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We developed a high-efficiency rotating triboelectric nanogenerator (R-TENG)-enhanced multilayered antibacterial polyimide (PI) nanofiber air filters for removing ultrafine particulate matter (PM) from ambient atmosphere. Compared to single-layered PI nanofiber filters, the multilayered nanofiber filter can completely remove all of the particles with diameters larger than 0.54 μm and shows enhanced removal efficiency for smaller PM particles. After connecting with aR-TENG, the removal efficiency of the filer for ultrafine particles is further enhanced. The highest removal efficiency for ultrafine particulate matter is 94.1% at the diameter of 53.3 nm and the average removal efficiency reached 89.9%. Despite an increase in the layer number, the thickness of each individual layer of the film decreased, and hence, the total pressure drop of the filter decreased instead of increasing. Moreover, the nanofiber film exhibited high antibacterial activity because of the addition of a small amount of silver nanoparticles. This technology with zero ozone release and low pressure drop is appropriate for cleaning air, haze treatment, and bacterial control.

A square-grid triboelectric nanogenerator (SG-TENG) is demonstrated for harvesting vibrational energy and sensing impulsive forces. Each square of the three-dimensional (3D)-printed square grid is filled with an aluminum (Al) ball. The grid structure allows the SG-TENG to harvest vibrational energy over a broad bandwidth and operate at different vibrational angles. The most striking feature of the SG-TENG is its ability of being scaled and integrated. After connecting two SG-TENGs in parallel, the open-circuit voltage and short-circuit current are significantly increased over the full vibrational frequency range. Being integrated with a table tennis racket, the SG-TENG can harvest the vibrational energy from hitting a ping pong ball using the racket, where a direct hit by the racket generates an average output voltage of 10.9 ± 0.6 V and an average output current of 0.09 ± 0.02 μA. Moreover, the SG-TENG integrated into a focus mitt can be used in various combat sports, such as boxing and taekwondo, to monitor the frequency and magnitude of the punches or kicks from boxers and other practitioners. The collected data allow athletes to monitor their status and improve their performance skills. This work demonstrates the enormous potential of the SG-TENG in energy harvesting and sensing applications.

The triboelectric nanogenerator (TENG) has emerged as a new and effective mechanical energy harvesting technology. In this work, a theoretical model for a rotary-sliding disk TENG with grating structure was constructed, including the dielectric-to-dielectric and conductor-to-dielectric cases. The finite element method (FEM) was utilized to characterize the fundamental physics of the rotarysliding disk TENG working in both contact and non-contact modes. The basic properties of disk TENG were found to be controlled by the structural parameters such as tribo-surface spacing, grating number, and geometric size. From the FEM calculations, an approximate V–Q–α relationship was built through the interpolation method, and then the TENG dynamic output characteristics with arbitrary load resistance were numerically calculated. Finally, the dependencies of output power and matched resistance on the structural parameters and rotation rate were revealed. The present work provides an in-depth understanding of the working principle of the rotary-sliding disk TENG and serves as important guidance for optimizing TENG output performance in specific applications.

In recent years, triboelectric nanogenerators have attracted much attention because of their unique potential in self-powered nanosensors and nanosystems. In this paper, we report a cylindrical spiral triboelectric nanogenerator (S-TENG), which not only can produce high electric output to power display devices, but also can be used as a self-powered displacement sensor integrated on a measurement ruler. At a sliding speed of 2.5 m/s, S-TENG can generate a short-circuit current (I SC) of 30 µA and an open-circuit voltage (V OC) of 40 V. As the power source, we fabricate a transparent and flexible hand-driven S-TENG. Furthermore, we demonstrate a self-powered S-TENG-based measuring tapeline that can accurately measure and display the pulled-out distance without the need for an extra battery. The results obtained indicate that TENG-based devices have good potential for application in self-powered measurement systems.

UV is a high-energy electromagnetic radiation that has been widely used in industrial production and the scientific research domain. In this work, a deep UV light emission was obtained using triboelectrification induced plasma discharge without any extra power supply. By a mechanical friction between polymer and quartz glass, the triboelectric charges cause a changing electric field, which may bring plasma discharge of low pressure gas (Ar-Hg) and give out 253.7 nm irradiation. The UV light caused by continuous friction can excite a trichromatic phosphor and afford a bright white light emission. A UV sterilization experiment shows that ∼98% of Escherichia coli can be killed in 30 min by UV irradiation, which reveals that a self-powered sterilization apparatus with good sterilization effect was fabricated. This work provides a novel design to fabricate a self-powered UV light emitting device using low-frequency mechanical friction and realizes the coupling of triboelectrification and plasma luminescence, which may further expand the application of UV light in special circumstances.

Harvesting mechanical energy from our surroundings to acquire a steady and high power output has attracted intensive interest due to the fast development of portable electronics. In this work, the disk-structured triboelectric nanogenerator (TENG) was prepared based on the mature printed circuit board (PCB) technology and the composite structure for effectively improving the utilization in space. A narrow grating of 1° was designed to produce high output. Operated at a rotation rate of 1,000 rpm, the TENG produces a high output power density of 267 mW/cm2 (total power output of 25.7 W) at a matched load of 0.93 MΩ. After introducing a transformer, the output power can be managed so that it can be directly used to charge a battery for a smart phone. With the PCB production technology, fabrication of high performance TENG at low cost and large-scale becomes feasible.

The triboelectric nanogenerator (TENG), based on the well-known triboelectric effect and electrostatic induction effect, has been proven to be a simple, cost effective approach for self-powered systems to convert ambient mechanical energy into electricity. We report a flexible and transparent paper-based triboelectric nanogenerator (PTENG) consisting of an indium tin oxide (ITO) film and a polyethylene terephthalate (PET) film as the triboelectric surfaces, which not only acts as an energy supply but also as a self-powered active sensor. It can harvest kinetic energy when the sheets of paper come into contact, bend or slide relative to one another by a combination of vertical contact-separation mode and lateral sliding mode. In addition, we also integrate grating-structured PTENGs into a book as a self-powered anti-theft sensor. The mechanical agitation during handling the book pages can be effectively converted into an electrical output to either drive a commercial electronic device or trigger a warning buzzer. Furthermore, different grating-structures on each page produce different numbers of output peaks by sliding relative to one another, which can accurately act as a page mark and record the number of pages turned. This work is a significant step forward in self-powered paper-based devices.