Fe/Co Double Hydroxide/Oxide Nanoparticles on N‐Doped CNTs as Highly Efficient Electrocatalyst for Rechargeable Liquid and Quasi‐Solid‐State Zinc–Air Batteries

Abstract Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the cornerstones of rechargeable zinc–air batteries (ZABs). The exploration and rational design of high‐performance, durable, and nonprecious metal bifunctional oxygen electrocatalysts is highly desired for the large‐scale application of rechargeable ZABs. Herein, an effective and straightforward coupling approach is developed to fabricate high‐performance bifunctional ORR/OER electrocatalysts based on novel nanostructured amorphous bimetal Fe/Co hydroxide/oxide nanoparticles (10–20 nm) inlaid on multiwalled N‐dopted carbon nanotubes (FeCo‐DHO/NCNTs). Fe/Co nanoparticles achieve a maximum contact area on the NCNTs, effectively facilitating the rapid electron transport and preventing the aggregation of nanoparticles. Consequently, the as‐prepared FeCo‐DHO/NCNTs show a half‐wave potential of 0.86 V for ORR and a low operating potential of 1.55 V at 10 mA cm −2 for OER in 1.0 m KOH, superior to most bifunctional oxygen electrocatalysts reported so far. Moreover, the assembled all‐solid‐state zinc–air batteries with FeCo‐DHO/NCNTs catalyst as the air electrode demonstrate remarkable stability over long‐term cycling and excellent charging–discharging performance, with a low voltage gap (1.085 V at 60 mA cm −2 ) and high energy efficiency (60% at 10 mA cm −2 ) under ambient conditions.