Eco-benign nanostructured triboelectric films of onion tunic-SnOx based TENG for sustainable and green energy generation

Triboelectric nanogenerators (TENG) are playing a vital role in generation of eco -friendly, cost effective power in self-powered form. Herein, a novel contact-separation mode based TENG is fabricated using waste biomaterial onion tunic (OT) as dielectric layer. Moreover, nanocomposite of OT with tin oxide SnOx (x = 1-2) (OT/SnOx composite), and tin oxide (SnO2) nanoparticles (NPs) are synthesized by chemical bath deposition (CBD) method, and used for making active dielectric layers for TENG. For comparative analysis, the biomaterials egg shell membrane (ESM), garlic tunic (GT), almond peel (ALM), bombax ceiba fibers (BOM), calotropis fibers (CALO) and highly electronegative inorganic material polytetrafluoroethylene (PTFE) have also been used as TENG dielectric layers. The synthesized materials are characterized by Fourier Transform Infrared spectroscopy (FTIR), X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy dispersive X-ray spectroscopy (EDX) and Thermogravimetric Analysis (TGA). The average particle size of SnO2 NPs and OT/SnOx is in the range of 17–24 nm and 50-60 nm, respectively. The highest output voltage of 19V is produced by TENG combination of SnO2 NPs - PTFE followed by OT/SnOx composite - PTFE (16.6V) and least voltage (10.7V) produced by BOM – PTFE as active dielectric TENG layers by manual tapping of 4–5 Hz. The extensive experimentation observation of single TENG output voltage peaks help in deciding the position in the triboseries of materials used in this study. This triboseries reflects that all biomaterials, NPs and OT/SnOx composite are highly electropositive in nature with respect to PTFE. The fabricated TENGs also tested to power tens of green Light emitting diodes (LEDs), small digital wrist watch and successfully produce range of voltages from mechanical energy of different human activities like walking, running, and jumping.