High‐Coupled Magnetic‐Levitation Hybrid Nanogenerator with Frequency Multiplication Effect for Wireless Water Level Alarm

Abstract Hybrid nanogenerators (HNGs) represent a promising avenue for water energy harvesting, yet their commercial viability faces hurdles such as limited power output, poor coupling, and constrained operational lifespans. Here, a highly coupled triboelectric‐electromagnetic magnetic‐levitation hybrid nanogenerator (ML‐HNG) is introduced that shows great potential for water energy harvesting. The ML‐HNG fulfills the challenges of high power output, strong coupling, and long operational lifespans. During the contact‐separation process of the triboelectric nanogenerator (TENG), the changing magnetic flux in the electromagnetic generator's coils generates a potential difference between the coils and Cu electrodes. The unique design of the ML‐HNG employs a shared coil electrode configuration, which enhances the coupling without adding extra volume. This integration allows the ML‐HNG to achieve multi‐frequency vibrations and multiple output cycles per external longitudinal movement, a phenomenon known as the frequency multiplication effect. With an average power density of 1.69 W m −3 in water, the ML‐HNG provides continuous power for a thermo‐hygrometer and can quickly drive a wireless water level alarm system within a minute. This groundbreaking hybrid nanogenerator design holds significant promise for the efficient and consistent harvesting of low‐frequency ocean wave energy, marking a substantial advancement in blue energy technology.