Improvement of output performance of solid oxide fuel cell by optimizing the active anode functional layer

Abstract

In this work, the effects of an anode functional layer (AFL) with various thicknesses on the physical properties of anode and the electrochemical performance of the anode-supported solid oxide fuel cells (SOFCs) have been systematically studied. Four anode-supported cells with controllable AFL thicknesses have been fabricated by the combined phase-inversion co-tape casting method, screen-printing and dip-coating method. An optimal thickness of the AFL of 7.6 μm is determined by the experimental results including the physical properties and electrochemical performance, and cell performance is significantly enhanced after the introduction of the AFL, which is ascribed to the remarkably increased triple-phase boundaries induced by the AFL. The bilayer anode-supported cells with 7.6 μm thick AFL exhibit a peak power density of 0.906 Wcm−2 and a total resistance of 0.47 Ωcm2 at 700 °C when the anode and the cathode are exposed a humidified H2 (3 vol% H2O) and ambient air, respectively. Additionally, when the anode side is fed with the diluted H2 (3 vol% H2O-97 vol% (10% H2–90% N2)), an excellent peak power density of 0.558 Wcm−2 is still achieved. These results demonstrate that the bilayer anode is a suitable candidate for high-performance SOFC applications, especially at a low hydrogen concentration.