Porous PDMS conformable coating for high power output carbon fibers/ZnO nanorod-based triboelectric energy harvesters

A new method for depositing PDMS directly onto conductive carbon yarns is proposed to produce Triboelectric Nanogenerator Yarns (TENG yarns) that can serve as the basic building blocks for energy scavenging wearables. The in-situ PDMS curing method described in this study allows the fast formation of a uniform thick coating over conductive surfaces regardless of their roughness. Single-electrode configuration TENG yarns are developed and their electrical output is optimized by precisely adjusting the PDMS layer thickness and by changing the chemical and physical nature of the carbon fiber (CF) yarns’ surface. Functionalizing the CF yarns’ surface with ZnO rods combined with porous PDMS coating can enhance their electrical output. The best results are achieved using this type of TENG yarns with an average diameter of 1.74 mm, which can be obtained after only 3 min of PMDS deposition by “in-situ” curing method. A maximum of 72 V peak-to-peak and 10 µA (74.1 µW cm⁻² of power density with a load resistance of 20 MΩ) is reached when applying an impact force of 600 N to a set of five TENG yarns connected in parallel. The output is stable even after 10,000 cycles and this set of TENG yarns is also able to light at least 28 LEDs when tapping by hand, proving a contribute towards the development of basic building blocks to power the future generation of wearables.