Hybrid inorganic–organic proton conducting membranes based on Nafion and 5wt.% of MxOy (M=Ti, Zr, Hf, Ta and W)

New nanocomposite proton conducting membranes based on a core–shell nanofiller for low relative humidity fuel cells

“…4 inset b) is associated with the thermal degradation of the polyether side chains. 23,24,[28][29][30]35 In contrast to the filler's stabilizing effect on the -SO 3 H groups, ZrTa tends to decrease the thermal stability of the polyether side groups likely due to the catalytic effect of the transition metal oxides. 30 The fourth mass elimination, detected between 400-500 uC range, is due to the decomposition of the fluorocarbon chains of the polymer matrix.…”

“…Water uptake by the hybrid membranes was measured by isothermal elimination at 30 and 120 uC by using the isothermal mass elimination of the materials as shown in eqn (1): 23,33 W:U:~w t t ð Þ{wt dry wt dry (1) where wt(t) and wt dry are the weight of the membrane at time t and in dry conditions, respectively. The W.U.…”

“…23,24 These studies indicated that: a) the amount of each of the four water domains detected in the bulk membranes depends on the acidity of M x O y oxocluster; b) the thermal, mechanical and electrical stability of the Nafion 1 host polymer depends on the concentration of dynamic R-SO 3 H … M x O y … HSO 3 -R cross-links in bulk material; and c) the concentration and strength of the dynamic R-SO 3 H … M x O y … HSO 3 -R cross-links occurring inside polar hydrophilic cages of the membranes increase along group IV and decrease along period VI of the periodic exhibits very favorable physicochemical properties in terms of elastic modulus and conductivity, which result from strong acid-base interactions that occur within the ion aggregate domains between HfO 2 and the sulfonic acid groups of host polymer matrix. 23,24 These interactions are due to the basic nature of HfO 2 . 23,24 It was also shown that the performance of proton-conducting membranes may be improved by blending the proton-conducting ionomer with another polymer bearing basic functionalities.…”

“…23,24 These interactions are due to the basic nature of HfO 2 . 23,24 It was also shown that the performance of proton-conducting membranes may be improved by blending the proton-conducting ionomer with another polymer bearing basic functionalities. [25][26][27] Recently, it was reported that Nafion/[(M1 m O n )?…”

“…The new ZrO 2 and Ta 2 O 5 -containing nanofiller is prepared with the intent of combining the improvements resulting from fillers with a ''core-shell'' morphology with the intrinsic characteristics of the individual oxides that will allow it to maintain strong R- 3 -R interactions and reduce the water uptake within the hybrid membranes. Of the group IV and period VI oxoclusters previously investigated, [22][23][24]28 32 The preparation of the nanofiller based on ZrO 2 and Ta 2 O 5 , indicated as ZrTa, is part of an effort to produce a ''chemical core-shell'' nanofiller and subsequently elucidate the effect of its chemistry and surface properties on the structure, properties and fuel cell performance of the resulting hybrid inorganic-organic membranes. 30 In addition, the water uptake, the thermal and structural properties will be examined.…”