Electrochemical Investigation of a Large SOFC Fed with n-Dodecane Reformate

In recent years, solid oxide fuel cells (SOFCs) have been extensively studied because of its potential as clean and efficient electric generators. Recently, SOFCs coupled with an external reforming have been suggested for the utilization in marine on-board applications. Diesel marine is the conventional fuel actually used; however, the stability of a conventional SOFC fed with a diesel reformate is not yet proven. Furthermore, the testing of a large area SOFC has a specific importance with the aim of the subsequent scaling up to a stack.

This study deals with the investigation of the degradation effects occurring onto the anode of a large area cell in presence of n-dodecane reformate. A commercial anode supported SOFC (10 × 10 cm²) with planar configuration having the composition Ni-YSZ/YSZ/YDC/LSFC, has been investigated in-situ electrochemically. The test bench used for this experiment is the conventional ECN test station showed in Figure 1. The electrochemical experiments concerned I-V curves (Figure 2) and impedance spectroscopy (Figure 3) carried out at OCV and at 0.9 V. Ex situ tests were also carried out in order to evaluate morphological and and physico-chemical modification on the discharged cell.

In the case of anodes (Ni-YSZ cermets), the degradation phenomena are recognized due to Ni agglomeration and carbon deposition. These microstructural changes in anode is expected to be highly dependent on operating conditions, such as operating temperature, operating voltage and water content in the feed.

Figure 1: ECN test bench (a) and commercial large area cell (b)