Graphene, an allotrope of carbon, was first isolated at the University of Manchester in 2004 by Sir Andre Geim and Sir Kostya Novoselov. In 2010, they had been awarded the Nobel Prize for Physics for their discovery. Graphene’s most unique property is that it is just 1 atom thick, making it the first 2-dimensional material. At present, the university remains the home of graphene research, with over forty industrial partners working on graphene-related projects.
Not too long ago, its scientists, working with European Thermodynamics Ltd, created low-cost thermoelectric materials that could be used to capture warmth from vehicles and convert it into electrical energy. That electricity can then be used to recharge the batteries in hybrid, plug-in hybrid, and electrical cars to provide them extra range.
The group—led by Prof Ian Kinloch, Prof Robert Freer, and Yue Lin—added a small quantity of graphene to strontium titanium oxide. The resulting composite was able to convert heat that would otherwise be wasted into an electrical current over a broad temperature range, starting at room temperature. Previously, thermo-electric materials only functioned at extremely high temperatures of around 700 degrees Centigrade.
“Our findings show that by introducing a small amount of graphene to the base material can cut back the thermal operating window to room temperature which offers an enormous range of potential for applications,” said Prof Freer. “This brand new material will convert 3-5% of the heat into electrical energy. That’s not a lot but, given that the average automobile loses roughly 70% of the energy supplied to it by its fuel to waste heat and friction, recovering even a small proportion of this with thermo-electric technology would be worthwhile.”
The numbers get a bit complicated, but if a standard internal combustion engine only converts 30% of its fuel into forward movement, recapturing only 3% of its wasted heat may translate into a 10% improvement in fuel economy. Car manufacturers today would be thrilled to make their vehicles 10% more fuel efficient as they battle to comply with tough new laws set to begin shortly in the US and Europe.
The quest to enhance fuel efficiency while retaining performance is of huge interest to automobile manufacturers. Not only could graphene boost fuel economy, it may also improve safety when used as a composite material in the chassis to reduce overall car weight.
Recapturing waste energy for tomorrow’s vehicles has led to proposals for tires that produce a small electrical voltage while driving as well as shock absorbers that do the same thing. Range is the new “Holy Grail” for makers of cars with batteries. Anything that helps add range to tomorrow’s automobiles will probably be gladly exploited by the auto industry.
Watch this helpful if somewhat light hearted video to learn more about graphene.