posted on 2024-01-19, 17:33authored byLijie Zhang, Yunan Jiang, Kang Zhu, Nai Shi, Zhengguo Chen, Ranran Peng, Changrong Xia
Ceria-based oxides, such as samaria-doped ceria (SDC),
are potential
electrolytes for low-to-intermediate-temperature solid oxide fuel
cells (SOFCs). The sinterability of these materials can be improved
by adding iron as the sintering aid. This work reveals that Fe is
soluble in SDC, forming an Fe-doped SDC solid solution. It is found
that the solubility is affected by the sintering temperature. Fe doping
has obvious effects on electrolyte properties, including sintering
characteristics, thermal expansion behaviors, and electrical conductivities
in both air and hydrogen atmospheres. The conductivity obviously increases
while the activation energy decreases by doping Fe. Compared with
that of the bare SDC electrolyte, the performance of the single cell
with the Fe-doped SDC is enhanced; for example, the peak power density
is increased by 52.8% to 0.726 W cm–2 at 600 °C
when humidified hydrogen is used as the fuel and ambient air is used
as the oxidant. The single cell showed stable operation at 600 °C
under a constant current density of 0.3 A cm–2 for
150 h. Therefore, the Fe-doped SDC solid solution shows promise as
a potential electrolyte for low-to-intermediate-temperature SOFCs.