Three-Dimensional Flower-Like MoS2@Carbon Nanotube Composites with Interconnected Porous Networks and High Catalytic Activity as Cathode for Lithium-Oxygen Batteries

Lithium-oxygen (Li-O-2) batteries show great potential to become one of the most promising energy-storage and conversion systems owing to their ultrahigh theoretical specific energy (similar to 3505 Whkg(-1)). However, commercialization of Li-O-2 batteries is constrained by a large charging overpotential caused by the sluggish electrode kinetics and low conductivity of the discharge product, resulting in unsatisfied energy efficiency and poor cyclability. In this paper, aiming to address these issues, we propose unique orderly arranged three-dimensional (3D) flower-like MoS2 nanospheres combined with carbon nanotubes (f-MoS2@CNTs) as an efficient cathode catalyst for Li-O-2 batteries. Homogeneously dispersed CNTs on the surface of MoS2 can not only increase the electrical conductivity and thereby lowering the charge overpotential, but also maintain the structural integrity of the cathode, improving the cyclic reversibility. Benefiting from the unique 3D flower-like structure with an interconnected porous network and the excellent catalytic activity of MoS2, the Li-O-2 battery with a f-MoS2@CNTs catalyst achieved a lower charge overpotential (1.02V) and exhibited excellent cyclic reversibility with 141 cycles until the terminal voltage decreased below 2 V at a current density of 500 mAg(-1). The reasonable design of the f-MoS2@CNTs-based cathode thus provides a promising solution for practical applications of Li-O-2 batteries.