Wet Chemical Synthesis And Properties Of Tin-based Anode Materials For Lithium Ion Batteries

As an important part of lithium ion battery,the anode materials has a critical role on the performance of the battery.In recent years,there are many studies of anode materials such as Si,Sn,Ge,Sb,their alloys and oxides have received considerable research attention for their high capacity as anode materials for Li-ion batteries.However,the large volume change upon charge/discharge process is a serious limitation as anode material,which leads to mechanical disintegration of the electrodes and rapid capacity fading.In this paper,compound method was applied to improve the electrochemical properties of Sn-based alloy and antimony tin oxide materials.1.A chemical reduction coprecipitation method was used to synthesize SnSb alloy anode material,by combining the electrospinning technology and hydrothermal method,the one dimensional nanofibers structure of PAN-SnSb composite materials and two-dimensional layered structure of RGO-SnSb composite materials were synthesized,respectively.The PAN – SnSb and RGO-SnSb composite anode material exhibits good electrochemical performance,these discharge specific capacities are 503mAh/g and 556mAh/g at current of 0.2A/g after 200 cycles,respectively.2.The SnSbZn-C composite nanofibers were successfully synthesized by electrospinning and carbonization.SnSb and SbZn nanoparticles were encapsulated in nanofibers and form a network structure,which displays remarkable performance through stable cyclability and high storage of lithium.For the 200 th cycle,the discharge capacities remained at 663mAh/g and the capacity retentions was 84%,the highly cycling stability could be attributed to the unique structure to accommodate the volume expansion generated during cycling,and it also prevented the particles from aggregating.3.Antimony tin oxide(ATO)-containing nanofibers were synthesized by a two-step process in this work,including electrospinning of SnCl2/SbCl3/PVP and calcination at 400°C-600°C in air.The electrospun fibers developed from solid to hollow structures through a Kirkendall diffusion process.Moreover,the fibers calcinated at 400 °C exhibited excellent cyclic stability,namely the capacity at the 200 th cycle was 730mAh/g at a current density of 0.2 A/g,which was 76% of its capacity at the 2nd cycle.These values were superior to those calcinated at 600°C,due to the alleviation of volume change,the large surface area and short diffusion length provided by the carbon matrix in the 400°C-treated ATO fibers.These results revealed the importance of combining the buffering carbon phase with the nano-fibrous structure for the improvement of SnO2-based electrode,and would pave the way for further enhancing the performance of anodes for LIBs.