Sustainable and Flexible Piezoelectric Nanogenerator with Hybrid Nanocomposites Based on High-Performance Synthesized BCZT Powder

Abstract

Hybrid piezoelectric nanocomposites (HPCs) for nanogenerators are strongly dependent on the properties of the materials used. Traditional methods, such as solid-state approaches, yield low piezoelectric properties, leading to nanogenerators (PENGs) with reduced capabilities. In this work, the piezoelectric material composition Ba0.85Ca0.15Zr0.10Ti0.90O3 (BCZT), prepared by an efficient sol–gel method, is proposed, and an HPC-based poly(dimethylsiloxane) (PDMS) polymer, including multi-walled carbon nanotube (MWCNT) fillers, is prepared from it. The impact of each filler concentration on the overall performance has been investigated. Both the synthesized particles and the resulting nanocomposites were thoroughly characterized. The structural characterizations by X-ray diffraction and Raman spectroscopy measurements confirm the high crystallinity and purity of the BCZT powder and the formation of a morphotropic phase at room temperature. PENGs with 15 wt % BCZT exhibit under harmonic excitations an open-circuit voltage of 4.5 V and an output power of 2.38 μW for a 330 kΩ load resistance. Incorporating MWCNTs into the HPC enhances the conductivity and promotes self-polarization. The nanogenerator with the same BCZT concentration doped with MWCNTs generates under harmonic excitations an open-circuit voltage of 8 V and an output power of 5.46 μW for a resistive load of 280 kΩ. Because of the large surface area of the MWCNTs, they tend to agglomerate by van der Waals forces, and this influences the homogeneity of the composites. To optimize the processing parameters, we investigated the influence of the sonication amplitude. The results show that increasing the sonication amplitude improves the homogeneity of the HPC, leading to high flexibility, mechanical resistance, stability, and sustainability over 2000 cycles of repetitive loading and high reliability after 1 year.