Determination of rate constants and reaction orders of vanadium-ion kinetics on carbon fiber electrodes

In the present work, the kinetic behavior of vanadium-ion reactions on novel single carbon-fiber electrodes is investigated. The theory of reaction orders and charge-transfer coefficients is reviewed and typical sources of error due to incorrectly determined electrochemically active surface area, inhomogeneous current density distributions, mass transfer resistances, and aging are highlighted. The measured rate constants are in a range of 2.5 ⋅ 10−7–1.1 ⋅ 10−5 s−1 for the positive and 7.0 ⋅ 10−8–2.6 ⋅ 10−6 s−1 for the negative electrolyte. Despite these different activities of individual fibers, the reaction orders of V2+, V3+, VO2+ and VO2+ species are precisely determined as a function of the concentration and the state of charge. Moreover, charge-transfer coefficients are calculated with two different approaches based on Tafel slopes and through adjustment of the Butler-Volmer equation.

Cite

Citation style:
Could not load citation form.

Access Statistic

Total:
Downloads:
Abtractviews:
Last 12 Month:
Downloads:
Abtractviews:

Rights

Use and reproduction: