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In the current daily life of people, the usage for disposable medical masks (DMMs) continues to be high. Discarded DMMs eventually become plastic pollution, threatening the marine environment seriously. At present, the common plastic recycling methods are extensive and not completely applicable for DMM recycling. In this work, according to the special structural and material characteristics of DMMs, a simple and effective recycling solution is proposed based on triboelectric nanogenerators (TENGs). First, a pulsed electric field system is designed and fabricated to treat the recycled films. The sterilizing rate reaches 91.8%, and the film surface potential is enhanced at the same time. Then, the feasibility of the treated films to be applied as the friction layers of TENGs is verified. Moreover, the recycled films are upgraded by chemical and physical methods, improving the output current of the basic TENG by 3.28 times. Finally, a complete TENG device is constructed to harvest water wave energy, 93.75% of which is made from recycled DMM materials. Under water waves, the power density of 18.22 W m−3 is achieved. Starting from TENG technology, this study combines circular economy and clean energy development, which is of significance for carbon neutralization. [ABSTRACT FROM AUTHOR]

With increasing global warming, catastrophic floods have threatened people's lives seriously and caused huge economic losses. However, present water hazard alarming systems generally rely on commercial batteries, limiting the intelligent development of disaster prevention planning and maintenance costs. In order to break the limitation, this work applies triboelectric nanogenerators (TENGs) to water hazard alarming. A spherical TENG device with four spiral units is designed to harvest water wave energy, and charge excitation modules (CEMs) are created and integrated with the TENG to improve its electric output. The output current and output power of the spherical TENG with CEMs can reach 15.09 mA and 24.48 mW, which are increased by 250.5 and 4.0 times, compared to the TENG without CEMs. Based on the charge excitation TENG, a self‐powered intelligent buoy is constructed. Utilizing the buoy to transmit 433 MHz radio frequency signals to 25 meters away, a water level alarm system and a water level information exchange system with a mobile phone are successfully realized. This work extends applications of TENGs toward water wave energy harvesting and provides a new strategy for water hazard alarming, which is conducive to the fields of carbon neutralization, Internet of Things, and disaster prevention. [ABSTRACT FROM AUTHOR]

Wind energy, as one kind of renewable and sustainable energy sources, is expected to solve the problem of energy consumption and environment deterioration. Here, an improved rotary triboelectric nanogenerator (TENG) using rabbit fur‐based soft‐contact (SCR‐TENG) with segmented structure for harvesting low‐speed wind energy is design and fabricated. The adopted soft raw‐rabbit fur shows excellent performance in triboelectrification and is beneficial to reducing frictional resistance and prolonging the lifetime of device. After 480 000 cycles, no obvious wear is observed on the dielectric film surface, and the transferred charge is not significantly attenuated. The mechanical‐to‐electrical energy conversion efficiency of 15.4% can be achieved. Moreover, self‐powered applications have been successfully demonstrated in night direction indication, insect trapping, soil moisture detection, ambient temperature and humidity detection, and signal transmission, powered by SCR‐TENG, toward smart farming. [ABSTRACT FROM AUTHOR]

Abstract: 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 µA, 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. [ABSTRACT FROM AUTHOR]

Ocean waves are one of the most promising renewable energy sources for large‐scope applications. Recently, triboelectric nanogenerator (TENG) network has been demonstrated to effectively harvest water wave energy possibly toward large‐scale blue energy. However, the absence of effective power management severely restricts the practicability of TENGs. In this work, a hexagonal TENG network consisting of spherical TENG units based on spring‐assisted multilayered structure, integrated with a power management module (PMM), is constructed for harvesting water wave energy. The output performance of the TENG network is found to be determined by water wave frequencies and amplitudes, as well as the wave type. Moreover, with the implemented PMM, the TENG network could output a steady and continuous direct current (DC) voltage on the load resistance, and the stored energy is dramatically improved by up to 96 times for charging a capacitor. The TENG network integrated with the PMM is also applied to effectively power a digital thermometer and a wireless transmitter. The thermometer can constantly measure the water temperature with the water wave motions, and the transmitter can send signals that enable an alarm to go off once every 10 s. This study extends the application of the power management module in the water wave energy harvesting. [ABSTRACT FROM AUTHOR]

Ocean wave energy, as one of the most abundant resources on the earth, is a promising energy source for large‐scale applications. Triboelectric nanogenerators (TENGs) provide a new strategy for water wave energy harvesting; however, its average performance in realistic water wave conditions is still not high. In this work, a whirling‐folded TENG (WF‐TENG) with maximized space utilization and minimized electrostatic shielding is constructed by 3D printing and printed circuit board technologies. The flexible vortex structure responds easily to multiform wave excitation with improved oscillation frequency. A standard water wave tank is established to generate controllable water waves to characterize the device performance. It is found to be determined by wave conditions and internal structure, which is also revealed by a theoretical dynamical analysis. The WF‐TENG can produce a maximum peak power of 6.5 mW and average power of 0.28 mW, which can power a digital thermometer to operate constantly and realize self‐powered monitoring on the TENG network to prevent possible damage in severe environments. Moreover, a self‐charge‐supplement WF‐TENG network is proposed to improve the output performance and stability. This study provides an effective strategy for improving the average power and characterizing the performance of spherical TENG towards large‐scale blue energy. [ABSTRACT FROM AUTHOR]