Concentration Dependence of VO<sup>2+</sup>Crossover of Nafion for Vanadium Redox Flow Batteries

Lawton, Jamie S.; Jones, Andrew R.; Zawodzinski, Thomas A.

doi:10.1149/2.004306jes

Cited by 65 publications

(60 citation statements)

References 26 publications

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“…The principle of this measurement has been reported in detail elsewhere. 28,29 During the measurement, VO 2+ rich solution was placed on one side of the battery, while a receiving solution of the same volume with no VO 2+ was circulated on the other side of the separator. The volume of the solutions on both sides was 20 mL.…”

Section: Methodsmentioning

confidence: 99%

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

Tang

Lawton

Sun

et al. 2014

J. Electrochem. Soc.

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Sulfonated Diels-Alder poly(phenylene) (SDAPP) membranes were synthesized and characterized as potential electrolyte separators for vanadium redox flow batteries. The SDAPP membranes studied had ion exchange capacities of 1.4, 1.8 and 2.3 meq/g. Transmission electron microscopy imaging shows that the ionic domains in SDAPP are roughly 0.5 nm in dimension, while Nafion has a hydrophilic phase width of around 5 nm. The sulfuric acid uptake by SDAPP was higher than that for Nafion, but the materials had similar water uptake from solutions of various sulfuric acid concentrations. In equilibration with sulfuric acid concentrations ranging from 0-17.4 mol · kg −1 , SDAPP with a IEC of 2.3 meq/g had the highest conductivity, ranging from 0.21 to 0.05 S · cm −1 , while SDAPP with a IEC of 1.8 had conductivity close to Nafion 117, ranging from 0.11 to 0.02 S · cm −1 . With varying sulfuric acid concentration and temperature, vanadium permeability in SDAPP is positively correlated to the membrane's IEC. The vanadium permeability of SDAPP 2.3 is similar to that of Nafion, but permeability values for SDAPP 1.8 and SDAPP 1.4 are substantially lower. The vanadium permeation decreases with increasing electrolyte sulfuric acid concentration. Vanadium diffusion activation energy is about 20 kJ · mol −1 in both SDAPP and Nafion.The vanadium redox flow battery (VRFB) has shown technical potential for large scale electrical energy storage. 1-3 One possible role of VRFBs is their integration with the electrical grid to "level off" supply and demand mismatches and to improve overall reliability and efficiency of the grid. 1 Another scenario for VRFB use is buffering stochastic energy sources, such as solar or wind, which will improve the stability of electricity output from these renewable resources. 1,4 A VRFB is essentially a regenerative fuel cell, with a flowing operation pattern similar to proton exchange membrane fuel cells. 5,6 In a VRFB the energy is carried by vanadium redox couples V 5+ /V 4+ and V 2+ /V 3+ in electrolyte solutions. The energy is interconverted between electrical and electrochemical forms by the battery cell or stack, where the functional core is the membrane electrode assembly. The function of the membrane is to separate positive and negative electrolyte solutions and conduct ionic current, while vanadium redox reactions take place on the electrode surface in each half-cell. During battery operation, electrolyte solutions are constantly fed through the battery to support electrochemical reactions and to generate steady current output or recharge the electrolyte solution.In the VRFB cell, the electrolyte separator is a primary limiting factor in the battery's performance. 3 As has been demonstrated, resistance from the separator is the most important source of the battery's internal resistance, impeding battery performance during high current density operation. 3,7 Ideally, the electrolyte separator should have high conductivity to minimize battery efficiency losses caused by internal resistance and also hig...

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Section: Methodsmentioning

confidence: 99%

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

Tang

Lawton

Sun

et al. 2014

J. Electrochem. Soc.

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“…Lawton et al [16] experimentally illustrated decreasing behavior of the permeation rate of VO 2+ through Nafion 117 with increasing sulfuric acid concentration in the electrolyte solutions. They suspected the trend to be mainly caused by increasing level of membrane dehydration and resultant stronger partitioning/clustering effects with more sulfuric acid.…”

mentioning

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Numerical analysis of vanadium crossover effects in all-vanadium redox flow batteries

Won

2015

Electrochimica Acta

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“…Membrane properties that have been shown to significantly affect transport in the membrane include the dehydrating effects of acid in the membrane as well as vanadium ion uptake and mobility in the membrane. [12][13][14][15] The effects of the components of the VRFB environment (i.e. exposure to acid, ion and counter ions, and water) on SDAPP membranes include decreased conductivity, vanadium crossover and water uptake in higher acid concentrations as well as lower ion exchange capacities (IEC).…”

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Characterization of Vanadium Ion Uptake in Sulfonated Diels Alder Poly(phenylene) Membranes

Lawton

Jones

Tang

et al. 2015

J. Electrochem. Soc.

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Sulfonated diels alder poly(phenylene) (SDAPP), alternative aromatic hydrocarbon membranes for vanadium redox flow batteries (VRFBs) are characterized using electron paramagnetic resonance (EPR). Membranes soaked in sulfuric acid and vanadyl sulfate are analyzed to determine the membrane environment in which the vanadyl ion (VO 2+ ) diffuses in the membranes. These results are compared to Nafion 117 membranes. In contrast to Nafion, the VO 2+ in SDAPP membranes exists in two different environments. The results of analysis of rotational diffusion determined from fits the EPR spectral lineshapes in comparison with previously reported permeation studies and measurements of partitioning functions reported here suggest that the diffusion pathways in SDAPP are considerably different than in Nafion. Vanadium redox flow battery (VRFB) technology has been investigated as an energy storage system for grid applications.1-3 While the battery architecture is generally similar to that of a proton exchange membrane fuel cell (PEMFC), the chemistry of the VRFB is substantially more complex. In particular, the presence of metal ions and sulfuric acid electrolyte adds additional levels of complexity due to the interactions of the electrolyte with all the material components. One major area of interest is the behavior of the vanadium ions and sulfuric acid in the ion exchange membrane that separates the negative and positive electrolytes. The membrane resistance and permeability have been shown to be responsible for many of the limits in battery operation.4 Also, the perfluourinated membranes currently used predominately in the battery systems are one of the most expensive components in the cell, second only to the cost of the vanadium itself. As such, significant effort has been given to developing membranes for VRFB applications. 5Earlier work on alternative membranes for PEMFC applications has resulted in a preponderance of publications detailing this chemistry and comparing the less expensive hydrocarbon membranes to perfluourinated membranes. [6][7] While this information is useful for advancements in membranes for VRFB application, it does not obviate a thorough understanding of the effects of the additional components of the VRFB in order to tailor membrane characteristics to further benefit the needs of VRFB operation. These include minimizing vanadium ion accessibility to the membrane in order to minimize vanadium crossover, maintaining a high proton conductivity, and retaining these characteristics in the presence of the acidic electrolyte without degradation.In the presence of concentrated electrolytes, such as the solutions of ∼5 M (or greater) acid and 1.5 M (or greater) vanadium used in the VRFB, the Donnan exclusion of anions from the membrane is overcome. Consequently, the membrane imbibes acid and vanadium in addition to water. This dramatically complicates the description of transport in the membrane. The previous under- * Electrochemical Society Active Member. * * Electrochemical Society Fellow. e Present addres...

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Concentration Dependence of VO²⁺Crossover of Nafion for Vanadium Redox Flow Batteries

Cited by 65 publications

References 26 publications

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

Numerical analysis of vanadium crossover effects in all-vanadium redox flow batteries

Characterization of Vanadium Ion Uptake in Sulfonated Diels Alder Poly(phenylene) Membranes

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Concentration Dependence of VO2+Crossover of Nafion for Vanadium Redox Flow Batteries

Cited by 65 publications

References 26 publications

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries

Numerical analysis of vanadium crossover effects in all-vanadium redox flow batteries

Characterization of Vanadium Ion Uptake in Sulfonated Diels Alder Poly(phenylene) Membranes

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Concentration Dependence of VO²⁺Crossover of Nafion for Vanadium Redox Flow Batteries