm-2. In comparison, pristine Zn suffers a sudden voltage drop due to a short circuit after 169 hours, and the Zn-Cu anode fails after 853 hours. Post-cycled anode characterizations and mathematical modelling, by incorporating the Zn2+ transport model with the electrochemical reaction model, revealed that the ZIF-8 layer minimizes Zn dendrites, enhancing the cycle life of ZIBs. The full-cell configuration, ZIF-8/Zn-Cu//-MnO2, exhibits excellent cycling performance at various C-rates (0.4 C to 4 C), delivering an initial discharge capacity of 204.02 mAh.g-1 at 0.4 C (1 C = 820 mA.g-1) and retaining 92.62% of its capacity after 1200 charge-discharge cycles. At a higher C-rate of 4 C, ZIF-8/Zn-Cu//-MnO2 delivers an initial discharge capacity of 64.12 mAh.g-1 with 85.56% of discharge capacity retention after 3000 cycles. This study broadens ZIF-8 MOFs applications in ZIBs and paves the way for developing stable MOF-based anodes for next-generation electrochemical energy storage systems.