Zincophilic Surface Engineering Enables Fast, Reversible Zn Plating/Stripping for High-Rate Alkaline Zn–Fe Flow Batteries

Alkaline zinc–iron flow batteries (AZIFBs) have broad application prospects in large-scale energy storage because of their inherent safety and low cost. Nevertheless, their commercial viability is hindered by zinc dendrite formation and dead zinc accumulation, especially under high current densities, where long-term stability remains a critical challenge. In this work, a highly zincophilic electrode is engineered by modifying carbon felt with indium oxide nanoparticles (In2O3-CF). This design provides uniform nucleation sites, lowers the nucleation overpotential, accelerates zinc deposition and stripping kinetics, and suppresses the hydrogen evolution reaction (HER). The In2O3-CF electrode enables an AZIFB to achieve a high power density of 955 mW cm–2 at 90% SOC. More importantly, the battery demonstrates exceptional long-term stability at a high current density of 160 mA cm–2, maintaining a Coulombic efficiency of ∼99.4% and an energy efficiency of ∼80.3% over 2000 cycles. This work highlights an effective electrode design strategy for achieving high-rate and long-life performance in zinc-based flow batteries.