A Comprehensive Review of Strategies toward Efficient Flexible Piezoelectric Polymer Composites Based on BaTiO3 for Next-Generation Energy Harvesting

The increasing need for wearable and portable electronics and the necessity to provide a continuous power supply to these electronics have shifted the focus of scientists toward harvesting energy from ambient sources. Harvesting energy from ambient sources, including solar, wind, and mechanical energies, is a solution to meet rising energy demands. Furthermore, adopting lightweight power source technologies is becoming more decisive in choosing renewable energy technologies to power novel electronic devices. In this regard, piezoelectric nanogenerators (PENGs) based on polymer composites that can convert discrete and low-frequency irregular mechanical energy from their surrounding environment into electricity have attracted keen attention and made considerable progress. This review highlights the latest advancements in this technology. First, the working mechanism of piezoelectricity and the different piezoelectric materials will be detailed. In particular, the focus will be on polymer composites filled with lead-free BaTiO3 piezoceramics to provide environmentally friendly technology. The next section will discuss the strategies adopted to enhance the performance of BaTiO3-based polymer composites. Finally, the potential applications of the developed PENGs will be presented, and the novel trends in the direction of the improvement of PENGs will be detailed.