Preparation Of Secondary Coated Lithium-ion Battery Anode

Today,the speed of human life is increasing,and at the same time,various energy consumption makes the topography and ecological destruction of the earth,so human beings are committed to seeking new green energy,it is hard to cause nature.Destruction,and the amount of energy generated is very considerable,but relatively,it is limited to time,space,and cannot be supplied anytime,anywhere,so it is one of the most important goals in the development of a portable energy.The lithium-ion batteries has become one of the most popular energy storage devices due to its characteristics of its storage capacity,relatively low materials.However,currently,the storage capacity(372 mAh/g)of lithium-ion batteries in graphite is increasingly unable to meet the needs of people's daily production life,so seeking new lithium-ion batteries is imminent.Silicon,which is high in the earth's crust,the theoretical capacity reach4200 mAh/g,also has a low price,makes it a potential anode material in the future.Moreover,its potential platform during discharge is close to that of graphite,and its safety performance is good.However,because silicon in the charge and discharge cycle will lead to volume expansion,the material will be crushed,resulting in the collapse of the battery structure,so the solution of the prescribed volume expansion is the focus of the current problem.Expanded graphite,which is used as structural support,and process materials by mechanical ball mill,so that the nano-silicon material was coated with expanded graphite.Through SEM,XRD,TGA,Raman,It demonstrates that nano-silica particles on the successful support of the expanded graphite surface and the successful coating of asphalt,and the combined electrochemical cycle performance evaluation is as follows:(1)Experimental data showed that the ball grinding method was treated with ball milling,and the ball resistance of the ball used and the nano-silicon content was found to have an effect on the capacity of the battery.Among them,20%(Si)=15:1 composite material can reach 1044 mAh/g for the first discharge of 100 mA/g 30 cycles,still maintained at 335 mAh/g;15%(Si)=15:1 composite material after the first discharge of 882 mAh/g,30 cycles at 100 mA/g,the battery can be maintained at 390 mAh/g.(2)Secondary coating for some of the raw materials,and it is desirable to improve cycle performance.P270 asphalt was divided into four groups of dissolved in NMP solution,and stirred through heating to give a secondary coating.The cycle performance of the new coating material is significantly improved,indicating that the action of asphalt is obvious.Where Si: asphalt=1:5 electrode material performs asphalt secondary coating,the composite material can reach 487 mAh/g of capacity after 100 mA/g of the first discharge of 902 mAh/g,100 cycles.Through the experiment of this thesis,the conditions of expanded graphite coating nano-silica material were studied,and the two coated were performed by asphalt for the prepared composite materials,improved the capacity of the material and lithium capacity and stability,provide reference for new silicon-based lithium batteries.