Layered perovskites as promising cathodes for intermediate temperature solid oxide fuel cells

The suitability of GdBaCo₂O₅₊as a cathode material for intermediate temperature solidoxidefuelcells has been evaluated. The¹⁸O/¹⁶O isotope exchange depth profile (IEDP) method has been used to obtain the oxygen surface exchange and oxygentracerdiffusion coefficients yielding optimum values for applicability infuelcells (k* = 2.8 10⁷cm s¹andD* = 4.8 10¹⁰cm²s¹at 575 C) especially in terms of lowactivationenergies (E_A^k= 0.81(4) andE_A^D= 0.60(4) eV). The same material has been characterized electrically as a part of a symmetrical electrochemical system (GdBaCo₂O₅₊/Ce_0.9Gd_0.1O_2x/GdBaCo₂O₅₊), by means ofimpedance spectroscopymeasurements, corroborating an excellent performance in the classical intermediate temperature range for solidoxidefuelcells (500700 C). An area specific resistance (electrodeelectrolyte interface) of 0.25 cm²at 625 C was achieved for a cell processing temperature of 975 C.Finally, layered perovskites are presented as a promising new family of materials for cathode use in solidoxidefuelcells at low temperatures.