Ibañez, Santiago E.Quintero, Alberto E.García-Salaberri, Pablo A.Vera Coello, Marcos2022-02-222022-02-222021-05Ibáñez, S. E., Quintero, A. E., García-Salaberri, P. A. & Vera, M. (2021). Effects of the diffusive mixing and self-discharge reactions in microfluidic membraneless vanadium redox flow batteries. International Journal of Heat and Mass Transfer, 170, 121022.0017-9310https://hdl.handle.net/10016/34201Microfluidic-based membraneless redox flow batteries have been recently proposed and tested with the aim of removing one of the most expensive and problematic components of the system, the ion-exchange membrane. In this promising design, the electrolytes are allowed to flow parallel to each other along microchannels, where they remain separated thanks to the laminar flow conditions prevailing at sub-millimeter scales, which prevent the convective mixing of both streams. The lack of membrane enhances proton transfer and simplifies overall system design at the expense of larger crossover rates of vanadium ions. The aim of this work is to provide estimates for the crossover rates induced by the combined action of active species diffusion and homogeneous self-discharge reactions. As the rate of these reactions is still uncertain, two limiting cases are addressed: infinitely slow (frozen chemistry) and infinitely fast (chemical equilibrium) reactions. These two limits provide lower and upper bounds for the crossover rates in microfluidic vanadium redox flow batteries, which can be conveniently expressed in terms of analytical or semi-analytical expressions. In summary, the analysis presented herein provides design guidelines to evaluate the capacity fade resulting from the combined effect of vanadium cross-over and self-discharge reactions in these emerging systems.15eng© 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.Atribución-NoComercial-SinDerivadas 3.0 EspañaVanadium redox flow batteryMembranelessCrossoverSelf-discharge reactionsReaction frontsCapacity faderesearch articleIngeniería IndustrialIngeniería Mecánicahttps://doi.org/10.1016/j.ijheatmasstransfer.2021.121022open access121022-1121022-15International Journal of Heat and Mass Transfer170AR/0000025995