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摘要: 采用聚乙烯醇（PVA）树脂炭化的方法，制备了PVA树脂炭包覆硅/不同纳米碳管复合材料，通过X-射线、高分辩电镜观察和电化学性能测试等手段比较研究了单壁、双壁和多壁纳米碳管作为弹性导电网络缓解硅在充放电过程中体积变化方面的效果。结果表明，单壁纳米碳管和双壁纳米碳管比多壁纳米碳管能够更好地缓解硅在循环过程中产生的结构和体积变化，这主要是因为其长径比大，缠裹效果更好。单壁纳米碳管和双壁纳米碳管具有相近的直径、长径比及宏观分布形式，但在循环过程中，双壁纳米碳管的结构稳定性好于单壁纳米碳管，进而其缓解硅结构变化的效果更好。
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关键词:
- 锂离子电池,硅,纳米碳管,炭化
Abstract: Silicon/carbon nanotube/polyvinyl alcohol (PVA)-derived carbon composites were prepared by carbonization of PVA, and the differences of single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs) and multi-walled carbon nanotubes (MWCNTs) as resilient conductive networks to buffer the volume change of the silicon were investigated. Due to the much higher aspect ratio, SWCNTs and DWCNTs provide a better wrapping effect than do MWCNTs to buffer the volume change of silicon. SWCNTs and DWCNTs have similar diameter, aspect ratio and aggregation form. However, DWCNTs exhibit better structure stability than SWCNTs during electrochemical cycling, and consequently contribute a higher degree of resiliency to buffer the volume change of the silicon. -
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