All-Weather Droplet-Based Triboelectric Nanogenerator for Wave Energy Harvesting.

The liquid-solid triboelectric nanogenerator (LS-TENG) has been demonstrated to harvest energy efficiently through the contact electrification effect between liquid and solid triboelectric materials, which can avoid the wear issue in solid-solid TENG. However, the droplet-based LS-TENG reveals the problems that it generally works with the continuous falling droplets or needs to be fully packaged, which greatly limit its practical application. Here, a droplet-based triboelectric nanogenerator (DB-TENG) with a simple open structure is designed to effectively solve these problems. The nonpackaged DB-TENG can work stably under extreme conditions with high humidity or high concentrations of salt, acid, or alkali solutions, showing the DB-TENGs can be flexibly utilized in all types of working environments with better reliability and lower maintenance costs. It is of great significance that the integrated DB-TENG network array can realize the all-weather ocean energy harvesting. Furthermore, under the simulated ocean wave, a scaled-up DB-TENG with considerable output performance can charge capacitors and drive electrical devices. Overall, the DB-TENG shows many advantages: simple open structure, all-weather working ability, timely supplement of water loss, no tight packaging, wear resistance, suitable for extreme working environments. This work provides a convenient and feasible way toward all-weather wave energy harvesting in real marine environments.