Trimetallic spinel Fe-Co3O4/NiCo2O4 nanoboxes as efficient cathode electrocatalyst for lithium-oxygen batteries

Lithium-oxygen (Li-O 2 ) batteries stand out as ideal candidates for next-generation energy storage due to their ultrahigh theoretical energy density. However, the sluggish kinetics of the oxygen reduction and evolution reactions at the cathode pose a major challenge, necessitating the development of efficient catalysts to overcome practical limitations. Herein, Fe-doped Co 3 O 4 /NiCo 2 O 4 heterostructures are synthesized as cathode catalysts via chemical etching, cation exchange, and thermal oxidation. The etching process creates a stable hollow nanocube structure that maximizes active site exposure while providing ample space for Li 2 O 2 storage and ion diffusion. A strongly interactive heterojunction forms at the Co 3 O 4 /NiCo 2 O 4 interface, with Fe doping further enhancing interfacial electron interaction to boost catalytic activity. When used in Li-O 2 batteries, this catalyst enables a remarkable discharge capacity of 9572 mAh g −1 , a low overpotential of 1.01 V, and stable cycling over 110 cycles, providing a new strategy for developing high-performance Li-O 2 battery cathodes.