Tiny bubble triboelectric nanogenerator functionalized by liquid film rupture

As an important energy carrier, bubble commonly exists in undersea and liquid-gas two-phase systems. Efficiently utilizing the bubble energy is critical for potential applications in energy harvesting and sensing in two-phase environment. However, the micro liquid layer inhibits the complete contact and restricts the performance. Herein, we proposed strategies for tiny bubble triboelectric nanogenerator (TB-TENG) featuring liquid film rupture to eliminate the screen between bubble and dielectric layer. We carried out optimization design by invasively rupturing the liquid film, achieving stable open-circuit voltage peak and transferred charge of 8.3 V and 3 nC by a 110-mu L bubble, with a high peak power density yielding the existing tube-based studies. Additionally, for noninvasive and spontaneous liquid film rupture, a scalable bubble regulator was fabricated, which integrated the irregularly dispersed bubbly flow into slug flow. We demonstrated the self-powered undersea gas leakage detection system combining the TB-TENG with the bubble regulator. Assisted with the good bubble regulation adaptability, the total leakage gas volume and rate were measured based on the voltage signal, with a varied leakage rate of 0.72-6 mL/min. The strategy provides insights for the related research in liquid-gas two-phase systems in nature and industry.