Ag₄I₂SeO₄ and Ag₃ITeO₄ – Two New Silver Solid Electrolytes

Abstract

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 ϫ 10 Ϫ3 at 30°C with an activation energy of 0.22 eV, between 30 and 51°C. It crystallizes as green crystals in Pna2 1 with a ϭ 9.3514 (1) Å , b ϭ 1071 13.1552(4) Å , c ϭ 7.0886(4) Å , V ϭ 871.80(6) Å 3 and Z ϭ 4. The crystal structure consists of isolated SeO 4 tetrahedra separated by Ag ϩ and I Ϫ ions. Ag 3 ITeO 4 crystallizes in P2 1 /c with a ϭ 19.6597(2) Å , b ϭ 7.1240(4) Å , c ϭ 13.3598(3) Å , β ϭ 97.795(2)°, V ϭ 1853.83(11) Å 3 and Z ϭ 12. The structure consists of 1 ϱ [TeO 4/2 O 2/1 ] 2Ϫ isopolyanions, extending along the b-axis. The chains are separated by Ag ϩ and I Ϫ ions. Ag 3 ITeO 4 has a silver ion conductivity of 7.4 ϫ 10 Ϫ5 Ω Ϫ1 cm Ϫ1 at 30°C, with an activation energy of 0.27 eV between 25 and 100°C.

Synthesis, Crystal Structure and Ionic Conductivity of Ag8I2(CrO4)3

“…Selected interatomic distances/Å and angles/° for Ag 8 I 2 (CrO 4 ) 3 . Estimated standard deviations are given in parentheses.Cr ( Similar silver coordination numbers and the corresponding bonding distances have been frequently observed in various silveroxide and silveriodine materials [7][8][9][10][11][12][13][14][15][16][17][18]. The shortest Ag-Ag distance observed is 2.880(1) Å (Ag2-Ag2).…”

“…The incorporation of silver ions in an immobile framework of complex oxoanions has proven to be an effective route to raise the silver ion conductivity. Recently, we expanded this field to composites containing AgI and silver selenates and tellurates, this way identifying Ag 3 ITeO 4 , Ag 4 I 2 SeO 4 and Ag 9 I 3 (SeO 4 ) 2 (IO 3 ) 2 as new silver solid electrolytes [17,18]. In the course of our structural investigation of crystalline analogues of the ion-conducting silver iodide silver oxyacid salt glasses, we have synthesized and characterized the compound Ag 8 I 2 (CrO 4 ) 3 .…”

Crystal structure of silver carbonate iodide Ag10(CO3)3I4

“…The crystal structures of quaternary inorganic compounds composed of silver and iodide ions and oxyanionic groups, such as Ag 2 I(NO 3 ) 2 (Birnstock & Britton, 1970), Ag 16 I 12 P 2 O 7 (Garrett et al, 1982), Ag 5 IP 2 O 7 (Adams & Preusser, 1999), Ag 4 IPO 4 (Oleneva et al, 2008), Ag 8 (CrO 4 ) 3 I 2 (Pitzschke et al, 2009b), Ag 9 (GeO 4 ) 2 I (Pitzschke et al, 2009c), Ag 8 I 4 V 2 O 7 (Adams, 1996), Ag 13 (AsO 4 ) 3 I 4 (Pitzschke et al, 2009a), Ag 4 I 2 SeO 4 (Pitzschke et al, 2008a), Ag 3 ITeO 4 (Pitzschke et al, 2008a), Ag 9 I 3 (IO 3 ) 2 (SeO 4 ) 2 (Pitzschke et al, 2008b) and Ag 26 I 18 (WO 4 ) 4 (Chan & Geller, 1977) have been reported.…”

Synthesis and Structure of Ag4Te(SO4) – a New Compound Featuring a Silver‐Telluride Framework

“…Quite a number of compounds of this type were discovered as a result of a detailed search for new silver‐ion electrolytes 19. Among them, those containing silver halogenides compose the most numerous group of compounds with relatively ordered frameworks, Ag 5 I(P 2 O 7 ) 14, Ag 4 I(PO 4 ) 15, and Ag 3 I(TeO 4 ) 17c being the examples. Compounds featuring silver‐telluride frameworks with different topology are known to a lesser extent [16, 20].…”