微米级P-Si@a-TiO2负极材料的制备及电化学性能

以微米级Al-Si合金粉为原料，采用去合金法和溶胶-凝胶法工艺制备了无定形TiO2包覆珊瑚状多孔Si结构的P-Si@a-TiO2材料，通过XRD、XPS、SEM和TEM测试对材料的结构和形貌进行了表征，分析并揭示了TiO2层的制备机理及包覆层厚度对复合材料电化学性能的影响规律。结果表明，珊瑚状多孔Si结构和适当厚度的包覆层可以有效缓冲材料的体积膨胀，提高电极的循环稳定性。当TiO2包覆层为10 nm时，对材料的改性效果最佳。此时的P-Si@a-TiO2材料的电极电势差仅为0.321 V，在1.0 A/g下循环50次后具有1357.4 mA·h/g的放电比容量，展现出优越的电化学性能。

Preparation and electrochemical performance of micron P-Si@a-TiO2 anode materials

Amorphous TiO2 coated porous Si (P-Si@a-TiO2) anode material was synthesized by the alloying method and the sol-gel method, using micron-sized Al-Si alloy powder as raw material. The structure and morphology of the materials were characterized by XRD, XPS, SEM and TEM. The preparation mechanism of TiO2 layer and the effect of different coating thickness on the electrochemical properties of the composite were revealed. The results showed that the coralloid porous structure and the appropriate thickness of the coating layer can effectively buffer the volume expansion of the material, and was conducive to improving the stability of the electrode. When the coating thickness was 10 nm, the modification effect was the best. The electrode potential difference of the P-Si@a-TiO2 material was only 0.321 V, after 50 cycles at the current density of 1.0 A/g, the discharge specific capacity reached 1357.4 mA·h/g, showing superior electrochemical performance.