PREPARATION OF Bi2O3-DOPED NiO/YSZ ANODE MATERIALS FOR SOFCs

Abstract

The NiO/YSZ anode materials of SOFCs with Bi2O3 as sintering aids were successfully prepared by dry-pressing process. The effects of Bi2O3 content on the sintering properties of NiO/YSZ anode materials were studied, including the effects on the density, open porosity, weight loss, phase composition, microstructure, mechanical strength and electrical conductivity. In particular, the weight loss, relative density and bending strength of the sintered NiO/YSZ ceramics increased with the increase of Bi2O3 content while the open porosity decreased gradually. The density of the NiO–YSZ ceramics with 6[Formula: see text]wt.% Bi2O3 sintered at 1250[Formula: see text]C could reach that of the ceramics without Bi2O3 sintered at 1400[Formula: see text]C. For Bi2O3 concentration higher than 6[Formula: see text]wt.%, phase transformation of zirconia from monoclinic to cubic structure occurs, causing volume change and microcracks in the anode materials. Therefore, the optimum adding amount of Bi2O3 is 6[Formula: see text]wt.%, which can reduce the sintering temperature to 1250[Formula: see text]C. The ceramics with 6[Formula: see text]wt.% Bi2O3 have relatively high bending strength and low sintering temperature. This is of great significance for improving the performance of the anode and cutting the cost.