The Effect of Ni Doping on the Performance and Electronic Structure of LSCF Cathodes Used for IT-SOFCs

6533b82cfe1ef96bd128f759

RESEARCH PRODUCT

The Effect of Ni Doping on the Performance and Electronic Structure of LSCF Cathodes Used for IT-SOFCs

Christoph J. Sahle M. Moretti Sala Leonarda F. Liotta Valeria La Parola Fabrizio Puleo Antonino Martorana Chiara Cavallari Alessandro Longo Dipanjan Banerjee

subject

Ni-doped Materials science Absorption spectroscopy LSCF Analytical chemistry chemistry.chemical_element 02 engineering and technology 010402 general chemistry Electronic Optical and Magnetic Materials; Energy (all); Physical and Theoretical Chemistry; Surfaces Coatings and Films 01 natural sciences Coatings and Films symbols.namesake Oxidation state Electronic Optical and Magnetic Materials Physical and Theoretical Chemistry Valence (chemistry)IT-SOFC Electronic Optical and Magnetic Material Doping 021001 nanoscience & nanotechnology 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dielectric spectroscopy Surfaces Nickel Energy (all)General Energy chemistry Settore CHIM/03 - Chimica Generale E Inorganica symbols 0210 nano-technology Raman spectroscopy Cobalt

description

We investigated the effect of nickel doping on the electronic structure and performance of nanostructured La0.6Sr0.4Co0.2Fe0.8-0.03Ni0.03O3-delta prepared by the one-pot sol gel method. The commercial undoped La0.6Sr0.4Co0.2Fe0.8O3-delta (ISCF0.8) was used as reference. Moreover, for comparison, Ni (3 mol %) was deposited by wetness impregnation over the La0.6Sr0.4Co0.2Fe0.8O3-delta. We show by in situ X-ray absorption spectroscopy at 900 degrees C under air flow that nickel enters the B perovskite site of the material and favors the stabilization of the cobalt oxidation state, as evidenced by the delay in the decrease of the average Co valence with respect to undoped samples. Our results are further supported by in situ X-ray Raman spectroscopy (YRS) that allowed us to monitor the temperature evolution of the 0 Kedge. XRS evidences that nickel-doped LSCF shows unmodified O2p-TM3d density of states, which proves that the Co oxidation state is preserved. Electrochemical impedance spectroscopy measurements were carried out over half-cell systems consisting of LSCF-based materials deposited onto a Ce0.8Gd0.2O2-delta electrolyte. The improvement of the electrochemical performances of the Ni-doped La0.6Sr0.4Co0.2Fe0.8-0.03Ni0.03O3-delta sample with respect to a reference Ni-impregnated LSCF is attributed to the stabilisation of the TM-O-6 structural units, which were recently proposed as the functional units for oxygen reduction.

year	journal	country	edition	language
2018-01-05	The Journal of Physical Chemistry C

https://doi.org/10.1021/acs.jpcc.7b07626