Metallic Nanoparticles and Proton Conductivity: Improving Proton Conductivity of BaCe0.9Y0.1O3-δ and La0.75Sr0.25Cr0.5Mn0.5O3-δ by Ni-doping

In this work we have used metallic nanoparticles to improve proton conductivity of the ceramic electrolyte BaCe0.9Y0.1O3-δ (BCY) and of the electrode material La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM). Instead of adding metallic nanoparticles as a separate phase, they were dissolved in the compounds as their oxidized form (Ni2+). The metal nanoparticles precipitated from compounds upon heating under reducing atmosphere. Below 600°C under reducing atmosphere, BaCe0.9-xY0.1NixO3-δ compounds exhibit higher conductivity than BCY. Thus, an increase of one order of magnitude was observed for BaCe0.7Y0.1Ni0.2O3-δ. A protonic contribution to the total conductivity is observed below 600°C. This phenomenon is more pronounced for the compounds containing more nickel in surface which can facilitate the dissociation of hydrogen and the incorporation of protons in the structure. La0.75Sr0.25Cr0.5Mn0.5-xNixO3-δ compounds show also a protonic contribution to the total conductivity below 400°C. NMR results confirmed that these compounds contain protons.