The Preparation Of Carbon Coated Tin Based Alloy Anode Materials By Sucrose Reduction

The anode materials based on tin metal have attracted much attention due to the higher theoretical specific capacity than traditional commercial graphite electrode materials. However, the large volume expansion of metal tin during the process of charging and discharging causing its capacity attenuation rapidly has impeded its commercial application. Carbon coating is an effective way to restrain the volume change during the process of charging and discharging.In this work, SnSb/C, Cu6Sn5/C and Sn-Sb-Cu/C were prepared by carbon thermal reduction using surgar as carbon source. And the effect of preparation process parameters on the phase composition, particles morphology and electrochemical properties of the prepared alloy were studied by diffraction of X-rays, scanning electron microscope, cyclic voltammetry, AC impedance and charge-discharge testing, etc.The optimal conditions of SnSb/C were as follows:sintering temperature 800℃, sintering time 4 h, and sucrose mass fraction 38.0%. The prepared SnSb/C delivered a capacity of 900.6 mAh·g-1 with a retention of 83.0% after 30 cycles at 0.3 C. Cu6Sn5/C prepared with 38.6 wt% sucrose at 900℃ for 4 h showed a capacity of 514.1 mAh·g-1 with a retention of 81.6% after 30 cycles at 0.3 C.In order to overcome the shortage of the binary alloy, the Sn-Sb-Cu/C ternary alloy anode materials were also prepared. Compared with the binary alloy, the electrochemical stability of the materials had certain enhancement. The sample prepared with a sucrose mass fraction of 48.4% showed a first discharge specific capacity of 854.0 mAh·g-1 with a retention ration of 81.8% after 30 cycles at 0.3 C.