A ZnFeNiCoCr high-entropy alloy for efficient bifunctional oxygen electrocatalysis

The dearth of efficacious and economic bifunctional oxygen electrocatalysts has constituted a significant impediment to the actual implementation of high-performance metal-air batteries. Here, we construct an efficacious bifunctional oxygen electrocatalyst ZnFeNiCoCr high-entropy alloy (HEA) nanoparticles for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) using a facile sol–gel strategy. The synthesized ZnFeNiCoCr HEA exhibits excellent bifunctional properties due to the synergistic effect between the metal elements. The overpotential of 305 mV at 10 mA·cm⁻² for OER and a half-wave potential of 0.864 V for ORR, which is excellent to that of commercial RuO₂ and Pt/C. Consequently, ZnFeNiCoCr HEA is utilized as a cathode catalyst for zinc-air batteries. The specific capacity of a zinc-air battery based on this HEA is 743 mAh·g⁻¹ and the battery undergoes a continuous charge/discharge cycle for over 400 h. The ZnFeNiCoCr HEA catalyst holds significant application potential in diverse electrochemical energy storage and conversion devices.