Iron‐Doped CoNi‐MOF‐Derived Carbon Coated CoNi Alloy Nanoparticles as Bifunctional Oxygen Electrocatalysts for Rechargeable Zinc–Air Batteries

Cost-effective highly efficient and robust bifunctional oxygen electrocatalysts are essential for commercialization of rechargeable zinc air batteries (ZABs). Doping is a simple and effective defect engineering approach for enhancement of electrocatalytic activities. Herein, Fe-doped, carbon-coated CoNi alloy nanoparticle catalysts, Fe-CoNi@C, derived from CoNi bimetallic metal-organic frameworks, are developed as outstanding bifunctional oxygen electrocatalysts for rechargeable ZABs. Fe-CoNi@C achieves an ultrasmall voltage gaps at 10 mA cm^-2 (ΔE₁₀) of 0.668 V, significantly smaller than 0.767 V of (Pt/C + IrO₂). The Fe-CoNi@C based ZAB delivers a high peak power density of 307.7 mW cm^-2 at a high current density of 521 mA cm^-2, largely surpassing the (Pt/C + IrO₂) based one (199.7 mW cm^-2 at 310 mA cm^-2), and exhibits excellent cycling stability with a stable operation of up to 1800 cycles (600 h), much longer than 940 cycles (313 h) achieved by the (Pt/C + IrO₂) based one.