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Microelectrode-based probing of charge propagation and redox transitions in concentrated polyoxometallate electrolyte of potential utility for redox flow battery

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dc.abstract.enConcentrated solutions of Keggin-type silicotungstic acid, as well as the system’s single crystals (H4SiW12O40*31H2O) and their colloidal suspensions have been tested using the microelectrode methodology to determine mass-transport, electron self-exchange and apparent (effective) diffusion-type coefficients for charge propagation and homogeneous (electron self-exchange) rates of electron transfers. Silicotungstic acid facilitates proton conductivity, and undergoes fast, reversible, multi-electron transfers leading to the formation of highly conducting, mixed-valence (tungsten(VI,V) heteropoly blue) compounds. To develop useful electroanalytical diagnostic criteria, electroanalytical approaches utilizing microdisk electrodes have been adapted to characterize redox transitions of the system and to determine kinetic parameters. Combination of microelectrode-based experiments performed in two distinct diffusional regimes: radial (long-term experiment; e.g., slow scan rate voltammetry or long-pulse chronoamperometry) and linear (short-term experiment; e.g., fast scan rate voltammetry or short-pulse chronocoulometry) permits absolute determination of such parameters as effective concentration of redox centers (C0) and apparent transport (diffusion) coefficient (Dapp). The knowledge of these parameters, in particular of [Dapp1/2 C0] seems to be of importance to the evaluation of utility of redox electrolytes for charge storage. For the colloidal suspension of silicotungstic acid (H4SiW12O40) crystals in the saturated solution, the following values have been obtained: Dapp = 1.8*10-6 cm2 s−1 and C0 = 1.1 mol dm−3, as well as the [Dapp1/2 C0] diagnostic parameter has reached the value as high as 6*10-3 mol/dm−3 cm s−1/2, provided that four electrons are involved in the H4SiW12O40 redox transitions. In this respect, the fact that crystals (dispersed solids) are characterized by high electron self-exchange rate (kex = 1.1*108 dm3 mol−1 s−1) and low activation energy (EA = 18.7 kJ mol−1) facilitating electron transfers between immobilized WVI and WV redox sites is also advantageous.
dc.affiliationUniwersytet Warszawski
dc.contributor.authorKulesza, Paweł
dc.contributor.authorFu, Yongsheng
dc.contributor.authorNoto, Vito Di
dc.contributor.authorNegro, Enrico
dc.contributor.authorVezzu, Keti
dc.contributor.authorAdamczyk, Lidia
dc.contributor.authorMiecznikowski, Krzysztof
dc.contributor.authorSkunik-Nuckowska, Magdalena
dc.contributor.authorJaniszewska, Claudia
dc.contributor.authorKesik, Anna
dc.contributor.authorRutkowska, Iwona
dc.date.accessioned2024-01-25T11:28:52Z
dc.date.available2024-01-25T11:28:52Z
dc.date.copyright2023-02-11
dc.date.issued2023
dc.description.accesstimeAT_PUBLICATION
dc.description.financeŚrodki finansowe, o których mowa w art. 365 pkt. 2 ustawy
dc.description.versionFINAL_PUBLISHED
dc.description.volume932
dc.identifier.doi10.1016/J.JELECHEM.2023.117263
dc.identifier.issn1572-6657
dc.identifier.urihttps://repozytorium.uw.edu.pl//handle/item/112419
dc.identifier.weblinkhttps://api.elsevier.com/content/article/PII:S1572665723001236?httpAccept=text/xml
dc.languageeng
dc.pbn.affiliationchemical sciences
dc.relation.ispartofJournal of Electroanalytical Chemistry
dc.relation.pages117263
dc.rightsCC-BY-NC-ND
dc.sciencecloudnosend
dc.subject.enRedox electrolyte
dc.subject.enSilicotungstic acid
dc.subject.enPhysical mass transport
dc.subject.enElectron self-exchange hopping
dc.subject.enKinetic parameters
dc.subject.enMicroelectrode-based diagnosis
dc.titleMicroelectrode-based probing of charge propagation and redox transitions in concentrated polyoxometallate electrolyte of potential utility for redox flow battery
dc.typeJournalArticle
dspace.entity.typePublication