Electrical conductivity of Ag +/Na + ion-exchanged titanosilicate glasses

• Published in: Solid state ionics Vol. 160; no. 3; pp. 281 - 288
• Main Authors: Funabiki, Fuji, Yano, Tetsuji, Shibata, Shuichi, Yamane, Masayuki
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2003
• Subjects: Ion exchange; Ionic conductivity; Silver ion conductor; Titanosilicate glass; 66.30.Hs; Silver ion conductor; Ion exchange; Ionic conductivity; 66.10.Ed; Titanosilicate glass
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/S0167-2738(03)00168-1

The Ag 2O–TiO 2–SiO 2 glasses were prepared by Ag +/Na + ion-exchange method from Na 2O–TiO 2–SiO 2 glasses at 380–450 °C below their glass transition temperatures ( T g), and their electrical conductivities were investigated as functions of TiO 2 content and the ion-exchange ratio (Ag/(Ag+Na)). In a series of glasses 20R 2O· xTiO 2·(80− x)SiO 2 with x=10, 20, 30 and 40 in mol%, the electrical conductivities at 200 °C of the fully ion-exchanged glasses of R=Ag were in the order of 10 −5 or 10 −4 S cm −1 and were 1 or 2 orders of magnitude higher than those of the initial glasses of R=Na. The glass of x=30 exhibited the highest increase of conductivity from 3.8×10 −7 to 1.3×10 −4 S cm −1 at 200 °C by Ag +/Na + ion exchange among them. When the ion-exchange ratio was changed in 20R 2O·30TiO 2·50SiO 2 system, the electrical conductivity at 200 °C exhibited a minimum value of 7.6×10 −8 S cm −1 around Ag/(Ag+Na)=0.3 and increased steeply in the region of Ag/(Ag+Na)=0.5–1.0. When the ion-exchange temperature was changed from 450 to 400 °C, the conductivity of the ion-exchanged glass of x=30 decreased. The infrared spectroscopy measurement revealed that the ion-exchange temperature of 450 °C induced a structural change in the glass of x=30. The T g of the fully ion-exchanged glass of x=30 was 498 °C. It was suggested that the incorporated silver ions changed the average coordination number of titanium ions to form higher ion-conducting pathway and resulted in high conductivity in the titanosilicate glasses.