TY - JOUR
T1 - Optimizing membrane thickness for vanadium redox flow batteries
AU - Chen, Dongyang
AU - Hickner, Michael A.
AU - Agar, Ertan
AU - Kumbur, E. Caglan
N1 - Funding Information:
The work was supported by the Office of Electricity (OE Delivery & Energy Reliability (OE), US Department of Energy (DOE) under contract DE-AC05-76RL01830. We also acknowledge the support from the Southern Pennsylvania Ben Franklin Commercialization Institute (Grant # 001389-002 ) and the Virginia S. and Philip L. Walker Jr., Faculty Fellowship from the College of Earth and Mineral Sciences at The Pennsylvania State University.
PY - 2013/6/5
Y1 - 2013/6/5
N2 - Two important intrinsic properties of proton exchange membranes for vanadium redox flow battery (VRFB) operation are proton conductivity and vanadium permeability. These characteristics are thickness-normalized quantities and depend on fundamental material parameters. However, the operational criteria of proton exchange membranes in these devices are the membrane resistance and vanadium crossover flux, both of which depend on membrane thickness. Herein, we explore the influence of the thickness of ion exchange capacity (IEC)-optimized sulfonated fluorinated poly(arylene ether) (SFPAE) membranes on their VRFB performance including charge/discharge behavior, charge depth, coulombic efficiency, voltage efficiency, energy efficiency and cell polarization. IEC-optimized SFPAE membranes with three different thicknesses (28μm, 45μm and 80μm) were prepared and tested in this study. It was found that the combined effects of the ohmic loss and electrolyte crossover loss in the VRFB, which were governed by membrane thickness, resulted in an optimal membrane thickness of 45μm for SFPAE under the conditions tested. Thicker membranes were observed to cause higher cell resistance while thinner membranes yielded larger vanadium crossover flux, both of which had negative impacts on the cell performance. The maximum power densities of the VRFBs assembled with 28μm, 45μm and 80μm SFPAE membranes were 267mWcm-2, 311mWcm-2 and 253mWcm-2 respectively, much higher than that of the VRFB assembled with N212 membrane, which was 204mWcm-2. These results supported our previous observation that SFPAE was superior to N212 with regard to VRFB performance. The data also indicated that there is an optimum membrane thickness for a given set of properties through which the cell performance can be significantly improved while keeping the membrane material constant.
AB - Two important intrinsic properties of proton exchange membranes for vanadium redox flow battery (VRFB) operation are proton conductivity and vanadium permeability. These characteristics are thickness-normalized quantities and depend on fundamental material parameters. However, the operational criteria of proton exchange membranes in these devices are the membrane resistance and vanadium crossover flux, both of which depend on membrane thickness. Herein, we explore the influence of the thickness of ion exchange capacity (IEC)-optimized sulfonated fluorinated poly(arylene ether) (SFPAE) membranes on their VRFB performance including charge/discharge behavior, charge depth, coulombic efficiency, voltage efficiency, energy efficiency and cell polarization. IEC-optimized SFPAE membranes with three different thicknesses (28μm, 45μm and 80μm) were prepared and tested in this study. It was found that the combined effects of the ohmic loss and electrolyte crossover loss in the VRFB, which were governed by membrane thickness, resulted in an optimal membrane thickness of 45μm for SFPAE under the conditions tested. Thicker membranes were observed to cause higher cell resistance while thinner membranes yielded larger vanadium crossover flux, both of which had negative impacts on the cell performance. The maximum power densities of the VRFBs assembled with 28μm, 45μm and 80μm SFPAE membranes were 267mWcm-2, 311mWcm-2 and 253mWcm-2 respectively, much higher than that of the VRFB assembled with N212 membrane, which was 204mWcm-2. These results supported our previous observation that SFPAE was superior to N212 with regard to VRFB performance. The data also indicated that there is an optimum membrane thickness for a given set of properties through which the cell performance can be significantly improved while keeping the membrane material constant.
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U2 - 10.1016/j.memsci.2013.02.007
DO - 10.1016/j.memsci.2013.02.007
M3 - Article
AN - SCOPUS:84875799757
SN - 0376-7388
VL - 437
SP - 108
EP - 113
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -