Bistable broadband hybrid generator for ultralow-frequency rectilinear motion

Abstract

In the natural environment, rectilinear motions normally take the form of low-frequency and broadband vibrations. This poses problems for devices aimed at harvesting energy from these motions, since conventional linear electromagnetic generators are inefficient under such conditions. Here we present a bistable triboelectric linear generator (BTLG) with nonlinear characteristics for low-frequency and broadband energy harvesting. In this device, a nonlinear structure is used to achieve the bistable contact–separation motion to widen the working bandwidth as well as enhance the energy harvesting efficiency in low-frequency range. Piezoelectric components are also used in the device without increasing the complexity of the structure, which can compensate for the defects that the contact-separation mode triboelectric nanogenerator cannot work at a small amplitude. Experiments show that a 10 μF capacitor can be charged to 0.12 V in 60 s at an ultralow frequency of 0.1 Hz. The frequency bandwidth of the BTLG is greatly broadened to 441% compared with a linear device. The proposed BTLG is capable of harvesting mechanical energy at low frequency with large working bandwidth, thus providing a effective method for energy harvesting of ambient low-frequency rectilinear motions.