Over-limiting Current and Control of Dendritic Growth by Surface Conduction in Nanopores
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Han-2014-Over-limiting current.pdf
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1.98 MB
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Author(s)
Han, Ji-Hyung
Bai, Peng
Bazant, Martin Z.
Khoo, Edwin Sze Lun
Date Issued
November 2014
Journal
Scientific Reports
Publisher
Nature Publishing Group
Citation
Han, Ji-Hyung, Edwin Khoo, Peng Bai, and Martin Z. Bazant. “Over-Limiting Current and Control of Dendritic Growth by Surface Conduction in Nanopores.” Sci. Rep. 4 (November 14, 2014): 7056.
Version
Final published version
Abstract
Understanding over-limiting current (faster than diffusion) is a long-standing challenge in electrochemistry with applications in desalination and energy storage. Known mechanisms involve either chemical or hydrodynamic instabilities in unconfined electrolytes. Here, it is shown that over-limiting current can be sustained by surface conduction in nanopores, without any such instabilities, and used to control dendritic growth during electrodeposition. Copper electrodeposits are grown in anodized aluminum oxide membranes with polyelectrolyte coatings to modify the surface charge. At low currents, uniform electroplating occurs, unaffected by surface modification due to thin electric double layers, but the morphology changes dramatically above the limiting current. With negative surface charge, growth is enhanced along the nanopore surfaces, forming surface dendrites and nanotubes behind a deionization shock. With positive surface charge, dendrites avoid the surfaces and are either guided along the nanopore centers or blocked from penetrating the membrane.
MIT Department
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Department of Mathematics
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1038/srep07056
