Generating an electron-blocking layer with BaMn1-xNixO3 mixed-oxide for Ce0.8Sm0.2O2−δ-based solid oxide fuel cells

Abstract

Doped ceria (DCO) has high oxygen ionic conductivity, but the electronic conduction due to the reduction of Ce4+ to Ce3+ degrades its usage as an electrolyte material for solid oxide fuel cells. Inserting an electron-blocking layer is an attractive strategy to deal with this problem. In order to generate a Ba-containing electron blocking layer for DCO-based single cells, we applied BaMn1-xNixO3 (x = 0, 0.25, 0.5) mixed-oxide as an anode precursor material, and studied the solid reactions of it with NiO and SDC under the cell preparation conditions. XRD analysis indicates that the BaMn1-xNixO3 precursors are primarily BaMnO3/BaNiO3-δ mixed-oxides. It is found that BaMn1-xNixO3 reacts with SDC to form BaCeO3 and a novel Ba2(NiMnCe)2O6 double perovskite. SEM/EDS analyses reveal that BaCeO3 tends to accumulates at the anode-electrolyte interface, as well as to fill the closed pores in the SDC electrolyte. A 4 μm-thick electron-blocking layer with BaCeO3 as the main component effectively eliminates the internal-short-circuit and enhances the performance of the cell. The open circuit voltage and peak power density of the cell with such an electron-blocking layer are 1.010 eV and 621 mW cm−2 respectively at 650 °C.