P-block element modulated 1 T phase MoS₂ with Ru lattice grafting for high-performance Li | |O₂ batteries.

Abstract

The metallic phase MoS₂ (1T-MoS₂) supported metal-nanocatalyst is an appealing material system for accelerating the redox kinetics of non-aqueous Li | |O₂ batteries. However, the drawbacks associated with the surface orbital steric effect and the internal electron coupling results in a detrimental effect for the stability of 1T-MoS₂, especially for the interface charge transfer. This makes it difficult to incorporate guest metal nanoparticles without compromising the 1 T phase support. To circumvent these issues, here we propose a p-block element (In-O) doping strategy to stabilize the 1 T phase MoS₂ by moderating the surface orbital steric effect and strengthening the internal chemical bonding, and thus for the epitaxial Ru nanocatalyst graft on the stabilized 1T-MoS₂ for Li | |O₂ batteries. The experimental and theoretical analyzes indicate that the In-O-MoS₂@Ru enhances the O₂ dissociation and facilitates the adsorption of LiO₂ intermediates. This effect promotes the growth of weakly crystalline Li₂O₂ films during oxygen reduction reaction, which can be more easily decomposed during the oxygen evolution reaction, thereby enhancing the bifunctional-catalytic kinetics. When employed at the positive electrode for non-aqueous Li | |O₂ batteries, In-O-MoS₂@Ru shows an overpotential of 0.37 V and a cycling life of 284 cycles at 200 mA g^-1 with a final discharge specific capacity of 1000 mAh g^-1 at 25 °C.