溶胶凝胶法制备纳米硅/氧化亚硅/碳复合负极材料

Sol-gel synthesis of nanometer silicon/silicon suboxide/carbon anode material

采用有机硅酯体系,通过溶胶凝胶法结合碳热还原反应,制备了具有碳包覆结构的堆叠型Si/SiOx/C复合负极材料。X射线衍射仪、扫描电子显微镜和元素分析仪测试结果表明:Si/SiOx/C复合材料是疏松多孔的微—纳结构二次颗粒,纳米硅的存在不影响碳热还原和碳包覆。电化学性能测试表明:SiOx/C材料与纳米硅复合可以将比容量和首次库伦效率提高至1 946.05 mAh/g和76.49%;Si/SiOx/C材料和石墨复配后在0.1 C的电流密度下100次循环后的可逆比容量为749.69 mAh/g,容量保持率达89.03%,具有优秀的电化学循环稳定性。

In this study,a stacked Si/SiO x/C composite anode material with a carbon-coated structure was prepared by a sol-gel method combined with a carbothermal reduction reaction using organic silicon.The results of X-ray diffractometry,scanning electron microscopy,and elemental analyzer show that the Si/SiO x/C material is a secondary particle with a porous micro-nano structure,and the presence of nanometer silicon does not affect the carbothermal reduction and carbon coating.The results of the electrochemical test indicate that the specific capacity and first coulomb efficiency of SiO x/C composite with nanometer silicon can be increased to 1946.05 mAh/g and 76.49%,respectively.The reversible specific capacity of Si/SiO x/C material blended with graphite is 749.69 mAh/g after 100 cycles at a current density of 0.1 C,and the capacity retention rate is up to 89.03%.It has excellent electrochemical cycle stability.