Polycrystalline material was electrochemically characterized and was clearly found to be an In3+-conducting solid electrolyte. Upon heating, it underwent a phase transition at between 250 and 260C and transformed from a monoclinic to an orthorhombic phase. The crystal structure in the high-temperature region was of Sc2(WO4)3-type. The conductivity was investigated, by means of impedance spectroscopy, at 300 to 700C. It was equal to about 3.7 x 10-5S/cm at 600C, with a corresponding activation energy of 59.5kJ/mol. Polarization data indicated that current transport occurred only via ionic charge carriers, with a transference number of about 0.99. Direct-current electrolysis data proved that trivalent In cations were definitely the mobile species. No current transport via oxide anions was observed.

Indium Tungstate, In2(WO4)3, an In3+ Conducting Solid Electrolyte. J.Kohler, N.Imanaka, G.Y.Adachi: Zeitschrift für Anorganische und Allgemeine Chemie, 1999, 625[11], 1890-6