Mesoporous Co-CoO/N-CNR nanostructures as high-performance air cathode for lithium-oxygen batteries

A bifunctional air cathode for the electrochemical oxygen reduction and evolution in a Li-O₂ battery comprising Co-CoO nanoparticles embedded in the nitrogen-doped carbon nanorods (Co-CoO/N-CNR) is presented. The nanorod morphology with mesoporous nanostructures can handle continuous formation and decomposition of Li₂O₂ and favors the transport of electrons and ions, therefore improves the rate capability and cycle stability. Moreover, the hierarchical mesoporous Co-CoO/N-CNR reduces the overall overpotential over the cycle and decreases the side reaction between Li₂O₂ and carbon surface, leading to a significant enhancement of the specific capacity and cycling capability. With the cooperative effect of Co-CoO/N-CNR and porous nature, Co-CoO/N-CNR cathode delivers a high discharge specific capacity of 10,555 mAh g⁻¹ at 100 mA g⁻¹ and long cycle stability for over 86 cycles without any capacity loss at a high cutoff capacity of 1000 mAh g⁻¹. Furthermore, excellent performance of 7514 mAh g⁻¹ at 500 mA g⁻¹ is achieved.