锂离子电池Si@void@C复合材料的制备及其电化学性能

以纳米Si颗粒为核心,正硅酸四乙酯(TEOS)为SiO_2源,采用Stober法在Si表面包覆一层SiO_2,再以多巴胺为碳源,通过碳化处理将SiO_2表面的聚多巴胺层转化成碳层。最后,用HF刻蚀SiO_2并留下空隙,得到Si@void@C复合纳米颗粒。利用X射线衍射、扫描电镜、透射电镜和恒流充放电测试对材料的物相、微观形貌和电化学性能进行表征。结果表明,在0.1 A·g~(-1)电流密度下,Si@void@C负极材料充放电循环100次后充电比容量仍然有1 319.5 mAh·g~(-1),容量保持率为78.4%,表现出优异的电化学性能。

Synthesis and Electrochemical Performance of Si@void@C Composite Anode Material for Lithium Ion Battery

The Si@void@C composites were prepared by a stober method with Si nanoparticles as the cores. This preparation process involved coating a SiO₂ layer through hydrolyzing and self-assembly approach of TEOS, coating a carbon layer through in-situ polymerization and high temperature carbonization of dopamine, and etching SiO₂ by HF. Crystalline structure, morphology and electrochemical performances of the composites were characterized by X-ray diffraction, scanning electron microscope, TEM and charge-discharge tests. The results indicate that the Si@void@C anode material retains a charge capacity of 1 319.5 mAh·g^-1 at current density of 0.1 A·g^-1 along with the capacity retention of 78.4% after 100 cycles, and shows an excellent electrochemical performance.