Understanding the Operating Mechanism of Aqueous Pentyl Viologen/Bromide Redox-Enhanced Electrochemical Capacitors with Ordered Mesoporous Carbon Electrodes

Autor:	Galen D. Stucky, Seung Joon Yoo, Anders Palmqvist, Brian Evanko, Elisabet Ahlberg, Giulio Calcagno
Rok vydání:	2021
Předmět:	Supercapacitor Materials science Viologen Electrolyte Electrochemistry Redox law.invention Capacitor chemistry.chemical_compound Chemical engineering chemistry law Bromide Electrode medicine General Materials Science medicine.drug
Zdroj:	ACS Applied Materials & Interfaces. 14:20349-20357
ISSN:	1944-8252 1944-8244
DOI:	10.1021/acsami.1c13378
Popis:	Compared to traditional electric double-layer capacitors, redox-enhanced electrochemical capacitors (redox-ECs) show increased energy density and steadier power output thanks to the use of redox-active electrolytes. The aim of this study is to understand the electrochemical mechanisms of the aqueous pentyl viologen/bromide dual redox system at the interface of an ordered mesoporous carbon (CMK-8) and improve the device performance. Cells with CMK-8 carbon electrodes were investigated in several configurations using different charging rates and potential windows. The pentyl viologen electrochemistry shows a mixed behavior between solution-based diffusion and adsorption phenomena, with the reversible formation of an adsorbed layer. The extension of the voltage window allows for full reduction of the viologen molecules during charge and a consequent increase in the specific discharge energy delivered by the cell. Investigation of the mechanism indicates that a 1.5 V charging voltage with a 0.5 A g-1 charging rate and fast discharge rate produces the best overall performance.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d0d0bb73c5e29925d7fbf7458b9f632d https://doi.org/10.1021/acsami.1c13378 Zobrazit plný text záznamu