Robust doped BaCeO3-δ electrolyte for IT-SOFCs

Abstract

Single phase polycrystalline BaZr0.3Ce0.5Y0.1Yb0.1O3 - δ electrolyte material was prepared by solid state reaction route. Rietveld analysis of the XRD data confirms the tetragonal symmetry in the I4/mcm space group with unit cell parameters of a = b = 6.0567(3) A and c = 8.5831(5) A. The addition of ZnO as a sintering additive was found to reduce the sintering temperature and enhance both overall sinterability and grain growth. Sintering temperature was reduced by 200–300 °C, and a very high relative density of about 98% was achieved at 1400 °C. Impedance spectroscopy in humidified 5% H2/Ar atmosphere shows that the protonic conductivity at 600 °C was 8.60 × 10−3 S cm−1. Thermal analysis performed in pure CO2 atmosphere shows very good chemical stability up to 1200 °C. Good biaxial flexure strength of 100–200 MPa was reported which makes this material a promising electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFCs).