Standard Article

Solid oxide fuel cells (SOFC)

Fundamentals and Survey of Systems

Fuel cell principles, systems and applications

  1. P. Holtappels1,
  2. U. Stimming2

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f104020

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Holtappels, P. and Stimming, U. 2010. Solid oxide fuel cells (SOFC). Handbook of Fuel Cells. .

Author Information

  1. 1

    Swiss Federal Institute for Materials Testing and Research (EMPA), Duebendorf, Switzerland

  2. 2

    Technische Universität München, Garching, Germany

Publication History

  1. Published Online: 15 DEC 2010

Abstract

Solid oxide fuel cells are fuel cells that operate in a temperature region between 650 °C and 1000 °C by using an oxygen ion conductor as the electrolyte. The ionic transported species are oxygen ions that allow the use of both hydrogen and carbon monoxide as well as directly applied methane as fuels while the oxidant is oxygen provided by air. The state-of-the art SOFC consists of an yttria-stabilized zirconia (YSZ) as the electrolyte, a ceramic metallic composite, a Ni-YSZ cermet as the fuel electrode and a ceramic composite of strontium doped lanthanum manganite and YSZ as the air electrode. The SOFC is, therefore, an all-solid state system for which different designs may apply.

Both tubular and planar concepts of SOFC cells and stacks have been developed since the 1960s. The best developed SOFC system is the tubular cell design from Westinghouse (now Siemens Westinghouse Power Corporation), operating at temperatures around 1000 °C. Planar cell designs which allow operating temperatures between 650 °C and 850 °C by using an anode supported electrolyte are under development. The two different concepts, the tubular and the planar design are described in detail and the impact of the supporting component upon important aspects as operating conditions, power density, sealing and contacting are addressed.

SOFC systems have mainly been considered for stationary generation of electricity in combined cycles and co-generation plants operating on natural gas or oil. New applications are opened in the area of remote power supply in residential but also automotive applications. Principles of systems considered for each application are described in the last section.

Keywords:

  • solid oxide fuel cell;
  • hydrogen;
  • carbon monoxide;
  • methane;
  • hydrocarbon fuel;
  • yttria-stabilized zirconia (YSZ);
  • cell designs: tubular;
  • planar;
  • anode supported;
  • co-generation systems;
  • automotive applications