Contact electrification of porous PDMS-nickel ferrite composites for effective energy harvesting

Energy harvesting technologies are becoming popular owing to their usage in the operation of low-power consumer electronics and as an alternative power source. Specifically, triboelectric nanogenerators (TENGs) have drawn much attention as they can efficiently scavenge waste mechanical energy into electrical output. Careful material selections can further improve the performance of TENGs. In this work, a spinel ferrite material with the chemical formula NiFe₂O₄ (NFO abbreviated further) is synthesized using a solid-state reaction route. The structural and magnetic property of the NFO has been studied, showing the cubic symmetry and ferromagnetic nature of the sample. The 3D tomography images of the PDMS-NFO composites were carried out using X-ray tomographic microscopy. To enhance the performance of the TENGs, we adopted a porous media by evaporation of water during the curing process of PDMS-NFO composites. A single-electrode operating mode was adopted for TENG fabrication. The electrical response of the device was carried out using different wt% and frequencies. The 12 wt% of NFO in PDMS (PN12 device) delivered a voltage, current, and charge of 60 V, 300 nA, and 34 nC, respectively. The charge density of the plain and porous composite-based TENG was compared to confirm the enhancement of the charge produced on the triboelectric layers. The commercial capacitors and energy harvesting based on a smart home were demonstrated using the TENG devices.