The water droplet with huge charge density excited by triboelectric nanogenerator for water sterilization

Application of triboelectric nanogenerator (TENG) in cancer prevention and adjuvant therapy

Cancer is a malignant tumor that kills about 940,000 people worldwide each year. In addition, about 30-77 % of cancer patients will experience cancer metastasis and recurrence, which can increase the cancer mortality rate without prompt treatment. According to the US Food and Drug Administration, wearable devices can detect several physiological indicators of patients to reflect their health status and adjuvant cancer treatment. Based on the triboelectric effect and electrostatic induction phenomenon, triboelectric nanopower generation (TENG) technology can convert mechanical energy into electricity and drive small electronic devices. This article reviewed the research status of TENG in the areas of cancer prevention and adjuvant therapy. TENG can be used for cancer prevention with advanced sensors. At the same time, electrical stimulation generated by TENG can also be used to help inhibit the growth of cancer cells to reduce the proliferation, recurrence, and metastasis of cancer cells. This review will promote the practical application of TENG in healthcare and provide clean and sustainable energy solutions for wearable bioelectronic systems.

Droplet Energy Harvesting System Based on Total-Current Nanogenerator

The droplet-based nanogenerator (DNG) is a highly promising technology for harvesting high-entropy water energy in the era of the Internet of Things. Yet, despite the exciting progress made in recent years, challenges have emerged unexpectedly for the AC-type DNG-based energy system as it transitions from laboratory demonstrations to real-world applications. In this work, we propose a high-performance DNG system based on the total-current nanogenerator concept to address these challenges. This system utilizes the water-charge-shuttle architecture for easy scale-up, employs the field effect to boost charge density of the triboelectric layer, adopts an on-solar-panel design to improve compatibility with solar energy, and is equipped with a novel DC-DC buck converter as power management circuit. These features allow the proposed system to overcome the existing bottlenecks of DNG and empower the system with superior performances compared with previous ones. Notably, with the core architecture measuring only 15 cm × 12.5 cm × 0.3 cm in physical dimensions, this system reaches a record-high open-circuit voltage of 4200 V, capable of illuminating 1440 LEDs, and can charge a 4.7 mF capacitor to 4.5 V in less than 24 min. In addition, the practical potential of the proposed DNG system is further demonstrated through a self-powered, smart greenhouse application scenario. These demonstrations include the continuous operation of a thermohygrometer, the operation of a Bluetooth plant monitor, and the all-weather energy harvesting capability. This work will provide valuable inspiration and guidance for the systematic design of next-generation DNG to unlock the sustainable potential of distributed water energy for real-world applications.

Power management strategy for unidirectional current pulsed triboelectric nanogenerator

Power management circuit (PMC) can efficiently store the output energy of pulsed triboelectric nanogenerator (Pulsed-TENG). Unidirectional current Pulsed-TENG (UP-TENG) has the advantage of without using rectifier bridge. However, the energy storage efficiency is limited for large capacitors at low capacitor voltage (<10 V). To solve this problem, PMC is optimized here. Firstly, rectifier diode is used to reduce the energy loss. Energy storage efficiency of PMC using rectifier diode (D-PMC) is higher than that of conventional PMC. Then, appropriate inductor is used to further form the optimized PMC (O-PMC), which reduces the energy loss of inductor. Results show that O-PMC using 100μH inductor has the highest energy storage efficiency. The actual test energy storage efficiency of O-PMC is 30.6%, which 3.4 times higher than that of D-PMC. Finally, an external capacitor is connected to electrodes of UP-TENG to form the EUP-TENG, which improves charging speed and output voltage of O-PMC. O-PMC using EUP-TENG can stably power calculator at low motion frequencies. O-PMC can be widely used in self-powered systems.

The effect of metal surface nanomorphology on the output performance of a TENG

In this work, the effect of charge density and nanomorphology of a metal tip on the output performance of a triboelectric nanogenerator (TENG) is studied. The basic working principle of the TENG is charge transfer after separation of a metal and a polymer. There are different charge densities on different kinds of metal surface nanomorphology, which significantly influences the output performance of the TENG. Copper samples with different nanomorphology were obtained by controlling pH value, current density, electrolyte concentration, and temperature during the electrodeposition of copper. The samples were characterized using XRD and SEM. The output performance of the TENG is closely related to the size, charge density distribution, and shape of the metal nanoparticles.