Synthesis Of Tin Sulfide/Expanded Graphite Composites And Their Lithium Storage Properties

With the rapid development of science and technology and the continuous improvement of the quality of human life,China's renewable energy is facing a crisis and environmental pollution is gradually increasing.The research and development of high performance energy storage equipment plays an important role in sustainable social development.However,as the use of green energy such as wind energy,solar energy,and tidal energy is limited by its objective factors,the development of electrochemical energy storage technology,changing the traditional model at the current stage,and achieving reasonable energy storage and transmission have become the current research hotspots.At present,the main anode material of commercial lithium ion batteries is graphite.Due to its lower theoretical specific capacity(372 m Ah·g^-1)and poor rate performance,it is difficult to meet contemporary needs.SnS₂ anode material is considered as a high storage lithium anode material with high potential due to its higher theoretical specific capacity,low lithium insertion potential,unique geometry.However,SnS₂ has poor electrical conductivity.When used as a lithium battery negative electrode material,the volume easily expands during charging and discharging,which causes rapid decay of the capacity.Therefore,suppressing volume expansion and improving the conductivity of the material have become the key to research.In this paper,new SnS₂/EG composites were synthesized by stannous chloride and thioacetamide,and expanded graphite as the supporting material,through secondary vulcanization,room temperature stirring and low temperature solvothermal methods.Raman,XRD,SEM,TEM and other characterizations confirmed that SnS₂ was successfully synthesized and supported on the surface of nanographite sheets of expanded graphite.The synergistic effect between SnS₂ and expanded graphite makes SnS₂/EG composites show better cycle stability and rate performance.The specificelectrochemical performance is as follows:?1?The SnS₂/EG composite synthesized under the secondary vulcanization condition,after cycling 150 times at a current density of100 mA·g^-1,the reversible capacity can reach 480 m Ah·g-1.?2?The synthesized SnS₂/EG composite was stirred at room temperature for 150 times at a current density of 100 mA·g^-1.Its reversible capacity was maintained at 550 m Ah·g-1,and its capacity was still at a current density of1 A·g-1 can stay at 210 m Ah·g-1.?3?The solvothermally synthesized SnS₂/EG composite at 75?,after cycling 100 times at a current density of 100 mA·g^-1,the reversible capacity can reach 800 m Ah·g-1.When the battery is at 2 A·g-1 charging and discharging for several times under the current density and then returning to100 mA·g^-1,the reversible capacity can still reach 750 m Ah·g-1.Through the research in this paper,not only several anode materials for lithium ion batteries with potential applications are provided,but also theoretical and technical support for the development of new SnS₂ based lithium battery anode materials.