Modulating Electronic Structure with Copper Doping to Promote the Electrocatalytic Performance of Cobalt Disulfide in Li–O2 Batteries

Introducing heteroatom into catalyst lattice to modulate its intrinsic electronic structure is an efficient strategy to improve the electrocatalytic performance in Li-O2 batteries. Herein, Cu-doped CoS2 (Cu-CoS2 ) nanoparticles are fabricated by a solvothermal method and evaluated as promising cathode catalysts for Li-O2 batteries. Based on physicochemical analysis as well as density functional theory calculations, it is revealed that doping Cu heteroatom in CoS2 lattice can increase the covalency of the CoS bond with more electron transfer from Co 3d to S 3p orbitals, thereby resulting in less electron transfer from Co 3d to O 2p orbitals of Li-O species, which can weaken the adsorption strength toward Li-O intermediates, decrease the reaction barrier, and thus improve the catalytic performance in Li-O2 batteries. As a result, the battery using Cu-CoS2 nanoparticles in the cathode exhibits superior kinetics, reversibility, capacity, and cycling performance, as compared to the battery based on CoS2 catalyst. This work provides an atomic-level insight into the rational design of transition-metal dichalcogenide catalysts via regulating the electronic structure for high-performance Li-O2 batteries.