Chemical Reactivity and Cathode Properties of LaCoO₃ on Lanthanum Silicate Oxyapatite Electrolyte

Abstract

Chemical reactivity and cathode properties of LaCoO3 were investigated using new oxide ion conductor, lanthanum silicate oxyapatite. The LaCoO3 is found to be good candidate for cathode of the lanthanum silicate oxyapatite solid-electrolyte since no chemical reaction occurred between the LaCoO3 and lanthanum silicate oxyapatite heating at 1273 K for 60 h in air. Based on electrochemical measurements, lower overpotential between the LaCoO3 and lanthanum silicate oxyapatite was confirmed compared to the overpotential at YSZ/LaCoO3 interface. From analysis on the extended interfacial conductivity as function of oxygen activity at the triple phase boundary at fixed temperature, the overpotential evaluated by impedance spectra is the rate limiting process by oxygen diffusion on the LaCoO3 surface. Comparing to the bulk conductivity of LaCoO3, the electrode resistance evaluated by impedance spectra was confirmed to be different from the electrical transport properties of the LaCoO3 bulk.

Anisotropic Electric Conductivity and Battery Performance in <i>C</i>-axis Oriented Lanthanum Silicate Oxyapatite Prepared by Slip Casting in a Strong Magnetic Field

“…Conversely, an oxide electrode or a nickel cermet electrode, which is commonly used in a general SOFC, must be used by considering its reactivity with the LSO electrolyte. It has been reported that the LaCoO 3 perovskite material is available for use as an air electrode, 18) and it has been considered that power generation can be improved based on the selection of the electrode material. As shown in Fig.…”

Investigation of Co3O4 and LaCoO3 Interaction by Performing N2O Decomposition Tests under Co3O4-CoO Transition Temperature

“…However, the limitations of ceria in SOFCs are due to the fact that at high temperatures or low oxygen partial pressures ceria exhibits mixed ionic and electronic conductivity [17]. On the other hand, perovskite type oxides conduct only ions, and compounds such as lanthanum cobaltate, LaCoO 3 (LCO), are often used in SOFCs as the cathode material [18][19][20].…”

Development of an electrochemical impedance analysis program based on the expanded measurement model

“…The SOFCtype cell was fabricated using yttria-stabilized zirconia (TZ-8Y, Tosoh Corp., Japan), lanthanum cobaltite (LaCoO 3 ) synthesized by a citrate combustion method, 38) and platinum paste (TR-7907, Tanaka Kikinzoku Kougyo, Japan). The three-terminal configuration cell was fabricated by the same procedure used in a previous study.…”

“…The three-terminal configuration cell was fabricated by the same procedure used in a previous study. 38) The impedance spectrum of the SOFC-type cell was measured at 1073 K under air using the potentio/galvanostat built-in frequency response analyzer (Reference-600, Gamry Instruments, USA). The frequency ranged from 1 MHz to 0.1 Hz with 10 points per order of magnitude arranged on a logarithmic scale.…”