Study Of Tin-based Alloy Anode Materials For Lithium-ion Battery

In this work,the developments of lithium-ion battery and anode materials were firstly reviewed.Li-ion batteries had been used in many electronic products since they were invented.In order to meet the requirements of pure electric vehicles and hybrid electric vehicles,novel advanced anode materials need to be developed.Tin-based materials had been intensively studied because they were advantageous on capacity,safety,cost,and stability.Cu-Sn anode materials were prepared by electroless deposition and electroplating,separately.Energy dispersive spectrometer(EDS),X-ray diffraction(XRD),scanning electron microscopy(SEM)and electrochemical measurements had been carried out to investigate the structure and morphology,and electrochemical properties of the prepared Cu-Sn anode materials.Tin thin-film electrode,prepared by electroless deposition of Sn on Cu film,showed initial discharge capacity 885.7 mAh/g and coulomb efficiency 84.7%at the first cycle,and the coulomb efficiency was above 90%after the first cycle.The capacity maintained around 465 mAh/g after 100 cycles.After the heat-treatment,the Cu-Sn intermetallic compound was formed,demonstrating a better cycling ability,but a low first cycle capacity and coulomb efficiency.Tin-copper core-shell material was prepared by electroless deposition of Sn on Cu powder.The material was composed of homogeneous particles.the content of tin was about 14.1%,and its initial discharge capacity was 275.4 mAh/g.The expansion of Cu-Sn electrode in the charge and discharge cycles can be controlled through adjusting the cut-off window,in order to improve the cycling performance.Finally,the Sn film electrode was also prepared by electroplating of Sn on Cu film.The cycling performance was not satisfactory because of the large volume expansion of relatively thick Sn-film.Carbon co-plating can change surface of the tin electrode,and the capacity of electrode was greatly improved with small amount of the carbon plated in Sn film.Its initial discharge capacity was 519.3 mAh/g,the capacity remained about 140 mAh/g after 30 cycles.A Cu6Sn5 intermetallic compound was formed after the heat-treatment.The improved charge-discharge capacity and cycling stability of the heat-treated electrode could be ascribed to the blended carbon in the tin electrode.