Enhanced-performance bio-triboelectric nanogenerator based on starch polymer electrolyte obtained by a cleanroom-free processing method

Abstract

The study of triboelectric nanogenerators (TENGs) has focused widely on the issue of elevating triboelectrifying capacity. A new recently discovered phenomena of the use of polymers electrolytes for TENGs has been shown to be positive. However, this has not been studied yet in a wide range of materials. Renewable materials, such as biopolymer electrolytes, are still poorly understood regarding their relation to TENG performance. Herein, a polymer electrolyte starch-based bio-TENG was fabricated using a low-cost processing method. The films were electrically characterized at distinct loads, frequencies, thicknesses. Moreover, we complexed the starch polymer with CaCl2 to increase the triboelectrifying capacity and performance. Starch films at 0.5% of salt concentration reached the highest voltage output (1.2 V), exceeding by three-fold of the initial output of the non-complexed pristine biopolymer (0.4 V). Furthermore, the electrical output performance varies positively at both thinner film thicknesses and elevated loads while moisture of films has been proved to be a critical parameter in the electrical performance of TENGs, showing that well dried films performed a higher electrical output than moist samples. Furthermore, despite crack generation after fatigue, starch electrolyte films of TENGs showed an inalterable electrical performance suitable for a bunch of applications. To demonstrate one of these applications we achieved to turn on 100 LEDs using starch electrolyte and silicone ecoflex as opponents in a TENG.