Preparation And Study Of Mesoporous Tin Oxide Anode Materials For Lithium-ion Battery

As a new-type power,the lithium-ion battery with high voltage,high specific capacity,no memory effect,no pollution and long cycle life,have far and wide application in various field.The anode materials is one of the key factor for the capacity and cycle life of lithium-ion battery,For its high specific capacity,Tin-oxide is a promising candidate of anode materials for rechargeable lithium-ion batteries in the future.In our paper,the mesoporous Tin-oxide as electrode materials was synthesized by molecule template using a cationic surfactant(CTAB)and non-ionic surfactant(NP-10)as template,and the hydrous tin chloride as the inorganic precursor under low ratio of sur/Sn⁴⁺and room temperature,at the same times,in view of the factors which is effect on the formation of mesoporous,such as the pH value,the amount of surfactant,various inorganic precursor.The samples were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscope(TEM),energy spectrum analysis (EDS),TGA-DTA,N₂-adsorption/desorption.By the XRD analysis result,we know that the mesoporous Tin-oxide was successfully synthesized at the ratio 2 of NH₃.H₂O/Sn⁴⁺. From the N₂-adsorption/desorption isotherms,the isotherm sharp which is the Brunauer fourth pattern and the pore size distribution that indicates the feature of mesoporous materials.In the images of TEM,we can see that parts of the sample after being dried at 60℃was crystal,which ruins the order of mesoporous at extent.The TGA of the as-synthesized sample showed the surfactant was mostly removed at 310℃,the pattern of XRD reveal the order of the order of the sample after calcinations at 400℃was destroyed, so we choose the 310℃as the calcined temperature.As a result from the EDS analysis,the calcined sample is primarily Tin-oxide,carbon and a little sodium,bromine,chlorine and SO on.In the last chapter,the electrochemical performances of Tin-oxide materials were studied.First,the mechanism of intercalation and deintercalation of lithium into Tin-oxide was investigated.Second,we learn the electrochemical performance of various Tin-oxide materials synthesized different method.Third,the charge/discharge performance under different electric current density was researched.At last,the mechanism of lithium intercalcation into porous was discussed.Apparently,the cycle performance of order mesoporous Tin-oxide as electrode is the best in the three Tin-oxide materials at the charge/discharge current density of 0.3mA/cm², the first reversible capacity is 600 mAh/g,after 40 cycles,remains 396 mAh/g.With the reducing in current dengsity,the charge/discharge performance of order mesoporous Tin-oxide is in crease in the process of cycling.The first reversible capacity of order mesoporous Tin-oxide charged at 0.2 mA/cm² is 661mAh/g,after 40 cycles,is 536mAh/g.For the porous Tin-oxide materials as electrode,the loss volume of the first irreversible capacity is very bigger than the theory loss capacity,basing on the analysis on voltage-volume curve graph and the graphs of differential capacity vs.voltage,we can conclude that lithium deposited in porous and synthesis more solid electrolyte interphase in the discharge process are responded and the lithium will emerge from the porous with the process of cycle.