Study On The Preparation And Lithium Storage Of The High-Performance Lithium Anode Materials Derived From Co-MOF

With the development of science and technology,energy storage equipments closely related to a variety of electronic digital products draw more and more extensive attention.Among them,lithium-ion battery?LIBs?as a clean energy,with long cycle life,high energy density,no memory effect,environment-friendly cause peoples'interest.However,due to the growing energy needs of people,the electrochemical and safety performance of LIBs also should be improved.Therefore,the development of new positive and negative materials,electrolytes,separator and other components of the battery has become a hot spot in the field of energy storage research.The current commercial LIBs anode material---carbon-based materials become an important factor in the further development of LIBs due to their own structural constraints,thus finding a new alternative of carbon material is particularly important.Metal-organic framework material?MOFs?is a kind of coordination polymer which has been developed rapidly in the past ten years.Transition metal ions are used as connection points and organic ligands are used to support 3D extension structure by self-assembly.The novel material general y has high porosity,adjustable channel pore size,large specific surface area and diverse topology which is widely used in catalysis,gas storage,sensor design,separation and energy storage.In this paper,a novel hexadecahedron consisting of N-doped carbon-coated cobalt sulfide cubes was designed based on the transition metal Co-based MOF template and its lithium ions storage properties were studied.In this paper,a hexadecahedron consisting of cobalt disulfide particles coated with nitrogen-doped carbon?denoted as CoS₂@NCH-600?were synthesized by pyrolysis and sulfuration of Co-based MOF template.The hexadecahedron consisting of cobalt particles coated with nitrogen-doped carbon denoted as?Co@NCH-600?,which is uniform in size and morphology,is synthesized by adjusting different pyrolysis temperatures,and then sulfured with sulfur powder to form the final CoS₂@NCH-600 product.The CoS₂@NCH-600 material has a very special structure:many shel-core structural Co@NCH-600 stack together product lots of channels.When CoS₂@NCH-600 as anode material in LIBs,these channels not only make electrolyte infiltrated into the electrode material more completely but also greatly al eviate the expansion problems during cycling.In addition,CoS₂@NCH-600 with shel-core structure has a great advantage in shortening the ion and electron transfer path.At the same time,nitrogen-doped carbon shell forms a highly conductive network,which improves the conductivity of the whole electrode material.As a result,the unique CoS₂@NCH-600 exhibits excel ent electrochemical performance.When the current density is 1 A g^-1,the charge capacity still maintains 779 mA h g^-1 after 1000 cycles.Even at a high current density of 20 A g^-1,there is still a charge capacity of 220 mA h g^-1 and the capacity is restored to initial when the current is back to 2 A g^-1.The excellent cycle life and outstanding rate performance make CoS₂@NCH-600 anode material have a brilliant prospect in practical application.