中国物理B ›› 2015, Vol. 24 ›› Issue (8): 86601-086601.doi: 10.1088/1674-1056/24/8/086601

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Surface-charge-governed electrolyte transport in carbon nanotubes

薛建明a b, 郭鹏a, 盛倩a   

  1. a State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China;
    b CAPT, HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, China
  • 收稿日期:2014-12-10 修回日期:2015-03-11 出版日期:2015-08-05 发布日期:2015-08-05
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11375031 and 11335003).

Surface-charge-governed electrolyte transport in carbon nanotubes

Xue Jian-Ming (薛建明)a b, Guo Peng (郭鹏)a, Sheng Qian (盛倩)a   

  1. a State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, China;
    b CAPT, HEDPS, and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, China
  • Received:2014-12-10 Revised:2015-03-11 Online:2015-08-05 Published:2015-08-05
  • Contact: Xue Jian-Ming E-mail:jmxue@pku.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11375031 and 11335003).

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摘要： The transport behavior of pressure-driven aqueous electrolyte solution through charged carbon nanotubes (CNTs) is studied by using molecular dynamics simulations. The results reveal that the presence of charges around the nanotube can remarkably reduce the flow velocity as well as the slip length of the aqueous solution, and the decreasing of magnitude depends on the number of surface charges and distribution. With 1-M KCl solution inside the carbon nanotube, the slip length decreases from 110 nm to only 14 nm when the number of surface charges increases from 0 to 12 e. This phenomenon is attributed to the increase of the solid–liquid friction force due to the electrostatic interaction between the charges and the electrolyte particles, which can impede the transports of water molecules and electrolyte ions. With the simulation results, we estimate the energy conversion efficiency of nanofluidic battery based on CNTs, and find that the highest efficiency is only around 30% but not 60% as expected in previous work.

关键词: efficiency, surface charge, slip

Abstract: The transport behavior of pressure-driven aqueous electrolyte solution through charged carbon nanotubes (CNTs) is studied by using molecular dynamics simulations. The results reveal that the presence of charges around the nanotube can remarkably reduce the flow velocity as well as the slip length of the aqueous solution, and the decreasing of magnitude depends on the number of surface charges and distribution. With 1-M KCl solution inside the carbon nanotube, the slip length decreases from 110 nm to only 14 nm when the number of surface charges increases from 0 to 12 e. This phenomenon is attributed to the increase of the solid–liquid friction force due to the electrostatic interaction between the charges and the electrolyte particles, which can impede the transports of water molecules and electrolyte ions. With the simulation results, we estimate the energy conversion efficiency of nanofluidic battery based on CNTs, and find that the highest efficiency is only around 30% but not 60% as expected in previous work.

Key words: efficiency, surface charge, slip

中图分类号:  (Diffusion and ionic conduction in liquids)

  • 66.10.-x
82.65.+r (Surface and interface chemistry; heterogeneous catalysis at surfaces) 83.50.Lh (Slip boundary effects (interfacial and free surface flows)) 66.10.cd (Thermal diffusion and diffusive energy transport)