Preparation Of Molybdenum Disulfide-based Nanomaterials Applied For Energy Storage

The energy crisis and environmental problems have become the serious challenge in the21st century.Electric cars and large-scale green integrated power grids are effective ways to solve this problem.Among various kinds of energy storage device,lithium/sodium ion batteries with the advantages of high energy density,long cycle life,low cost and environmental friendly have become the potential batteries for grid energy storage and electric cars.Currently,carbon materials such as graphite,carbon nanotubes and graphene are the main electrode materials for LIBs and NIBs,but the specific capacity of carbon anode limits the development of ion batteries,and simple improvement of preparation process is difficult to obtain the breakthrough.Therefore,it's urgent to develop new type of electrode materials with high specific capacity,long cycle life and excellent rate performance.Recently,the research proves that MoS₂ has a better performance of energy storage due to its unique physical and chemical properties.In this thesis,we prepared the hollow MoS₂ nanospheres,MoS₂/Sb 2D composite nanomaterials and MoS₂/SnS/C ternary composites,and their performance of energy storage was studied,the main research contents and innovation points are as follows:?1?The ZnS@MoS₂ core-shell nanospheres were firstly prepared by a nanotemplate-assisted hydrothermal method.After the removal of ZnS with dilute hydrochloric acid,hollow MoS₂ nanospheres were successfully obtained.The as-achieved HNS displayed a unique hollow structure assembled by ultrathin nanosheets with rich defects.Furthermore,the HNS exhibited an enhanced performance in electrochemical energy storage,i.e.it shows a discharge capacity of LIBs with 750 mAh g^-1 at a current density of 100 mA g^-1even after 50 cycles,and a specific capacitance of 142.0 F g^-1 at a current density of 1 A g^-1for the supercapacitor.The values are much higher than solid counterpart sample,the better performance is attributed to the unique structure with higher specific area and shorter length of ion transportation.?2?The development of advanced anode materials is the crux to the enhanced performance of sodium ion batteries,which is a potential substitute to lithium ion batteries.In this work,two-dimensional coupling nanostructures with Sb nanoplates embedded ultrathin few-layered MoS₂ nanosheets?MoS₂/Sb?have been synthesized through a one-pot solvothermal method.The assembled sodium battery with the anode of MoS₂/Sb yields a high reversible capacity of 666 mAh g^-1 and 454 mAh g^-1 at current densities of 0.1 A g^-1 and 10 A g^-1,respectively,demonstrating its good cyclicity and rate performance.The tightly embedded contact between ultrathin MoS₂ nanosheets and Sb nanoplates not only improve the electronic conductivity,but accommodate the volume expansion of metallic Sb and prevent the restacking of few-layer MoS₂ nanosheets.Therefore,the synergetic effects of the two dimensional nanocomponents are responsible for their excellent performance.?3?Two-dimensional MoS₂/SnS/C interoverlapped nanostructure attached with SnS nanoparticles has been prepared through a simple solvothermal method and applied for the LIBs and NIBs.When the composite materials as the anode materials for the LIBs,the electrode deliver a high rate performance and yield discharge capacities of 517 mAh g^-1 and302 mAh g^-1 at current densities of 0.1 A g^-1 and 2 A g^-1,respectively.When the composite materials as the anode materials for the NIBs,the electrode deliver a high rate performance and yield discharge capacities of 541 mAh g^-1 and 418 mAh g^-1 at current densities of 0.1 A g^-1 and 2 A g^-1.