在纳米孔碳电极中对离子扩散的封闭,溶解和电吸效应
Clarisse Pean1,2,3, Barbara Daffos2,3, Benjamin Rotenberg1,3
1Sorbonne Universités, UPMC Univ Paris 06, CNRS , Laboratoire PHENIX, F-75005 Paris, France.
Journal of the American Chemical Society
|September 16, 2015
概括
超级电容在多孔碳上使用离子吸附来储存能量. 纳米孔中的离子扩散速度比散装电解质慢,这是由于封闭和溶解效应,影响快速充电.
科学领域:
- 电化学
- 材料科学
- 纳米技术
背景情况:
- 超级电容器通过在多孔碳上进行离子吸附提供高功率传输.
- 使用纳米孔碳增加能量密度需要了解离子运输机制.
- 电气化纳米孔内的离子传输对于超级电容器的性能至关重要,但人们对其了解甚少.
研究的目的:
- 阐明超级电容器中电化纳米孔内的离子传输机制.
- 研究离子封闭,溶解和电吸收对离子扩散的影响.
- 作为应用电位的函数来确定孔内导电率和扩散系数.
主要方法:
- 结合电化学实验与分子动力学模拟.
- 在时间尺度的层次上分析了离子扩散动态.
- 量化的孔内离子导电性和扩散系数.
主要成果:
- 纳米孔内的离子扩散比散装电解质要慢 (大小1级).
- 扩散的特点是受限制,溶解和电吸收影响的多个时间尺度.
- 与电吸收相比,离子溶解发生在更快的时间尺度上.
结论:
- 了解纳米孔碳中的离子运输机制是优化超级电容器能量密度和充电速度的关键.
- 封闭,溶解和电吸集体决定了离子扩散动态.
- 这项研究为控制超级电容的基本过程提供了关键的见解.
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