No abstract

The crumpled N-doped reduced graphene oxide wrapped Mn 3 O 4 nanorods (Mn-NrGO) composite are synthesized via a combination of spray pyrolysis and a hydrothermal process for lithium ion batteries. The Mn 3 O 4 nanorods are uniformly dispersed in the conductive matrix of crumpled N-doped reduced graphene oxide, forming a uniform wrapped composite and stopping them from restacking, which synergistically enhanced the Li + ion conductivity. The well-defined Mn 3 O 4 nanorods, strong interaction between Mn 3 O 4 and NrGO, and highly graphitic properties of Mn-NrGO result in superior reversible capacity, long cycle life, and superior rate performance of approximately 1500 mAh/g at 0.1 C after 100 cycles and >660S mAh/g at 1.0 C after 500 cycles. K E Y W O R D S anode, lithium ion batteries, manganese oxide (Mn 3 O 4), nitrogen doped reduced graphene oxide (NrGO), spray pyrolysis

Low-cost, vanadium-based mixed metal oxides mostly have a layered crystal structure with excellent kinetics for lithium-ion batteries, providing high energy density. The existence of multiple oxidation states and the coordination chemistry of vanadium require cost-effective, robust techniques to synthesize the scaling up of their morphology and surface properties. Hydrothermal synthesis is one of the most suitable techniques to achieve pure phase and multiple morphologies under various conditions of temperature and pressure. We attained a simple one-step hydrothermal approach to synthesize the reduced graphene oxide coated Nickel Vanadate (rGO@Ni3V2O8) composite with interconnected hollow microspheres. The self-assembly route produced microspheres, which were interconnected under hydrothermal treatment. Cyclic performance determined the initial discharge/charge capacities of 1209.76/839.85 mAh g−1 at the current density of 200 mA g−1 with a columbic efficiency of 69.42%, which improved to 99.64% after 100 cycles. High electrochemical performance was observed due to high surface area, the porous nature of the interconnected hollow microspheres, and rGO induction. These properties increased the contact area between electrode and electrolyte, the active surface of the electrodes, and enhanced electrolyte penetration, which improved Li-ion diffusivity and electronic conductivity.