Li-Salt of Adipic Acid Incorporated Flexible Poly(vinylidene fluoride) Composite for Piezoelectric Energy Harvester with Superior Energy Density Toward Self-Powered Traffic Monitoring System
Ananya Aishwarya, Suvankar Mondal, Akanksha Adaval, Titas Dasgupta, Arup R. Bhattacharyya
Abstract
The development of the composite material based on poly(vinylidene fluoride) (PVDF) incorporating lithium salt of adipic acid (Li-AA) presents a promising avenue for sustainable and renewable energy generation via piezoelectric nanogenerators. In this study, PVDF/Li-AA composites were prepared through melt-mixing, followed by the fabrication of thin films using compression molding and solution casting techniques, with Li-AA concentration ranging from 1% to 10% by weight. Analysis via Fourier transform infrared spectroscopy (FTIR) confirmed hydrogen bonding interactions between −CF 2 moieties of PVDF and the acid functional groups of Li-AA. Additionally, FTIR analysis revealed that the solution-cast PVDF/Li-AA composite containing 10 wt % Li-AA exhibited the highest polar phase amount (∼ 65%) among all the composites, with remnant polarization of ∼4.2 × 10 –3 μC/cm 2 (50 Hz and 500 V). Furthermore, the solution cast PVDF/Li-AA composite film containing 10 wt % Li-AA achieved the highest piezoelectric coefficient ( d 33 value ∼ 42 pm/V), indicating superior piezoelectric response. Energy harvesting devices fabricated using compression molded and solution-cast films demonstrated an output voltage of ∼80 and ∼100 V, respectively, obtained from PVDF/Li-AA composite containing 10 wt % Li-AA. Furthermore, devices fabricated with compression molded and solution-cast composite films containing 10 wt % Li-AA exhibited higher power densities of ∼80 and ∼100 μW/cm 2, respectively. Finally, PVDF/Li-AA composite film based self-powered speed sensor was fabricated for speed detection of the vehicles.