Research On Structure And Properties Of Sealing Glass For Solid Oxide Fuel Cell

Solid Oxide Fuel Cell（SOFC）is an conversion device that can transform chemical energy directly into electrical energy by electrochemical reaction,which has the advantages of high energy conversion efficiency,environmental friendly,fuel flexibility,etc.The planar solid oxide fuel cell（p-SOFC）has become the focus of fuel cell research at home and abroad due to its high power density and low cost.However,one of the most significant technology barriers for the p-SOFC development and commercialization is to realize the effective high temperature sealing.According to the domestic and foreign research and literature reports,the BaO-Al₂O₃-SiO₂glass-ceramic were selected for SOFC sealing,and the structure and properties of BAS sealing glass were investigated.The first part of this paper is focus on the effect of BaO values on structure and properties of sealing glass.The results show that the coefficient of thermal expansion of the glasses declined as the content of BaO increases,and Ba-1、Ba-2、Ba-3 glasses CTE among（10.0¹2.0）×10^-6℃^-1,the heat treatment time has little influence on CTE,which is matched with 8YSZ and Crofer22APU and suitable for SOFC sealing.The main crystaline phase of the glass after heat treated is the needle-like hexacelsian,and the heat treatment time and temperature had no significant effect on the crystallization properties.The resistivity of the glass is high,which is 8.56×10⁶?·cm at 500℃.The bending strength of the sealing glass approximated 80 MPa.According to the results of the first part of this paper,the Ba-3 sealing glass were selected for base component,to investigate the effect of B₂O₃ values on structure and properties of sealing glass.The results show that the number of crystallization is larger with B₂O₃ values increasing from 4.8 wt%to 6.8wt%;the glasses create phase separation when the B₂O₃ values is high than 6.8wt%,with B₂O₃ additional increasing,phase separation phenomenon is more serious.The main crystaline phase of the glass after heat treated is the needle-like hexacelsian.With B2O3 values increasing the coefficient of thermal expansion of glass increasing.The bending strength of the sealing glass decreasing after the first increase,the maximum bending strength reach117MPa when the B₂O₃ values is 6.8wt%.According to the results of the first and second part of this paper,the effect of Y₂O₃ on structure and properties of sealing glass and combined situation with 8YSZ were investigated.The results show that with Y2O3 values increasing,the crystal concentration,coefficient of thermal expansion and bending strength of the sealing glass decreased after the first increase.The coefficient of thermal expansion and bending strength of the sealing glass reach 10.41×10^-6℃^-1 and 134 MPa when the Y₂O₃ values is 4wt%.The resistivity and situation of Y-1 sealing glass combined with 8YSZ was investigated.The results show that no crack,holes,interfacial reaction,and elements diffused can be observed,the Y-1sealing glass combined well with 8YSZ.The resistivity of the glasses are higher than 10⁴?·cm at 400℃ and 450℃.