Pore former addition in the preparation of highly porous anode using phase-inversion technique for solid oxide fuel cell

Abstract

A detailed study on the anode structure of solid oxide fuel cell (SOFC) is very crucial in developing high performance power generating devices, given how porous electrodes are known to provide a number of active sites for reaction, consequently accelerate fuel conversion. This present study investigates the feasibility of pore former addition to nickel oxideyttria stabilized zirconia (NiO-YSZ) anode, fabricated via phase inversion-based casting and sintering technique. The loading of two types of pore former (i.e. polyetheretherketone [PEEK] and corn starch) was varied from 0 to 10 wt % of total suspension. The effects of pore former loading and its types were examined based on anode morphology using scanning electron microscopy (SEM), crystal phase by X-ray diffraction (XRD), apparent porosity based on standard ASTM C373-88, and bending strength using three-point bending test. Results had shown that higher loading of pore former increased the porosity, yet significantly reduced the bending strength. SEM images of anode displayed that by generating more connected open pores through the addition of 2 wt.% PEEK, it produced an effective porous structure. In fact, the sample recorded to be 67 % mechanically stronger compared to the best loading which is corn starch (4 wt.%). Based on these findings, PEEK can be used as pore former in anode fabrication that creates appropriate porosity, which benefits gas diffusion and also provides good mechanical strength as an anode support.