Study On Performance Of Molybdenum Disulfide Composites In Hydrogen Evolution Reaction And Lithium Ion Batteries

With the continuous consumption of non-renewable energy,the pollution of fossil fuels to the environment continues to increase.Hydrogen is one of the cleanest fuel,and correspondingly the preparation of low-cost and high-efficiency catalysts for hydrogen evolution reaction（HER）possesses great social value.5G has sounded a new round of technological revolution for smartphones and new energy vehicles powered by batteries.Rechargeable batteries,which are key components for energy storage,need improved performance derived from high-performance electrode materials.Theoretical and experimental results show that molybdenum disulfide is an efficient catalyst for water splitting with good application prospects and an electrode material for lithium ions storing.In this paper,the following work has been carried out to improve the performance of molybdenum disulfide in electrocatalytic hydrogen evolution and storage of lithium ions:（1）For the first time,we use water vapor as the heating medium,microwave as the heat source,sodium molybdate and thiourea as raw materials,household microwave oven（medium fire mode）and homemade reactor to synthesize molybdenum disulfide.The principle is as follows:first,the mixed solution is kept at60°C for a certain period of time,and after the thiourea is fully hydrolyzed,the aqueous solution is heated by microwave to rapidly evaporate water to generate steam.The steam trapped in the homemade reactor absorbs microwaves to generate high heat,so that the reactants rapidly synthesize the sheet of molybd enum disulfide in 5minutes.（2）Combining oxided graphene and acid-treated carbon nanotubes,which have microwave absorption properties,we have successfully synthesized two-dimensional sheet stack structure of MoS₂/rGO and a 3D structure of MoS₂/CNT（one-dimensional CNTs are interspersed between two-dimensional small layer between molybdenum disulfide）.The combination of graphene or carbon nanotubes with molybdenum disulfide successfully reduced the HER overpotential.The overpotentials of pure MoS₂,MoS₂/rGO-1,MoS₂/rGO-2,MoS₂/CNT-1,MoS₂/CNT-2 at 10 mA/cm² were277 mV,216 mV,218 mV,225 mV,and 194 mV（vs.reversible hydrogen electrode）.And the Tafel slopes were 98.7 mV·dec^-1,56.66 mV·dec^-1,56.76 mV·dec^-1,72.99mV·dec^-1,and 52.70 mV·dec^-1,respectively.The mechanism of the change of the morphology of the composite and the effect of different van der Waals forces between the substrate and molybdenum disulfide on the hydrogen evolution performance were studied.（3）The pure molybdenum disulfide synthesized by microwave is highly self-assembled by the negatively charged Ti₃C₂T_x with the addition of the cationic surfactant dodecyltrimethylammonium bromide（CTAB）.The self-supporting film is prepared,and the strength of the film is enhanced by ad ding carboxymethyl cellulose（CMC）binder.It is directly used as a negative electrode material for lithium ion batteries.MoS₂/MXene has a very high capacity.In the first circle,the coulombic efficiency was 72.5%at 50 mAh·g^-1.After 100 cycles of galvanostatic charge-discharge and 90 cycles at different current densities,the specific capacity is maintained above 350 mAh·g^-1.