Synthesis And Studies On Tin-Based Composite Oxides As Anode Materials For Lithium Ion Batteries

Rechargeable lithium-ion battery has the better applying prospect in the battery market. The property of battery is greatly depended on choosing the optimal anode materials. Now the commercial carbon anode material can't meet the needs of the consumers for large capacity, so a lot of researches have focused on finding new large capacity anode material candidates.On the basis of systematically reviewing the developments of anode materials of lithium ion battery in this paper, with Zn₂SnO₄ and Mg-Sn composite oxides anode materials as objects of the research, they were characterized by thermo-gravimetric and differential thermal analysis(TG/DTA), X-ray diffraction(XRD), scanning electron microscopy(SEM). In the end, they were used as the anode materials of the lithium-ion battery, and their electrochemical performance were studied in detail. Our work was shown as the following:1. Inverse spinel Zn₂SnO₄ particles were successfully prepared via a hydrothermal method. The effect on the product purity and crystallinity were studied with respect to the hydrothermal reaction temperature and alkaline concentration. The difference of electrochemical performance on the as-prepared product at various alkaline concentrations and electrochemical mechanism of charging-discharging at the best conditions were specially analyzed. It showed that the optimized product, which was prepared with 0.2M of NaOH solution at 220℃for 24h, exhibited a relatively good electrochemical performance.2. The Zn₂SnO₄ round particles were derived by co-precipitation synthesis and the influenced on purity, particle size and electrochemical performance of as-prepared product were obtained by firing the precursor under different temperature. The results showed that the product of Zn₂SnO₄ had better electrochemical performance, which was synthesized at 750℃. The first specific discharge and charge capacity was 1811.7mAh/g and 1031.0mAh/g, respectively. The discharge capacity remained 593.3mAh/g after 20 cycles.3. Mg-Sn composite oxide precursors were synthesized by the hydrothermal and co-precipitation methods. A series of products could be obtained by the decomposition of precursor at different temperatures for 4h. The samples were investigated by thermo-gravimetric and differential thermal analysis, X-ray diffraction and scanning electron microscopy. It is showed that the precursor with the cubic shape was prepared via a hydrothermal reaction and the shape was retained after calcinations and co-precipitation method used in the experiment resulted in the composite oxide particle with irregular shape, demonstrating that the reaction condition of precursors were the key parameter influencing the composition and morphology of resulting particles. Larger difference of electrochemical properties was obtained under two kinds of conditions. The sample possessed relatively better electrochemical properties through hydrothermal reaction.