Increase of Anode Performance of SOFC by Reverse Current Treatment

Abstract

The electrochemistry in the anode functional layer is still one of the performance limiting factors for the standard planar anode-supported SOFC (ASC). In this contribution we present an effective method for the improvement of anode performance. It is based on a short-time application of a high current density in reverse direction (reverse current treatment, RCT). The measured impedance data sets show a progressive decrease of the overall area specific polarization resistance (ASRpol), when the ASC is exposed to a series of RCT. The change in ASRpol could be attributed to the electrochemical polarization loss in the anode functional layer (AFL), which was reduced by 40 %. Post-test analysis with FIB/SEM revealed the formation of a nanoscaled and highly porous Ni/YSZ layer between electrolyte (YSZ) and anode (Ni/YSZ). The hereby increased length of the electrochemically active triple phase boundary (TPB) is regarded to be the cause for this distinct improvement.