Triboelectric nanogenerators (TENG) are intriguing mechanical energy harvesting devices that could power small portable devices and detectors or charge batteries[1,2]. The working principles of TENG are based on friction-related contact electrification. Most commonly, a TENG consists of two connected conductive electrode layers from which at least one is covered with polymer insulator.[3] Recently, several research groups have demonstrated that the performance of TENG can be enhanced using ferroelectric films as contacting surfaces. Interestingly, using ferroelectric films from the same material that are inversely polarized on the opposite side of TENG further increases the performance due to magnified electrostatic induction. It appears that the piezoelectric charges created on the ferroelectric layers during contacting (pressing) drive electrostatic induction and enhance the overall performance of TENG. Therefore, as surface charges do not have a critical role in these nanogenerators, it would be more appropriate to refer to such devices as piezoelectric-electrostatic generators (PEEG).