Preparation, characterization and electrochemical property of Sn–Fe–Mo–Al2O3 multi-phase composites Original Research Article

A novel technique has been developed to synthesize Sn–Fe–Mo–Al2O3, while nanoscale dispersion of a highly active tin phase was finely distributed in a stable inert multi-phase. The precursor was prepared by co-precipitation method with SnCl4, FeCl3, AlCl3 and (NH4)6Mo7O24 as the raw materials. Sn–Fe–Mo–Al2O3 mixture was produced by reducing the precursor with H2. The product was characterized by X-ray diffraction (XRD), ICP and scanning electron microscopy (SEM). The performance of the electrode was investigated. The Sn–Fe–Mo–Al2O3 electrode was found to have an initial charge capacity of over 461 mAh/g, and a reversible volumetric capacity of 2090 mAh/cm3, which is two times larger than that of graphite electrode (800 mAh/cm3). The coulomb efficiency in the first cycle was over 55%, but its cyclability was not improved significantly. In order to enhance the cycle performance, we investigated the anode after heat treated at 270 °C for 12 h. Under the same condition, the first charge–discharge characteristics were almost equivalent to the as-coated anode, and the retention capacity ratio after 20 cycles was improved from 41.1% to 86.5%. The heat-treated Sn–Fe–Mo–Al2O3 electrode exhibited better cycle life. The electrochemical reaction of the Sn–Fe–Mo–Al2O3 electrode with Li may obey the alloying–dealloying mechanism of LixSn(x⩽4.4) formation in the other tin-based electrodes.