Chitosan-Loaded Lead-Free Sodium Bismuth Titanate Composite Flexible Triboelectric Nanogenerator for Energy Harvesting, Biomechanical Sensing, and Smart-Path Touch-Lighting for Safe Walking Applications

Due to the limited availability of fossil fuels and skyrocketing carbon emissions, there is a growing need for the generation of energy from sustainable sources. A significant place in the energy harvesting system has been occupied by triboelectric nanogenerators (TENGs), which are among the technologies under consideration. Increasing demand for sustainable, self-sufficient energy solutions has driven the advancement of flexible and environmentally friendly TENG devices. Nevertheless, there remains a continual need to substantially increase the electrical output and boost the durability of the TENG technology to assure sustained high performance. In this context, we fabricated a flexible TENG utilizing sodium bismuth titanate-chitosan (NBT/chitosan) composite film and PDMS film. Lead-free ferroelectric ceramic NBT particles were synthesized through the traditional solid-state synthesis approach. NBT was added into a chitosan matrix to improve the triboelectric output by enhancing dielectric properties and charge transfer efficiency. The constructed device exhibited a maximum output voltage of 162.5 V and a current of 4.1 µA, resulting in a power density of 1.34 W·m⁻². The NBT/chitosan TENG was connected to an ArduinoUNO to activate a pathway light in real-time, responding to human walking motion, thereby demonstrating its potential for intelligent outdoor lighting and motion-sensing applications.