Gluing Ba0.5Sr0.5Co0.8Fe0.2O3−δ with Co3O4 as a cathode for proton-conducting solid oxide fuel cells

The Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) + Co3O4 composite material is evaluated as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs), which provides a new strategy to solve the thermal mismatch problem between the cathode and electrolyte without impairing the cathode performance. BSCF is a well-known cathode material for intermediate-temperature SOFCs, but its performance for H-SOFCs is unsatisfactory. One reason for the relatively low performance is the poor contact between the BSCF cathode and the electrolyte due to the high thermal expansion of BSCF. The relatively low melting point of Co3O4 is taken in this study as an advantage to bond the BSCF cathode to the electrolyte, mitigating the poor contact problem for the BSCF with the electrolyte. Furthermore, the addition of Co3O4 promotes the catalytic activity of the BSCF cathode as demonstrated by experimental studies and first-principles calculations, leading to an impressively high performance of BSCF-based cathodes for H-SOFCs.