ac and dc conductivity studies of pelletised 12-tungstophosphoric acid and 12-tungstosilicic acid hexahydrates

Polyoxometalate–Polymer Hybrid Materials as Proton Exchange Membranes for Fuel Cell Applications

“…They explained that the differences of proton conductivity between different measurements might relate to the mechanism of 1 H self-diffusion which had much stronger temperature dependence at lower temperatures (T < 7 °C). They further used a combination of AC and direct current (DC) techniques to characterize the proton conductivity in pelletized hexahydrates of H 3 PW 12 O 40 and H 4 SiW 12 O 40 [40] and the proton conductivity of H 3 PW 12 O 40 ·6H 2 O at elevated temperatures [41]. Also, dielectric relaxation spectroscopy has been used for the bulk proton conductivity of pelletized H 3 PW 12 O 40 ·6H 2 O [42].…”

“… a, b, c. The exact values of the conductivity in these three pelletized compounds were not given directly, but shown in a figure of typical temperature dependent AC conductivity [40], in which the conductivity of them were in the range from 6 × 10 −5 to 2 × 10 −4 S cm −l and in the order of a > c > b. n.d. = not determined.…”

Proton conducting H5BW12O40 electrolyte for solid supercapacitors

“…12,[38][39][40] To compare BWA and SiWA at the same level of hydration, both samples were heated at 80-90 C overnight before characterization. In the 400-1100 cm À1 region, the structure and interaction of the HPA are well characterized as the The composition and structure of the bulk BWA crystals were investigated with XRD.…”

“…1,[5][6][7] Their performance is strongly dependent on the humidity and the temperature of the operating environment. [10][11][12][13][14] HPAs belong to a large family of metal-oxygen clusters of early transition metals formulated as H z [X x M m O y ], where M is the addenda atom and X is the heteroatom. Solid proton conductors in a polymer-in-salt conguration have proven to be a good alternative.…”

Studies of heteropoly acid/polyvinylidenedifluoride–hexafluoroproylene composite membranes and implication for the use of heteropoly acids as the proton conducting component in a fuel cell membrane

“…The heteropoly acids (HPAs), a subset of the well-known inorganic metal oxides known as polyoxometallates [3,4], are class of an intriguing set of solid state proton conducting super acids. HPAs based on the Keggin structure have some of the highest reported solid-state proton conductivities at room temperature [5] and proton transport in these materials has been extensively studied [6][7][8][9][10][11][12]. The HPAs are becoming an increasingly popular proton conducting additives in ionomer composite membranes for use under dry and/or elevated temperature conditions [2].…”