Flow‐Regulated Charge Management for High‐Performance Solid‐Liquid Triboelectric Nanogenerators

ABSTRACT Solid‐liquid triboelectric nanogenerators (SL‐TENGs) have emerged as a promising technology for harvesting low‐frequency water energy. However, their practical output remains limited, as charge accumulation and discharge are intrinsically coupled during dynamic solid‐liquid interactions, restricting most reported devices to milliwatt level. Here, a flow‐regulated charge management strategy is reported that decouples charge accumulation from discharge through siphon‐driven transitions between electrically isolated droplet flow and electrically continuous liquid column flow. This mechanism enables progressive charge storage followed by collective release, significantly amplifying the electrical output. The resulting device achieves an open‐circuit voltage of 4250 V, a short‐circuit current of 6.8 mA, and a maximum instantaneous output power of 5 W without external driving components. Quantitative electrical measurements and surface potential analysis confirm that this enhancement arises directly from the flow‐regulated charge dynamics. These findings establish flow‐regulated charge management as a general design principle for high‐performance SL‐TENGs and provide new insights into regulating interfacial charge dynamics through fluid engineering. By directly powering high‐power commercial lamps and enabling self‐powered rainfall sensing, the device also demonstrates practical utility for both energy delivery and environmental monitoring, advancing the potential of SL‐TENGs for rainfall energy harvesting.