Hydrazine hydrate could replace hydrogen fuel cells

William Atkins
Saturday, 03 November 2007 05:01

Science - Energy

Fuel cells are being developed that use hydrogen. However, hydrogen is expensive because it needs platinum, a precious metal, to break down the hydrogen atoms. But, hydrazine hydrate uses cobalt or nickel, which are much cheaper elements.       

Engineers at the Daihatsu unit of Yoyota, located in Ryuo, Japan, are developing a fuel cell that uses hydrazine hydrate, rather than hydrogen, to power automobiles and other motorized vehicles.

Hydrazine hydrate is a compound of hydrogen, nitrogen, and water, with molecular symbol: H₂NNH₂OH₂O. It is a colorless liquid that has been used as a part of jet aircraft fuel.

The Daihatsu engineers contend that hydrazine hydrate is much better than hydrogen because it (1) has higher output, (2) is easier to store and deliver, (3) has no carbon dioxide emissions, and (4) is less expensive to use.

It is less expensive to use than hydrogen because hydroxide ions uses cobalt or nickel as the electrode catalyst to break down the hydrazine hydrate molecules rather than platinum to break down hydrogen molecules. Cobalt and nickel are both much cheaper to use than platinum.

Conventional hydrogen fuel cells have highly acidic electrolyte membranes, which mean that platinum must be used because it can resist the highly corrosive nature of the hydrogen fuel cell structure. In hydrazine hydrate fuel cells, however, alkaline electrolyte membranes are used instead, which do not require such expensive materials.

The result of this study by the Daihatsu team appears in the October 22, 2007 issue of the German chemistry journal Angewandte Chemie.

The Daihatsu team will continue its research in order to resolve issues of performance, durability, and other factors related to the technology. However, they are hopeful that this new technology will bring down the cost of fuel cell driven vehicles down to about the cost of internal combustion driven vehicles.

The Daihatsu website (“Daihatsu Develops New Fuel Cell Technology That Uses No Precious Metals—New technology has zero CO2 emissions, conserves resources and significantly reduces cost”) describes the technology in more detail.