A NOVEL THIN-FILM ELECTROCHEMICAL DEVICE FOR ENERGY-CONVERSION

ENVIRONMENTAL concerns have led to renewed interest in fuel cells, in which gases such as hydrogen and oxygen are combined electrochemically such that the exothermicity is converted directly to electrical energy and the only reaction product is water. Conventional fuel cells are also more fuel-efficient than heat engines, but for technological reasons they are far too costly for widespread commercial use. Here I report the observation of gas → electricalenergy conversion processes occurring within very thin films. I observe voltages as large as 1 volt between platinum electrodes separated by thin (<500 nm) gas-permeable, ionically conducting membranes, when one electrode is exposed to, for example, a mixture of air and hydrogen at room temperature. These observations contrast with the behaviour of conventional fuel cells, which cannot operate if the gases are mixed, and could radically simplify fuel-cell design. On the basis of these results, I suggest a simple manufacturing process by which small fuel cells could be made available at low cost. © 1990 Nature Publishing Group.