Electrochemical equilibrium of air-referenced oxygen sensors in liquid LBE and analysis for determination of oxygen solubility

Abstract

This paper presents the development of oxygen sensors based on four electrode materials lanthanum strontium cobalt ferrite (LSCF), lanthanum strontium manganese (LSM), platinum (Pt) and silver (Ag), and yttria-stabilized zirconia (YSZ) solid electrolyte. The responsiveness, accuracy, stability and repeatability of the various oxygen sensors were evaluated. The findings indicate that the LSCF, LSM and Ag electrode oxygen sensors exhibit optimal operational suitability, whereas the Pt electrode oxygen sensor is suitable for environments exceeding 650 K. The performance of 5YSZ solid electrolytes is more susceptible to low temperature effects than that of 8YSZ solid electrolytes. And the output electromotive force (EMF) as a function of temperature for the liquid LBE in a saturated oxygen environment was obtained, show as: $E=1.1307-5.9443\times {10}^{-4}T$, within 473 ∼ 823 K. Furthermore, the oxygen solubility of the liquid LBE was determined by combining the aforementioned thermodynamic data, show as: $\ln C_{O,S}=7.09-10922/T$, (C_O,S in wt.%).