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

Abstract

Here, 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. Lastly, vanadium diffusion activation energy is about 20 kJ·mol -1 in bothmore » SDAPP and Nafion.« less

Authors:
 [1];  [1];  [2];  [3];  [1];  [1];  [1];  [4];  [1]
  1. Univ. of Tennessee, Knoxville, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  4. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1265394
DOE Contract Number:
AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the Electrochemical Society; Journal Volume: 161; Journal Issue: 12
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE

Citation Formats

Tang, Zhijiang, Lawton, Jamie S., Sun, Che-Nan, Chen, Jihua, Bright, Michael I., Jones, Amanda M., Papandrew, Alex B., Fujimoto, Cy H., and Zawodzinski, Thomas A. Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries. United States: N. p., 2014. Web. doi:10.1149/2.0631412jes.
Tang, Zhijiang, Lawton, Jamie S., Sun, Che-Nan, Chen, Jihua, Bright, Michael I., Jones, Amanda M., Papandrew, Alex B., Fujimoto, Cy H., & Zawodzinski, Thomas A. Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries. United States. doi:10.1149/2.0631412jes.
Tang, Zhijiang, Lawton, Jamie S., Sun, Che-Nan, Chen, Jihua, Bright, Michael I., Jones, Amanda M., Papandrew, Alex B., Fujimoto, Cy H., and Zawodzinski, Thomas A. Wed . "Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries". United States. doi:10.1149/2.0631412jes.
@article{osti_1265394,
title = {Characterization of Sulfonated Diels-Alder Poly(phenylene) Membranes for Electrolyte Separators in Vanadium Redox Flow Batteries},
author = {Tang, Zhijiang and Lawton, Jamie S. and Sun, Che-Nan and Chen, Jihua and Bright, Michael I. and Jones, Amanda M. and Papandrew, Alex B. and Fujimoto, Cy H. and Zawodzinski, Thomas A.},
abstractNote = {Here, 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. Lastly, vanadium diffusion activation energy is about 20 kJ·mol-1 in both SDAPP and Nafion.},
doi = {10.1149/2.0631412jes},
journal = {Journal of the Electrochemical Society},
number = 12,
volume = 161,
place = {United States},
year = {Wed Sep 03 00:00:00 EDT 2014},
month = {Wed Sep 03 00:00:00 EDT 2014}
}
  • In this paper, we report on the performance of Diels Alder poly(phenylene) membranes in vanadium redox flow batteries. The membranes were functionalized with quaternary ammonium groups to form an anion exchange membrane (QDAPP) and with sulfonic acid groups to form a cation exchange membrane (SDAPP). Both membrane classes showed similar conductivities in the battery environment, suggesting that the ion conduction mechanism in the material is not strongly affected by the moieties along the polymer backbone. The resistance to vanadium permeation in QDAPP was not improved relative to SDAPP, further suggesting that the polarity of the functional groups do not playmore » a significant role in the membrane materials tested. Both QDAPP and SDAPP outperformed Nafion membranes in cycling tests, with both achieving voltage efficiencies above 85% while maintaining 95% coulombic efficiency while at a current density of 200 mA/cm 2.« less
  • Sulfonated Diels Alder poly(phenylene) (SDAPP) was examined for vanadium redox flow battery (VRFB) use. The ion exchange capacity (IEC) was varied from 1.4, 1.6 and 2.0 meq/g in order to tune the proton conductivity and vanadium permeability. Coulombic efficiencies between 92 to 99% were observed, depending on IEC (lower IEC, higher coulombic efficiencies). In all cases the SDAPP displayed comparable energy efficiencies (88 - 90%) to Nafion 117 (88%) at 50mA/cm2. Membrane durability also was dependent on IEC; SDAPP with the highest IEC lasted slightly over 50 cycles while SDAPP with the lowest IEC lasted over 400 cycles and testingmore » was discontinued only due to time constraints. Accelerated vanadium lifetime studies were initialed with SDAPP, by soaking films in a 0.1 M V5+ and 5.0 M total SO4-2 solution. The rate of degradation was also proportional with IEC; the 2 meq/g sample dissolved within 376 hours, the 1.6 meq/g sample dissolved after 860 hours, while the 1.4 meq/g sample broke apart after 1527 hours.« less
  • 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 suggestmore » that the diffusion pathways in SDAPP are very different than in Nafion.« less
  • As an alternative to the expensive Nafion® ion exchange membrane, an inexpensive commercially-available Radel® polymer was sulfonated, fabricated into a thin membrane, and evaluated for its performance in a vanadium redox flow battery (VRFB). The sulfonated Radel (S-Radel) membrane showed almost an order of magnitude lower permeability of V (IV) ions (2.07×10-7 cm2/min), compared to Nafion 117 (1.29×10-6 cm2/min), resulting in better coulombic efficiency (~98% vs. 95% at 50 mA/cm2) and lower capacity loss per cycle. Even though the S-Radel membrane had slightly higher membrane resistance, the energy efficiency of the VRFB with the S-Radel membrane was comparable to thatmore » of Nafion due to its better coulombic efficiency. The S-Radel membrane exhibited good performance up to 40 cycles, but a decay in performance at later cycles was observed.« less
  • A sulfonated poly(sulfone) (S-Radel{reg_sign}) membrane with high proton conductivity and low vanadium ion diffusion showed high initial performance in a vanadium redox flow battery (VRFB) but suffered damage during charge/discharge cycling. The S-Radel membrane had different degradation behaviors in flow cell cycling and ex-situ vanadium ion immersion tests. The S-Radel membrane immersed in V5+ solution cracked into small pieces, but in the VRFB cell, the membrane underwent internal delamination preferentially on the side of the membrane that faced the positive electrode. A vanadium-rich interface was observed near the membrane surface that experienced delamination and Raman spectroscopic analysis of the surfacesmore » of the membrane indicated a slightly depressed 1026 cm-1 band corresponding to the sulfonate SO2 stretch for the degraded surface. Even though the S-Radel membrane underwent severe mechanical damage during the flow cell cycling, significant chemical degradation was not obvious from the spectroscopic analyses. For the VRFB containing an S-Radel membrane, an increase in membrane resistance caused an abnormal voltage depression during the discharge cycle. The reversible increase in membrane resistance and severe mechanical degradation of the membrane during cycling may be attributed repeated formation and dissolution of particles inside the membrane. The mechanical stresses imposed by the particles coupled with a small amount of chemical degradation of the polymer by V5+, are likely degradation mechanisms of the S-Radel membrane in VRFBs under high state-of-charge conditions.« less