Platinum Metals Rev., 1990, 34, (2), 80
A Novel Device for Energy Conversion
News of an interesting new fuel cell concept, using thin-film devices for energy conversion, was presented at the Grove Anniversary Fuel Cell Symposium by Dr. C. K. Dyer of Bell Communications Research (1), and further details have since been published (2, 3). The devices consist of two platinum electrodes deposited on either side of very thin (<50 μ m) gas permeable and ion conducting membranes.
One electrode in the fuel cell is deposited on an impermeable support, such as quartz. The membrane separator is applied, and an upper porous electrode is then laid over it. When this upper electrode is exposed to hydrogen and oxygen or air mixtures, a potential of up to one volt is observed between the electrodes, and currents of 2 to 3 mA/cm2 may be drawn.
Lower performances are achieved using electrode pairs of palladium/platinum, palladium/ palladium and platinum/nickel, with open circuit voltages of 740 mV, 450 mV and 600 mV, respectively. Significantly, using methanol vapour as a fuel in pure oxygen, up to 640 mV can be obtained at atmospheric temperature and pressure, with platinum electrodes.
Although specific power levels are relatively low (1 to 5 mW/cm2), each assembly is extremely thin, and hence power densities of 100 W/kg of fuel cell are presently obtainable, and 1000 W/kg appears possible.
The author foresees simply constructed, inexpensive fuel cells, operating on mixed fuel/oxidant gases fulfilling a range of functions from replacing high-use batteries, to new applications in information processing.
- 1C. K. Dyer, “The Grove Anniversary Fuel Cell Symposium”, London, September 1989, published in Platinum Metals Rev., 1989, 33, ( 4 ), 169
- 2C. K. Dyer, Nature, 1990, 343, ( 6258 ), 547
- 3T. E. Mallouk, ibid., 515