在对齐和包装的单壁碳纳米管中,离子扩散和电化学电容
Ali Izadi-Najafabadi1, Don N Futaba, Sumio Iijima
1Nanotube Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565, Japan.
Journal of the American Chemical Society
|December 15, 2010
概括
对齐的碳纳米管使其结构平行的离子迅速扩散,显著优于活性碳. 这种异型离子传输会影响电化学电容器的性能,特别是在更高的放电率下.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 纳米技术纳米技术
背景情况:
- 离子扩散对于电化学储能装置至关重要.
- 碳纳米管为增强的离子传输提供独特的结构性质.
- 纳米材料中的无otropic 扩散可以影响设备性能.
研究的目的:
- 在对齐的单壁碳纳米管 (SWCNT) 电极中直接测量离子扩散系数.
- 调查SWCNT中离子扩散的异构性质.
- 为了评估异型扩散对电化学电容器性能的影响.
主要方法:
- 在对齐的SWCNT电极内使用KSCN在酸中直接测量离子扩散.
- 离子扩散系数与SWCNT对齐平行和垂直的比较.
- 在不同放电速率的电化学电容器中评估SWCNT电极的性能.
主要成果:
- 与对齐的SWCNT平行离子扩散实现了接近理论极限的速度,比活性炭快20倍 (1 × 10−5 cm2/s vs 5 × 10−7 cm2/s).
- 垂直于SWCNTs的离子扩散明显较慢 (8 × 10−7 cm2/s).
- 电化学电容器在低速率下表现出类似的性能,但垂直方向表现出66%的电容性下降,而平行方向在更高速率下降14%,具有较低的额定功率.
结论:
- 对齐的SWCNT可促进高效的异性离子离子运输.
- 电极中的SWCNT的方向极大地影响了电化学设备的性能,特别是功率密度和电容保持.
- 优化纳米管对齐对于最大限度地发挥基于SWCNT的储能系统的潜力至关重要.
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