Surface polarity tuning through epitaxial growth on polyvinylidene fluoride membranes for enhanced performance of liquid-solid triboelectric nanogenerator

Although liquid-solid triboelectric nanogenerator (LS-TENG) has been taken into consideration as a remarkable promising renewable clean energy source for electronic devices, their performances are still limited to be practically utilized owing to the weak polarity and inadequate functional groups of triboelectric materials. In this work, we propose a high-performance LS-TENG reached from surface polarity tuning through epitaxial growth on polyvinylidene fluoride (PVDF) membrane. The PVDF surface functional is treated with silica nanoparticles (SiNPs) through chemical bonding and then grafted with negatively charged 1H,1H,2H,2H-Perfluorooctyltriethoxysilane (FOTS) to forming the FOTS/SiNPs/PVDF (FSiP) membrane. The proposed membrane can induce fluorine-bearing silane chains and increase the interfacial polarization, leading to the outstanding hydrophobic property and dielectric constant. In consequence, the output power of FSiP-TENG demonstrates superior triboelectric performance with a current of 5.79 μA, a voltage of 28.3 V, and the highest power density of 420 mW/m2, a 10.8 times improvement compared to the PVDF-TENG. Considering the excellent durability, stability, and water-resistant, the FSiP-TENG can develop into a water energy harvesting device and a liquid self-powered sensor to be used in our daily life.