Improving Electrical Performance and Lifespan of Liquid‐Based Triboelectric Nanogenerator via Charge‐Inducing Structure

Abstract Among triboelectric nanogenerators (TENGs), liquid‐based TENGs (L‐TENGs) have attracted attention owing to their advantage of using abundant water resources as an energy source. However, their electrical performance is lower than that of solid–solid (S–S) contact TENGs because of their relatively low charge density. In addition, the ions dissolved in water neutralize the surface charge of the polymer, reducing the long‐term stability of L‐TENGs. To address this problem, this study developed a new strategy that not only enhances the electrical performance but also the durability of the L‐TENG. A simple charge‐inducing structure (CIS) is designed to provide a strong surface charge in the reservoir via S‐S contact. Hereby, the electrical output during the liquid‐solid contact increased from 38.8 to 122.7 V in V OC and from 79 to 253 µA in I CC . Moreover, this structure overcomes the limitation of the L‐TENG, which significantly decreases output due to the influence of existing ions and enables extension of the electrical lifespan. Based on this structural design, a portable aqua ball exercise device is developed with long‐term usability and presented an application for visualizing movements in real‐time. Consequently, enhancing the electrical output and durability through the water inertia and CIS structure presents a new strategy for commercializing L‐TENGs.