Highly robust and efficient metal-free water cup solid-liquid triboelectric nanogenerator for water wave energy harvesting and ethanol detection

Recently, low-frequency mechanical energy harvesters based on solid-liquid contact electrification have garnered widespread attention for their unique advantages in wear resistance, high charge transfer efficiency, and novel insights into electron-ion interactions at the solid-liquid interface, particularly in material identification. Hence, we designed an robust and efficient water cup triboelectric nanogenerator (WC-TENG) that only uses ordinary drinking water and plastic water cups as primary materials, achieving high-efficiency power output while eliminating the need for metal electrodes and effectively addressing the issue of corrosion in generator components. Experimental results indicate that, at an operating frequency of 2 Hz, the WC-TENG generates an open-circuit voltage (Voc) of 249.71 V, a short-circuit current (Isc) of 4.21 mu A, and a transferred charge (Qsc) of 188.85 nC. The WC-TENG is capable of harvesting water wave energy with low frequency and low vibration amplitude. Furthermore, the introduction of ethanol disrupts the potential balance at the solid-liquid interface by impeding electron transfer and reducing the WC-TENG's electrical output, but as the ethanol volatilizes, the device gradually returns to its original potential state, demonstrating its potential as a selective ethanol sensor. This design not only advances the development of corrosion-resistant, high-performance energy harvesters but also opens up new possibilities for low-cost, sustainable, and environmentally adaptable sensing technologies.