Energy-from-waste: A triboelectric nanogenerator fabricated from waste polystyrene for energy harvesting and self-powered sensor

Development of human civilization is not only depleting the natural resources, but also wasting the resources by producing pollutants. The problems associated with both the growing energy demand and pollutant waste may be tackled by adopting the approach of resource recovery from waste and subsequently reuse it for energy conversion. Triboelectric nanogenerator (TENG), which harvests electrical energy from mechanical vibrations ubiquitously available in the environment, has been proposed as potential alternative of batteries for wireless and self-sustaining internet of things (IoT) devices. This work demonstrates a possible approach of wasted resource recovery and its reuse in energy harvesting. Polystyrene (PS) is extracted from the packaging waste that is subsequently used to realize a TENG. Peak power density of the waste poystyrene TENG (WPS-TENG) is 4.05 W/m 2 at load resistance ~3.3 MΩ. Impressive value of triboelectric charge density (~90 μC-m -2 ) of the device may be attributed to the induced porosity of WPS film. Moreover, the WPS-TENG remains stable, at least up to 20,000 contact/separation cycles and 180 days. Density functional theory (DFT) analysis is carried out to understand the contact electrification (CE) between PS and polytetrafluroethylene (PTFE) and a possible physical mechanism for electron transfer is presented. Power management of the WPS-TENG is demonstrated by using a switched-capacitor based power management circuit. An approach of on-road vehicle speed detection is also demonstrated by employing WPS-TENG based self-powered speed sensors. • Report of highly-performed low-cost triboelectric nanogenerator (TENG) from recycled consumer-waste polystyrene film • Impressive output power density of 4.05 W/m 2 and triboelectric charge density of ~90 μC-m -2 • Device stability for at least 20000 cycles and more than 180 days • Demonstration of TENG-based self-powered vehicle speed detection for traffic surveillance system • Density functional theory (DFT) analysis of contact electrification in waste polystyrene