Anode-supported single-chamber SOFC for energy harvesting from exhaust gases of thermal engine

Pauline Briault (1, 2, 3) , Jean-Paul Viricelle (1, 2, 3) , Mathilde Rieu (1, 2, 3) , Richard Laucournet (4) , Bertrand Morel (4)

1 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
2 LGF-ENSMSE - Laboratoire Georges Friedel
3 PRESSIC-ENSMSE - Procédés et REactivité des Systèmes Solide-gaz, Instrumentation et Capteurs
4 LITEN - Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux

Solid oxide fuel cells operating in mixed gas atmospheres (Air /hydrocarbon mixture), the so-called single chamber SOFCs (SC-SOFCs), are based on the same working principle as the conventional “two-chambers” SOFCs, but the absence of sealing between the two compartments provides an easier operation. This configuration has several advantages over conventional SOFCs. Indeed, new cell geometries, stack assembly and miniaturization of cells are more easily conceivable, opening the way to new applications such as energy recovery in the exhaust gas by conversion of unburned hydrocarbons into electricity. This forward-looking energy recovery system could be applicable to automotive vehicles as well as to plants. Yano et al. and Nagao et al. in 2008 demonstrated the feasibility of such a device by investigating a stack of 12 cells, electrolyte supported Ni-SDC/YSZ/LSM SC-SOFCs, incorporated at the exit of a scooter engine. However, optimization of the system including architecture, gas mixture and materials modification may lead to enhanced performances. In this study, a gas mixture closer to real exhaust conditions has been selected. It is composed of hydrocarbons (HC: propane and propene), oxygen, carbon monoxide, carbon dioxide, hydrogen and water. Only oxygen content has been varied leading to different gas mixtures characterized by the ratio R=HC/O₂. Concerning the cell components, a cermet composed of nickel and the electrolyte material, Ce_0.9Gd_0.1O_1.95 (GDC) is used as anode and two cathode materials, Pr₂NiO_4+δ (PNO) and La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF), have been selected. Anode support is prepared by tape casting; then electrolyte material is screen-printed on top of the green tape previously cut into 22.5 mm diameter discs. Cathode and gold mesh screen printing and sintering conclude cell preparation. These cells have then been tested in various gas mixtures for temperatures ranging from 400°C to 600°C. Ni-GDC/GDC/LSCF-GDC cell operation has delivered a maximum OCV of 706 mV and a power density reaching 16mW/cm² at 500°C with R=HC/O₂=0.21. The performances of 22.5 mm diameter cells in various configurations will be presented as well as preliminary results on larger cells (5*5cm²) both in single cell and stack configuration.

Mots clés: thermal engine; exhaust gases; SC-SOFC; Anode-supported single-chamber

Domaines: Génie des procédés

Pauline Briault, Jean-Paul Viricelle, Mathilde Rieu, Richard Laucournet, Bertrand Morel. Anode-supported single-chamber SOFC for energy harvesting from exhaust gases of thermal engine. IDHEA (International Discussions on Hydrogen Energy and Applications), May 2014, Nantes, France. ⟨hal-01107597⟩