Fabrication and characterization of inert-substrate-supported tubular single cells by dip-coating process

Abstract

A tubular single cell supported by an inert substrate with a configuration of porous yttria-stabilized zirconia (YSZ) supporter/Ni anode current collector/Ni–Ce0.8Sm0.2O1.9 anode/YSZ/Ce0.8Sm0.2O1.9 bi-layer electrolyte/La0.6Sr0.4Co0.2Fe0.8O3-δ cathode has been fabricated by a cold isostatic pressing and dip-coating process. The effects of pore morphology and porosity of the YSZ supporter on the mechanical strength and electrochemical performance of the single cell have been investigated with respect to the content of poly (methyl methacrylate) (PMMA) pore former. The average pore size and porosity of the YSZ supporter increase with the amount of pore former used, facilitating the gas diffusion process at the anode and reducing the polarization resistance of the single cell whereas leading to a decline of the mechanical strength. A preferred pore former content is determined to be 25 wt.% based on a trade-off of the mechanical strength and electrochemical performance. The single cell with 25 wt.% PMMA in YSZ supporter shows a bending strength of 21 ± 1 MPa and a maximum power density of 337 mW cm−2 at 800 °C in hydrogen. Moreover, the inert-substrate-supported tubular single cell displays a satisfactory redox cycling stability, maintaining 95% of its initial performance within seven redox cycles.