Electrical characterisation of ceramic conductors for fuel cell applications

Ln electrochemical devices, such as direct methanol fuel cells (DMFCs) or p roton exchange membrane fuel cells (PEMFCs), it is necessary to reduce Pt l oading to 0.3 mg/cm(2) at the electrodes. Furthermore, partial Pt replaceme nt by other electrocatalysts is desirable. Use of ceramic compounds as elec trodes might be an important technology innovation. The transition metal pe rovskite oxides LaNiO3-delta, SmCoO3, which have been selected as candidate materials for this application, are metallic conductors and some undergo m etallic-semiconductor transitions. The combustion synthesis method is used to prepare the corresponding powders. Specific surface areas as high as 10 m(2)/g and average particle size of the order of 10 nm were achieved. depen ding on precursors/fuel rate used. The as-prepared powders were XRD amorpho us. The electrical characterisation of these materials was carried out by C omplex Impedance Spectroscopy on four-probe arrangement samples. (C) 2000 E lsevier Science B.V. All rights reserved.