In-situ growth of CoNi bimetal anchored on carbon nanoparticle/nanotube hybrid for boosting rechargeable Zn-air battery

Exploring highly efficient non-precious metal based catalysts for bifunctional oxygen electrode is crucial for rechargeable metal-air batteries. In this study, with MOFs as precursors, a facile coprecipitation method is designed to realize in-situ growth of the CoNi anchored carbon nanoparticle/nanotube (CoNi/N-CNN) hybrid, which can achieve the simultaneous maximum exposure of both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) active centers. Benefiting from the unique structure, the CoNi/N-CNN catalyst exhibits excellent electrocatalytic performance for ORR (Eonset = 1.183 V, E1/2 = 0.819 V) and a low operating voltage of 1.718 V at 10 mA cm-2 (Ej=10) for OER. Delightfully, the home-made rechargeable Zn-air battery with CoNi/N-CNN delivers a high discharge power density up to 209 mW cm-2, and an outstanding charge-discharge cycling stability. The boosted bifunctional elec-trocatalytic activity can be ascribed to the strong coupling effect between Co/Ni center sites and defect -rich N-anchored carbon featured with porous and nanotube structure, which can introduce uniformly dispersed active sites, tailored electronic configuration, superb conductivity and convenient charge trans-fer process. The hybrid non-precious bimetal based electrocatalyst provides the possibility to develop the low-cost and high-efficient ORR/OER bifunctional electrocatalysts in rechargeable metal-air battery. (c) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

In this study, a facile coprecipitation method was used to synthesize CoNi anchored carbon nanoparticle/nanotube (CoNi/N-CNN) hybrid with MOFs as precursors for efficient bifunctional oxygen electrode in metal-air batteries. The CoNi/N-CNN catalyst exhibited excellent performance for both ORR and OER, providing high discharge power density and outstanding cycling stability for rechargeable Zn-air batteries. The enhanced electrocatalytic activity was attributed to the strong coupling effect between Co/Ni center sites and defect-rich N-anchored carbon structures.