Tuning the Interfacial Reaction Between Bismuth‐Containing Sealing Glasses and Cr‐Containing Interconnect: Effect of ZnO

Abstract

The interfacial reaction between sealing glasses and Cr‐containing interconnect presents a challenge for the development of solid oxide fuel cell (SOFC). In this work, we report that the interfacial reaction between bismuth‐containing sealing glasses and Cr‐containing interconnect can be tailored by ZnO dopant. The addition of ZnO contributes to a more open glass structure, resulting in the facilitated diffusion of ions in glass and thus the increase in the interfacial reaction. On the other hand, the further increase in ZnO content enhances the Bi3+→Bi5+ transition in glasses and reduces the redox interfacial reaction by consuming the oxygen available at the glass/metal interface. In addition, good joining can be observed at the sealing interface between ZnO‐containing glass‐ceramics and Crofer 22 APU, held in air at 700°C for 1400 h. Moreover, the glass‐ceramics show considerable electrical stability in oxidizing and reducing atmospheres. The reported results support the suitability of prepared glass‐ceramics as sealing materials for SOFC applications.

Structure, crystallization, and performances of alkaline‐earth boroaluminosilicate sealing glasses for SOFCs

“…Second, Cr and Fe elements diffuse from the steel to the glass surface since the elemental change in the interface manifests itself as a continuous, gradual trend although it is steep (see lower panel of Figure 8). Cr can react with glass, forming a dense layer at the interface, as reported previously 29,30 . This is also why the CG layer is more difficult to fall off the steel substrate compared to the MG and SG layers.…”

“…Table 4 also shows that the T g and T d values of the three standard glass samples vary with the heat-treatment duration in different trends. For sample MG, T g and T d decrease 29 with extending the heat-treatment time. For sample CG, T g remains nearly unchanged, but T d increases.…”

“…The mapping was conducted through an analytical software embedded in the Raman spectrometer. In addition, the 29 Si magic-angle spinning (MAS) NMR spectra of the studied three types of glasses were acquired using a Bruker DSX-400 MHz spectrometer.…”

“…The phase in Area 5 (Figure 4C,D) could be the feldspar crystals (CaAl 2 Si 2 O 8 or SrAl 2 Si 2 O 8 ), since the peaks at ~500 cm −1 and ~1000 cm −1 arise from the bending modes of Si-O-Si(Al) and the stretching vibration of Si-O-Si in feldspar. 15,18,20,23 To detect the structural changes in the three glass systems with varying the heat-treatment duration, 29 Si NMR measurements were conducted as shown in Figure 5. In the standard glass samples (Figure 5A), the strongest broad peaks lie between −72 and −115 ppm, which are mainly assigned to Q 1 , Q 2 , Q 3 , and Q 4 .…”

Effect of Nb2O5 doping on improving the thermo-mechanical stability of sealing interfaces for solid oxide fuel cells

“…The borosilicate glass system with Bi 2 O 3 dopant also stabilizes the B-O network, which is beneficial for reducing the detrimental interfacial reaction between sealing glass and cathode 12 . Moreover, the B 2 O 3 -SiO 2 -Bi 2 O 3 glass system with ZnO dopant inhibits the chemical interaction between glass and interconnect 13 . Therefore, appropriate amount of 8 mol.% Nb 2 O 5 (2, 4 and 8 mol.%) is added to a B 2 O 3 -SiO 2 -Bi 2 O 3 glass system to condense the glass network structure in this work.…”