Effect of Gd2O3 doping on structure and boron volatility of borosilicate glass sealants in solid oxide fuel cells—A study on the La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode

Abstract Boron volatility is one of the most important properties of borosilicate-based glass sealants in solid oxide fuel cells (SOFCs), as boron contaminants react with lanthanum-containing cathodes, forming LaBO 3 and degrading the activity of SOFCs. Here, we report that the reaction between the volatile boron and a La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) cathode during polarization can be significantly reduced by doping aluminoborosilicate glass with Gd 2 O 3 . Specifically, the Gd cations in glass with 2 mol.% Gd 2 O 3 dissolve preferentially in the borate-rich environment to form more Gd-metaborate structures and promote the formation of calcium metaborate (CaB 2 O 4 ); they also condense the B–O network after heat treatment, which suppresses poisoning by boron contaminants on the LSCF cathode. The results provide insights into design and development of a reliable sealing glass for SOFC applications.