Comparison of X-ray Nanotomography and FIB-SEM in Quantifying the Composite LSM/YSZ SOFC Cathode Microstructure

X-ray nanotomography and focused ion beam scanning electron microscopy (FIB-SEM) provide unique opportunities to interrogate the 3D microstructure of solid oxide fuel cell (SOFC) electrodes with unprecedented spatial resolution with elemental specificity. Using x-ray nanotomography with differential absorption imaging across the Mn K-absorption edge (6539 eV), and energy selected backscatter detection for FIB-SEM, these two techniques have been applied to obtain 3D elemental mapping of the LSM, YSZ and pore phases in the cathode microstructure. Measurements taken by non-destructive x-ray imaging and FIB-SEM serial sectioning include three-phase boundary areas (nominal and effective); phase volume fraction; and phase contiguity. The results presented demonstrate the viability of nanotomography as a characterization technique and provide key insights into the SOFC cathode microstructure. The effects of instrument resolution on microstructural characterization are addressed and the roles of FIBSEM and x-ray nanotomography in future SOFC microstructural characterization efforts are discussed.