Mixed Conductivity and the Conduction Mechanism of the Orthorhombic CaZrO3 based Materials

Abstract Solid state reaction technique was employed to fabricate oxygen sensors based on Y, Cr co-doped CaZrO3. The X-ray diffraction, scanning electron microscopy, electrochemical impedance spectroscopy, electron-blocking method were employed to investigate the crystal structure, surface morphology, and electrical properties such as phase formation, microstructure, the oxygen vacancy concentration, ionic conductivity, and total conductivity. Furthermore, the efficacy of Cr-dopant on the features of Y0.08Ca0.92Zr1-xCrxO3-δ was systematically investigated. The obtained results from the XRD demonstrated development of orthorhombic perovskite structure of Y0.08Ca0.92Zr1-xCrxO3-δ and the occurrence of CaCrO4 with a large increase in Cr-doping amount. Moreover, the results of the electrical properties elucidated higher electronic and ionic conductivities of Y0.08Ca0.92Zr1-xCrxO3-δ with Cr-doping level increasing. The excellent improvement of multivalent chromium ions on the electrical properties, the mechanism of charge compensation and oxygen ions conduction in lattice are discussed in details.