Reversible polycolour change of viologens from violet through transparent to white

Hoshino, Katsuyoshi; Oikawa, Yosuke; Sakabe, Ichiro; Komatsu, Tatsuya

doi:10.1016/j.electacta.2009.08.029

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…We chose viologen (V) as a model anolyte to match the redox activity of the bromide catholyte and test the utility of tetrabutylammonium complexing agent in a full cell. While many families of redox-active anolytes should be compatible with the TBABr/Br – catholyte, viologens have the advantage of an electrochemically reversible V 2+ /V •+ redox couple. ,− In addition, V/Br cells typically have potential plateaus around 1.2–1.3 V, which coincides ideally with the thermodynamic stability window of water.…”

Section: Results and Discussionmentioning

confidence: 99%

Fundamentally Addressing Bromine Storage through Reversible Solid-State Confinement in Porous Carbon Electrodes: Design of a High-Performance Dual-Redox Electrochemical Capacitor

et al. 2017

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Research in electric double-layer capacitors (EDLCs) and rechargeable batteries is converging to target systems that have battery-level energy density and capacitor-level cycling stability and power density. This research direction has been facilitated by the use of redox-active electrolytes that add faradaic charge storage to increase energy density of the EDLCs. Aqueous redox-enhanced electrochemical capacitors (redox ECs) have, however, performed poorly due to cross-diffusion of soluble redox couples, reduced cycle life, and low operating voltages. In this manuscript, we propose that these challenges can be simultaneously met by mechanistically designing a liquid-to-solid phase transition of oxidized catholyte (or reduced anolyte) with confinement in the pores of electrodes. Here we demonstrate the realization of this approach with the use of bromide catholyte and tetrabutylammonium cation that induces reversible solid-state complexation of Br/Br. This mechanism solves the inherent cross-diffusion issue of redox ECs and has the added benefit of greatly stabilizing the reactive bromine generated during charging. Based on this new mechanistic insight on the utilization of solid-state bromine storage in redox ECs, we developed a dual-redox EC consisting of a bromide catholyte and an ethyl viologen anolyte with the addition of tetrabutylammonium bromide. In comparison to aqueous and organic electric double-layer capacitors, this system enhances energy by factors of ca. 11 and 3.5, respectively, with a specific energy of ∼64 W·h/kg at 1 A/g, a maximum power density >3 kW/kg, and cycling stability over 7000 cycles.

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Section: Results and Discussionmentioning

confidence: 99%

Fundamentally Addressing Bromine Storage through Reversible Solid-State Confinement in Porous Carbon Electrodes: Design of a High-Performance Dual-Redox Electrochemical Capacitor

et al. 2017

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“…The result is that a high oxidation potential is needed, or the incomplete vanishment occurs due to an incomplete oxidation (ghost image formation). 5,[26][27][28] As for the above-described ITO/DDV composite film electrode, its coloration and decoloration are carried out in an extremely narrow potential range. Therefore, when a twoelectrode-type cell is formed, it can be expected that the driving voltage of the coloration and decoloration will be very low.…”

Section: Cyclic Voltammetry and Spectroelectrochemistrymentioning

confidence: 99%

Electrochromic properties of ITO nanoparticles/viologen composite film electrodes

Nakajima

Yamada

Komatsu³

et al. 2012

RSC Adv.

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“…These molecules have long been known, [31] and they are used as herbicides. [32] More recently, interest has surrounded their use in electrochromic systems, [33][34][35][36] in artificial photosynthesis, [37] and in chemical sensors. [38,39] The viologens are well suited to the study of electron-transfer phenomena because of their ability to form a stable radical following a one-electron reduction, and to be subsequently reoxidised to reform the dication.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Electron‐Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

Cook

Horrocks

2016

ChemElectroChem

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The standard heterogeneous rate constants for the reduction of a series of viologen derivatives with a range of inter‐ring torsion angles were measured at Bi and Pt electrodes. The electrode potentials for the first one‐electron reduction of the viologens vary from −684 mV to −1070 mV vs. Ag/0.01 m Ag+; this enabled a comparison of the behaviour of metallic (Pt) and semi‐metallic (Bi) electrodes over a wide range of applied potentials. The differential capacitance (6.5 μF cm−2) of Bi/MeCN,TBAPF6 interfaces at the potential of zero charge (pzc=−0.60 V) is at least an order of magnitude greater than that calculated on the basis of the bulk Bi carrier density (3×1017 cm−3) and the differential capacitance (9.5 μF cm−2) of Pt/MeCN interfaces at their pzc (−0.43 V) is of the same order. The series of viologen derivatives exhibited simple one‐electron redox behaviour and showed similar rate constants at Pt (1.8×10−4–1.6×10−3 cm s−1) and Bi electrodes (1.1×10−4–1.9×10−3 cm s−1) after application of the Frumkin correction. These results demonstrate that the density of states at the Bi surface is much higher than in bulk. Finally, the Frumkin‐corrected standard rate constants were observed to be inversely correlated with the inter‐ring torsion angle of the viologens.

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Reversible polycolour change of viologens from violet through transparent to white

Cited by 8 publications

References 14 publications

Fundamentally Addressing Bromine Storage through Reversible Solid-State Confinement in Porous Carbon Electrodes: Design of a High-Performance Dual-Redox Electrochemical Capacitor

Fundamentally Addressing Bromine Storage through Reversible Solid-State Confinement in Porous Carbon Electrodes: Design of a High-Performance Dual-Redox Electrochemical Capacitor

Electrochromic properties of ITO nanoparticles/viologen composite film electrodes

Heterogeneous Electron‐Transfer Rates for the Reduction of Viologen Derivatives at Platinum and Bismuth Electrodes in Acetonitrile

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