Interfacial charge-transfer in ZnO@Bi2O3 heterostructures via chemical foaming regulates aqueous zinc–nickel batteries

Aqueous zinc-nickel batteries suffer from severe anode challenges including dendrite growth, self-corrosion, and hydrogen precipitation, which drastically limit their cycle life and performance. Herein, a novel chemical foaming strategy was proposed to scalably fabricate ZnO@Bi₂O₃ heterostructures. ZnO nanocrystals (∼30–80 nm) intimately integrate with Bi₂O₃ via chemically bonded heterointerfaces were prepared combined with thermal decomposition of zinc nitrate hexahydrate and the physical confinement of polyvinylpyrrolidone. Depth-profiling XPS analysis confirms that Bi₂O₃ not only forms a permeable barrier against alkaline electrolyte penetration but also induces interfacial charge redistribution via Bi–O–Zn covalent bonding, which regulates Zn(OH)₄²⁻ migration pathways and suppresses dendrite formation and electrode corrosion. The optimized ZnO@Bi₂O₃-M electrode delivers a coulombic efficiency of over 80 % after 600 cycles at 25 mA cm⁻², accompanied by a specific capacity of 481.8 mAh g⁻¹, and maintains 167.7 mAh g⁻¹ even at 60 mA cm⁻². This study proposes a novel design strategy for high-performance aqueous zinc-nickel battery anode materials via interfacial engineering, coupled with a scalable synthesis route paving the way for industrial implementation.