Boosting the Charge Output of Enclosed Liquid-Based Nanogenerators by Electrowetting-Assisted Charge Injection Approach

Liquid-based nanogenerators (L-NGs) have emerged as a promising solution for clean energy, appreciated for their minimal friction and effective contact at solid-liquid interfaces. Enclosed L-NGs, in particular, offer the benefits of enhanced durability and versatility. However, a key issue with enclosed L-NGs is the low charge density resulting from triboelectrification at the liquid-solid interface. In this study, this challenge is addressed by employing an electrowetting-assisted charge injection (EWCI) approach to significantly enhance the charge output of the enclosed nanogenerator, which this study refers to as the EW-NG. After EWCI treatment, the charge density has been enhanced by approximately ninefold, achieving a volumetric output charge density of 19.1 mC m⁻³, surpassing previous reports. The EWCI also ensures stable charge retention, contributing to the device's exceptional robustness, as evidenced by no significant degradation during intermittent testing over six months. Moreover, the high flexibility of the water within the device allows for operation in various modes and the generation of power from diverse mechanical energy sources. The EW-NG has been successfully demonstrated to power an LCD screen with a size of 10 inches. This adaptability highlights the device's significant potential for applications in energy harvesting and self-powered electronic systems in the field of the Internet of Things.