Ni/Co Nanoparticles Supported on N-Doped Hollow Carbon Composites as High-Performance Catalysts for Rechargeable Li-O2 Battery

Lithium-oxygen (Li-O 2 ) batteries have become one of the most promising next-generation energy storage systems due to their high theoretical specific capacity. However, Li-O 2 batteries still face the problem of high charging voltage due to incomplete decomposition of discharge products. Here, a nitrogen-doped hollow spherical carbon composite containing Ni/Co nanoparticles was prepared by hydrothermal and pyrolysis strategies, and used as positive catalyst for Li-O 2 batteries to adjust the morphology of the discharge product. The porous hollow carbon sphere provides sufficient space for the storage of discharge products. Nitrogen-doped carbon nanospheres can change the local charge density, improve the electron transfer performance, and reduce the resistivity of carbon nanospheres. In addition, the abundant M-N x active groups enhance the affinity of the positive electrode to the reaction intermediates, thus regulating the morphology of the discharge product Li 2 O 2 . Benefiting from the above synergistic advantages, the electrochemical performance of the Li-O 2 battery including round-trip efficiency, discharge capacity, and cycling stability is greatly improved. Graphical Abstract