November 2010

In situ secondary ion mass spectrometry (SIMS) is used to investigate the diffusion of different ions out of lanthanum strontium manganese oxide (LSM) as a function of the applied potential with high lateral resolution in the 0.1 µm range. LSM is used as a cathode material in solid oxide fuel cells (SOFCs). Manganese, strontium and lanthanum show a voltage-dependent segregation onto or away from the electrolyte (yttria stabilized zirconium oxide (YSZ)). This process is exemplarily shown in the upper picture by the secondary ion images of manganese. Brighter colors indicate higher ion intensities in the examined area. Both the applied potential and the polarization time are shown in the arrows above the images. These in situ measurements are offer valuable mechanistic information on the oxygen reduction and transport during fuel cell operation. The image size is 500 µm times 500 µm. Picture submitted by M. Falk