A Self‐Powered and Efficient Triboelectric Dehydrator for Separating Water‐in‐Oil Emulsions with Ultrahigh Moisture Content

Oil–water emulsions are a considerable hazard to the environment, ecology, and human health, if not appropriately treated. This study proposes a self‐powered and efficient triboelectric dehydrator (TED) based on a wind‐driven freestanding rotary triboelectric nanogenerator (FR‐TENG) to separate water‐in‐oil emulsions. This TED can form a high‐voltage electric field in the emulsion when the FR‐TENG is driven by mechanical energy. The dehydration performance of the TED is analyzed in detail through multiphysics‐coupled models and experiments. It is found that the TED can dehydrate water‐in‐oil emulsions with a wide range of initial moisture contents. In particular, even when the initial moisture content is 60%, which is near the phase inversion concentration of the emulsion, the dehydration rate of the TED can still reach 99.41%. In addition, the performance of TED is demonstrated in a simulated situation of wind, suggesting that the present TED has great potential application for separating oil–water emulsions by harvesting environmental energy.