Metallic Nanoparticles and Proton Conductivity: Improving Proton Conductivity of BaCe_(0.9)Y_(0.1)O_(3-δ) and La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3-δ) by Ni-doping

摘要

In this work we have used metallic nanoparticles to improve proton conductivity of the ceramic electrolyte BaCe_(0.9)Y_(0.1)O_(3-δ) (BCY) and of the electrode material La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5)O_(3-δ) (LSCM). Instead of adding metallic nanoparticles as a separate phase, they were dissolved in the compounds as their oxidized form (Ni~(2+)). The metal nanoparticles precipitated from compounds upon heating under reducing atmosphere. Below 600°C under reducing atmosphere, BaCe_(0.9-x)Y_(0.1)Ni_xO_(3-δ) compounds exhibit higher conductivity than BCY. Thus, an increase of one order of magnitude was observed for BaCe_(0.7)Y_(0.1)Ni_(0.2)O_(3-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. La_(0.75)Sr_(0.25)Cr_(0.5)Mn_(0.5-x)Ni_xO_(3-δ) compounds show also a protonic contribution to the total conductivity below 400°C. NMR results confirmed that these compounds contain protons.