Weili Deng

Lawn Structured Triboelectric Nanogenerators for Scavenging Sweeping Wind Energy on Rooftops.

A novel triboelectric nanogenerator (TENG) is designed, based on flexible and transparent vertical-strip arrays, for environmental wind-energy harvesting. Given the low cost, simple structure, and wide applicability, the TENGs present a green alternative to traditional methods used for large-scale wind-energy harvesting.

Rotating-Disk-Based Hybridized Electromagnetic–Triboelectric Nanogenerator for Sustainably Powering Wireless Traffic Volume Sensors

Wireless traffic volume detectors play a critical role for measuring the traffic-flow in a real-time for current Intelligent Traffic System. However, as a battery-operated electronic device, regularly replacing battery remains a great challenge, especially in the remote area and wide distribution. Here, we report a self-powered active wireless traffic volume sensor by using a rotating-disk-based hybridized nanogenerator of triboelectric nanogenerator and electromagnetic generator as the sustainable power source. Operated at a rotating rate of 1000 rpm, the device delivered an output power of 17.5 mW, corresponding to a volume power density of 55.7 W/m(3) (Pd = P/V, see Supporting Information for detailed calculation) at a loading resistance of 700 Ω. The hybridized nanogenerator was demonstrated to effectively harvest energy from wind generated by a moving vehicle through the tunnel. And the delivered power is capable of triggering a counter via a wireless transmitter for real-time monitoring the traffic volume in the tunnel. This study further expands the applications of triboelectric nanogenerators for high-performance ambient mechanical energy harvesting and as sustainable power sources for driving wireless traffic volume sensors.

Self-Powered Safety Helmet Based on Hybridized Nanogenerator for Emergency

The rapid development of Internet of Things and the related sensor technology requires sustainable power sources for their continuous operation. Scavenging and utilizing the ambient environmental energy could be a superior solution. Here, we report a self-powered helmet for emergency, which was powered by the energy converted from ambient mechanical vibration via a hybridized nanogenerator that consists of a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG). Integrating with transformers and rectifiers, the hybridized nanogenerator can deliver a power density up to 167.22 W/m(3), which was demonstrated to light up 1000 commercial light-emitting diodes (LEDs) instantaneously. By wearing the developed safety helmet, equipped with rationally designed hybridized nanogenerator, the harvested vibration energy from natural human motion is also capable of powering a wireless pedometer for real-time transmitting data reporting to a personal cell phone. Without adding much extra weight to a commercial one, the developed wearing helmet can be a superior sustainable power source for explorers, engineers, mine-workers under well, as well as and disaster-relief workers, especially in remote areas. This work not only presents a significant step toward energy harvesting from human biomechanical movement, but also greatly expands the applicability of TENGs as power sources for self-sustained electronics.

Self-Powered Acceleration Sensor Based on Liquid Metal Triboelectric Nanogenerator for Vibration Monitoring

An acceleration sensor is an essential component of the vibration measurement, while the passivity and sensitivity are the pivotal features for its application. Here, we report a self-powered and highly sensitive acceleration sensor based on a triboelectric nanogenerator composed of a liquid metal mercury droplet (LMMD) and nanofiber-networked polyvinylidene fluoride (nn-PVDF) film. Due to the ultrahigh surface-to-volume ratio of nn-PVDF film and high surface tension, high mass density, high elastic as well as mechanical robustness of LMMD, the open-circuit voltage and short-circuit current reach up to 15.5 V and 300 nA at the acceleration of 60 m/s2, respectively. The acceleration sensor has a wide detection range from 0 to 60 m/s2 with a high sensitivity of 0.26 V·s/m2. Also, the output voltage and current show a negligible decrease over 200,000 cycles, evidently presenting excellent stability. Moreover, a high-speed camera was employed to dynamically capture the motion state of the acceleration sensor for insight into the corresponding work mechanism. Finally, the acceleration sensor was demonstrated to measure the vibration of mechanical equipment and human motion in real time, which has potential applications in equipment vibration monitoring and troubleshooting.

Enhanced performance of ZnO microballoon arrays for a triboelectric nanogenerator

In recent years, triboelectric nanogenerators (TENGs), harvesting energy from the environment as a sustainable power source, have attracted great attention. Currently, many reports focus on the effect of surface modification on the electrical output performance of the TENG. In this work, we have fabricated vertically grown ZnO microballoon (ZnOMB) arrays on top of pyramid-featured PDMS patterned film, contacted with PTFE film to construct the TENG. The electrical output performances of the designed TENG are presented under external forces with different frequencies. The corresponding output open-circuit voltage with ZnOMBs could reach about 57 V the current density about 59 mA m-2 at 100 Hz, which was about 2.3 times higher than without any ZnO. The global maximum of the instantaneous peak power could reach 1.1 W m-2 when the external load resistance was about 2 MΩ. Furthermore, the electrical output of the fabricated device could light 30 commercial LED bulbs without any rectifier circuits or energy-storage elements. This clearly suggests that this kind of surface modification can dramatically enhance the output performance of the TENG. Moreover, the design of TENG demonstrated here can be applied to various energy harvesting applications.

Microstructure-Based Interfacial Tuning Mechanism of Capacitive Pressure Sensors for Electronic Skin

In order to investigate the interfacial tuning mechanism of electronic skin (e-skin), several models of the capacitive pressure sensors (CPS) with different microstructures and several sizes of microstructures are constructed through finite element analysis method. The simulative pressure response, the sensitivity, and the linearity of the designed CPS show that the sensor with micropyramids has the best performance in all the designed models. The corresponding theoretically predicted sensitivity is as high as 6.3 × 10−7 fF/Pa, which is about 49 times higher than that without any microstructure. Additionally, these further simulative results show that the smaller the ratios of of pyramid, the better the sensitivity but the worse the linearity. When the ratio of of pyramid is about , the sensitivity and the linearity could reach a balance point. The simulative results evidently provide the important theoretically directive significance for the further development of e-skin.

Self-Powered Nanocomposites under an External Rotating Magnetic Field for Noninvasive External Power Supply Electrical Stimulation

Electrical stimulation in biology and gene expression has attracted considerable attention in recent years. However, it is inconvenient that the electric stimulation needs to be supplied an implanted power-transported wire connecting the external power supply. Here, we fabricated a self-powered composite nanofiber (CNF) and developed an electric generating system to realize electrical stimulation based on the electromagnetic induction effect under an external rotating magnetic field. The self-powered CNFs generating an electric signal consist of modified MWNTs (m-MWNTs) coated Fe3O4/PCL fibers. Moreover, the output current of the nanocomposites can be increased due to the presence of the magnetic nanoparticles during an external magnetic field is applied. In this paper, these CNFs were employed to replace a bullfrogs sciatic nerve and to realize the effective functional electrical stimulation. The cytotoxicity assays and animal tests of the nanocomposites were also used to evaluate the biocompatibility and tissue integration. These results demonstrated that this self-powered CNF not only plays a role as power source but also can act as an external power supply under an external rotating magnetic field for noninvasive the replacement of injured nerve.