Simple solid oxide fuel cells

A new concept of solid oxide fuel cells (SOFCs), the simple SOFCs, that is simply composed of an electronic conductor and an ionic conductor is investigated, which evidently simplifies the assembly and further maintenance of the cell system. High-performance interconnect material chromium deficient lanthanum calcium chromites La_0.7Ca_0.3Cr_0.97O_3-δ (LCC97) perovskite oxides are prepared by a modified Pechini method and examined as both anode and cathode materials for SOFCs based on the state-of-the-art YSZ electrolyte. Chemical compatibility, sintering character, electrical conductivity and thermal expansion are investigated to characterize the compatibilities of LCC97 with YSZ. The XRD analysis indicates LCC97 chemically compatible with YSZ. The LCC97 sintered at 1250 °C have the conductivity of 62.0 S cm^-1 at 850 °C in air, which is about 2.6 times as high as that of La_0.7Ca_0.3CrO_3-δ with no chromium deficiency. At 850 °C, the ASRs is only 0.15 Ω cm² for LCC97-YSZ composite cathode. LCC97-based simple SOFCs (LCC97-YSZ/YSZ/LCC97-YSZ) offer promising performance using H2 as fuel and thick YSZ electrolytes. An open-circuit potential of 1.06 V, a maximum power density of 92.1 mW cm^-2, and a polarization resistance of the electrodes of 2.17 Ω cm² are achieved at 850 °C.