Dependence of solid oxide fuel cell electrode microstructure parameters on focused ion beam – Scanning electron microscopy resolution

Abstract

Dependence of microstructure parameters on the resolution of focused ion beam-scanning electron microscopy (FIB-SEM) images was evaluated for nickel-yttria stabilized zirconia (Ni-YSZ) electrode of solid oxide fuel cell (SOFC). Three dimensional microstructure was reconstructed by FIB-SEM images at voxel size of 3 nm which is the highest resolution among the reported SOFC researches. Volume fraction, triple phase boundary (TPB) density and specific surface areas were calculated with various resolutions. Dependences of TPB density and specific surface areas on resolution were clearly shown. Changes of these parameters at high resolution were attributed to the surface roughness caused by the image drift in the scanning electron microscopy imaging. Accurate vales of TPB density and specific surface area were estimated by extrapolation from several values at coarser resolutions and compared with those at typical resolutions which are normally applied in conventional microstructure analysis of SOFC electrodes. The result indicates that the dependence on resolution should be taken into account for the quantitative analysis of microstructure parameters.

Influence of Initial Powder Morphology on Polarization Characteristics of Nickel/Gadolinium-Doped-Ceria Solid Oxide Fuel Cells Electrode

“…The details of the image processing are described previously. 35,36 The volume fractions, surface area, mean particle intercept length, triple-phase-boundary (TPB) density, double-phase-boundary (DPB) density and tortuosity factors were calculated. The algorithms used for calculations are described in the earlier publication.…”

Magnetic Alignment of Anode Microstructure in Solid Oxide Fuel Cell

“…The connectivity, tortuosity factor and TPB density were calculated from the three-dimensional (3D) microstructure which was reconstructed by FIB-SEM (NVision 40, SII Nanotechnology Inc.). 11,27,28 Both pixel size of the SEM and FIB milling distance were set at 30 nm. Size of the reconstructed volume was approximately 10 × 10 × 10 μm 3 .…”

“…Image segmentation was carried out based on the Ref. 28. For impedance measurement, the symmetrical cells that were fabricated according to the process described in Fabrication procedure section were set in a testbench (BEL-SOFC).…”

Reconstructing porous structures from FIB-SEM image data: Optimizing sampling scheme and image processing

“…An additional source of artificial anisotropy is the typical non-cubic shape of the imaged fields of view [9,25,26,27] which are often much smaller in z-direction than in xy-direction.…”

“…The effects of coarsening the lateral resolution on estimation accuracy for geometric and transport properties of structures reconstructed from FIB-SEM data have been studied in [25,26], and [28]. In [25], a solid nickel-yttria stabilized zirconia (Ni-YSZ) electrode is investigated. The volume fraction is found to be almost constant, whereas the surface density depends on resolution as expected.…”