Electrical Conductivity of NiO-Gadolinia Doped Ceria Anode Material for Intermediate Temperature Solid Oxide Fuel Cells

Abstract

In this paper, NiO-Gadolinia Doped Ceria (10 mole % Gadolinia) NiO-GDC10 composite with Nickel varying from 50 to 65 wt.% has been prepared by conventional solid state reaction method. The structural and microstructural properties have been evaluated by X-ray diffraction and scanning electron microscopy, respectively. The electrochemical behavior of the composites with varying concentration of Ni has been investigated by AC impedance spectroscopy. Both the grain and grain boundary conductivities have been determined as a function of temperature in the range of 773-973 K. The highest total electrical conductivity (σGi+σGb) have been achieved as 0.28 x10-3 Scm-1 at 973 K with activation energy of 0.40 eV for composition of GDC10 with 65 wt % of NiO (NiO-GDC-65:35 wt.%). The influence of microstructure on electrical properties of the composites has been analyzed and the conductivities have been compared with the conventional NiO-YSZ (50:50) composite in order to fabricate Ni-GDC based anode material of better performance.