Preparation And Electrochemical Properties Of Si-based And Sn-based Materials For Lithium Ion Battery Anodes

With an array of outstanding advantages,such as high energy density,no memory effect,free of environment pollution and excellent cycle performance,lithium ion battery has become one of the most promising green power source and has been widely applied and highly developed in recent years.However,facing with with the development of electric vehicles and portable electronics,there is a rapidly growing demand for better battery with higher capacity and better cycle performance.In the research of lithium ion battery,the study of lithium ion battery anode materials is a key point.Due to the easy preparation,high theoretical specific capacity,silicon-based and tin-based anode materials have attracted more and more attention over recent years.On the basis of reviewing the research progress of lithium ion battery silicon-based and tin-based anode materials in detail,two kinds of silicon-based anode materials?porous Si@C and porous Si@C/graphene?and three kinds of tin-based anode materials?hollow ZnSnO₃ boxes@Ag,porous NiO/SnO₂ and porous NiO/SnO₂/graphene?were prepared in this work.The composition,morphology and structure as well as their lithium-storage performance were studied.The effects of the as-prepared anode materials' different components and morphologies on the easing of the volume change of the material and the lithium exaction/insertion performance during discharge-charge processes were discussed.The main content of this work in detail are shown as below:?1?Porous Si@C anode dual-material was prepared was prepared via a hydrothermal method and a magnesium reduction process by using glucose as the carbon precursor.The components,structure and the morphology of the material were investigated by means of XRD,SEM,FTIR,Raman and TEM.The lithium-storage performance of the as-prepared porous Si@C anode dual-material was tested as well.The results show that the lithium storage performance of the porous Si@C material with a thin uniform coating layer is improved in comparison with the Si anode material.At the same time,the effect of the carbon layer and the porous structure on the improvement of the lithium-storage performance was also discussed.?2?To improving the performance of material,porous Si@C/graphene anode ternary-material was prepared on the basis of the preparation of the porous Si@C anode dual-material via a two-step hydrothermal method and a magnesium powder reduction process.The components,structure and the morphology of the material were investigated by means of SEM,XRD,FTIR,Raman,XPS and TEM.The lithium-storage performance of the as-prepared porous Si@C/graphene anode ternary-material was tested as well.The results show that the ternary-material has a unique triple buffering structure and has a higher reversible capacity and a better cycle performance in comparison with the silicon and the porous Si@C anode materials.The rate capability test shows that the ternary-material still enjoys all-right cycle stability even at an increased current density.In addition,the formation mechanism of the ternary-nanostructure and the effect of the ternary-nanostructure on the improvement of the lithium-storage performance were also discussed.?3?Hollow ZnSnO₃ boxes@Ag anode dual-material was prepared by using the silver nitrate as the silver precursor.XRD?SEM?TEM?XPS and Ranman were used to characterize the components,structure and the morphology of the material.The lithium-storage performance of the as-prepared hollow ZnSnO₃ boxes@Ag anode dual-material was tested and the results show that the dual-material has a higher reversible specific capacity and better cycle stability and lower resistance in comparison with the hollow ZnSnO₃ boxes.The effect of the addition of silver and the hollow structure on the improvement of the lithium-storage performance was also discussed and the effect of the silver content on the electrode electrochemical performance hollow of ZnSnO₃ cubes @ Ag composite was studied.?4?Porous NiO/SnO₂ anode dual-material was prepared by introducing low active material NiO in SnO₂,XRD?SEM and TEM were used to characterize the components,structure and the morphology of the material.The lithium-storage performance of the as-prepared Porous NiO/SnO₂ anode dual-material was tested and the results show that the the as-prepared material exhibits a good reversibility and a favorable cycle stability.The effect of the addition and the porous ostructure on the lithium-storage performance was also discussed.?5?To improving the performance of material,porous NiO/SnO₂/graphene anode ternary-material with a special stucture was prepared on the basis of the preparation of the porous NiO/SnO₂ anode dual-material via introduction of graphene.The components,structure and the morphology of the material were investigated by means of SEM,XRD,Raman,XPS and TEM.The lithium-storage performance of the as-prepared porous NiO/SnO₂/graphene anode ternary-material was tested as well.Theresults show that the ternary-material has a better cycle performance in comparison with the porous NiO/SnO₂ anode dual-material.In addition,the effect of the special structure on the improvement of the lithium-storage performance was also discussed.