Bionic Fish-Shaped Triboelectric-Electromagnetic Hybrid Generator via a Two-Stage Swing Mechanism for Water Flow Energy Harvesting and Condition Monitoring.

The water flow energy of rivers is an important renewable and clean energy that plays a vital role in human life but is challenging to harvest at low flow velocity. This work proposes a bionic fish-shaped triboelectric-electromagnetic hybrid generator (BF-TEHG) via a two-stage swing mechanism for harvesting water flow energy. It is designed to simulate the shape of fish, effectively improving its ability to utilize low-velocity water flow energy and enabling it to operate at a minimum flow rate of 0.24 m/s. Furthermore, the impact of motion parameters on electrical performance is studied. The triboelectric and electromagnetic power-generation units can generate peak powers of 0.55 and 0.34 mW in the simulated river environments with a flow velocity of 0.98 m/s. In applications, after being immersed in water for 40 days, the BF-TEHG maintains its electrical performance without reduction, indicating excellent water immersion durability. Therefore, this work proposes an efficient strategy to harvest low-velocity water flow energy and provides an acceptable candidate for monitoring water flow conditions.

Gyroscope-Structured Triboelectric Nanogenerator for Harvesting Multidirectional Ocean Wave Energy.

Wave motion in the ocean can generate plentiful energy, but it is difficult to harvest wave energy for practical use because of the low frequency and random directional characteristics of wave motion. In this paper, a gyroscope-structured triboelectric nanogenerator (GS-TENG) is proposed for harvesting multidirectional ocean wave energy. Its inner and outer generation units can operate independently in different directions, and they all adopt the friction mode of surface contact. While realizing noninterference multidirectional energy harvesting, the power generation area is increased. In the experiments, under acceleration of 6 m/s2 with variations in excitation angle, the GS-TENG can output direct currents of 0.8-3.2 µA, and the open-circuit voltages of the inner and outer generation units can reach 730 and 160 V, respectively. When the devices are networked and placed in the water, the electrical energy generated by the GS-TENGs can enable commercial thermometers to operate normally. The attenuation of direct-current output by the GS-TENG in the experiment of 30 days in water is about 8%, which verifies the good durability of the device in the water environment. Therefore, the GS-TENG has excellent application prospects in the wave energy harvesting field.