A highly proton-/vanadium-selective perfluorosulfonic acid membrane for vanadium redox flow batteries
A highly proton-/vanadium-selective perfluorosulfonic acid (Nafion) membrane modified by phosphotungstic acid (PWA)-anchored nano Kevlar fibers (NKFs) and nano silica particles (NSP) for a vanadium redox flow battery (VRB) was fabricated through solution casting. The nanohybrid composed of NKFs, NSP...
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Published in | New journal of chemistry Vol. 43; no. 28; pp. 11374 - 11381 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
15.07.2019
|
Subjects | |
Online Access | Get full text |
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Summary: | A highly proton-/vanadium-selective perfluorosulfonic acid (Nafion) membrane modified by phosphotungstic acid (PWA)-anchored nano Kevlar fibers (NKFs) and nano silica particles (NSP) for a vanadium redox flow battery (VRB) was fabricated through solution casting. The nanohybrid composed of NKFs, NSP and PWA exhibited excellent compatibility with the polymer matrix, and effectively suppressed the vanadium ion crossover. In addition, the anchoring of PWA was of great significance for maintaining the ion exchange capacity and constructing continuous proton transport channels. The optimal Nafion-(NKFs@NSP/PWA) membrane presented a high proton conductivity (0.079 S cm
−1
) and a low vanadium permeability (6.27 × 10
−7
cm
2
min
−1
), resulting in an ion selectivity of 1.26 × 10
5
S min cm
−3
, which is much higher than that of recast Nafion (0.34 × 10
5
S min cm
−3
). Moreover, the VRB assembled with the modified membrane showed a lower self-discharge rate, higher battery efficiency and superior capacity retention than that with the recast Nafion over a range of current densities from 40 mA cm
−2
to 100 mA cm
−2
.
The polar clusters of Nafion are blocked by the incorporation of the nanohybrid, which contributes to suppress vanadium ions crossover. |
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Bibliography: | Electronic supplementary information (ESI) available: Materials characterization methods and VRB test details; structural formula of PWA, NKFs and Nafion; physical diagram for the measurement of vanadium ions permeability; UV-vis absorption standard curve of PWA; EDS and elemental content of NKFs@NSP and NKFs@NSP/PWA; detailed data on charge-discharge voltage and capacity; digital images of the membranes. See DOI 10.1039/c9nj01453e |
ISSN: | 1144-0546 1369-9261 |
DOI: | 10.1039/c9nj01453e |