Going with the flow

US Engineers have built a fuel cell with no membrane that mimics the flow of toothpaste being squeezed from a tube.

The device could prove more efficient than conventional fuel cell designs for use in consumer electronics and military devices, and cost less to produce, University of Illinois researchers believe.

The team threw away the membrane usually needed to separate the fuel and oxidant by using ‘laminar flow’ behaviour. The fluids flow through micro-scale channels, which induce different flow behaviour compared with large-scale pipes. As a result, the two liquids have no turbulence and so meet without mixing, passing over the anode and cathode in a simple Y-shaped channel.

Researcher Prof Paul Kenis said a key advantage of the fuel cell is that it can use more reactive alkaline chemistry, which is superior to conventional acidic systems in the same way that alkaline batteries perform better. ‘Alkaline chemistry is quicker and the reaction kinetics are better,’ he said. ‘But the majority of alkaline fuel cells are expensive and are used in space programmes. They can only run on ultra-pure hydrogen.’