Energy conversion from unsorted post-consumer plastic waste using piezoelectric, triboelectric, and pyroelectric nanogeneration mechanisms

Abstract This study investigates the energy-harvesting potential of unsorted post-consumer plastic packaging waste through piezoelectric, triboelectric, and pyroelectric effects. The waste included typical commodity polymers as high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET). When employed as nanogenerators, heterogeneous waste plastic blends demonstrated the ability to convert mechanical and thermal inputs into electrical energy, facilitated by physical contacts among plastics (triboelectricity) and mechanical deformation of processing additives in the plastics (piezoelectricity), as well as temperature gradients (pyroelectricity). Significant results include output voltage values above 130 V, short-circuit current density, and charge density of 50±2 mAcm-2 and 390±21 nCm-2, respectively, obtained for the triboelectric pair of PET bottle film and the blend of PS/HDPE/PP enriched with 60 wt. % of PET. Furthermore, the so-called rejected recyclable plastic waste, which is a residual fraction of plastic waste still largely landfilled, generated output voltages above 60 V when paired with PET bottle in triboelectric setup. These findings reveal that such plastic waste has a promising capacity for energy harvesting, indicating a novel use for low-value waste in sustainable energy applications.