Grain and grain boundary transport in BaCe0.5Zr0.3Ln0.2O3−δ (Ln – Y or lanthanide) electrolytes attractive for protonic ceramic fuel cells application

Abstract Protonic ceramic fuel cells (PCFCs) belong to very attractive energy conversion systems, which are able to operate effectively at low- and intermediate temperature ranges. The improvement of their electrochemical characteristics is feasible through the optimization of their functional materials. In the present work, emphasis is given to the highly conductive and stable cerate-zirconate electrolytes of BaCe 0.5 Zr 0.3 Ln 0.2 O 3−δ (where Ln = Y, Dy, Sm and Nd). Studying the transport properties of these materials in individual form and in PCFC assembly, it is shown that the Dy-doped sample exhibits higher grain (bulk) and grain boundary conductivity in comparison with the most studied Y-doped ones. The single PCFC based on a rather thick 30 μm electrolyte displays about 160 and 290 mW cm −2 at 600 and 700 °C, respectively. These values are comparative with those obtained for PCFCs fabricated with similar electrolytes and Co-free cathode materials, confirming the perspective of cerate-zirconates doped by other lanthanides.