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　LaBO3　and　degrading　the　activity　of　SOFCs.　Here,　we　report　that　the　reaction　between　the　volatile　boron　and　a　La0.6Sr0.4Co0.2Fe0.8O3-δ　(LSCF)　cathode　during　polarization　can　be　significantly　reduced　by　doping　aluminoborosilicate　glass　with　Gd2O3.　Specifically,　the　Gd　cations　in　glass　with　2　mol.%　Gd2O3　dissolve　preferentially　in　the　borate-rich　environment　to　form　more　Gd-metaborate　structures　and　promote　the　formation　of　calcium　metaborate　(CaB2O4);　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.　©　2018　Elsevier　B.V.