Supermolecule And Ionic Liquid Assilsted Synthesis Of Molybdenum Disulfide/graphene Hybrids And Their Characterizations And Applications

Bulk MoS₂ is traditionally used as the lubricant due to its two dimensional layer structure.Recently,based on the discovery of single layer graphene,single-or few-layer MoS₂ was synthesized.Because the intriguing structure,the single-or few-layer MoS₂ possesses peculiar properties that are used in the battery materials and the catalyst of hydrogen evolution reaction?HER?.However,the low conductivity and the restacking resulting from the Van der Waals interaction between adjacent planes greatly limit the application of the single-or few-layer MoS₂.Improvement is needed for further applications.To incorporate MoS₂ with conductive substance?like amorphous carbon,carbon nanotube and graphene etc.?is a practical way.Among all the conductive substance,graphene not only has high conductivity and specific surface area,but also has good flexibility and chemical stability.What is more,the layer structure that is analogous to the MoS₂ makes it a suitable matrix for MoS₂ to grow on.In the applications of MoS₂/graphene hybrid materials,graphene inhibits the restacking of the MoS₂,stabilizes the structure and promotes the electron transferring,greatly improves the future of the application.In this paper,a series of MoS₂/graphene materials were synthesized through a hydrothermal route with the help of other reactants?like supermolecule?.Then,characterizations and electrochemical tests were conducted.The forming of the hybrids and the enhancement of its electrochemical properties were discussed.Tests have shown,the MoS₂/graphene materials showed great performances when used as the anode material for lithium ion batteries and high activity for HER;the main research conclusions are as follow:?1?MoS₂/graphene hybrids as anode for lithium ion batteries:MoS₂/reduced graphene oxide?rGO?hybrids were synthesized using commercialized graphene oxide?GO?suspension,Na₂MoO₄ and L-cys with the help of a pillar[5]arene through a hydrothermal route and heat treatment was conducted for further use.Characterizations have shown that few layer MoS₂ was dispersed evenly onto the surface of graphene.When tested as the anode of lithium ion batteries,the reversible capacity of it reached 1289 mAh g^-1 at current density of 100 mA g^-1;high rate tests shown that its reversible capacity was 963 mAh g^-1 at current density of 1000 mA g^-1;after 1100 cycles,the reversible capacity still remained 996 mAh g^-1 at current density of 500 mA g^-1.?2?MoS₂/N-doped graphene composites as anode for lithium ion batteries:First,graphene oxide sheets were prepared from graphite power by the modified Hummers method.Then the MoS₂/N-doped graphene composites were prepared using graphene oxide,NH3 H2O,ionic liquid,Na₂MoO₄ and L-cysteine through a hydrothermal route.Characterizations like XRD,SEM,TEM/HRTEM and XPS were used to study the materials.Electrochemical tests showed that MoS₂/N-doped graphene composites performed well as the anode material for lithium ion storage.Its capacity reached 1169 mAh g^-1 at the current density of 100 mA g^-1,and its capacity is as high as 782 mAh g^-1 at the current density of 1000 mA g^-1.After 800 cycles at the current density of 500 mA g^-1,its capacity stayed at about 800 mAh g^-1 showed its good cycling stability.?3?MoS₂/graphene hybrids as catalyst for HER:MoS₂/rGO hybrids were fabricated using commercialized GO suspension,Na₂MoO₄ and L-cysteine with the help of a pillar[5]arene through a hydrothermal route.XRD,SEM,TEM,IR spectrum and EDS tests were conducted to characterize the materials finding out that the interlayer space of MoS₂ was enlarged from 0.63 nm to 1.0 nm and MoS₂ was evenly dispersed on the surface of graphene providing more active edges.When tested as the catalyst for HER,the material had a low Tafel slope of 44.5 mV/dec.