Bismuth tungstate/neodymium-doped ceria composite electrolyte for intermediate-temperature solid oxide fuel cell: Sintering aid and composite effect.

We demonstrate the utilization of bismuth tungstate (Bi 2 WO 6 , BW) as a sintering aid and reinforcement component into neodymium-doped ceria (Nd 0.2 Ce 0.8 O 3-δ , NDC) to fabricate bismuth tungstate/neodymium-doped ceria composite electrolyte for intermediate-temperature solid oxide fuel cells (IT-SOFC). The presence of BW lowers the sintering temperature of NDC electrolyte to 1000 °C. Moreover, at 600 °C, the electrical conductivity of 5 mol.% BW-incorporated NDC (5BW-NDC) composite electrolyte is 7.12 times higher than the NDC. It is worth mentioning that the enhanced electrical conductivity of 5BW-NDC composite electrolyte does not include the contribution from electronic conductivity. Furthermore, NDC and 5BW-NDC exhibit excellent compatibility with La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3-δ cathode and NiO anode in terms of thermal expansion coefficient and chemical reactivity. The oxygen reduction reaction at 5BW-NDC composite electrolyte/cathode interface is significantly enhanced by ∼40% compared to NDC. Moreover, 5BW-NDC electrolyte-supported SOFC delivers a power density of 0.86 W cm−2 at 700 °C, which is 45.76% higher than the NDC-based SOFC. The output performance remains stable during high-temperature operation for 120 h, which indicates the stability and chemical compatibility of the as-synthesized composite electrolyte with other cell components. The results reveal that BW-NDC composite is a potential electrolyte material for stable and high-performance IT-SOFCs. • A novel BW-NDC composite ceramics is developed to act as electrolyte of SOFCs. • BW-NDC ceramics is densified at 1000 °C due to BW played the role of sintering aid. • BW-NDC exhibits 7.27 times higher ionic conductivity than that of NDC. • ∼40% improvement of oxygen reduction reaction and power density with BW-NDC ceramics. [ABSTRACT FROM AUTHOR]