Hybrid Triboelectric and Piezoelectric Energy Harvester Based on Zinc Oxide/Titanium Dioxide/PDMS Nanocomposites

Abstract

Hybrid energy harvesters that generate electrical energy from ambient mechanical inputs are attractive solutions for low-power applications. The performance of an energy harvester strongly depends on the properties of the materials used for its fabrication. The addition and optimization of nanoparticles in a polymer matrix to form a nanocomposite film are expected to enhance the energy generation capability of the active layers. In this work, the potential piezoelectric and dielectric properties of zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles are explored to develop a hybrid tribo/piezoelectric energy harvester (HyTPEnG). The ZnO and TiO₂ filler concentrations are optimized in PDMS and used as active layers for the HyTPEnG. The HyTPEnG thus fabricated was evaluated for its voltage generation capability by using qualitative and quantitative techniques. The addition of nanoparticles and stacking of the multilayer polymer nanocomposite enhanced the output voltage of HyTPEnG, from ∼10.6 V to ∼9.1 V of the pristine PDMS-based device to ∼131 V and ∼125 V for qualitative (random finger tapping) and quantitative mechanical inputs (3 N). The proposed HyTPEnG excelled in testing scenarios for force dependency and temporal stability. The HyTPEnG exhibited ∼120 μW/cm² across a load resistance of 1 MΩ and charged a 1 μF capacitor to ∼6.28 V in 20 s. The device powers low-power electronic gadgets like a 2 × 2 × 2 LED tower, calculator, thermometer, digital watch, and mouse, showcasing its potential applications as a secondary power source for low-power electronic gadgets for personal applications including wearables, sensors, and flexible electronics and biomedical applications such as in implants and drug delivery.