Ionic diode based devices or circuits can be applied, for example, in electroosmotic pumps or in desalination processes. Aquivion ionomer coated asymmetrically over a Teflon film (5 μm thickness) with a laser-drilled microhole (approximately 10 μm diameter) gives a cationic diode with a rectification ratio of typically 10-20 (measured in 0.01 M NaCl with ±0.3 V applied bias). Steady state voltammetry, chronoamperometry, and electrochemical impedance spectroscopy data are employed to characterize the ionic diode performance parameters. Next, a COMSOL 6.0 finite element model is employed to quantitatively assess/compare transient phenomena and to extract mechanistic information by comparison with experimental data. The experimental diode time constant and diode switching process associated with a distorted semicircle (with a typical diode switching frequency of 10 Hz) in the Nyquist plot are reproduced by computer simulation and rationalized in terms of microhole diffusion-migration times. Fundamental understanding and modeling of the ionic diode switching process can be exploited in the rational/optimized design of new improved devices.

Original languageEnglish
Pages (from-to)39905-39914
Number of pages10
JournalACS Applied Materials and Interfaces
Issue number33
Early online date11 Aug 2023
Publication statusPublished - 23 Aug 2023

Bibliographical note

E.B.C.N. and E.P. acknowledge support from FAPESP (São Paulo Research Foundation, Grant Numbers 2013/07296-2, 2021/03592-2, 2022/06229-9), Shell, and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation, CNPq (Grant Number 407878/2022), and CAPES (Code 001). F.M. thanks for the initial financial support by the EPSRC (EP/K004956/1).


  • accumulation−depletion
  • desalination
  • diffusion−migration
  • electrochemical impedance spectroscopy
  • ionic diode

ASJC Scopus subject areas

  • Materials Science(all)


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