Fuel Cells: Intermediate Temperature Solid Oxides

Abstract

Fuel cells are electrochemical energy conversion devices that convert chemical energy in fuels directly into electrical energy, without the process of combustion. As a result, they are not constrained by the same thermodynamic limitations as those of heat engines and therefore have the potential to achieve higher efficiencies. High‐temperature solid oxide fuel cells (HT‐SOFCs) operate up to 1000 °C. These fuel cells achieve very high system efficiencies when integrated with gas turbines for large‐scale stationary applications. However, operation at such high temperatures means that the components of the stack need to be predominantly ceramic, in addition to expensive high‐temperature metal alloys. For smaller scale applications, there is a trend to move to lower operating temperatures, into the so‐called intermediate‐temperature (IT) range of 500–750 °C. In doing so, a wider range of construction materials can be used, offering reduced system cost and, in principle, improved performance durability. In this article, we introduce the IT‐SOFC and explain their main operational advantages. We also focus on the combination of inorganic materials and processing routes that go to make reduced temperature SOFC operation possible.

Ionically Conducting Ceramics as Active Catalyst Supports

“…Ionic conductivity of ZrO 2 doped with a trivalent metal oxide is the highest in the case of Sc 3+ , because its ionic radius is most identical to that of Zr 4+ . 99 However, cost considerations make Y 2 O 3 a better choice.…”

“…Kilner et al and Gatlow explained that a smaller ionic size mismatch between the host and the dopant was preferable for obtaining a high conductivity. Ionic conductivity of ZrO 2 doped with a trivalent metal oxide is the highest in the case of Sc 3+ , because its ionic radius is most identical to that of Zr 4+ . However, cost considerations make Y 2 O 3 a better choice.…”

Microwave synthesis of mesoporous Cu-Ce0.8Sm0.2O2−δ composite anode for low-temperature ceramic fuel cells

“…in the range below 600 C, since it can allow cheaper fabrication, stainless steel as interconnecting materials, and prolonged lifetime [4]. There are two crucial points to lower the operation temperature of CFCs: reduction of the ohmic resistance of electrolyte by either decreasing thickness or explore functional materials with higher ionic conductivity, and/or development of highperformance electrodes compatible with the electrolyte material [5]. Regarding to explore new electrolyte materials with enhanced ionic conductivity, our group has developed new nanostructured composite electrolytes materials for lowtemperature CFCs lately.…”