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Ag 4 I 2 SeO 4 and Ag 3 ITeO 4 – Two New Silver Solid Electrolytes
Author(s) -
Pitzschke Dragan,
Curda Jan,
Cakmak Güliz,
Jansen Martin
Publication year - 2008
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200800027
Subject(s) - ionic conductivity , crystallography , crystal structure , conductivity , stoichiometry , differential scanning calorimetry , ion , ionic bonding , fast ion conductor , materials science , analytical chemistry (journal) , x ray crystallography , chemistry , electrolyte , diffraction , physics , electrode , organic chemistry , chromatography , thermodynamics , optics
Two new silver solid electrolytes, Ag 4 I 2 SeO 4 and Ag 3 ITeO 4 , have been synthesized by solid state reactions starting from stoichiometric mixtures of Ag 2 O and AgI with SeO 2 , or TeO 2 , respectively, at elevated oxygen pressures. The new materials have been characterized using powder X‐ray diffraction, differential scanning calorimetry, ionic conductivity measurements and single crystal structure determination. Both compounds, Ag 4 I 2 SeO 4 and Ag 3 ITeO 4 , show an abrupt increase in the ionic conductivity in the temperature range of 50 to 70 °C and 90 to 130 °C, respectively. Ag 4 I 2 SeO 4 has a silver ion conductivity of 1.6 × 10 −3 at 30 °C with an activation energy of 0.22 eV, between 30 and 51 °C. It crystallizes as green crystals in Pna 2 1 with a = 9.3514(1) Å, b = 13.1552(4) Å, c = 7.0886(4) Å, V = 871.80(6) Å 3 and Z = 4. The crystal structure consists of isolated SeO 4 tetrahedra separated by Ag + and I − ions. Ag 3 ITeO 4 crystallizes in P 2 1 / c with a = 19.6597(2) Å, b = 7.1240(4) Å, c = 13.3598(3) Å, β = 97.795(2)°, V = 1853.83(11) Å 3 and Z = 12. The structure consists of $^{1}_{\infty}\rm [TeO_{4/2}O_{2/1}]^{2-}\}$ isopolyanions, extending along the b‐axis. The chains are separated by Ag + and I − ions. Ag 3 ITeO 4 has a silver ion conductivity of 7.4 × 10 −5 Ω −1 cm −1 at 30 °C, with an activation energy of 0.27 eV between 25 and 100 °C.