NiSe2@NiO heterostructure with optimized electronic structure as efficient electrocatalyst for lithium-oxygen batteries

•Electron redistribution at the interface between NiSe2 and NiO optimizes the adsorption energy of reaction intermediates.•Modulation of electronic density around Fermi energy level generates high conductivity of NiSe2@NiO.•Hierarchical structure of NiSe2@NiO exposures of catalyst active sites and enhances mass transfer.•The discharge specific capacity of the battery is as high as 11512 mA h g−1 and it can cycle steadily for over 360 h.