Synthesis Of The Ternary Compound Of Tin Selenide Sulfide And Lithium And Sodium Storage Properties

The development of society promotes the advancement of science and technology.Nowadays,people’s progress theme is shifting to green and sustainable energy,which makes a good tendency for the evolution of energy storage batteries.Lithium-ion batteries,which exhibit high energy density and excellent cycling performance,have been widely used for commercial energy storage.Sodium-ion batteries have a lot of advantages,such as high energy density,inexpensive raw materials and low cost,and are considered as the great potential candidate in the scale smart grid field.This work focuses on the anode materials for both lithium-ion batteries and sodiumion batteries.Tin is the one of best choose because of the advantages,such as low cost,high theory specific capacity(for Li-ion battery: 994 mA hg-1;for Na-ion battery: 847 mA hg-1)and environment friendly.However,the problem of volume change can greatly harm its electrochemical performance during cycling.Thus,we successfully synthesize a novel ternary tin-based chalcogenide: SnSe0.5S0.5,and then the modification treatment will be done to further improve the electrochemical properties.This work will demonstrate the synthesis of SnSe0.5S0.5 by polyol-method.Furthermore,a series of characterization and electrochemistry tests will be completed.After analysis,for lithium-ion battery,the SnSe0.5S0.5 anode exhibits a specific capacity of 681 mA hg-1 at 500 mA g-1 after 200 cycles,and for sodium-ion battery,it can sustain a capacity of 350 mA hg-1 after 50 cycles at 200 mA g-1.In order to further improve the Li/Na-ion storage performance of SnSe0.5S0.5,the SnSe0.5S0.5/C composite will be synthesized by hydrothermal method.After modification,carbon bulks and carbon spheres cross-link with the SnSe0.5S0.5 to form a perfect conductive network,and this structure allows the electrochemical performance undergo visible improvement.The SnSe0.5S0.5/C anode for lithium-ion battery can still exhibits a reversible capacity of 625 mA hg-1 after 1000 cycles at 500 mA g-1,and for sodium-ion battery,after 100 cycles at 200 mA g-1,a high discharge capacity of 430 mA hg-1 is kept.Finally,we make analysis to the electrochemistry reaction mechanism in lithiumion battery via the in-situ technology.The results show the electrochemical reaction of anode during the cycling.In addition,the study on pseudocapacitance in SnSe0.5S0.5/C composite demonstrates capacity effect not only accelerates the kinetic process,but it also improves the electrochemical performance.