Competitive Coordination Structure of Interface Enables Synergistic Regulation of Mass-Charge Transfer for Stable Zinc Electrodes under High Current Density.

Aqueous zinc-nickel batteries show great potential for large-scale energy storage because of their inherent safety, high working voltage, and high theoretical specific capacity. However, zinc dendrites and hydrogen evolution side reactions lead to poor stability of zinc electrodes, resulting in a short cycle life of zinc-nickel batteries. To mitigate these challenges, an In-anchored zeolitic imidazolate framework-8 (In-ZIF8) interface layer is constructed in-situ on ZnO as an anode active material of zinc-nickel batteries. The ZIF8 layer with high zinc affinity and a porous structure promotes the dissociation of Zn(OH)42- ions and ion migration, contributing to uniform ion distribution. The anchored In serves as an electron conductor to uniformize the electric field. Meanwhile, the in-situ formation of the interface creates a competing coordination environment, leading to charge redistribution at the ZnO-protective layer interface and causing the reconfigured electronic structure and reduced band gap, further homogenizing the electric field and facilitating the reaction kinetics. With synergistic regulation of mass and charge transfer, dendrite-free and side reaction-free Zn deposition is achieved. A symmetric cell with the In-ZIF8-modified zinc electrode exhibits good cycling stability (over 500 h at 17 mA cm-2, 17 mAh cm-2). The assembled zinc-nickel battery (N/P = 1) delivers an extended cycling lifetime, achieving a stable cycling performance over 840 h for the 5 Ah battery configuration at 10 A (∼138 mA cm-2). This work proposes a facile method of reasonable interface engineering for improving the stability of the zinc electrode at high current density.