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Materials – Lead-free electromechanics

Oak Ridge National Laboratory

December 2, 2015 – Piezoelectric materials convert mechanical stress into electrical energy in products from electric cigarette lighters to ultrasound machines. Unfortunately most contain lead, which is toxic. “Lead is extremely active in these materials, so we need to find another chemical element with the same properties,” said Valentino Cooper, a Department of Energy Early Career Award recipient at Oak Ridge National Laboratory who uses supercomputers to study materials at the level of atoms and electrons. With theoretical calculations based on newly obtained geometries from experiments, Cooper’s team revealed an easy transition between phases of bismuth ferrite. This advance opens the door for tuning electromechanical response in products that can be strained to generate a current (e.g., clothing that coverts forces from movement into electricity) or subjected to a current to change a material’s shape (think advanced fuel injectors).