Spherical Triboelectric Nanogenerators Based on Spring-Assisted Multilayered Structure for Efficient Water Wave Energy Harvesting

Making use of water wave energy at large is one of the most attractive, low-carbon, and renewable ways to generate electric power. The emergence of triboelectric nanogenerator (TENG) provides a new approach for effectively harvesting such low-frequency, irregular, and random energy. In this work, a TENG array consisting of spherical TENG units based on spring-assisted multilayered structure is devised to scavenge water wave energy. The introduction of spring structure enhances the output performance of the spherical TENG by transforming low-frequency water wave motions into high-frequency vibrations, while the multilayered structure increases the space utilization, leading to a higher output of a spherical unit. Owing to its unique structure, the output current of one spherical TENG unit could reach 120 mu A, which is two orders of magnitude larger than that of previous rolling spherical TENG, and a maximum output power up to 7.96 mW is realized as triggered by the water waves. The TENG array fabricated by integrating four units is demonstrated to successfully drive dozens of light-emitting diodes and power an electronic thermometer. This study provides a new type of TENG device with improved performance toward large-scale blue energy harvesting from the water waves.