Irregular and low‐frequency mechanical energy, including ocean energy, is widely distributed but mostly wasted. Triboelectric nanogenerator (TENG) has been proved as a very promising ocean energy harvesting technology. However, the traditional cylindrical pendulum TENG (CP‐TENG) can only work effectively in a narrow frequency bandwidth. In this work, a triboelectric nanogenerator enabled by coupling the swing‐rotation switching mechanism with a potential energy storage/release strategy (SR‐TENG) is presented. It can convert various swing/vibration mechanical energies into electric energy, and it has a controllable output performance whether it works under intermittent rotation mode or continuous rotation mode. This coupling results enable SR‐TENG to efficiently harvest low‐frequency mechanical energy from 0.3 to 5 Hz. Therefore, its bandwidth is about four times larger than that of CP‐TENG. The peak power density of SR‐TENG can reach 10.1 W m−3 at 1.8 Hz and 15.4 W m−3 at 5 Hz, respectively. Moreover, its durability is improved greatly due to its non‐contact working mode. Based on this SR‐TENG, several applications toward smart ocean, including a self‐powered and wireless hydrological information monitoring system, are demonstrated successfully. These strategies are very helpful to improve the bandwidth, the output performance, and the durability of TENGs.

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The triboelectric nanogenerator (TENG) is an emerging technology proven to have great potential in rainwater energy harvesting. However, most studies have focused only on single-position droplets, and there needs to be more research on multi-position, large-scale rainwater energy. In this work, we develop a multi-position and multi-layered triboelectric nanogenerator (MM-TENG) for large-scale raindrop energy harvesting. The multi-position structure can harvest multiple droplets in the horizontal direction. The water reservoir with multiple holes can convert a large amount of water into droplets, ensuring the output performance of the TENG. The multi-layered structure improves the efficiency of space utilization, as demonstrated by the current integration calculation, where a double-layered structure increases the output by 15.27% and a three-layered structure increases the output by 38.2% at the same height. Finally, we successfully lit up 50 LEDs and drove a commercial calculator with the power generated by the MM-TENG. This work provides a practical guide for collecting large-scale raindrop energy and self-driven sensing of the rainwater environment.

The development and utilization of new energy sources is an effective means of addressing the limits of traditional fossil energy resources and the problem of environmental pollution. Triboelectric nanogenerators (TENG) show great potential for applications in harvesting low-frequency mechanical energy from the environment. Here, we propose a multi-cylinder-based triboelectric nanogenerator (MC-TENG) with broadband and high space utilization for harvesting mechanical energy from the environment. The structure consisted of two TENG units (TENG I and TENG II) assembled by a central shaft. Both an internal rotor and an external stator were included in each TENG unit, operating in oscillating and freestanding layer mode. On one hand, the resonant frequencies of the masses in the two TENG units were different at the maximum angle of oscillation, allowing for energy harvesting in a broadband range (2.25–4 Hz). On the other hand, the internal space of TENG II was fully utilized, and the maximum peak power of the two TENG units connected in parallel reached 23.55 mW. In contrast, the peak power density reached 31.23 Wm−3, significantly higher than that of a single TENG unit. In the demonstration, the MC-TENG could power 1000 LEDs, a thermometer/hygrometer, and a calculator continuously. Therefore, the MC-TENG will have excellent application in the field of blue energy harvesting in the future.