Piezoelectric materials and devices have drawn extensive attention for energy harvesting due to their excellent electromechanical conversion properties. With increasing concerns about environmental problems in traditional lead-based piezoelectric materials, it is imperative to develop lead-free piezoelectric alternatives. This paper is intended to give a brief review on the most recent advances in both inorganic (with an emphasis on piezoelectric ceramics and ZnO nanostructures) and organic (i.e. polyvinylidene difluoride (PVDF) and its copolymers and their composites, and biopolymers) lead-free piezoelectric materials. State-of-the-art piezoelectric devices, namely, nanogenerators, sensors, and transducers, are also introduced with detailed examples. Finally, the challenges and perspectives of lead-free piezoelectric materials and devices are given.

Mythology? Reality? Innovative technologies have achieved the conversion and storage of renewable energies as the hero did in Chinese myths.