Constructing the double oxygen vacancy in Ni-doped Co3O4 to enhance the electrochemical performance in lithium-oxygen batteries

Lithium-oxygen batteries (LOBs), as an outstanding representative of high-energy-density energy storage technology, are gradually becoming a research focus. However, its technological breakthrough is still limited by several key challenges, including the slow reaction kinetics, the irreversible accumulation of discharge products, and the complex side reactions. In response to the existing challenges, this study successfully develops an oxygen- rich metal-organic skeleton-derived nickel doping Co3O4 material (Ni-Co3O4-Vo) as a cathodic catalyst for LOBs through an integrated design strategy ranging from surface structure to electronic structure. This strategy cleverly combines two techniques, nickel doping and NaBH4 chemical treatment, to achieve the efficient introduction of double oxygen vacancies. The nickel doping strategy has a profound impact on the electronic structure of the catalyst and enhances the electrical conductivity of the material, while the NaBH4 treatment primarily affects the surface structure of the catalyst, effectively increasing the specific surface area and thus exposing more potential active sites. More importantly, the presence of oxygen vacancies in the material also significantly affects the electron cloud distribution around the Co-O bond, optimizing the adsorption energy of the intermediates on the catalyst surface. The series of well-designed structural and electronic property adjustments collectively endow the Ni-Co3O4-Vo material with excellent catalytic activity. Consequently, the obtained Ni-Co3O4-Vo cathode demonstrates significantly enhanced electrochemical performance, achieving a specific capacity of up to 5275 mAh g-1 and 337 stable cycles, together with a "fast-charge-slow-discharge" cycling capability of more than 1400 h. This work offers a novel perspective for the development of LOBs cathode catalysts.