Fe–Ni Alloy Nanoclusters Anchored on Carbon Aerogels as High‐Efficiency Oxygen Electrocatalysts in Rechargeable Zn–Air Batteries

Abstract In this work, Fe–Ni alloy nanoclusters (Fe–Ni ANCs) anchored on N, S co‐doped carbon aerogel (Fe–Ni ANC@NSCA catalysts) are successfully prepared by the optimal pyrolysis of polyaniline (PANI) aerogels derived from the freeze‐drying of PANI hydrogel obtained by the polymerization of aniline monomers in the co‐presence of tannic acid (TA), Fe 3+ , and Ni 2+ ions. In addition, the optimal molar ratio of the TA, Fe 3+ , and Ni 2+ ions for synthesis of Fe–Ni ANC@NSCA catalysts are 1:2:5, which can guarantee the formation of carbon aerogel composed of quasi‐2D porous carbon sheets and the formation of high‐density Fe–Ni ANCs with an ultrasmall size between 2 to 2.8 nm. These Fe–Ni ANCs consisting of N 4 –Fe–O–Ni–N 4 moiety are proposed as a new type of active species for the first time, to the best of the authors’ knowledge. Thanks to their unique features, the Fe–Ni ANC@NSCA catalysts show excellent performance in oxygen reduction reaction with a half‐wave potential ( E 1/2 ) of 0.891 V and oxygen evolution reaction (260 mV @ 10 mA cm −2 ) in alkaline media as bifunctional catalysts, which are better than the state‐of‐the‐art commercial Pt/C catalysts and RuO 2 catalysts. Moreover, Zn–air battery assembled with the Fe–Ni ANC@NSCA catalysts also shows a remarkable performance and exceptionally high stability over 500 h at 5 mA cm −2 .