An Easily Scalable Multilayer Rotary Electret Generator Based on Bipolar Electrets

Electret generators, which harvest ambient mechanical energy to power electronic devices, have emerged as a potential sustainable solution for power supply and have attracted widespread interest. However, the realization of high electrical outputs as well as the simplification of machining processes and structural designs remain challenges. Herein, an easily scalable multilayer rotary electret generator (REG) based on bipolar electrets is proposed to provide a solution to the above problems. The bipolar electret films are utilized for the preparation of REG, eliminating the need for the conventional patterned bipolar charging process. The output performance of the REG under different parameters is investigated and the structural parameters of the REG are optimized. Results show that the electrical output of the REG increases linearly with the number of rotor layers. Compared to the conventional single-layer rotor with electrets on one side, the ten-layer rotor with electrets on both sides increases the output voltage and current by ≈18 times. The REG with the ten-layer rotor achieves a maximum average power of 58.7 mW at 360 rpm. As a demonstration, over 500 blue light emitting diodes in series are lit using the multilayer REG.