Production of piezoelectric aerogel materials, increasing efficiency in energy harvesting

In this study, aerogel composite materials with piezoelectric properties were synthesised and their performances in energy harvesting applications were investigated in detail. Within the scope of the research, polyvinyl alcohol (PVA)-based, medium conductive and thermally resistant polybenzimidazole (PBI) and piezoceramic material (barium calcium titanate zirconate (BCZT) and zinc oxide (ZnO)) doped composite aerogels were prepared. The obtained piezoaerogel was dried at 50 bar and 120 °C by critical carbon dioxide drying method and three-dimensional macroporous structures were preserved. Surface morphological properties and macroporosity distribution graph of composite aerogels were analysed by FESEM. Energy harvesting was increased by pressing the obtained piezoaerogel samples at 60 °C. As a result of FTIR and TGA analyses performed to investigate the structural properties of aerogels, it was determined that PBI doping increased the thermal resistance and all three aerogels were completely degraded at a temperature of approximately 480 °C. The output voltages generated as a result of mechanical impacts applied to the material were recorded and analysed by oscilloscope. According to the results of the study, a significant increase in piezoelectric performance was observed by using BCZT and ZnO dopants in the range of 1%-3%. In samples with 2 cm² surface area, a maximum output voltage of 19.0 V was obtained as a result of the force applied by finger pressure. In addition, the output power density and current value produced by the piezoaerogel were determined by measurements made by the two-probe method. The maximum output power was measured as 1,280x10-3 W for 0.95 mm thick piezoaerogel material. 3% BCZT doped sample was found to have the highest output power.