What Is an Ammonia Fuel Cell?
An ammonia fuel cell is a type of fuel cell that generates electricity using ammonia as the hydrogen supply source to the fuel cell.
Ammonia is an inexpensive substance that can be synthesized in large quantities, is easier to transport and store than hydrogen, and does not emit carbon dioxide when burned or decomposed.
An ammonia fuel cell is being developed as a more energy-efficient solution to the hydrogen supply problems associated with fuel cells.
Uses of Ammonia Fuel Cells
Ammonia fuel cells are still in the development stage, and currently, only about 1kW units are being operated on a trial basis. However, they are expected to be used in industrial and residential power generation systems.
It is expected to be used as a power generation source due to its excellent energy efficiency and low environmental impact since it does not emit carbon dioxide or nitrogen oxides.
Principle of Ammonia Fuel Cells
Like other fuel cells, ammonia fuel cells generate electromotive force by converting the chemical energy generated when hydrogen is oxidized to form water into electricity.
The basic structure of the ammonia fuel cells is similar to that of a solid oxide fuel cell, consisting of a fuel electrode, an air electrode, and a solid electrolyte made of ceramics, etc. The hydrogen oxidation reaction occurs on the fuel electrode side and the oxygen reduction reaction on the air electrode side.
Ammonia fuel cells, however, use a different hydrogen supply method. Instead of hydrogen from reformed city gas, ammonia is supplied directly to the device. Ammonia is decomposed into nitrogen and hydrogen, and since this reaction is endothermic, it proceeds spontaneously without the use of a catalyst at the operating temperature of the solid electrolyte fuel cell, 700°C or higher, to produce hydrogen.
Research is also underway to develop a polymer electrolyte fuel cell that can operate at relatively low temperatures, in which the ammonia fuel cells are pre-heated to decompose ammonia into hydrogen and nitrogen, which are then supplied to the cell.