Reducing the reaction between boron-containing sealing glass-ceramics and lanthanum-containing cathode: Effect of Bi2O3

The volatile boron from boron-containing sealing materials often reacts with lanthanum-containing cathode, leading to the formation of LaBO3 and consequently significant degradation of cathode. The reaction between boron-containing sealing glass-ceramics and lanthanum-containing cathode thus presents a challenge for the development of solid oxide fuel cell (SOFC). Here we report for the first time that such a reaction can be significantly reduced by Bi2O3 dopant in sealing glass-ceramics. In particular, the formation of LaBO3 can be prohibited in reaction couple between glass containing 9 mol.% Bi2O3 and lanthanum strontium cobalt ferrite (LSCF) cathode. The addition of Bi2O3 enhances the [BO3] → [BO4] transition in glass structure and therefore improves the thermal stability of boron species in glass matrix. In addition, Bi2O3 dopant also favors the formation of BiBO3, which dramatically reduces boron volatility from sealing glass-ceramics. The reported results provide an effective approach for solving the sealing challenge.