硅/碳复合材料的高温热解法制备及其电化学性能 |
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引用本文: | 王建平,田文怀,杨道均,吴宁宁. 硅/碳复合材料的高温热解法制备及其电化学性能[J]. 北京科技大学学报, 2015, 0(8): 1044-1048. DOI: 10.13374/j.issn2095-9389.2015.08.011 |
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作者姓名: | 王建平 田文怀 杨道均 吴宁宁 |
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作者单位: | 北京科技大学材料科学与工程学院,北京,100083 |
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摘 要: | 采用高温热解方法成功地合成了高容量硅/碳复合负极材料.通过X射线衍射分析、热重分析、扫描电子显微镜观察、透射电子显微镜观察、恒电流充放电测试、循环伏安法等手段研究了复合材料的性能.结果表明:硅/碳复合材料由Si、C以及少量SiO2组成;硅/碳复合材料中碳的质量分数约在39%左右;经电化学性能测试,在电流0.2 mA下,该硅/碳复合材料首次充电容量768 mAh·g-1,首次库仑效率75.6%,70次循环后可逆比容量仍为529 mAh·g-1,平均容量衰减率为0.44%.这些性能改善归因于硅/碳复合材料中碳的引进,硅表面存在的碳涂层提供了一个快速锂运输通道,降低了电池的阻抗并且充放电过程中稳定了电极的组成.
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关 键 词: | 锂离子电池 复合材料 负极材料 热解 电化学性能 |
Synthesis and electrochemical properties of silicon/carbon composites prepared by high temperature pyrolysis |
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Abstract: | Silicon/carbon composites as anode materials for lithium batteries with high power capacity were synthesized by a high temperature pyrolysis method. The performances of the silicon/carbon composites were investigated by X-ray diffraction, thermogravi-metric analysis, scanning electron microscopy, transmission electron microscopy, galvanostatic cell cycling, and cyclic voltammetry. It is found that the silicon/carbon composites consist of silicon, carbon and few silicon dioxide phases, and the carbon content is about 39%. Electrochemical cycling tests of button cells show that the specific capacity is far more than that of carbon materials. The initial charge capacity of the silicon/carbon composites is 768 mAh·g-1 at a current of 0. 2 mA and the initial coulombic efficiency is 75. 6%. After 70 cycles the reversible specific capacity is 529. 0 mAh·g-1 and the average capacity deterioration rate of each cycle is 0. 44%. These improvements can be attributed to the introduction of carbon in the Si/C composites and carbon coatings on the Si surface, which provide a rapid lithium transport pathway, reduce the cell impedance and stabilize the electrode structure during charge/discharge cycles. |
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Keywords: | lithium-ion batteries composite materials anode materials pyrolysis electrochemical properties |
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