Porous Carbon Networks Decorated with Cobalt on CoFe₂O₄ as an Air-Breathing Electrode for High-Capacity Rechargeable Lithium-Air Batteries: Role of Metallic Cobalt Nanoparticles

The development of cost-effective efficient bifunctional electrocatalysts for metal-air batteries is an important aspect for its commercialization. We demonstrate the effect of Co nanoparticles and/or the porous carbon matrix in pristine CoFe₂O₄ (CFO) electrocatalysts towards the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). The Co/CoFe₂O₄-carbon network (CCFOC) with a high surface area and good conductivity offered more active sites for oxygen adsorption as well as accelerated electron transfer kinetics, leading to superior ORR and OER activities. A Li-air battery split cell was fabricated using the CCFOC as an air-breathing electrode, which exhibited a high discharge capacity of 4320 mAh g⁻¹ at a high current density of 100 mA g⁻¹ with an acceptable cycling stability and columbic efficiency. The fabricated coin cell or the split cell Li-air battery could power a commercial 2.8 V green LED bulb continuously for more than 6 h.