Interface engineering induced selenide lattice distortion boosting catalytic activity of heterogeneous CoSe2@NiSe2 for lithium-oxygen battery

The cactus-like CoSe2@NiSe2 heterogeneous material prepared via interface engineering is favorable for promoting the charge transfer kinetics. It is worth mentioning that the Jahn-Teller distortion degree of CoSe2 and NiSe2 does not match, which can induce disordered atomic arrangement and slight lattice distortion. This disordered atomic arrangement and lattice distortion promote the formation of a large number of active sites by reducing the surface energy, thereby greatly improving the battery performance. [Display omitted] •Lattice-distorted heterogeneous CoSe2@NiSe2 is deliberately fabricated.•The mismatch of the Jahn-Teller effect drives the formation of lattice distortion.•The fine atomic array distortion is the active site for oxygen redox reactions.•The lattice-distorted CoSe2@NiSe2 based Li-O2 cell shows improved performance. The sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics greatly limit the development of lithium-oxygen (Li-O2) batteries. Therefore, developing efficient electrocatalysts with high stability to boost oxygen involved reactions is particularly important for promoting the application of Li-O2 batteries. Here, CoSe2@NiSe2 heterostructure with distinct heterogeneous interfaces was fabricated via deliberate interface engineering. The formation of heterogeneous interface promotes local fine atomic array distortion that can act as an additional active site of ORR/OER. In addition, CoSe2@NiSe2 with a distinct heterogeneous interface is favorable for the formation of built-in electric field during charging/discharging to enable electrodes with fast electrical transfer rates and reaction kinetics. Synergistically, the additional active sites brought by the fine atomic array distortion are highly conducive to the reversible formation and decomposition of the product. Undoubtedly, batteries with CoSe2@NiSe2 exhibit excellent discharge/charge capacity (3530.1 mA h g−1 and 3485.6 mA h g−1), low overpotential (1.21 V) and excellent electrochemical stability for over 1200 h.