Understanding Transient Ionic Diode Currents and Impedance Responses for Aquivion-Coated Microholes

Author(s)

Carneiro-Neto, Evaldo Batista ; Li, Zhongkai ; Pereira, Ernesto ; Mathwig, Klaus ; Fletcher, Philip J. J. ; Marken, Frank

• Document type: Journal article
• Source: ACS APPLIED MATERIALS & INTERFACES; v. N/A, p. 10-pg., 2023-08-11.

Abstract

Ionic diode based devices or circuits can be applied,for example,in electroosmotic pumps or in desalination processes. Aquivion ionomercoated asymmetrically over a Teflon film (5 & mu;m thickness) witha laser-drilled microhole (approximately 10 & mu;m diameter) givesa cationic diode with a rectification ratio of typically 10-20(measured in 0.01 M NaCl with & PLUSMN;0.3 V applied bias). Steady statevoltammetry, chronoamperometry, and electrochemical impedance spectroscopydata are employed to characterize the ionic diode performance parameters.Next, a COMSOL 6.0 finite element model is employed to quantitativelyassess/compare transient phenomena and to extract mechanistic informationby comparison with experimental data. The experimental diode timeconstant and diode switching process associated with a distorted semicircle(with a typical diode switching frequency of 10 Hz) in the Nyquistplot are reproduced by computer simulation and rationalized in termsof microhole diffusion-migration times. Fundamental understandingand modeling of the ionic diode switching process can be exploitedin the rational/optimized design of new improved devices. (AU)

• FAPESP's process: 21/03592-2 - Finite element modeling and simulation of electrochemical devices
• Grantee: Evaldo Batista Carneiro Neto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 22/06229-9 - Rectified electroosmotic transport of drugs
• Grantee: Evaldo Batista Carneiro Neto
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor