Application of BaO-CaO-Al2O3-B2O3-SiO2 glass-ceramic seals in large size planar IT-SOFC

摘要

BaO-CaO-Al2O3-B2O3-SiO2 (BCAS) glass-ceramics can be used as sealant for large size planar anode-supported solid oxide fuel cells (SOFCs). BCAS glass ceramics after heat treatment for different times were characterized by means of thermal dilatometer, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the coefficients of thermal expansion (CTE) of BCAS glass-ceramics are 11.4 x 10(-6) K-1, 11.3 x 10(-6) K-1 and 11.2 x 10(-6) K-1 after heated at 750 degrees C for Oh, 50 h, and 100 h, respectively. The CTE of BCAS matches that of YSZ, Ni-YSZ and the interconnection of SOFC. Needle-like barium silicate, barium calcium silicate and hexacelsian are crystallized in the BCAS glass after heat-treatment for above 50 h at 750 degrees C. The glass ceramics green tape prepared by aqueous tape casting can be directly applied in sealing the cell of SOFCs with 10 cm x 10 cm. The open circuit voltage (OCV) of the cell keeps 1.19 V after running for 280 h at 750 degrees C and thermal cycling 10 times from 750 degrees C to room temperature. The maximum power density is 0.42 W/cm(2) using pure H-2 as fuel and air as oxidation gas. SEM images show no cracks or pores exist in the interface of BCAS glass ceramics and the cell. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.