Using triboelectric nanogenerators (TENGs) to harvest blue energy in the ocean is advanced technology at present. In wave environments, the wave magnitude is constantly changing, so designing a TENG that can adjust the energy harvesting ability is necessary. Herein, a graded energy harvesting triboelectric nanogenerator (GEH-TENG) is fabricated, in which double generation units can operate in different transmission states to adapt to wave changes. Under small waves, the GEH-TENG is in the primary transmission state. Once waves are large enough, it enters the secondary transmission state, realizing graded energy harvesting to enhance power generation performance. Experiments show that when the input frequency is 1.0 Hz and the amplitude is 120 mm, the GEH-TENG can generate 0.7 mJ of energy in a single operation cycle, which is 2.3 times of it without grading. Moreover, it can be placed on the shore to monitor ocean wave conditions. An idea of graded energy harvesting is proposed in this study, and the proposal provides useful guidance for practical applications of TENGs in ocean wave condition monitoring.

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