Dual-ligand engineered CoNi alloy/N-doped carbon nanotubes bifunctional ORR/OER electrocatalyst for long-lifespan rechargeable Zn-air batteries

The development of carbon-encapsulated alloy catalysts, through a rational design that integrates highly active Me-N-C sites, is essential for improving the reaction kinetics of both oxygen reduction (ORR) and oxygen evolution reactions (OER). This advancement is pivotal for the progression of efficient rechargeable zinc-air batteries (RZABs). In this study, we investigates a CoNi alloy decorated N-doped carbon nanotube (CoNi-NCNT) electrocatalyst using a dual-ligand strategy. Experimental characterizations and theoretical calculations reveales that the electronic modulation of the 3 d orbitals of the CoNi alloy by the CoN 3 sites enhances electronic conductivity during the ORR/OER process, leading to exceptional bifunctional activity. Electrochemical evaluations demonstrates the outstanding performances of CoNi-NCNT, with a half-wave potential of 0.81 V (versus RHE) for ORR and a low overpotential of 1.52 mV for OER at 10 mA cm −2 . Moreover, the CoNi-NCNT catalyzed Zn-air battery exhibits a remarkable specific capacity of 780 mAh g −1 and an exceptionally extended lifespan exceeding 800 h. This underscores the potential of this alloy strategy in the development of high-performance bifunctional ORR/OER electrocatalysts.