硅表面氧化增强硅炭复合负极材料性能研究

Properties of silicon surface oxidation reinforced silicon carbon composite anode material

以球形天然石墨、硅、植物纤维为原料,使用双氧水对硅表面进行氧化处理,然后与球形天然石墨、植物纤维复合,再经1000℃氮气保护烧结处理制得锂离子电池负极材料。采用XRD分析复合材料的物相结构和组成,SEM和TEM表征材料的表面形貌和微观结构,并结合XPS对材料进行了元素组成和硅的化合价态分析,探究硅的表面氧化程度和效果。结果表明,氧化处理在硅表面形成了一层致密而均匀的二氧化硅硬壳。恒流充放电测试结果表明,1.5%双氧水氧化处理制备的样品在20℃、0.1C(1C=1000 mA/g)条件下,首次充电容量为460.1 mAh/g,充放电库伦效率为86.0%,并进行了0.3C、0.5C倍率充放电测试,与未使用双氧水氧化制备的样品相比,氧化处理样品的容量、倍率、循环性能得到了明显提升。

The spherical natural graphite,silicon and plant fiber are used as raw materials,the silicon surface is oxidized with hydrogen peroxide,and then combined with the spherical natural graphite and plant fiber,finally the anode material of lithium ion battery is prepared by sintering treatment at 1000℃under a nitrogen atmosphere.XRD is used to analyze the phase structure and composition of the composites,SEM and TEM are used to characterize the surface morphology and microstructure of the composites,and XPS are combined to analyze the elemental composition of the materials and the valence state of silicon,to explore the degree and effect of silicon surface oxidation.The results show that a dense and uniform silica shell is formed on the silicon surface.When used as the anode material in Li-ion batteries,the sample prepared by 1.5%hydrogen peroxide oxidation shows the initial charge capacity of 460.1 mAh/g and the coulombic efficiency of 86.0%at 20℃and 0.1 C(1C=1000 mA/g).Compared with the samples prepared without hydrogen peroxide oxidation,the capacity,rate and cycle performance of the sample treated with oxidation are significantly improved.