<i>Ksp</i> ‐Regulated Electrochemically Etching Strategy: BaSO <sub>4</sub> ‐Decorated NiCo‐LDH with Strong Built‐in Electric Field for High‐Performance Aqueous Alkaline Zinc Batteries
Liuxu Wei, Yupeng Wang, Ran Gao, Jiapei Liu, Qi Zhang, Jun Xing, Xiao-Dan Xia, Zhenyu Xiao, Lei Wang
Abstract
Abstract Although layered double hydroxides (LDHs) provide structural advantages for alkaline zinc‐ion battery (AZIB) cathodes via their inherent layered architecture, their intrinsic low electrical conductivity and anisotropic ion transport limits charge transfer kinetics. A Ksp ‐regulated electrochemical etching strategy is first proposed to solve this challenge by exploiting the dramatic solubility difference between BaSO 4 and Co/NiSO 4 . The thermodynamic selectivity enables the precise construction of BaSO 4 nanodot‐anchored NiCo‐LDH heterostructures (BS@CN‐LDH) within a rapid minute‐scale process, achieving atomic‐level control over heterointerface architecture. Density functional theory (DFT) calculations coupled with UPS analysis reveal a strong built‐in electric field (BEF) at the heterointerface (ΔΦ = 0.70 eV), driving interfacial charge redistribution of 0.013 e from NiCo‐LDH to BaSO 4 . The optimized BS@CN‐LDH electrode material exhibits a high specific capacity of 450.5 mAh g −1 at a current density of 2 mA cm −2 , maintaining 83.3% excellent cycling stability after 10 000 cycles. Moreover, the as‐fabricated BS@CN‐LDH//rGO‐Zn AAZB cell achieves a record energy density of 747.9 Wh kg −1 at a power density of 0.27 kW kg −1 , surpassing most reported zinc‐based energy storage devices. This Ksp ‐regulated etching strategy provides critical insights into electric field engineering of heterostructured materials to resolve the persistent electron/ions transfer kinetics for dramatically increased energy storage performance.