Effect of pre-calcined ceramic powders at different temperatures on Ni-YSZ anode-supported SOFC cell/stack by low pressure injection molding

摘要

Recently, powder injection molding (PIM) has been exploited in the field of solid oxide fuel cells (SOFCs), especially for fabricating anode supports. The current study employs low pressure injection molding (LPIM) to manufacture near net shape, porous, tubular NiO-yttria stabilized zirconia (YSZ) anode supports for anode supported SOFCs. The study investigates the effects of pre-calcining temperature of the ceramic powder on the microstructure, porosity and electrochemical performance of the cells in detail. Archimedes tests reveal that the porosity of an unreduced NiO-YSZ anode with 900 degrees C pre-calcined powder reaches a high of 25.9%, approaching the optimal value of 26%. Meanwhile, the anode prepared under this condition possesses more porous and homogeneous microstructures. At 800 degrees C, with humidified hydrogen as fuel and ambient air as the oxidant, the single cell with 900 degrees C pre-calcined powder delivers a maximum power density of 671 mW cm(-2) while the cell with raw powder, 555 mW cm(-2), and the cell with 1000 degrees C pre-calcined powder, 648 mW cm(-2). A four-cell stack is assembled by connecting four single cells in series. The stack could provide a maximum output power of 4.6 W and an open circuit voltage of 3.2 V when fuelled with humidified hydrogen at 800 degrees C.