Preparation And Lithium-ion Storage Property For Metal Compounds With High Capacity

As the most potential storage battery,lithium-ion battery（LIB）is developing towards the directions of higher specific energy and better safety,the key of which is to exploit the superior electrode materials.Metal chalcogenide compounds are one of the most promising anode materials for lithium-ion batteries because of their high theoretical specific capacity.However,the poor conductivity and large volume effect of these materials seriously limit their practical application.For addressing the above issues,this article effectively improves ion diffusion dynamics and structure stability of metal chalcogenide by controlling the material size,element composition and framework structure,such as the design of nano structure,coating carbon arrays and the construction of special framework,which can boost the development and application of metal chalcogenide compound anode materials in lithium-ion battery.（1）For improving the structure stability of metal chalcogenide,this works designed the strategy of nano-materials construction,and prepared Zn Mn₂O₄ nanomaterials by one-step room-temperature liquid phase method.This nano structure can effectively restrain the volume variation and shorten the ion diffusion channels,optimizing the structure stability and enhancing the reaction kinetics,respectively.Thus,the Zn Mn₂O₄ nano-materials express the outstanding reversible capacity(0.1 A g^-1,884.5 m A h g^-1)and excellent long cycle stability(1.0 A g^-1,400 cycles,1028.9 m A h g^-1).（2）In order to simultaneously improve the conductivity and structure stability of metal chalcogenide,in this work,the dual modification strategy of 3D carbon array coating nanomaterials was designed.Meanwhile,3D Zn Sn S₃ nanodots are constructed by the in-situ sulfidation of bimetal Zn Sn-organic frameworks,which are enwound with the connected three-dimensional（3D）N-doped graphene framework.In the designed Zn Sn S₃@NG with hierarchical architecture,the synergistic effect of advanced Zn Sn S₃ nano-materials and the superior-conductive 3D carbon network provides a stable framework structure to regulate the structure pulverization without agglomeration and improves the conductivity to enhance the reaction kinetics synchronously,obviously improving the lithium-ion storage capability.The results of electrochemical performance illustrate that the modified materials obtain a prominent reversible capacity of 516.5 m A h g^-1 at an ultrahigh current density of 5 A g^-1 over 1500 long cycles.（3）In order to comprehensively enhance the reversible specific capacity and cycling stability of metal chalcogenide,the multidimensional modification strategy of nanomaterials design,coating carbon matrix and hollow polyhedron structure construction has been employed in this work.According to the nanoscale Kirkendall effect coupled with hydrothermal method and facile post-calcination,the Co_0.85Se nanograins with polyhedron-in-polyhedron structure can be obtained by the selenylation reaction of zeolitic imidazolate framework（ZIF-67）,which is coated by the in-situ formed amorphous carbon and interconnected graphene nanosheets with enormous N-doping atoms.It is found that this designed dual-carbon structure are good for mitigating the volume variation,and boosting Li/electron transport rate simultaneously,thus obtaining a prominent lithium-ion storage performance.When employed as the LIB anode materials,the Co_0.85Se@NG composites exhibit excellent reversible lithium storage properties and superior capacity retention(2 A g^-1,1000cycles,787.7 m A h g^-1;98.2%).