Scientists from The University of Manchester, working with European Thermodynamics Ltd, have found that graphene could lead to greener, more fuel efficient cars in the future by converting heat into electricity. The team, led by Professor Ian Kinloch, Professor Robert Freer and Yue Lin, added a small amount of graphene to strontium titanium oxide to create a composite that can convert heat which would otherwise be lost as waste into an electric current over a broad temperature range, going down to room temperature.
“Current oxide thermoelectric materials are limited by their operating temperatures which can be around 700 degrees Celsius,” explains Freer. “This has been a problem which has hampered efforts to improve efficiency by utilizing heat energy waste for some time. Our findings show that by introducing a small amount of graphene to the base material can reduce the thermal operating window to room temperature which offers a huge range of potential for applications.”
For cars, that means directing the heat to recharge batteries or powering a fuel-intensive air conditioning system. The scientists estimate the average car currently loses around 70 percent of energy generated through fuel consumption to heat. So far, the new graphene composite can convert 3 to 5 percent of that heat into electricity.
“That is not much but … recovering even a small percentage of [wasted energy] with thermoelectric technology would be worthwhile,” says Freer.
In addition to its fuel-saving capabilities, graphene can also be a composite material in the chassis or bodywork to reduce weight compared to traditional materials.