Chapter 5

NiO-Ce0.9Gd0.1O1.95 Composites and their Cermets as Anode Materials for SOFC

Allan J.M. de Araujo, Gabriel M. Santos, Joao P. de F. Grilo, Rubens M. do Nascimento, Carlos A. Paskocimas, Moisés R. Cesario and Daniel A. de Macedo

Abstract

The anode of a Solid Oxide Fuel Cell (SOFC) is the component responsible for releasing electrons. It must present some prerequisites such as porosity (30-40 wt.%) and mixed conductivity (ionic and electronic). To achieve that, it often consists of a ceramic-metal composite (cermet) material. Ni-YSZ cermet is the material most commonly used as anode SOFC, however it presents low electrochemical efficiency below 750 °C. With this in mind, new materials have been studied, and Ni-GDC cermet has shown promising results. This chapter focused mainly on a brief review of NiO-Ce0.9Gd0.1O1.95 (NiO-GDC) composites and their Ni-GDC cermets as SOFC anode materials. The chapter reports the history, concept, operation principle, reaction mechanisms and components of SOFCs, addressing recent works in the field. The synthesis of NiO-GDC composites by a one-step synthesis method (polymer-based method) is compared with the conventional mechanical mixing method. Impedance spectroscopy is shown to be a crucial technique to investigate the electrical properties of SOFC functional materials. The chapter ends with a literature review on the electrical properties of NiO-GDC composites and their cermets.

Total Pages: 162-197 (36)

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