Recycled Thermocol Nanofibers Based Smart Triboelectric Nanogenerators for AI-Assisted Switching.

The accumulation of non-biodegradable thermocol (expanded polystyrene, EPS) waste presents a critical environmental challenge and an untapped resource for sustainable energy technologies. In this work, we demonstrate a waste-to-functional-material strategy by transforming discarded thermocol into electrospun EPS nanofibers and employing them as an efficient tribonegative layer in a triboelectric nanogenerator (TENG). Unlike conventional polymer films, the nanofibrous EPS architecture introduces high surface roughness and electrospinning-induced dipole alignment, leading to markedly enhanced charge generation. The resulting TENG delivers an open-circuit voltage of ∼159 V, a short-circuit current of ∼22 µA, and a maximum output powerdensity of 2083 mW/m2, outperforming widely used triboelectric polymers such as PTFE and PET. The device further exhibits excellent mechanical durability, long-term stability over six months, and robust performance under varying humidity and temperature conditions. Beyond energy harvesting, the TENG is implemented as a self-powered intelligent switching interface, where machine-learning-assisted signal processing enables reliable operation of a digital elevator system. This study establishes recycled EPS nanofibers as a high-performance triboelectric material and demonstrates their potential for sustainable, intelligent, and self-powered electronic systems.