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.