• Tullmar, Peter Blennow
• Klemensø, Trine
• Weber, André
• Hjelm, Johan
• Kromp, Alexander
• Ramousse, Severine
• Leonide, André

Abstract

A metal-supported solid oxide fuel cell design offers competitive advantages, for example reduced material costs and improved robustness. This paper reports the performance and stability of a recently developed metal-supported cell design, based on a novel cermet anode, on a 25cm2 (1cm2/16cm2 active area) cell level. An electrochemical performance comparable to state-of-the-art anode-supported cells is demonstrated.Detailed electrochemical analysis allowed assignment of the overall polarization losses quantitatively to gas diffusion in the metal support, electrooxidation in the anode functional layer, oxygen reduction in the mixed ionic-electronic conducting cathode and an additional polarization process with a rather high relaxation frequency, which may be assigned to an insulating corrosion interlayer.The durability of the cells was investigated by means of galvanostatic operation for periods of up to 1000h as well as the dynamic behavior, such as redox-, load- and thermal cycling tests.The galvanostatic stability tests indicated a fair, but significant degradation rate (∼5% decrease in cell voltage/1000h at 650°C and 0.25Acm−2). Furthermore, the metal-supported cells underwent an endurance test of 100 redox cycles at 800°C without severe degradation nor total failure.

Topics

• impedance spectroscopy
• corrosion
• Oxygen
• durability
• electrochemical characterization method