Hydrogen insertion and protonic conductivity in lead phosphate Pb3(PO4)2

Annealing effects, anomalous dielectric properties and conductivity of As-diluted lead phosphate Pb3(P1–xAsxO4)2

“…This indicates that under the above mentioned conditions the dominant contribution to the conductivity is protonic for both, the as-grown and annealed samples. Annealing in wet argon increases the concentration of mobile protons by a factor of six in accordance with the results of [11]. the anomalous temperature behaviour of conductivity on heating, because strong superposition of ac conductivity and different dielectric relaxation mechanisms occurs.…”

“…Here H h corresponds to the activation enthalpy of the dc conductivity. It should be noted that the values of H h are close to those of pure lead phosphate (0.45 eV) [10,11] where direct evidence of the protonic conductivity in this crystal was obtained. It can be seen that for all as -grown as well as annealed samples the temperature dependencies of s dc do not depend on the composition.…”

“…This property of lead phosphate led to basic research and the application of lead phosphate might be interesting as a solid proton electrolyte which operates at moderate temperatures. However, precise determination of the absolute values of the bulk conductivity is difficult because in the temperature range 400-800 K large frequency dependent dielectric anomalies occur [10][11][12][13]. Such anomalies are qualitatively similar to those observed in perovskite-type crystals [3][4][5][14][15][16][17].…”

“…It was shown previously that in the temperature range 300-800 K the conductivity of pure and As-diluted Pb 3 (PO 4 ) 2 depend on the annealing atmosphere [10]. Recently [11] it was shown that hydrogen can be inserted into lead phosphate by thermal treatment in wet atmospheres. As a result the protonic conductivity of nominally pure compounds increases by a factor of 4-5.…”

Polyphosphate composite: conductivity and NMR studies

“…Inorganic material with water included [2][3][4], without water [5][6][7], salts of inorganic oxygen acids [8][9][10][11][12] and oxide ceramics [13,14] have been intensively investigated. Polyphosphate glasses [15], aluminum polyphosphate [16] and ammonium polyphosphate [17][18][19] were rarely considered, even though these materials exhibit high conductivities in the middle temperature range (0.1 S cm À1 at 300 8C), since the nature and dynamics of the species responsible for the charge transport are not yet clear.…”