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Improved phase stability and electrochemical performance of (Y,In,Ca)BaCo 3 ZnO 7+δ cathodes for intermediate temperature solid oxide fuel cells

2014; Elsevier BV; Volume: 39; Issue: 34 Linguagem: Inglês

10.1016/j.ijhydene.2014.09.091

1879-3487

Matthew West, Arumugam Manthiram,

Magnetic and transport properties of perovskites and related materials

Abstract With an aim to combine the performance-enhancing properties of Ca with the stability-promoting properties of In in the s wedenborgite YBaCo 4 O 7+ δ -based cathodes for solid oxide fuel cells (SOFC), cation-substituted Y 1− x − y In x Ca y BaCo 3 ZnO 7+ δ (0.2 ≤ ( x + y ) ≤ 0.5) oxides have been explored. All samples presented in this work are stable in air after 120 h exposure to 600, 700, and 800 °C. Increasing In content shows a negligible impact on polarization resistances ( R p ), but causes an increase in the activation energies ( E a ) of (Y,In,Ca)BaCo 3 ZnO 7+ δ + Gd 0.2 Ce 0.8 O 1.9 (GDC) composite cathodes on 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte supported symmetric cells. Increasing Ca content shows a decrease in R p and an increase in E a on similar electrochemical cells. All (Y,In,Ca)BaCo 3 ZnO 7+ δ samples investigated here show superior performance compared to the unsubstituted YBaCo 3 ZnO 7+ δ + GDC cathode in the range of 400–800 °C. Especially, the Y 0.5 In 0.1 Ca 0.4 BaCo 3 ZnO 7+ δ + GDC composite cathode exhibits good performance on GDC electrolytes in the range of 400–600 °C. With superior phase stability and electrochemical performance, the (Y,In,Ca)BaCo 3 ZnO 7+ δ series of oxides are attractive cathode candidates for intermediate temperature SOFCs.