Study Of Synthesis And Electrochemical Properties Of Two-dimensional Transition Metal Dichalcogenides/carbon Composites

In recent years,with the development of society,energy demand has increased rapidly.At present,over 80%of energy consumption comes from non-renewable fossil fuels such as coal,petroleum,and natural gas.These fossil fuels are increasingly depleted and consumed.The process inevitably releases CO2,nitrogen oxides and other harmful substances,which has caused the greenhouse effect and exacerbated global warming and other serious environmental problems.In order to cope with the energy crisis and environmental issues,there is an urgent need to develop renewable environmentally friendly energy materials and new efficient energy storage systems.Water dissociates hydrogen energy and efficient electrochemical energy storage systems such as rechargeable battery is considered to be the most practical,environmentally friendly and sustainable clean energy.Therefore,the most important thing is to develop catalytic materials which can effectively catalyze water decomposition reactions and energy storage materials that can efficiently store energy.In decade years,ultra-thin two-dimensional(2D)layered transition metal dichalcogenides(TMDCs)have attracted much attention due to their unique properties and huge potential in energy field.In order to achieve its tunable properties and best application performance,the researchers are dedicated to the research of 2D multimetal chalcogenide nanocomposites materials,including ternary metal chalcogenides with good crystal structure,alloyed TMDCs,heteroatom-doped TMDCs and nano-carbon composite structure.These novel two-dimensional multilayered layered chalcogenide nanomaterials show some unique properties and have a variety of potential that can be used for applications including electronic/optoelectronics,catalysis,sensors,biomedicine,energy storage and conversion.In this paper,we obtained the following conclusions by studying the preparation,synthesis and application of the composite structure of molybdenum disulfide and carbon nanomaterials.The details of this dissertation are summarized briefly as follows:1.We prepared single-walled carbon nanotube nonwoven fabrics by a chemical vapor floating catalytic(CVD)process.Then the IT phase MoS2 nanoplates were grown on single-walled carbon nanotube nonwovens in situ by a high temperature hydrothermal reaction.Under multiple synergistic effects,the 1T-MoS2@SWCNTs composite electrocatalysts had an ultra-low initial overpotential of approximately 170 mV,a minimal Tafel slope of 40 mV/decade,and excellent stability.2.The metal phase 1T-MoS2/C composite material with large layer spacing was first synthesized by combining high temperature hydrothermal and physical quenching method.This special 1T-MoS2 and C layer structure had a strong cooperative coupling effect,which made it had a high specific capacity of 410 mAh/g and excellent long cycle stability(1000 cycles)in SIBs application.