Controllable morphological transformations of nickel metal–organic frameworks for nickel–zinc batteries

Abstract Constructing hierarchical nanostructures with highly exposed surfaces is a promising strategy for developing advanced cathode materials in aqueous batteries. Herein, we employed a competitive coordination strategy to optimize the characteristics of nickel metal–organic framework (Ni‐MOF). Specifically, the acetate ions were employed as precise regulators, exerting a distinct influence on the morphology of the Ni‐MOF and leading to a structural transition from a block structure to a two‐dimensional (2D) layered structure. The optimized Ni‐MOF exhibits a unique superstructure composed of hierarchical 2D layers assembled into flower‐like architectures. This distinctive superstructure increases the electrochemically active surface area of Ni‐MOF (N‐2) and provides abundant pathways for electron/ion transfer, thereby facilitating efficient electrochemical reactions. Remarkably, the assembled aqueous alkaline N‐2//Zn battery demonstrated enhanced specific capacity (0.446 mAh·cm −2 at 1 mA·cm −2 ) and excellent maximum energy/power density (0.789 mWh·cm −2 /17.262 mW·cm −2 ). This work not only offers valuable insights into regulating MOF morphology, but also makes a contribution toward enhancing the application potential of MOFs in aqueous batteries.