Alkaline Hydrazine Fuel Cells

AU these points, and uncertainties as to the potential lifetime, have led to a strongly reduced set of candidate applications for AFC-based power plants. The volume of research and engineering work has shrunk accordingly. 

Most organizations and companies stopped work in this area between 1990 and 1995, and some of them switched to other systems when work on fuel cells with acidic, proton-conducting membranes began to take off in the mid-1990s. 

In a hydrazine-oxygen (or air) fuel cell with alkaline electrolyte, the following reactions take place  

First news about hydrazine-oxygen (or hydrazine-air) fuel cells with alkaline electrolytes appeared in the early 1960s. Gillibrand and Lomax (1962) reported building a rather primitive hydrazine-oxygen fuel cell of the jar type without 

Many research efforts went into elucidating the behavior of different catalysts in the hydrazine oxidation reaction. Like the oxygen electrode, the open-circuit potential of a hydrazine electrode deviates from the thermodynamic value (—1.22 V) and in certain cases comes close to that of the hydrogen electrode 

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Since a discussion of alkaline membrane fuel cells based on fuels other than hydrogen is beyond the scope of this work, only a short hst of references is provided as a suggestion for further readings. Matsuoka et al., ammig others, showed interesting first results for alcohol-based AMFCs [32, 38—43]. Some initial work has also been done with alkaline membrane fuel cells based on glycerin [44], hydrazine [45, 46] and even on ammonia [47, 48]. Finally, an... 

In the 1960s, several versions of alkaline fuel cells (AFCs) using liquid hydrazine as a fuel were built, including those for a motorcycle driven by Karl Kordesch. Hydrazine is also very active electrochemically and yields fuel cells with high-performance indicators. However, apart from its high cost, hydrazine has another notable defect It is highly toxic. Therefore, the use of hydrazine fuel cells has been limited to a few special areas (chiefly for the military). 

In alkaline fuel cells (AFCs), the electrolyte is 34-46% KOH, immobilized on a porous support, and the operating temperature is 60-120 °C. Because the environment is alkaline, Raney nickel (a finely divided form of nickel) can be used in place of expensive platinum. However, the alkali will be neutralized by any CO2 in the hydrogen fuel, so AFCs are not suitable for operation with reformed hydrocarbons but can be fueled with alcohols or hydrazine. AFCs were used successfully on the Apollo space missions. 

The moped looked pretty normal except for a couple of metal boxes— the fuel cell and a NiCad battery—mounted in the frame ahead of and underneath the rider. Kordesch converted the Austrian-made Puch (bought at Sears, Roebuck) in 1966, and he drove it on public roads during his years at Union Carbide. There were two 16-volt, 400-watt hydrazine-air alkaline fuel cells and a Ni-Cad battery. The batteries could be switched in parallel or series for speed control. The range was about 60 miles on 2 liters of a 64 percent aqueous hydrazine, with an easy top speed of 25 miles per hour. 

Kordesch was not the only person, nor was he the first, to try hydrazine for fuel cell power. Others had the same idea. In the 1960s, the now-defunct Allis-Chalmers Manufacturing Company built a small 3-kilowatt golf cart powered by that exotic fuel. Earlier, Monsanto Research Corporation developed a 20-kW hydrazine-air alkaline fuel cell system for a 3A-ton Army truck. In 1972, Shell Research in England put a 10-kW hydrazine-air system in a Dutch-built DAF-44 car. In 1982, according to Kordesch s book,... 

In the 1960s, several versions of alkaline fuel cells using liquid hydrazine as a fuel were built. 

In the 1970s, a number of studies dealing with the design of hydrazine-oxygen fuel cells with alkaline electrolyte were published. Several prototypes of such fuel cells were actually built for portable devices and for various military objects, but, owing... 

In 2003, it was suggested to use this substance in a fuel cell with proton-conducting (i.e., an acid) membrane. Hydrazine was used as a 10% aqueous solution of hydrazine hydrate (N2H4-H20). In the aqueous solution, hydrazine, on account of its strong alkaline properties, dissociates into the ions N2H5+ and OH . The anodic oxidation of hydrazine can be written in terms of the equation ... 

Union Carbide Corp. (UCC) developed AFCs for terrestrial mobile applications starting in the late 1950s, lasting until the early 1970s. UCC systems used liquid caustic electrolytes the electrodes were either pitch-bonded carbon plates or plastic-bonded carbon electrodes with a nickel current collector. UCC also built fuel cell systems for the U.S. Army and the U.S. Navy, an alkaline direct hydrazine powered motorcycle, and the Electrovan of General Motors. Finally, Professor Karl V. Kordesch built his Austin A-40 car, fitted with UCC fuel cells with lead acid batteries as hybrid. It was demonstrated on public roads for three years. The years of research and development are very well summarized in reference (5) Brennstofflyatterien. 

In a fuel cell, hydrazine, N2H4, is oxidised to nitrogen, and oxygen is reduced to water. The standard electrode potentials for the reduction of N2 to N2H4 and of O2 to H2O at 298 K are —1.155 V and +0.401 V, respectively, both under alkaline conditions. 

The workers prepared metallic hydrophilic porous electrodes of areas up to 45 cm and plastic-supported semihydrophobic electrodes. They put together a five-membered hydrogen-air module with alkaline electrolyte of the output first to 500 W, later up to 1000 W [277,335-342]. Fuel cells with liquid fuel, hydrazine [343] and formiate, were also tested. 

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