Improved durability of protonic ceramic fuel cells with BaZr0.8Yb0.2O3–δ electrolyte by introducing porous BaZr0.1Ce0.7Y0.1Yb0.1O3–δ buffer interlayer

Abstract

Long-term durability of anode-supported protonic ceramic fuel cells (PCFCs) with BaZr0.8Yb0.2O3–δ (BZYb20) electrolyte is evaluated at 600 °C over 1000 h operation. To prevent a decrease in cell performance caused by Co diffusion from a La0.6Ba0.4CoO3−δ (LBC)-based cathode into the BZYb20 electrolyte, a porous buffer interlayer of BaZr0.1Ce0.7Y0.1Yb0.1O3–δ (BZCYYb) is placed at the interface between the cathode and electrolyte. By introducing the BZCYYb buffer interlayer, although the power density of the PCFC deteriorates slightly due to adding the ohmic resistance of the interlayer, the long-term durability for 1000 h operation remarkably improves, e.g., degradation rate decreases from 4.8 % kh−1 to 0.9 % kh−1. Moreover, the PCFC with the BZCYYb buffer interlayer achieves a stable operation with a degradation rate of 0.8 % kh−1 for 3000 h. Electron probe microanalysis confirms that the BZCYYb buffer interlayer prevents diffusion of Co from the LBC-based cathode into the BZYb20 electrolyte even after 3000 h operation.