Enhanced Gas Diffusion in Reversible Solid Oxide Cell Fabricated by Phase-Inversion Tape Casting

Abstract

A hydrogen-electrode-supported solid oxide cell (SOC) is fabricated by phase-inversion tape casting technique and its electrochemical performance is investigated with particular focus on high fuel utilization operation and reversible operation. Structure of the hydrogen-electrode support layer is also analyzed. Electrochemical performance of the cell is measured and compared with that obtained from a conventional cell having homogenous porous structure in the hydrogen electrode support. Equivalent circuit fitting analysis is performed for quantitative understanding of impedance spectra. The results indicate that the finger-like pores in the hydrogen-support layer introduced by the phase-inversion process can significantly enhance gas diffusion property of the layer and hence improve cell performance particularly at lower reactant concentrations. Also, asymmetry in cell performance between fuel cell and electrolysis cell modes is suppressed, which is desirable for reversible operation of SOCs.