Novel polyolefin/silicon dioxide/H3PO4 composite membranes with spatially heterogeneous structure for phosphoric acid fuel cellстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 19 июля 2013 г.
Аннотация:Novel composite membranes based on polyolefins for intermediate and high temperature
(120e160 C) phosphoric acid fuel cells with polymer matrices have been synthesized and
their properties have been studied, including testing in operating fuel cells. In contrast to
polybenzimidazoles uniformly swelling with H3PO4, which are typically used as
membrane-separators in such a type of fuel cells, the proposed materials have heterogeneous
internal structure with spatially separated condensed bundles of non-swelling rigid
polymer-silica composite matrix and proton-conducting channels filled with phosphoric
acid. Such a heterogeneous structure may potentially provide improved balance between
proton conductivity and mechanical stability of the membranes in comparison with the
homogeneously swollen PBI structures. The composite porous films based on polyethylene
and polypropylene have been prepared in several different ways and filled with network of
silicon dioxide. The SiO2 phase forms hydrophilic three-dimensional well-percolated
channels. The affinity between the SiO2 phase and the liquid phosphoric acid is responsible
for capillary retention of the liquid electrolyte in the porous matrix (phosphoric acid wets
SiO2 surface). Besides, the framework of SiO2 phase enhances the mechanical stability of
the membranes at high temperatures. Maximum proton conductivity of 0.033 S/cm is
achieved at 160 C for fuel cell with the obtained polyethylene-based membrane. The best
performance is detected for fuel cells on polypropylene-based membrane, which provides
0.5 V at 0.4 A/cm2 at 140 C being supplied with hydrogen and air. The proposed concept is
aimed to mimic spatially-non-uniform Nafion-type membranes instead of using uniformly
swollen polybenzimidazoles.