Sustainable Highly Charged Polyimide in Non-Contact Mode Triboelectric Nanogenerator

We report on a new dielectric, a C₆₀-containing block polyimide (PI-b-C₆₀). This was realized by introducing C₆₀ as pendent groups into a polymer backbone. When this dielectric was used in a non-contact mode triboelectric nanogenerator (TENG), it achieved high output power and reliable operation. Compared with perfluoroalkoxy alkane film-based TENGs, the TENG based on PI-b-C₆₀ generated 4.3 times higher output power and a superior charge density of over 300 μC m⁻² with a 3 times slower charge decay rate. These results are most likely due to the excellent charge-retention characteristics induced by the most negative electrostatic potential of C₆₀ within the backbone, and these characteristics were confirmed by surface potential measurements. Furthermore, in the course of our work, two non-contact mode applications, a keyless electronic door lock system and a speed sensor with a tonewheel for a car, were developed. Without an ion injection process being needed, very sensitive and reliable operations of the speed sensor were successfully demonstrated, even under very humid conditions (∼99% RH).