Measurement of electronic conductivity in mixed ionic and electronic conductor (MIEC) via a novel embedded microcontact method

Abstract

Electronic conductivity plays an important role on the performance and durability of energy devices containing mixed ionic and electronic conductors (MIEC). Over the past decades, it has been realized that the classical Hebb-Wagner(H-W) method has some critical limitations or issues that may limit its accuracy or testing feasibility, such as relatively long relaxation time towards steady state and challenges on sealing. In this study, we reported an embedded microcontact ionic blocking electrode to minimize these issues. Using this method, the activation energy in Ce0.9Gd0.1O1.95 (GDC10) are measured, respectively as, 2.51 and 1.44 eV, for n type electronic and p type hole conductivity. The values are similar to those reported in literature as 2.51 and 1.45 eV, respectively, for n and p type conduction also in GDC10 via non-embedded ionic-blocking electrode. At a refence oxygen partial pressure of 0.21 atm, the n type conductivity, σe(0), is obtained as 1.05×10−7, 2.81×10−6, 4.28×10−5 S cm−1 at 600, 700, and 800 °C, respectively, and the p type conductivity, σh(0), is obtained as 1.18×10−4, 5.86×10−4, 3.51×10−3 S cm−1 at 600, 700, and 800 °C, respectively. The new method could be an effective technique to determine electronic conduction in other MIECs.