Fe and Cu co-encapsulated by nitrogen-doped carbon for zinc-air battery applications

Abstract

Zinc-air batteries (ZABs) have attracted attention for their environmental friendliness, durability, safety and high energy density. The superior performance of rechargeable ZABs hinges on the activity of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Here, we successfully develop a Fe, Cu co-doped ZIF-derived N-doped carbon (FeCux-NC) catalyst, featuring a lamellar “red blood cell” structure. In the ORR process, the optimized FeCux-NC catalyst achieves a half-wave potential of 0.925 V under alkaline conditions, 70 mV higher than commercial Pt/C catalysts, and exhibits good stability. In the OER process, at 10 mA cm−2, the overpotential is measured at 510 mV and the Tafel slope value is 55.2 mV dec−1. When utilizing optimized FeCux-NC catalyst without RuO2 at a catalyst loading of 2 mg cm−1, the assembled ZABs demonstrate a power density of 85 mW cm−2 at 140 mA cm−2, while maintaining excellent cycling stability (with only a 0.11 V increase in the voltage interval between charging and discharging over 300 cycles), thereby realizing the dual function of ORR/OER.