Investigation On The Preparation And Lithium Storage And Photocatalytic Performances Of SnO₂/Graphene Composites

SnO2 is a wide band gap n-type semiconductor with unique optical and electrical and catalytic properties.It is widely used in lithium ion batteries,photocatalysis and gas sensors.As anode material of lithium ion batterys,SnO2 has the advantages of high theoretical capacity,low voltage platform,environmental friendliness and rich mineral resources,and it has been considered as one of the most promising anode materials of lithium ion batterys.As photocatalyst,SnO2 has the advantages of fast photocatalytic reaction speed,mild reaction conditions,low energy consumption,good catalytic performance and no secondary pollution.However,the large volume expansion of SnO2 during the charging and discharging process results in poor cycling and high current charge-discharge performance of electrode materials.Due to its wide band gap,fast recombination of photogenerating carriers results in low photocatalytic efficiency and it can only absorb ultraviolet light.In this paper,SnO2/RGO composites were prepared by coprecipitation/freeze-drying.The lithium storage performance as anode materials for lithium ion batteries and photocatalytic degradation of methylene blue of SnO2/RGO composites were studied.SnO2/RGO composites were prepared by coprecipitation/freeze-drying method.The effects of different proportions and calcination temperatures on lithium storage and photocatalytic performances of the materials were investigated.The electrochemical performance of the materials were studied by cyclic voltammetry,electrochemical impedance spectroscopy and galvanostatic charge-discharge.XRD,SEM,XPS,Raman and BET were used to characterize the structure of the materials.The results showed that the samples with sintering temperature of 500℃ and GO:SnCl4·5H2O is 1:3(SnO2/RGO-500-3)had the best lithium storage performance and photocatalytic performance.At the current density of 0.1 A/g,the specific capacity of the first discharge of the material reaches 1348 mA h/g,and the specific capacity of the discharge after 100 cycles is 679 mA h/g.Catalytic degradation of methylene blue under light also showed the best activity.