A triboelectric-piezoelectric hybrid nanogenerator for rotational energy harvesting based on bistable cantilever beam

This study presents a triboelectric-piezoelectric hybrid nanogenerator for harvesting rotational energy based on a bistable cantilever beam. The nonlinear bistable behavior effectively enhances the collision force with the triboelectric nanogeneration (TENG) boundary, enlarges the effective contact area of the triboelectric functional materials, and significantly increases the deformation of the piezoelectric cantilever beam, thereby improving the overall electrical output performance of the system. Excessive deformation of the piezoelectric cantilevers is effectively constrained by the TENG boundary, which prevents the degradation and failure of the piezoelectric material. A prototype is prepared and verified experimentally. The effects of key parameters on the output performance are systematically analyzed. According to the results on the overall electrical output of hybrid nanogenerator with and without bistable behavior, the hybrid nanogenerator with bistable behavior achieved an energy density of 29.04 W/m3 at a rotational speed of 450 r/min, which is 2.65 times higher than that of the hybrid nanogenerator without bistable behavior. In addition, the rotational speed range is broadened by more than 1.5 times, and the prototype can realize self-powered temperature monitoring and wireless transmission. Overall, the proposed rotational energy harvester with a magnetic coupling cantilever bistable behavior and TENG boundary mechanism offers a novel means to improve the electrical performance of energy harvesting systems for self-powered internet of things.