Synthesis and characterization of Nd0.6Sr0.4Co1−yMnyO3−δ (0 ≤ y ≤ 1.0) cathodes for intermediate temperature solid oxide fuel cells

Nd0.6Sr0.4Co1−yMnyO3−δ (0 ≤ y ≤ 1.0) oxides have been investigated as cathode materials for intermediate temperature solid oxide fuel cells (SOFC). The samples form a single-phase solid solution with an orthorhombic perovskite structure and the lattice parameters and volume increase with increasing Mn content y. The degree of oxygen loss at high temperatures and the thermal expansion coefficient (TEC) decrease with increasing y due to a stronger Mn-O bond. The electrical conductivity decreases with y and the system exhibits a metal to semiconductor transition at around y = 0.2. The electrocatalytic activity and power density measured with single cell SOFC decrease with increasing y due to a decrease in oxygen exchange and mobility as well as charge transfer kinetics, arising from a decrease in the oxide ion vacancy concentration and electrical conductivity.