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New Approach for Investigating Diffusion Kinetics Within Capacitive Deionization Electrodes Using Electrochemical Impedance Spectroscopy

Lenz, Magdalena; Zabel, Jana; Franzreb, Matthias

Capacitive deionization (CDI) has become an important research topic in terms of water purification as it is a cost- and energy efficient approach for the desalination of brackish water. Carbon- based materials are often used as electrodes in this process due to a variety of morphologies and their suitable performance in this field. In recent studies it has been already shown that a conscientiously chosen set of electrode properties has an enormous effect on the performance behavior of CDI cells. However, most of the studies focus on the optimization of the electrosorption capacity, while the question on how material properties influence the kinetic behavior of a CDI setup has been less intensively studied so far. Here we show that the kinetic effects of electrode materials can be studied in great detail by using electrochemical impedance spectroscopy (EIS). EIS studies of CDI electrodes have been reported before, however, in contrast to these we introduce a method of presenting and analyzing EIS results. This is especially suitable for extracting the frequency ranges in which different rate limiting mechanisms dominate. The new Nyquist Incline Frequency plot (NIF) shows the local slope of the Nyquist plot in dependency of the applied frequency. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000121334
Veröffentlicht am 16.07.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Funktionelle Grenzflächen (IFG)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2020
Sprache Englisch
Identifikator ISSN: 2296-8016
KITopen-ID: 1000121334
HGF-Programm 47.02.06 (POF III, LK 01) Zellpopul.auf Biofunk.Oberflächen IFG
Erschienen in Frontiers in Materials
Verlag Frontiers Media
Band 7
Seiten Art. Nr.: 229
Vorab online veröffentlicht am 14.07.2020
Schlagwörter capacitive deionization, kinetic effects, electrochemical impedance spectroscopy, material characterization, carbon-based materials, ion diffusion
Nachgewiesen in Web of Science
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