Application of a triple-conducting heterostructure electrolyte of Ba0.5Sr0.5Co0.1Fe0.7Zr0.1Y0.1O3-δ and Ca0.04Ce0.80Sm0.16O2-δ for high performance low-temperature solid oxide fuel cell.

Rauf, Sajid; Zhu, Bin; Shah, M A K Yousaf; Tayyab, Zuhra; Attique, Sanam; Ali, Nasir; Mushtaq, Naveed; Wang, Baoyuan; Yang, Changping; Asghar, Muhammad Imran; Lund, Peter D

Dual-ion electrolytes with oxygen ion and proton-conducting properties are among the innovative solid oxide electrolyte, which exhibits a low ohmic resistance at temperatures below 550oC. BaCo0.4Fe0.4Zr0.1Y0.1O3-δ with a perovskite-phase cathode has demonstrated efficient triple charge conduction (H+/O2-/e-) for high-performance cathode in low-temperature solid oxide fuel cell (LT-SOFC). Here we designed another type of triple-charge conducting perovskite oxide based on Ba0.5Sr0.5Co0.1Fe0.7Zr0.1Y0.1O3-δ (BSCFZY) which formed a heterostructure with ionic conductor Ca0.04Ce0.80Sm0.16O2-δ (SCDC) showing both a high ionic conductivity of 0.22 Scm-1 and an excellent power output of 900 mW/cm2 in a hybrid-ion LT-SOFC. In addition to demonstrating that a heterostructure BSCFZY-SCDC approach can be a good functional electrolyte, the existence of hybrid H+/O2- conducting species in BSCFZY-SCDC was confirmed. The hetero-interface formation between BSCFZY and SCDC can be explained by energy band alignment which was verified through UV-Vis and UV photoelectron spectroscopy (UPS). The interface may help in providing a pathway to enhance the ionic conductivities and to avoid short-circuiting. Various characterization techniques are being used to probe the electrochemical and physical properties of the material containing dual-ion characteristics. The results indicate that the triple charge conducting electrolyte is a potential candidate to further reduce the operating temperature of SOFC, but simultaneously maintaining a high performance.