Research On Preparation Of MoS₂/Reduced Graphene Oxide Composites And Its Electrochemical Properties

Molybdenum disulfide?MoS₂? and graphene are expected to be prepared layered assembly composites due to their special two-dimensional structure. Through controlling the interaction between the two kinds of layer materials, the uniform composite process can be achieved for three-dimensional composites with high conductivity and structure stability. These composites not only provide ample space for intercalation and deintercalation of lithium ion, but also avoid the destruction of structure during the charge-discharge process, thus the composites are expected to be used as anode materials for high performance lithium ion secondary batteries.In this paper, the solvothermal intercalation ultrasonication method has been used to prepare MoS₂ nanosheets with a lateral size from 200 to 500 nm in uniform dispersion with concentration at 0.35 mg/ml. Three dimensional multilayer MoS₂/reduced graphene oxide?RGO? nanocomposites are prepared by a solution-processed self-assembly induced by Na+ ion with in situ chemical reduction method. The results show that the solvothermal intercalation followed by ultrasonication method can obtain higher concentration of MoS₂ nanosheets dispersion and improve the preparation efficiency than ultrasonication method only. Fourier transform infrared spectrum and X-ray photoelectron spectroscopy indicated that the interaction between Na+ ions and oxygen containing groups on graphene oxide?GO? surface is the key to cause self assemblies process. The morphology characterization results show MoS₂ with smaller size were wrapped in large aggregates of RGO and good interface between them. The measurement of lithium ion batteries shows that MoS₂/RGO exhibits excellent reversible capacity, stability and rate capability. Especially, MoS₂/RGO-3 with a weight ratio of MoS₂ to GO of 3:1 shows a maximum reversible capacity of 1180 mAh/g after 80 cycles at current density of 100 mA/g and an excellent rate performance of 750 mAh/g at 3 A/g. Good battery performance of MoS₂/RGO with 3D unique layered-structures are attributed to the combined effects of continuous conductive networks of RGO, good interface facilitating charge transfer, and strong RGO sheets preventing the volume expansion. Results indicate that 3D multilayer MoS₂/RGO prepared by a facile solution-processed assembly can be developed for high-performance LIBs.