Latest Publications

DOI: 10.1021/acs.jpcc.9b01047 

The Journal of Physical Chemistry

Oxide-carbonate composite electrolytes are complex materials whose peculiar conductivity performances are yet to be fully understood. Stability issues however arise when the carbonate is combined to an oxide such as TiO2, preventing practical fuel cell application of TiO2-based composites. To investigate the origin of such instability, a combined experimental and Density Functional Theory based approach is here presented and applied to the LiKCO3-TiO2 composite, focusing on energetic, electronic and vibrational properties. The origin of the instability of this composite could be traced back to the intrinsic reducible nature of TiO2, with inserted Li being almost fully oxidized and stabilized by reduced Ti atoms at the oxide surface, thus facilitating LixTiO2 phases formation and accumulation close to the interface between the oxide and the carbonate. This demonstrates that although the interface formation is critical for en...

The Journal of Physical Chemistry C 2018

DOI: 10.1021/acs.jpcc.8b02174

A comprehensive density functional theory investigation of conduction mechanisms of both intrinsic and extrinsic species found in oxide–carbonate composite electrolyte materials used in solid oxide fuel cell is presented. An interface model of yttria-stabilized zirconia–LiKCO3 is used as a case study to investigate transport properties, considering different mechanistic assumptions suggested in the literature over the years. Results clearly indicate that interfaces play an extremely important role in influencing the ionic conductivity performances of these electrolytes. In particular, redistribution of ions of both phases can lead to the formation of the so-called space-charge layer at the interface, which then favorably influences the transport of intrinsic cations or extrinsic protons in particular. These results constitute an important first step toward the understanding of the electrochemical processes and transpo...

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