In 2012, the Obama administration announced fuel-efficiency standards that would require U.S. vehicles to average 54.5 miles per gallon by 2025. Improving gas mileage could help reduce greenhouse gas emissions and global dependence on fossil fuels. While converting waste heat into electrical energy is not a new concept, the compounds that have previously been used for this are heavy, costly, toxic or only operate at high temperatures.
The researchers at the University of Manchester started with a material called strontium titanium dioxide and added a small amount of graphene, a stable material with excellent conductive properties. The resulting composite was able to capture and convert heat into electric current efficiently over a broad temperature range.