Cellulose/chitosan film based triboelectric-piezoelectric coupled nanogenerator for wearable mechanosensing and energy harvesting

Abstract

Intelligently harnessing energy from the surrounding environment through various nanogenerators presents an ideal avenue to enable self-powered electronics. Herein, we developed a lightweight, flexible bilayer-structure coupled nanogenerator composed of a Hydroxypropyl cellulose (HPC)/chitosan (CTS)/carbon nanotube (CNT) film as the positive triboelectric layer, (PVDF)/polydimethylsiloxane (PDMS) aerogel as the negative layer. The triboelectric positive layer incorporates HPC and CTS biopolymers with multiple functional groups, thereby enhancing the polarity of the positive layer. Meanwhile, the incorporation of CNT in the biopolymer triboelectric film diminishes the contact impedance of the film, further increasing the voltage output (V_OC). The negative PVDF/PDMS aerogel layer, which exhibits both triboelectric and piezoelectric functions, features a high specific surface area, thus allowing for the coexistence of triboelectric and piezoelectric charges. This triboelectric-piezoelectric coupled nanogenerator displays an impressive sensitivity of 112.5 mV kPa⁻¹, excellent stability (maintaining consistent V_OC over 10,000 cycles), mechanical robustness, and robust energy harvesting capabilities. The simultaneous generation of triboelectric charges and piezoelectric charges due to the high specific surface area is proposed for the first time, offering significant promise for diverse applications ranging from various mechano-sensing to mechanical energy collection and storage.