静电纺丝制备一维结构Si/TiO_2/C负极复合材料及性能研究

Research on Preparation and properties of Si/TiO_2/C composite with one-dimensional structure prepared by the electrospinning method using as the anode material

研究通过静电纺丝工艺制备了锂离子电池负极复合材料Si/TiO_2/C,研究了硅与二氧化钛比例对其电化学性能的影响,发现Si与TiO_2摩尔比为1∶4的样品在0.1 C倍率循环50圈之后的比容量为322.8 mAh·g^(-1),优于其他比例样品,同时,交流阻抗谱(EIS)表明,该样品内阻明显低于其它样品。扫描电镜观察发现硅颗粒分散于一维棒状锐钛矿氧化钛之间,其充放电过程中较大的体积膨胀得到缓冲,同时碳的存在提高了复合材料的电导率,因此从整体上改善了所制备复合材料的电化学性能。

Si/TiO2/C composite was prepared by the electrospinning method. The influence of Si/TiO_2 molar ratio on the electrochemical properties was studied. It was found that the capacity for the composite with the Si/TiO_2 mole ratio of 1 ∶ 4 was 332.8 m Ah·g-1 after 50 cycles at 0.1C charging/discharging rate, which was higher than that of other samples. Moreover, the electrochemical impedance spectroscopy（EIS） showed that the internal resistance of the composite with the Si/TiO_2 mole ratio of 1 ∶ 4 was 171 Ω, which was lower than that of other samples. On the basis of the scanning electronic morphology（SEM） data, it was observed that the Si particles were dispersed among the anatase TiO_2 with one-dimensional（1-D） structure, which would buffer the huge volume expansion for Si during the charging/discharging process due to the smaller strain effect of the TiO_2. Meanwhile, the electronic conductivity for the composite would be improved due to the introduction of the carbon. Therefore, on the basis of the two reasons mentioned above, the electrochemical performances for Si/TiO_2/C composite were improved.