MnO2 / BaTiO3 / PDMS Hybrid Nanocomposite - Based Thin Films for Hybrid Piezoelectric and Triboelectric Energy Harvesting

Hybrid Piezo-Tribo-electric energy harvesting systems (HPTEH) employ suitable materials and device configurations to convert vibrational energy into electrical output. Using an economical hydrothermal technique, flexible piezoelectric films composed of BaTiO3/PDMS nano-composites were fabricated for energy harvesting applications. Despite their many desirable qualities, including high energy density, low weight, and compact design, BaTiO3 based Piezoelectric devices generally have low current density. The addition of MnO2, can improve the dielectric properties and enhance electron transfer capabilities of the composite. BaTiO3/PDMS ceramic-polymer nanocomposite films incorporated with two different weight percentages (2% and 5%) of Manganese Dioxide (MnO2) nano powder were used for the study. The fabricated flexible nanogenerator films- Pristine PDMS, BaTiO3/PDMS and the MnO2 incorporated BaTiO3/PDMS films - were used to create hybrid Piezoelectric – Triboelectric energy harvesting devices. These films were cut into square shape with three layers: copper films at the top and bottom acting as the electrodes, and the Pristine PDMS film, BaTiO3/PDMS nanocomposite film or the MnO2 incorporated BaTiO3/PDMS hybrid nanocomposite film acting as the active layer for Piezoelectric- triboelectric potential generator device under external excitations. The Piezoelectric and triboelectric properties of these devices were subsequently characterized and evaluated. The PDMS/BaTiO3/MnO2 hybrid nanocomposite devices showed synergistic improvements. The best results observed with 5% MnO2 doping, where the Vpp reached 8 V in the tap test and 7.2 V in the point force test. This resulted in a device that, generated significant output voltages while maintaining flexibility, heat resistance, and stretchability. These improvements demonstrate the effective balance achieved between the piezo-triboelectric properties of BaTiO3 and the enhanced dielectric constant offered by MnO2.