Coupling CoNi-LDH and Fe₂N Nanoparticles on N-Doped Biomass-Derived Carbon as Oxygen Electrocatalyst for Rechargeable...

The engineering of structure and composition is crucial and challenging for modulating electrocatalytic activity. Herein, a bifunctional electrocatalyst, CoNi@Fe₂N/C, is designed and prepared by coupling CoNi-layered double hydroxides (CoNi-LDH) nanosheets and Fe₂N nanoparticles on 3D N-doped biomass-derived carbon through pyrolysis and electric field induction. CoNi@Fe₂N/C delivers remarkable bifunctional electrocatalytic activity with a narrow overpotential gap (ΔE) of only 0.63 V for ORR and OER, surpassing commercial Pt/C+RuO₂. Additionally, the aqueous rechargeable zinc-air batteries (RZABs) assembled with CoNi@Fe₂N/C as a catalyst on the air electrode show a high peak power density (177.4 mW cm^-2) and excellent durability (over 360 h). The high stability of 3D biomass-derived carbon assures the high durability of catalysts. Assistance of electric field induction ensures the uniform dispersion of CoNi-LDH nanosheets on 3D N-doped biomass-derived carbon. The interaction at the interface between two components appropriately modulates the electronic structure of hybrids via charge transfer to promote reaction kinetics. This work will provide a practical avenue to create ORR/ OER bifunctional biomass-derived catalytically active carbon hybrid catalysts for efficient RZABs.