Electrical characterisation of ceramic conductors for fuel cell applications

In electrochemical devices, such as direct methanol fuel cells (DMFCs) or proton exchange membrane fuel cells (PEMFCs), it is necessary to reduce Pt loading to 0.3 mg/cm exp 2 at the electrodes. Furthermore, partial Pt replacement by other electrocatalysts is desirable. Use of ceramic compounds as electrodes might be an important technology innovation. The transition metal perovskite oxides LaNiO sub 3- delta , SmCoO sub 3 , which have been selected as candidate materials for this application, are metallic conductors and some undergo metallic-semiconductor transitions. The combustion synthesis method is used to prepare the corresponding powders. Specific surface areas as high as 10 m exp 2 /g and average particle size of the order of 10 nm were achieved, depending on precursors/fuel rate used. The as-prepared powders were XRD amorphous. The electrical characterisation of these materials was carried out by Complex Impedance Spectroscopy on four-probe arrangement samples.