Standard Article

Phosphoric acid electrolyte fuel cells

Fundamentals and Survey of Systems

Fuel cell principles, systems and applications

  1. J. M. King1,
  2. H. R. Kunz2

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f104015

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

King, J. M. and Kunz, H. R. 2010. Phosphoric acid electrolyte fuel cells. Handbook of Fuel Cells. .

Author Information

  1. 1

    Manchester, CT, USA

  2. 2

    University of Connecticut, Department of Chemical Engineering, Storrs, CT, USA

Publication History

  1. Published Online: 15 DEC 2010


Phosphoric acid electrolyte fuels cells were the first fuel cells to be commercialized with the 200 kW ™PC-25 power plant of UTC Fuel Cells (formerly International Fuel Cells). The technology base was developed over many years and included input from the technology of other types of fuel cells. Improvements in fuel processing which converts hydrocarbon fuel to hydrogen, the cell stack that converts hydrogen to direct current power, the inverter that converts direct current to alternating current and controls ancillaries, were all required. The overall power plant design and ancillary component technology required substantial development to meet requirements for practical application. Fuel cell power plants were evaluated for various applications as the technology evolved. This section describes the applications and evolution of the components. The cell technology evolution is then described in more detail. All of the materials in the stack required modification to increase cell performance and allow operation at higher temperatures. Anode catalysts were developed with improved tolerance to the presence of carbon monoxide in the hydrogen fuel gas. Cathode catalysts were improved to reduce the performance loss associated with the oxygen reduction reaction, the main contributor to the cell polarization. In both cases, the quantities of precious metals used in the electrodes were reduced by more than an order of magnitude. The separator plates, electrode gas diffusion layers, and porous matrix for holding the electrolyte between the electrodes were all improved to provide higher cell performance and durability.


  • catalyst;
  • oxygen electrode;
  • hydrogen electrode;
  • phosphoric acid fuel cells;
  • electrolyte migration;
  • platinum;
  • platinum alloys;
  • carbon monoxide;
  • Tafel slope;
  • diffusion layer