Tin pyrophosphate, SnP2O7, was prepared with various initial molar ratios of phosphorus vs. metal ions, Pini/Sn, and different heat-treating temperatures from 573 to 923K. The preparation conditions were optimized giving consideration to the influence of H3PO4 concentration, Pini/Sn molar ratio and heat-treating temperature. The ionic conduction behaviors were investigated by means of electrochemical methods including ac impedance spectroscopy, hydrogen and water vapour concentration cells, etc. in the temperature range of 323–523 K. The results indicated that the samples obtained from 85% H3PO4 and SnO2 nanopowders with Pini/Sn ≥ 2.4 were a single cubic phase, and that in wet hydrogen atmosphere, the samples were almost pure ionic conductors, the ionic conduction was contributed mainly by proton and partially by oxide ion. An ionic conductivity of 2.17 x 10− 2 S/cm was achieved for the sample prepared from Pini/Sn = 2.8 under wet hydrogen atmosphere at 448 K.

Ionic Conduction in Undoped SnP2O7 at Intermediate Temperatures. H.Wang, J.Xiao, Z.Zhou, F.Zhang, H.Zhang, G.Ma: Solid State Ionics, 2010, 181[33-34], 1521-4