Triboelectric nanogenerators (TENGs) have shown promising potential for large-scale blue energy harvesting. However, the lack of reasonable designs has largely hindered TENG from harvesting energy from both rough and tranquil seas. Herein, a fully symmetrical triboelectric nanogenerator based on an elliptical cylindrical structure (EC-TENG) is proposed for all-weather blue energy harvesting. The novel elliptical cylindrical shell provides a unique self-stability, high sensitivity to wave triggering, and most importantly, an anti-overturning capability for the EC-TENG. Moreover, benefiting from its internal symmetrical design, the EC-TENG can produce energy normally, even if it was overturned under a rude oscillation in the rough seas, which distinguishes this work from previous reported TENGs. The working mechanism and output performance are systematically studied. The as-fabricated EC-TENG is capable of lighting 400 light-emitting diodes and driving small electronics. More than that, an automatic monitoring system powered by the EC-TENG can also monitor the water level in real-time and provide an alarm if necessary. This work presents an innovative and reliable approach toward all-weather wave energy harvesting in actual marine environments.

Triboelectric nanogenerators (TENGs) to harvest ocean wave blue energy is flourishing, yet the research horizon has been limited to centimeter‐level TENG. Here, for the first time, a TENG shell is advanced for ocean energy harvesting to 0.5 m and an excellent frictional areal density of 1.03 cm⁻¹ and economies of scale are obtained. The unique structure of the multi‐arch shape is adopted to untie the difficulty of fully getting the extensive friction layer contact. An inside steel plate is vertically placed in the center of every TENG block, which can activate the TENG to achieve complete contact even at a tilt angle of 7 degrees. The proposed half‐meter TENG (HM‐TENG) has a broad response band from 0.1 to 2 Hz, a total transferred charge quantity up to 67.2 µC, and one single TENG can deliver an open‐circuit voltage of 368 V. Coupled with the self‐stabilizing and susceptible features the ellipsoid shell brings, the HM‐TENG can readily accommodate itself to the all‐weather, all‐sea wave energy harvesting. Muchmore, the HM‐TENG is also applied to RF signal transmitters. This work takes the first step toward near‐meter‐scale enclosures and provides a new direction for large‐scale wave energy harvesting.