Flexible Three-Dimensional Hierarchical Porous Multifunctional Electrodes for Enhanced Performance by Electrodepositing Perovskite CeFeO3 on Carbon Foam

Rechargeable lithium-oxygen cells are promising because of their high theoretical energy density, but they still face some challenges for applications. To address the problems like large polarization and poor reversibility of oxygen electrodes, a reversible binder-free three-dimensional (3D) hierarchical porous cathode was constructed by electrodepositing perovskite cerium orthoferrite CeFeO3 nanoparticles on flexible graphite foam (GF) via a facile way. It exhibits a low overpotential for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) and delivers a high initial discharge capacity of 11.53 mAh·cm–2 at 0.04 mA·cm–2, about 10 times that of pristine GF. The charge transfer resistance of GF is reduced by about 81% by CeFeO3, while the ORR and OER peak current densities are increased by 982 and 1167%, respectively. Furthermore, CeFeO3 can efficiently suppress the side reactions of GF to reduce the overpotential and improve the cycle performance during cycles. Multifarious results reveal that the superior catalytic activities of CeFeO3 and hierarchical porous structure are responsible for the excellent electrochemical performance. It paves a novel way to develop a multifunctional electrocatalyst for oxygen electrodes by combining catalysis and microstructure using a green electrochemical method.