Enhanced bifunctional oxygen electrochemical catalytic performance using La-doped CoFe2O4 spinel supported by 3D-G for Zn-air batteries

The preparation of bifunctional catalysts for oxygen reduction (ORR) and oxygen evolution (OER) is crucial for Zn-air batteries. Here, we report a La doped CoFe2O4 spinel catalyst supported on threedimensional graphene (3D-G), where La can facilitate electron transfer from Co to Fe, leading to increased electron cloud density in Fe and improved catalytic performance. The redshift of the G peak in the Raman spectra indicates the interaction between the p bond of 3D-G and d orbitals in La0.2CoFe1.8O4. La0.2CoFe1.8/3D-G exhibits superior ORR performance (E1/2 = 0.86 V vs. RHE) and OER performance (Ej=10 = 1.55 V vs. RHE) to CoFe2O4/3D-G (E1/2 = 0.831 V vs. RHE, Ej=10 = 1.603 V vs. RHE). Furthermore, it demonstrates excellent bifunctional oxygen catalytic performance while maintaining high power density and stability in liquid zinc-air batteries (ZABs) and flexible ZABs (F-ZABs). This work presents a viable strategy for utilizing rare earth element doped spinels to enhance oxygen catalyst and ZABs performance. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.