Coordination-etching fabrication of ZIF-67-derived nickel–cobalt layered double hydroxides for aqueous Ni-Zn batteries

Abstract

Aqueous zinc-based batteries (ZBBs) are promising for grid-scale energy storage owing to their safety and cost-effectiveness; however, their practical application is hindered by rapid capacity fading and unstable cathodes caused by sluggish Zn²⁺ kinetics and structural degradation in alkaline electrolytes. Herein, to address these challenges, we utilize amphiphilic polymer (PVP) to realize the composite of nickel-based complexes and ZIF-67. The hierarchical nickel–cobalt layered double hydroxide (NiCo-LDH) was prepared by metal ion exchange strategy. PVP-mediated-mediated suppression of agglomeration, combined with Ni²⁺-induced framework reconstruction, synergistically modulated the morphology, resulting in mesoporous nanosheets with hydroxyl-rich surfaces. This design generated high-valence Co³⁺ species through charge-compensation-driven oxidation, thereby significantly accelerating Zn²⁺ ion diffusion and reducing the interfacial resistance. The optimized NiCo-LDH-100 cathode (Ni:Co = 3:1) achieves cycling stability and exceptional energy/power densities (0.49 mWh cm^–2/49.1 mW cm^–2). This study provides a solution for the cathode instability of Ni-Zn batteries through a coordination-derivatization strategy, which is promising for advancing sustainable energy storage technologies.

Graphical Abstract