Preparation And Electrochemical Properties Of MoS₂ And Its Composites

With the rapid development of portable consumer electronics and new energy vehicles,high specific energy and high specific power lithium ion battery?LIB?materials are required.In this paper,TiNb₂O₇ nanorods,MoS₂ nanosheets,MoS₂@TiNb₂O₇ nanocomposite structures,SnO₂ nanoparticles and MoS₂@SnO₂nanocomposite structures were prepared by sol-gel method and hydrothermal method.The above materials are used as anode materials for LIB,and their electrochemical properties are studied to improve the conductivity and capacity of the electrode materials.The main research content includes the following two parts.The TiNb₂O₇ nanorods were prepared by sol-gel method,and then the MoS₂@TiNb₂O₇ nanocomposite structure was prepared by two-step hydrothermal method combined with hydrothermal method and sol-gel method.XRD,XPS,BET,SEM,EDS and TEM were used to characterize the surface morphology,crystal structure,material composition and bonding properties of the prepared materials.The results show that the TiNb₂O₇ material is a typical nanorod structure with a rod length of about 2-3?m and a diameter of about 100-300 nm.The MoS₂ material has a distinct sheet structure;MoS₂@TiNb₂O₇ is a composite structure.The anode materials of LIB were fabricated using TiNb₂O₇,MoS₂,MoS₂@TiNb₂O₇ materials for comparison.In the potential range of 0.01-3.00 V vs.Li/Li⁺,the LIB based on MoS₂@TiNb₂O₇ exhibits a high capacity of 925 and 771 mAh/g at 50 and 200 cycles at a current density of 0.5 A/g,respectively.Excellent rate performance of 579 mAh/g at 4 A/g.The MoS₂@TiNb₂O₇ negative electrode material has excellent electrochemical properties,excellent reversible capacity,rate performance,and cycle stability.The electrochemical performance of MoS₂ as a negative electrode material is improved by the addition of TiNb₂O₇.The SnO₂ nanoparticles were prepared by hydrothermal method.The MoS₂@SnO₂ nanocomposite structure was prepared by two-step hydrothermal method.The surface morphology,crystal structure and bonding properties of the prepared materials were characterized by XRD,SEM and TEM.The results show that the SnO₂ material is a typical sheet-like structure with a diameter range of 200-250nm.The MoS₂@SnO₂ is a composite structure.The SnO₂ and MoS₂@SnO₂ anode material of LIB were fabricated by the above materials.In the potential range of0.01-3.00 V vs.Li/Li⁺,the LIB based on MoS₂@SnO₂ exhibits a high capacity of 794and 669 mAh/g after 50 and 200 cycles of a current density of 0.5 A/g,respectively.At 4 A/g,it still has a specific capacity of 219 mAh/g.The SnO₂ nanostructure alleviates its deformation during charge and discharge,and the high capacity of SnO₂also compensates for the low capacity and poor conductivity of MoS₂.Therefore,the MoS₂@SnO₂ nanomaterial prepared by this method can use as a negative electrode material for LIB.The MoS₂@SnO₂ negative electrode material exhibits better electrochemical performance than that of pure MoS₂,which includes high specific capacity,good cycle performance and high rate performance.