Research For Preparation And Electrochemical Performance Of Transition Metal(Fe,Co) Chalcogenide(S,Se)

Lithium-ion batteries has drawn wide attention of researchers due to the advantages of high power density,high energy density,long cycle life,charge and discharge rapidly,and environmentally friendly.The traditional commercial anode material graphite cannot meet the current requirements for high safety,high power and high capacity.Therefore,it is urgent to develop new high-performance anode materials,which has important scientific significance and practical application value.Due to the conversion reaction mechanism in the transition metal chalcogenide,higher capacity can be provided.Therefore,we selected the transition metal(iron,cobalt)chalcogen(sulfur,selenium)compounds as specific research objects and prepared them by various chemical methods.The electrode material is modified by graphene or the like to improve their electrochemical performance,and the following results are obtained:1,Graphene-modified iron disulfide material FeS2/G was synthesized by solvothermal method.The electrochemical performance of FeS2 is effectively improved by modified with graphene.2,The cobalt sulfide material embedded in graphene(CoS@G)was synthesized by solvothermal method.When CoS is combined with graphene,the rate and cycle performance are significantly improved.3.The Fe-ZIF@GO precursor was obtained by complexing iron-based zeolitic imidazolate framework(Fe-ZIF)with graphene oxide,and carbon-coated iron diselenide embedded in nitrogen-doped graphene sheets(FeSe2/C@NGS)was obtained by selenization.FeSe2/C@NGS composite shows excellent electrochemical performance.4,The cobalt diselenide embedded in nitrogen-doped carbon sheets(CoSe2@NCS)was obtained by selenizing cobalt-based metal organic framework(Co-MOF)precursor.The nano-scale CoSe2 particles are embedded in the micron-sized NCS to obtain a unique micro-nano structure,which provides a high-speed conductive network and shortens the ion diffusion path,thus exhibiting excellent electrochemical performance.