Triboelectric-piezoelectric hybrid nanogenerator based on BaTiO3-Nanorods/Chitosan enhanced output performance with self-charge-pumping system

Recent advances in achieving flexible triboelectric nanogenerators (TENGs) focus widely on utilizing and modifying abundant natural biopolymer. Boosting power generation and conversion efficiency continue to prevail. In this work, three main strategies were proposed to enhance the output performance of chitosan-based TENGs; 1) hybridization with lead-free piezoelectric nanorod, 2) introduction of a soft electrode using bacterial cellulose/carbon nanotube composite to enhance contact efficiency, and 3) enhancement of charge density of the triboelectric friction layer using a self-charge pumping (SCP) module. Under the same testing conditions of 48 ± 5% relative humidity, ~0.55 Hz of frequency, ~250 N of compressive force at 25.0 ± 0.5 °C, and the combination of 7 wt% lead-free piezoelectric BaTiO3 nanorods (BT-NRs) in the chitosan matrix, the highest open-circuit voltage (Voc) of ~111.4 V, short circuit (Isc) of ~21.6 μA/cm2, and also output power density of 756 μW/cm2 was achieved. By using an integrated SCP module, the TENGs can provide a Voc, Isc and peak power output of 247.2 V, 36.7 μA/cm2 and 1568 μW/cm2, respectively. This electrical power output rises to over 4-fold more power enhancement than that of pristine chitosan TENGs. The TENGs demonstrate remarkable mechanical stability and reliability upon cyclical contact for up to 3000 times. This work provides a promising strategy for achieving high-output, eco-friendly triboelectric nanogenerators. By boosting the output performance via continuous charge pumping, ultrahigh effective charge density was achieved successfully in flexible chitosan/BT-NR biocomposites that can push output performance towards real applications of TENGs.