Interfacial nanoparticles of Co 2 P/Co 3 Fe 7 encapsulated in N-doped carbon nanotubes as bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries

Heterostructures have been generally proven bene ficial to the electrocatalysis performance due to tailorable electronic structures. Herein, we develop a facile one-step strategy to synthesize Co 2 P/Co 3 Fe 7 heterointerfacial nanoparticles encapsulated within N-doped carbon nanotubes (Co 2 P/Co 3 Fe 7 @N-C). The electrocatalyst exhibits a bifunctional oxygen evolution/reduction reaction (OER/ORR) activity ( DE = 0.669 V) that far exceeds that of commercial Pt/C + Ir/C catalysts ( DE = 0.76 V). In this study, Co 2 P/ Co 3 Fe 7 @N-C-based zinc air batteries (ZABs) exhibit a higher power density (151.6 mW/cm 2 ) and longer stability (1600 cycles) than commercial Pt/C + Ir/C-based ZABs (80 mW/cm 2 , 450 cycles). Density functional theory calculations reveal that the interfacial electronic interaction between Co 2 P and Co 3 Fe 7 play key roles in boosting bifunctional ORR/OER ef ficiency. This work may open a new pathway for the rational design of superior bifunctional oxygen electrocatalysts for rechargeable metal-air batteries through interfacial engineering. (c) 2024 Published by Elsevier Ltd.