Biomimetic PVA-PVDF-based triboelectric nanogenerator with MXene doping for self-powered water sterilization

The harsh environment at sea level can reduce the harvesting efficiency of triboelectric nanogenerators (TENGs) for blue energy. Based on this, the doping ratio of MXene was optimized and was applied to enhance the moisture resistance, anti-fouling, wear resistance and dielectric properties of PVA triboelectrode. 8 wt% MXene doping provides more hydrogen bonding sites on PVA surface, thereby adsorbing more water molecules as electropositivity materials and improves its anti-fouling performance by forming hydration layer. Meanwhile, MXene increases the load capacity of hybrid transfer film and greatly improves the wear resistance of PVA film, and can form microcapacitor to improve its dielectric properties. In addition, biomimetic PVDF electrode was prepared by imitating the hydrophobic mechanism of leaves and significantly improved the anti-fouling and moisture resistance of PVDF. The Voc and Isc of TENG reached to 1056V and 36.6 μA at 95% humidity and improved by 2.37 times. The charge density and binding energy of PVA/MXene and PVA before and after adsorbed water molecule were calculated by DFT. Furthermore, the self-powered water sterilization system based on PVA/MXene-PVDF-based TENG achieved a sterilization rate of 98.99% at the flow rate of 2000 mL min−1, which was much higher than ordinary AC power (86.80%).