Lithium-oxygen batteries (LOBs) with superior energy density are recognized as a promising next-generation energy storage device for electric vehicles. However, the morphology and particle size of Li 2 O 2 as well as the parasitic products Li 2 CO 3 give an essential impact on electrochemical properties . To address these issues, a free-standing Co 3 O 4 -NiO@Ni electrode with Co 3 O 4 -NiO heterostructure nanoneedle arrays on Ni foam was fabricated. The Co 3 O 4 -NiO heterostructure would control the morphology and size of Li 2 O 2 . The free-standing carbon-free electrode design would avoid the generation of Li 2 CO 3 . Ultrathin Li 2 O 2 film is preferentially generated within the Co 3 O 4 -NiO heterostructure nanoneedles during the discharge process. The film-like morphology of Li 2 O 2 would decrease the Li 2 O 2 /electrode interfacial resistance and charge overpotential, and enhance the discharge capacity. The free-standing Co 3 O 4 -NiO@Ni electrode exhibits an improved electrochemical performance with a high discharge specific capacity of 7905 mAh g −1 at 0.1 A g −1 and good cyclic stability of 120 cycles at 0.1 A g −1 with a cutoff capacity of 500 mAh g −1 . This work provides a new strategy for improving the electrochemical performance of LOBs through the morphology control of Li 2 O 2 .
The metallic phase MoS 2 (1T-MoS 2 ) supported metal-nanocatalyst is an appealing material system for accelerating the redox kinetics of non-aqueous Li | |O 2 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-MoS 2 , 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 MoS 2 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-MoS 2 for Li | |O 2 batteries. The experimental and theoretical analyzes indicate that the In-O-MoS 2 @Ru enhances the O 2 dissociation and facilitates the adsorption of LiO 2 intermediates. This effect promotes the growth of weakly crystalline Li 2 O 2 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 | |O 2 batteries, In-O-MoS 2 @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.
危险品化学品经营许可证（带存储）