IN-SITU AND OPERANDO STUDIES OF ENERGY MATERIALS FOR SOLID OXIDE FUEL CELLS USING NEUTRONS AND SYNCHROTRON RADIATION

JIMENEZ, CATALINA E.; NAPOLITANO, FEDERICO R.; BASBUS, JUAN F.; SANTAYA, MARIANO; SERQUIS, ADRIANA; MOGNI, LILIANA V.

Cancun

Congreso; XXVIII International Materials Research Congress (IMRC-2019); 2019

Materials Research Society (MRS) and Sociedad Mexicana de Materiales (SMM)

The complexity of the process involved in the development of new technological devices requires the use of complementary characterization techniques in order to understand the whole phenomena. This situation is particularly applicable on the field of high temperature electrochemical devices such as Solid Oxide Fuel Cells (SOFC). Energy materials for these devices are exposed to extreme environments conditions such as high temperature, high reducing or oxidizing atmosphere and, depending of its function, they work under cathodic/anodic polarization conditions or gradient of potentials. These non-ambient conditions could induce modification on the bulk and surface electronic and atomic structures of materials that can impact in the performance. In the same way, the polarization conditions could modify the bulk and surface characteristics.In this work, we discuss preliminary results on in-situ and operando characterization of both, proton conductor electrolyte and C-tolerant anode perovskite-based materials.The proton conductor electrolytes for SOFC is an interesting proposals for the O-free oxidation of C-based fuels allowing the co-generation of energy and values added product such as C2 hydrocarbons. However, because these materials are mixed proton and O-ion conductors, the elucidation of the true range of temperature where H-ionic conductivity dominates, is fundamental for the device formulation. Then, our work was focused to the correlation between the atomic and electronic structures of BaCe0.4Zr0.4Y0.2O3-δ and its proton conductivity by applying in-situ and operando measurements of X-ray and neutron diffraction as well as X-ray absorption spectroscopy in combination with Impedance Spectroscopy (IS).The perovskite-based anodes were proposed to replace state of art Ni-YSZ anodes due to its higher tolerance to C-based fuels. In our case, we are interested in Ni-doped Sr(Ti,Fe)O3 perovskite where the formation of FeNi nanoparticles on the surface, when the anode is exposed to fuel atmosphere, improves even more the anode performance in comparison to Ni-free perovskite. In-situ and operando measurements of X-ray spectroscopies in combination with IS under different atmosphere and polarization voltage allow to obtain insights into the surface chemistry of the electrodes at the solid/gas interface helping to identify formed chemical species and oxidation states and its role in the improvement of electrode performance.