Abstract
The ionic conductive behavior of Sn0.9In0.1P2O7 ceramic was investigated under various atmospheres within the temperature range of 130-230oC. Similar to high-temperature-mixed-conductive perovskite oxides at high temperatures (such as SrCe0.95Yb0.05O3-x, La0.9Sr0.1Ga0.8Mg0.2O3-x at 600-1000oC), Sn0.9In0.1P2O7 can conduct both protons and oxide-ions at low temperatures (130-230oC). The conductivity of Sn0.9In0.1P2O7 reaches 0.019 S/cm at 200oC in wet nitrogen. Its transport numbers determined by steam concentration cells are about 0.8 for proton and 0.1 for oxide-ion. The performance at 170oC for methanol fuel cells using mixed-ion conductive Sn0.9In0.1P2O7 as the electrolyte is higher than that at 235oC using pure proton conductive CsH2PO4 electrolyte. This is possibly attributed to the direct oxidation of CO at the anode by the oxide-ions generated at the cathode and moved through the Sn0.9In0.1P2O7 electrolyte.
