Generating power from waste heat

via www.aist.go.jp

A sprinkling of graphene may conjure a long-sought material into existence

ANY sufficiently advanced technology, as Arthur C. Clarke once observed, is indistinguishable from magic. And one that seems routinely to be ascribed magical properties is graphene. It has been proposed for the manufacture of transistors and light bulbs, as a replacement for bone and a way of delivering drugs, for storing power and for transmitting it, and for lubricating things and waterproofing them. Its latest suggested role, though, is to help turn heat directly into electricity.

The Seebeck effect, first seen in 1821 by a German physicist of that name, is a property of some materials whereby heating part of an object made of that material drives electrons from the hot part to the cold part, creating a current. Generating electricity from heat in this way will never substitute for creating it in a power station specially designed for the purpose but it might, some believe, permit the exploitation of heat that would otherwise go to waste—that produced by car engines, for example; or, indeed, by the power station itself.

The problem is that materials which exhibit a strong enough Seebeck effect to be potentially useful do so only in narrow temperature ranges. One promising candidate is strontium titanium oxide—but it exhibits the effect only when it is heated to between 700° and 750°C. However, two materials scientists, Robert Freer and Ian Kinloch, who work at Manchester University, in Britain, suspected they might be able to extend that range by adding graphene—which, not coincidentally, was discovered at Manchester in 2003. As they report in Applied Materials and Interfaces, they think they have succeeded.

Read more: Generating power from waste heat: Hot stuff