Preparation And Electrochemical Properties Of SnO₂/Biomass Carbon Composites

In recent years,with the continuous development of science and technology,people's demand for portable electronic equipment,electric vehicles and other emerging industries is increasing,lithium-ion batteries have been widely concerned.As a new energy equipment,lithium-ion battery has the advantages of outstanding energy density,high coulomb efficiency and stable charge discharge cycle performance.At present,the most widely used anode material is graphite,its theoretical capacity is 372 mAh g^-1,which can not meet the demand of people for high energy density lithium-ion batteries.In order to solve this problem,SnO₂ anode material has been widely studied,and its theoretical capacity can reach 782 mAh g^-1.However,due to the huge volume expansion?>300%?in the process of charging and discharging,SnO₂ anode materials cause serious pulverization and aggregation,so it is of great significance to modify SnO₂ anode materials.In this paper,rice husk,corn straw and hemp straw are used as raw materials to prepare carbon source,which not only reduces the waste of biomass resources,but also reduces the cost of carbon source.Rice husk,corn straw,hemp straw biomass carbon can alleviate the volume expansion of SnO₂,also can improve the conductivity of the electrode,thus improving the electrochemical performance of the composite.In this paper,SnO₂/biomass carbon composite was tested by electrochemistry and its microstructure was analyzed.The main research contents and conclusions are as follows:?1?Rice husk was treated with NaOH solution to extract cellulose,and ultrafine SnO₂ nanoparticles were coated with cellulose as carbon source.SnO₂/rice husk cellulose composite was obtained by hydrothermal reaction and further carbonization.In order to prove the excellent electrochemical performance of SnO₂/rice husk cellulose,the contrast glucose coated ultrafine SnO₂ nanoparticles?SnO₂/glucose?were obtained under the same experimental conditions.It is found that SnO₂/rice husk cellulose has excellent electrochemical performance.The specific discharge capacity of SnO₂/rice husk cellulose can reach 930 mAh g^-11 after 100 cycles at 0.2 C,and it can reach 586 mAh g^-11 at 1 C.?2?Porous corn straw carbon was prepared by soaking corn straw in CaCl₂solution and activating the treated corn straw at high temperature.Through hydrothermal reaction,the ultrafine SnO₂ nanoparticles were put into the porous corn straw carbon channel,and the SnO₂/porous corn straw carbon composite with special three-dimensional structure was obtained.Compared with the pure porous corn carbon,the discharge specific capacity of SnO₂/porous corn straw carbon was greatly improved.The effect of doping ratio on the electrochemical performance of the composite was studied.When the ratio of SnO₂ to porous corn straw carbon is 1:1,the electrochemical performance of the composite is better.After 100 cycles at 0.2 C,the specific discharge capacity can still be maintained at 623 mAh g^-1?3?The mixture of ZnCl₂ and hemp straw was ground and carbonized at high temperature to obtain hemp straw carbon.SnO₂/hemp straw carbon composite was prepared by fully compounding ultrafine SnO₂ nanoparticles with hemp straw through hydrothermal reaction.The effect of different calcination temperature on the electrochemical properties of the composite was studied.When calcination temperature was 500?,SnO₂/hemp straw carbon composite showed more outstanding electrochemical properties.The discharge specific capacity after 100cycles at 0.2 C is stable at 556 mAh g^-1.