Your car wastes around 60% of the energy you put into it as heat. But that could soon change, thanks to a new way to boost the efficiency of thermoelectric materials that are able to convert heat into electricity

Adding small chunks of thermoelectric material to any heated surface, like a car exhaust or a computer processor, could produce essentially free energy.


But existing thermoelectric materials have poor efficiencies, as described by their zT figure. Despite decades of study, the best commercial thermoelectrics have a zT of around 1. To compete with mechanical engines that convert heat into electricity a zT of 3 to 4 is considered essential, but is far from being achieved.