Fe, N co-doped bifunctional carbon materials derived from ZIF-67 for high-performance zinc-air batteries

Breakthroughs in engineering high-efficiency non-noble electrocatalysts represent the cornerstone for enabling mass commercialization of zinc-air batteries (ZABs). A fundamental research challenge involves concurrently enhancing the electronic conduction and porous architectures of ZIF-67-derived catalysts for both oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). In this study, ZIF-67 serves as a precursor, and a non-precious, highly active bifunctional catalyst, N/FeCoNC (800), is successfully fabricated through Fe, N co-doping. The material features a three-dimensional interconnected pore structure, which in addition to merely enhancing the surface area and porosity, also demonstrates excellent electrical conductivity, where both the OER and ORR processes in ZABs are accelerated. Regarding ORR efficiency, N/FeCoNC (800) exhibits a high onset potential (E onset ) reaching 0.93 V (vs. Reversible Hydrogen Electrode (RHE)), a half-wave potential (E 1/2 ) reaching 0.83 V (vs. RHE), and a limiting current density (JL) of 4.3 mA cm −2 , in line with commercial Pt/C (0.95 V, 0.85 V, 4.4 mA cm −2 ). The catalyst demonstrates exceptional oxygen reduction performance, maintaining a near-ideal 4e − pathway ( n = 3.91–3.99) with 91 % current retention after prolonged 30,000-s operation, indicating strong long-term stability. For OER performance, N/FeCoNC (800) exhibits a low overpotential (273 mV) as well and a favorable electrochemical active surface area (19.75 mF cm −2 ). ZABs assembled with this catalyst shows excellent electrochemical stability, cycling for over 850 h. This study suggests a cutting-edge solution for synthesizing efficient bifunctional precious-metal-free catalysts from doped ZIFs composite materials. • Fe, N Co-doped N/FeCoNC (800) catalyst is fabricated using ZIF-67 skeleton. • N/FeCoNC (800) exhibits remarkable catalytic performance during both ORR and OER. • Assembled ZAB demonstrates excellent cycling stability over 850 h.