Measurement of VO²⁺ Transference Number in Nafion with Varying Concentrations of Sulfuric Acid

Abstract

Crossover in Vanadium Redox Flow Batteries (VRFB) has an important impact on performance and is dependent on several physical properties, including the transference number. In this work, model-guided design of experiment was used to determine vanadium transference number in fully-hydrated ion-selective membranes, while minimizing uncertainties related to unknown or unmeasured properties. The transference number of VO2+ in Nafion 117 for varying ratios of H2SO4 to VOSO4 was measured, and the analysis showed that the transference number estimate can be obtained with 5% or less uncertainty. The VO2+ transference number sharply decreased as acid was added to the electrolyte. The variation in the transference number with the ratio of H2SO4 to VOSO4 was fit to a model to obtain the product of the ratio of vanadium-to-proton partition and diffusion coefficients.

Hydration Effects on the Permselectivity-Conductivity Trade-Off in Polymer Electrolytes

“…Uncertainty analysis in the t c m estimates were conducted using a Markov Chain Monte Carlo (MCMC) algorithm, similar to the work conducted in the literature. 55 Figure 3 presents the MCMC results of t c m for each separator by comparing the experimental data to the mathematical model. The accepted values of the MCMC algorithm were binned, normalized, and fit to Gaussian distributions to estimate the mean and standard deviation of t c m for each membrane.…”

“…The solid lines in Figure B are the results from the numerical simulation using the best-fit t c m values for each separator. Uncertainty analysis in the t c m estimates were conducted using a Markov Chain Monte Carlo (MCMC) algorithm, similar to the work conducted in the literature Figure presents the MCMC results of t c m for each separator by comparing the experimental data to the mathematical model.…”

Vanadium (II) Sulfate for the Reductive Leaching of Chalcopyrite: Replacing Smelting with Electrolysis for Copper Production

“…Argon gas was used to purge oxygen from the anolyte during the electrochemical generation of V 2+ . There is a possibility of inconsistencies in the concentrations of V 2+ and H + in the negative electrolyte of the VRFB between experiments due to the transport of ions from the catholyte during the electrochemical generation of the V 2+ ion [62–65] …”

“…There is a possibility of inconsistencies in the concentrations of V 2 + and H + in the negative electrolyte of the VRFB between experiments due to the transport of ions from the catholyte during the electrochemical generation of the V 2 + ion. [62][63][64][65] Reduction of CuFeS…”

Single-layer graphene as a highly selective barrier for vanadium crossover with high proton selectivity

“…Vanadium crossover would inevitably lead to self-discharge of the battery [16], water imbalance, and coulombic efficiency loss [12]. The water imbalance in vanadium-RFB results from proton permeation through the membrane (with concomitant drag of water molecules), crossover of water molecules bound to vanadium ions, and osmotic-driven water transport due to vanadium ion concentration difference.…”