Ni‐phase erosion losses at a Ni‐pore interface of microtubular solid oxide fuel cells during 5218 h of operation

Abstract

AbstractA microtubular solid oxide fuel cell (μT‐SOFC) with an anode buffer layer in the inner wall of the anode is successfully fabricated. The anode buffer layer comprises nickel (Ni), gadolinium‐doped ceria, and ruthenium (Ru), of which Ru exhibits excellent stability in mixed impurity gases. At 700°C, the maximum power density of the μT‐SOFC reaches around 0.76 W/cm2 under a hydrogen flow rate of 10 sccm. After 5218 h of operation at a constant current density of 0.2 A/cm2 at 650°C, there is almost no degradation (0.093%/kh) in area‐specific resistance after 2000 h of operation under the protection of the anode buffer layer. The aggregation and migration of nanoscale Ni particles are observed at the Ni particle boundary near the triple‐phase boundary (TPB), with gradual corrosion of the Ni particles. Ni migration and loss in the TPB are determined as reasons for the decay of the fuel cells during their long‐term operation. Moreover, Ni in an amorphous state is also observed on the periphery of the Ni particles, indicating that during the corrosion process of Ni, transformation to the amorphous state occurred, which impairs the catalytic activity and electronic conductivity of Ni, resulting in a deterioration in its performance.