A Novel Lanthanum-based Solid Oxide Fuel Cell Electrolyte Composite with Enhanced Thermochemical Stability toward Perovskite Cathode

Lanthanum-based electrolytes for Solid Oxide Fuel Cells (SOFCs) gain extensive attention due to their lower activation energy and low-cost preparation to convert the energy stored in gaseous chemicals into electricity. In this context, a La9.33Si6O26-La0.8Sr0.2Ga0.8Mg0.2O2.55 (LSO-LSGM) SOFC electrolyte composite with various mass ratio LSO:LSGM (w/w) (5:0, 4:1, 3:2, 2:2, 2:3, 1:4) are successfully prepared for the first time using different LSO precursors with various mass target of 3g (LSO-LSGMA) and 5g (LSO-LSGMB), respectively. The result shows that the lower mass target in the synthesis of LSO induced formation of protoenstatite and coesite secondary phases on the composite of LSO-LSGM based on XRD, FTIR, and XPS analysis. The SEM micrograph suggests that agglomeration occurred more in LSO-LSGMA than in LSO-LSGMB. Generally, the composites signified high chemical stability on La0.8Sr0.2Co0.6Fe0.4O2.55 (LSCF) cathode based on the XRD analysis. The LSO-LSGMA composites which contained a high percentage of protoenstatite and coesite resulted in an additional peak of MgSi2Sr, especially for the sample with the mass ratio of 41 (LSO-LSGM41) suggesting that the chemical stability of LSO-LSGMA on LSCF cathode is much lower than LSO-LSGMB.