The Electrical and Thermal Properties of Sodium Sulfate Mixed with Lithium Sulfate, Yttrium Sulfate, and Silicon Dioxide

Abstract

Sodium sulfate mixed with lithium sulfate, yttrium sulfate, and silicon dioxide was prepared. The thermal and electrical properties of its phases were investigated. The Na2SO4‐Li2SO4‐Y2false(SO4)3‐SiO2 samples are similar to the Na2SO4‐I phase (a high temperature phase), which is appreciably effective for Na+ ionic conduction. Phase transformation was considerably suppressed by mixing. Electromotive force (EMF) was measured, using Na2SO4‐Li2SO4‐Y2false(SO4)3‐SiO2 as a solid electrolyte, by constructing an SO2 gas concentration cell. The measured EMF's at 823 and 773 K were in fairly good accordance with the calculated EMF's for inlet SO2 gas concentration between 30 ppm and 1%, and 500 ppm and 0.5%, respectively.

Ionic Conducting Lanthanide Oxides

“…This results in a Na + ion conductivity that is comparable to Na 2 SO 4 −NaVO 3 −Y 2 (SO 4 ) 3 and prevents the electrolyte from becoming ductile. By further additional mixing of lithium sulfate with Na 2 SO 4 −Y 2 (SO 4 ) 3 −SiO 2 solid electrolyte, the conductivity becomes approximately 320 times higher than pure sodium sulfate at 700 °C, which is within the high Na + ion conductive I phase region …”

Sulfur Dioxide Gas Detection with Na2 SO 4 ‐ Li2 SO 4 ‐ Y 2 ( SO 4 ) 3 ‐ SiO2 Solid Electrolyte by a Solid Reference Electrode Method

“…Although many studies on the oxidation of metals have been carried out, few papers dealing with the effect of an external electric field on a growing oxide can be found in the literature (6-i i). A theoretical treatment of this problem was recently developed in Fromhold's book (12), while previously it was treated by Kofstad (13). The results obtained by Jorgensen (7, 8, I0), for instance, seem to confirm this effect, although other authors (14,15) did not find any influence of the external electric field on the oxidation kinetics.…”

“…The difference between the measured and calculated EMF at 823 K was approximately 70 mV except at 30 ppm. The reason for the deviation of the EMF from the measured EMF line (broken line) at 30 ppm, is ascribed to the difficulty in the decomposition of sodium sulfate from the electrolyte because the measuring temperature is as low as 823 K. In our previous investigation with a sulfur dioxide gas concentration cell method (12), the Na2SO4-Li2SO4-Y~(SO4)~-SiO2 electrolyte was found to work even at 823 K. Therefore, the difference at 873 and 823 K is not attributed to the electro- CoS04-Co304 solid reference electrode.--The variation of the EMF for the Na~SO~-Li2SO4-Y2(SO4)3-SiO~ solid electrolyte at 973 K is shown in Fig. 6.…”

Thermal analysis

“…It is possible to use electrical conductivity measurements to determine phase transitions in certain solid states and this approach is utilized in a study on AgoSI^Br* solid solutions (195). A similar technique was used for the Na2S04-Li2S04-Y2(S04)3-Si02 system (196). Results of electrical conductivity studies in solid cross-linked dimethylsiloxane-ethylene oxide copolymer networks containing sodium have been published (197).…”