Highly efficient pyroelectric generator for waste heat recovery without auxiliary device

Waste heat is very abundant and widespread in our lives. Using pyroelectric generators (PEG) to capture the ambient heat energy is meaningful. Here we fabricated a highly efficient PEG using nanocomposite. The nanocomposite was made of P(VDF-TrFE-CFE) and barium strontium titanate (BST) nanoparticles and boron nitride (BN) nanosheets, which has excellent thermal conductivity and high polarization. The output current density of PEG can reach 1.7 μA/cm2, it is a great improvement for PEG devices. In addition, we present a new evaluation method for standardizing the performance of a PEG, which is use η (the ratio between the power density and the heat flux) as the thermos-electric conversion efficiency of PEG. Furthermore, a PEG-unit was designed and fabricated, which was cleverly connected by PEG and a plane spiral spring, it can better utilize external vibration to realize waste heat recovery without auxiliary device. The PEG-unit can be used for energy recovery in the process of train running and it can light up the LED lamp bead for 10 s within five minutes operation.