Adsorption and Diffusion of VO2+ and VO2 + across Cation Membrane for All‐Vanadium Redox Flow Battery |
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| Authors: | Jin‐qing Chen Ji‐chu Yang |
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| Affiliation: | Department of Chemical Engineering , Tsinghua University , Beijing 100084, The People's Republic of China |
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| Abstract: | A method based on a selectivity coefficient and the Nernst‐Planck equation is proposed to determine diffusion coefficients of vanadium ions across a cation exchange membrane in VO2+/H+ and VO2 +/H+ systems. This simplified method can be applied to high concentrations of vanadium ions. Three cation exchange membranes were studied. The logarithmic value of the selectivity coefficient was linearly dependent on the molar fraction of vanadium ions in solution. The diffusion coefficient of vanadium ions decreased with decreasing water content. The membrane with the lowest diffusion coefficient was selected as a battery separator and showed the lowest capacity loss of the studied membranes. |
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| Keywords: | Selectivity coefficient diffusion coefficient vanadium ions ion exchange membranes |
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