Lead-free and flexible piezoelectric nanogenerator based on CaBi₄Ti₄O₁₅ Aurivillius oxides/ PDMS composites for efficient biomechanical energy harvesting

The development of a new class of perovskite materials and enhancing its capability as an energy harvester that scavenges energy from various sources to power electronics systems has attracted significant attention. Herein, we report a cost-effective approach to synthesize a perovskite material, explore its properties, and further develop a high-performance flexible nanogenerator based on hybrid piezoelectric composite. The Aurivillius-based oxide, CaBi₄Ti₄O₁₅ (CBTO) was fabricated via a mixed oxide reaction and crystallized in an orthorhombic symmetry at room temperature. The material properties were elucidated to act as a parallel plate capacitor that will further act as a base for the development of filter circuits. Aurivillus/PDMS composite films were used to fabricate a flexible Aurivillus-based piezoelectric nanogenerator (A-PENG) to act as a self-powered exercise counter and power the electronics. The A-PENG was systematically analyzed under different conditions such as weight percentage, before and after poling, and acceleration effects. In addition, device stability, and capacitor charging-discharging tests were performed. This study elucidated the formation of lead-free ceramic materials that were used to make a flexible composite film for the realization of a piezoelectric harvester acting as a sustainable energy source.