A tin dioxide (SnO 2) sensor was fabricated by inkjet printing onto polyimide foil. Gold electrodes and heater were printed on each side of the substrate. A SnO 2 based ink was developed by sol-gel method and jetted onto the electrodes. A final annealing at 400°C compatible with the polymeric transducers allowed to synthetize the SnO 2 sensing film. Electrical measurements were carried out to characterize the response of the fully printed sensors under oxidizing and reducing gases. The device was heated up at a temperature between 200 and 300°C using the integrated heater. The proper operation of the full printed metal-oxide gas sensors was validated under exposure to carbon monoxide and nitrogen dioxide, in dry and wet air.

International audienceFour cathode materials for single chamber solid oxide fuel cell (SC-SOFC) [La0.8Sr0.2MnO3-δ (LSM), Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF), Sm0.5Sr0.5CoO3-δ (SSC), and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF)] were investigated regarding their chemical stability, electrical conductivity, catalytic activity, and polarization resistance under air and methane/air atmosphere. Electrolyte-supported fuel cells, with Ce0.9Gd0.1O2-δ (CGO) electrolyte and a Ni-CGO anode, were tested in several methane/air mixtures with each cathode materials between 625 and 725 °C. These single cells were not optimized but only designed to compare the four studied cathodes. The decrease of methane-to-oxygen ratio from 2 to 0.67 strongly increased the performance of fuel cells for all cathode materials but the effect of temperature was not always significant. Cells with SSC, BSCF, and LSCF have shown a maximum power density about 20 mW cm-2 while the cell with LSM has given only 5 mW cm-2

The performance of lanthanum nickelate, La 2 NiO 4 + δ (LNO), as a cathode in IT-SOFCs with the electrolyte cerium gadolinium oxide, Ce 0.9 Gd 0.1 O 2 − δ (CGO), has been investigated by AC impedance spectroscopy of symmetrical cells. A significant reduction in the area specific resistance (ASR) has been achieved with a layered cathode structure consisting of a thin compact LNO layer between the dense electrolyte and porous electrode. This decrease in ASR is believed to be a result of contact at the electrolyte/cathode boundary enhancing the oxygen ion transfer to the electrolyte. An ASR of 1.0 Ω cm 2 at 700°C was measured in a symmetrical cell with this layered structure, compared to an ASR of 7.4 Ω cm 2 in a cell without the compact layer. In addition, further improvements were observed by enhancing the cell current collection and it is anticipated that a symmetrical cell consisting of a layered structure with adequate current collection would lower these ASR values further.