s Co Nanoparticles Decorated MoS2 Nanosheets Grown on Reduced Graphene Oxide as Cathode Catalyst for Li-air Batteries

Background: Li-air batteries have attracted huge attention in recent years due to the ultrahigh theoretical specific energy. The development of high-performance and low-cost cathode electrocatalysts for Li-air batteries is of great importance and has faced great challenges. Objective: This study aimed to design a new kind of cathode catalyst material for Li-air batteries. Methods: In this study, MoS2-rGO-Co was fabricated through a hydrothermal treatment following a chemical reduction process. A series of characterizations, including XRD, SEM, Raman, and XPS, were employed to explore the structure, morphology, and composition information of MoS2-rGOCo. The performance and stability of the MoS2-rGO-Co-based Li-air battery were tested in electrochemical measurements. Results: A composite of Co nanoparticles decorated flower-like MoS2 nanosheets grown on reduced graphene oxide (rGO), denoted as MoS2-rGO-Co, was successfully prepared. The MoS2-rGO-Cobased Li-air battery showed superior electrochemical performance with a capacity of 6591 mAh g^-1, a reduced overpotential of ∼500 mV, and enhanced cycling stability. Conclusion: Through a combination of hydrothermal method and chemical reduction, the hybrid cathode catalyst of MoS2-rGO-Co was successfully synthesized, which exhibited great electrochemical performance and stability in the Li-air battery. The high electrocatalytic activity of the composite benefits from the synergistic effect of MoS2 and Co as well as the rGO substrate, in which the high conductivity substrate provides the efficient electron transfer channel and the optimized electron structure of active components improves the electrocatalytic activity in battery reaction. All these advantages make great contributions to the superior performance of Li-air batteries. Our strategy paves a new way for exploring excellent electrocatalysts applied to other energy fields.