Rolling friction contact-separation mode hybrid triboelectric nanogenerator for mechanical energy harvesting and self-powered multifunctional sensors

Collecting mechanical energy in the surrounding environment to power small electronic devices is an ideal method as a green and clean power source. Based on the working mechanism and the advantages of triboelectric nanogenerator (TENG), a robust rolling friction contact-separation mode TENG (CS-TENG) has been fabricated for harvesting vertical rotation energy by utilizing the integrated cylindrical surface with the conjunction of rolling contact electrification and electrostatic induction. The output current of the CS-TENG can maintain 96% (origin: 1.72 μA, final: 1.66 μA) after two days continuous work a rotation speed of 300 r/min. Furthermore, an electromagnetic and triboelectric hybrid contact-separation mode nanogenerator (HCS-TENG) has been further designed by coupling magnets in the rolling cylinders with copper coils as an electromagnetic generator (EMG) in the acrylic cylinder to implement the multi-functional properties. The gear transmission structure makes the device more facile to be installed on the rotation objects. The output performances of CS-TENG and EMG under various rotation speeds were systematically studied. It shows that the CS-TENG with six units can deliver an output power of 0.15 mW/cm2 and the 100 μF capacitor can be charged to 6 V in less than 1 min by the hybridized nanogenerator at a rotating rate of 700 r/min. In addition, utilizing the output signal's intrinsic characteristics of CS-TENG, a self-powered rotation speed and displacement sensor using the dual cylinder structure TENG has been achieved for these rotating mobile devices that are inconvenient to get an additional power supply in the grimmest circumstances such as moon car or other celestial and tough environment detection equipment. This multifunctional TENG device reveals a significantly potential application in the grimmest circumstances as power source, self-powered electronics and sensor systems.