Scientists have claimed a breakthrough in converting waste heat to electricity by developing a new thermoelectric material which they say is best in the world. The Northwestern University finding offers hope to tap the waste energy as nearly two-thirds of it is lost as heat. With a very environmentally stable material that is expected to convert 15 to 20 per cent of waste heat to useful electricity, thermoelectrics could see more widespread adoption by industry. Possible areas of application include the automobile industry, heavy manufacturing industries and places were large combustion engines operate continuously. Waste heat temperatures in these areas can range from 400 to 600 degrees Celsius, the sweet spot for thermoelectrics use. The new material, based on the common semiconductor lead telluride, is the most efficient thermoelectric material known. It exhibits a thermoelectric figure of merit of 2.2, the highest reported to date. The performance of the new material is nearly 30 per cent more efficient than its predecessor.