Search Results (70)

Triboelectric nanogenerators have attracted extensive attention as they can complete sensing during energy conversion, triggering a series of self-powered designs. Traditional TENG bipolar independent fabrication technology requires secondary motion control, which limits its application scenarios. In this work, we propose a flag-type TENG prepared using in situ electrospinning technology, in which the connecting region is obtained by electrospinning deposition of PVDF on nylon as the receiving electrode. The active area is isolated with silicone oil paper. After electrospinning, the silicone oil paper was removed, and the distance between the nylon and PVDF is far beyond the van der Waals range. Thus, contact separation can be effectively carried out under the action of wind. The device has been proven to be able to be used for monitoring wind conditions at high-speed rail stations and enables completely self-powered monitoring of the wind level using self-powered LED coding. The device no longer relies on additional batteries or wires to work, providing additional ideas for future self-powered system design. Full article

This study proposes a novel capacitor-based energy representation model for triboelectric nanogenerators (TENGs). Using this model, the energy conversion behavior of contact–separation-mode TENGs (CS-TENGs) is analyzed with particular attention to their inherent dual-capacitor structure. According to the relationship of high-voltage and high-energy output characteristics of CS-TENGs, a specialized energy harvesting circuit is designed, featuring a dual high-voltage switch that enables bidirectional charge transfer and efficient electromagnetic energy conversion. This switch forms the core of a new rectifier bridge and energy storage topology optimized for intermittent mechanical inputs. Experimental results confirm the validity of the proposed energy model and demonstrate that the developed topology significantly enhances energy harvesting and storage efficiency. The integration of theoretical modeling with circuit innovation offers a comprehensive and effective strategy for improving the electrical performance of CS-TENG systems. This work bridges the theoretical gap in dual-capacitor modeling with a practical rectifier design, offering an integrated solution for real-world TENG energy harvesting challenges. Full article

In this study, a contact–separation triboelectric catalytic device was designed and constructed to systematically investigate the underlying degradation mechanism. The device enabled precise control of the contact–separation process between frictional surfaces. Polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) films were selected as the triboelectric pair, and methylene blue (MB) was used as the model organic pollutant. Experimental results demonstrated that the contact–separation process in an aqueous environment effectively promotes the degradation of organic dyes. For an MB solution with an initial concentration of 5 mg/L, a degradation efficiency of 40.34% was achieved within 3 h. Moreover, the device exhibited excellent repeatability and stability, with no significant decline in performance after 15 h of continuous operation. Control experiments confirmed that the degradation originates specifically from the contact–separation interaction between the PTFE and PET surfaces. Free radical quenching experiments identified superoxide radicals (·O₂⁻) and hydroxyl radicals (·OH) as the primary reactive species responsible for degradation. Based on these findings, a microscopic mechanism is proposed: during contact, triboelectric charging generates electrons (e⁻) and holes (h⁺) on the surfaces; upon separation, these charges interact with the solution—e⁻ reduce dissolved oxygen to form ·O₂⁻, while h⁺ oxidize hydroxide ions (OH⁻) to produce ·OH. The combined action of ·O₂⁻ and ·OH ultimately results in the efficient degradation of MB. Full article

When testing the output of piezoelectric devices under different pressures, the friction between the pressure platform and the device causes a large amount of frictional electrical signals to be mixed in the output piezoelectric signal, seriously affecting the measurement accuracy of the piezoelectric signal. The current solution is to encapsulate the contact interface with identical materials to suppress triboelectric interference. However, this work has shown that even when contact separation is implemented at the interface of same media, triboelectric signals can still be generated. The heterogeneous potential distribution of the same material in contact separation has been discovered for the first time through the contact interface potential distribution, proving that charge transfer still exists between the same materials. Atomic force microscopy (AFM) was used to analyze the microstructure of the interface, and it was found that the existence of the surface tip structure would enhance the electron loss. Based on this, a new electron transfer model for surface–tip electron cloud interaction is proposed in this work. In addition, by comparing the output voltage characteristics of the triboelectric nanogenerators (TENGs) of seven polymer materials (e.g., polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyimide (PI), and polyethylene terephthalate (PET)), it was found that the open circuit voltage of PP material was only 0.06 V when they friction with each other, which is 2–3 orders of magnitude lower than other materials. When PP materials are applied to the package of piezoelectric devices, the precision of piezoelectric output characterization can be improved significantly, and a new experimental basis for a triboelectric theory system can be provided. Full article

The pursuit of eco-friendly and renewable power generation has driven technological breakthroughs in nanoscale engineering, particularly regarding triboelectric nanogenerators (TENGs). These devices have become a focus of interest due to their capacity to effectively transform kinetic energy into electrical power via combined triboelectrification and electrostatic charge separation mechanisms. TENGs now find expanding implementations across multiple fields including in flexible electronics, autonomous sensing systems, and ambient energy conversion technologies. Enhancing TENG performance critically depends on the strategic design and application of nanostructures and nanomaterials. Nonetheless, challenges such as material selection, compatibility, homogeneous dispersion, interfacial stability, and production scalability must be overcome to advance TENG technology. Moreover, the mechanisms by which nanomaterials contribute to the triboelectric effect remain insufficiently understood, underscoring the necessity for systematic theoretical models. This review provides a comprehensive overview of recent advancements in integrating nanostructures and nanomaterials into TENGs, elucidating their roles, advantages, and underlying mechanisms in enhancing energy conversion efficiency, while identifying key challenges and proposing future research directions. Full article

In this study, to enhance the output performance of a contact-separation mode triboelectric nanogenerator (TENG), a zinc oxide nanorod (ZnO NR) film with piezoelectric properties was integrated into a Polydimethylsiloxane (PDMS) film as the dielectric layer. The working mechanism of the PDMS-ZnO NR-based TENG was theoretically analyzed in two stages: charge transfer during contact electrification on the material surface and charge movement in the electrostatic induction process. The output characteristics of the PDMS-ZnO NR-based TENG were investigated and compared with those of a PDMS-based TENG. The experimental results demonstrate that the PDMS-ZnO NR-based TENG reached an open-circuit voltage of 39.34 V, representing an increase of 64.5% compared to the PDMS-based TENG. The maximum output power of a 4 cm × 4 cm PDMS-ZnO NR-based TENG reached 82.2 μW. Using a specially designed energy-harvesting circuit, the generated electrical energy was stored in a capacitor, which was charged to 1.47 V within 1 min and reached 3 V in just 2.78 min. This voltage was sufficient to power over 20 LEDs and small sensors. Additionally, the TENG was integrated into the sole of footwear, where the electrical signals generated by compression could be utilized for step counting and gait analysis. Full article

Powering wearable and portable devices, triboelectric nanogenerators (TENGs) are a considerably promising technology. Low-cost production, ease of fabrication, optimal efficiency, and high output performance are always key concerns in developing energy harvesting technologies. Optimum efficiency and high output are always key concerns. This research addresses the ongoing challenge of raising efficient, flexible, and lightweight energy harvesting systems for recent wearable technologies. In this research, a triboelectric nanogenerator is proposed for harvesting the triboelectric effect. Using polyurethane (PU), a bendable TENG that is in the vertical contact separation mode was developed. UV-curable PU forms the basis of TENGs. A sponge, repurposed from landfill waste, acts by means of a spacer to maintain a consistent air gap between the tribo-layers for enhanced triboelectrification. The triboelectric nanogenerators formed a V_oc approaching 500 V and a current of ~2 µA and also showed high performance with a power density of 8.53 W/m². In addition, the triboelectric nanogenerator can light LEDs and charge capacitors, making it a self-powered energy source for portable devices, Wi-Fi, and monitoring systems. The proposed TENG provides a capable solution for sustainable, self-powered wearable electronics and has the potential for further development in energy-efficient and eco-friendly applications. Full article

This paper aims to fabricate a hybrid piezoelectric/triboelectric nanogenerator via fusion deposition modeling as a proof of concept in the wearable device industry. The nanogenerator structure consists of a TPU/ZnO nanocomposite and an Ecoflex layer. The nanocomposite layer is fabricated using two different weight percentages (15 wt% and 20 wt%) and poled piezoelectric sheets, generating 2.63 V to 3.46 V. Variations regarding the nanogenerator’s physical parameters were implemented to examine the effect on nanogenerator performance under different frequencies. The hybrid nanogenerator enabled energy harvesting for wearable devices. It was strapped on the side of the wrist to generate a potential difference with the motion of the wrist, creating a contact separation piezoelectric/triboelectric nanogenerator. Furthermore, a piezoelectric sheet was placed at the bottom of the wrist to harvest energy. The hybrid nanogenerator provided a maximum triboelectric response of 5.75 V and a maximum piezoelectric response of 2.85 V during wrist motion. The piezoelectric nanogenerator placed at the bottom of the wrist generated up to 4.78 V per wrist motion. Full article

Smart textiles provide a significant technological advancement, but their development must balance traditional textile properties with electronic features. To address this challenge, this study introduces a flexible, electrically conductive composite material that can be fabricated using a continuous bi-component extrusion process, making it ideal for sensor electrodes. The primary aim was to create a composite for the filament’s core, combining multi-walled carbon nanotubes (MWCNTs), polypropylene (PP), and thermoplastic elastomer (TPE), optimised for conductivity and flexibility. This blend, suitable for bi-component extrusion processes, exemplifies the role of advanced materials in combining electrical conductivity, mechanical flexibility, and processability, which are essential for wearable technology. The composite optimisation balanced MWCNT (2.5, 5, 7.5, and 10 wt.%) and TPE (0, 25, and 50 wt.%) in a PP matrix. There was a significant decrease in electrical resistivity between 2.5 and 5 wt.% MWCNT, with electrical resistivity ranging from (7.64 ± 4.03)10⁴ to (1.15 ± 0.10)10⁻¹ Ω·m. Combining the composite with 25 wt.% TPE improved the flexibility, while with 50 wt.% TPE decreased tensile strength and hindered the masterbatch pelletising process. The final stage involved laminating the composite filament electrodes, with a 5 wt.% MWCNT/PP/(25 wt.% TPE) core and a TPE sheath, into a textile triboelectric impact detection sensor. This sensor, responding to contact and separation, produced an output voltage of approximately 5 V peak-to-peak per filament and 15 V peak-to-peak with five filaments under a 100 N force over 78.54 cm². This preliminary study demonstrates an innovative approach to enhance the flexibility of conductive materials for smart textile applications, enabling the development of triboelectric sensor electrodes with potential applications in impact detection, fall monitoring, and motion tracking. Full article

Waste minimization is a major way to achieve sustainable development. Electrostatic separation is already used in the recycling industry for processing certain mixtures of shredded plastics originating from waste electric and electronic equipment. Standard tribo-electrostatic separators use electric forces to deflect the trajectories of triboelectrically charged particles in the electric field generated between two vertical plate electrodes connected to high voltage supplies of opposite polarities. However, the efficiency of this device is often limited by the impacts between the particles and the electrodes, which diminish the recovery and the purity of the end product. An innovative electrostatic separator was specifically designed to mitigate this risk. The innovation lies in using two rotating co-axial vertical cylindrical electrodes and assisting the movement of the particles with downward-oriented air flow to reduce their impact on the electrodes and improve the quality of the recovered products. The aim of this study was to optimize the operation of the patented electrostatic separator by using experimental design methodology to obtain quadratic polynomial models of the recovery and the purity of the products as functions of the high voltage applied to the electrode system and of the air flow through the device. The experiments were conducted with a granular mixture composed of 88% polypropylene (PP) and 12% high-impact polystyrene (HIPS) particles, extracted from the recycling process of waste electrical and electronic equipment, and triboelectrically charged in a fluidized bed device. A voltage of 50 kV combined with an air flow rate of 1700 m³/min maximized the recovery and the purity of PP and HIPS products collected at the outlet of the separator. These results open promising prospects for expanding the use of tribo-electrostatic separation for efficient recycling of granular waste plastics. Full article

Triboelectric separation, a solvent-free method, was investigated as a tool for protein enrichment in wheat flour. Gluten–starch model mixtures, flour, and reground flour fractions were evaluated for their separation characteristics (selectivity and efficiency). Mass yield, protein content, particle size distribution, and SEM analysis were used to assess performance. Selectivity and efficiency increased with gluten concentration, peaking at 63% for the 50% gluten mixture, but declined at higher concentrations. The 15% gluten benchmark demonstrated effective protein separation, with protein enrichment occurring in the ground electrode fraction and a corresponding depletion in the positive electrode fraction. In contrast, flour and reground flour fractions exhibited reduced separation efficiency, showing protein depletion in both electrode fractions due to agglomeration. The benchmark achieved the highest separation efficiency (47%), followed by reground flour (41%) and flour (7%). Finer particles in reground flour enhanced chargeability and GE deposition, while larger agglomerates in flour reduced efficiency, leading to material accumulation in the cups. Pre-milling helped detach protein and starch to some extent but also triggered re-agglomeration. Larger particles were influenced more by gravitational forces. These findings highlight the complexity of wheat flour fractionation and the need to optimize particle size and charge distribution to improve protein enrichment through triboelectric separation. Full article

The increasing use of lithium-containing materials highlights the urgent need for their recycling to preserve resources and protect the environment. Lithium-containing slags, produced during the pyrometallurgical process in lithium-ion battery recycling, represent an essential resource for lithium recovery efforts. While multiple methods for lithium recycling exist, it is crucial to emphasize environmentally sustainable approaches. This study employs dry forced triboelectrification (FTC) to recover valuable components from slag powder, commonly known as engineered artificial minerals (EnAMs). The FTC method is used to change the charge of the target material and achieve a neutral state while other materials remain charged. The downstream electrostatic separator enables the charged particles to be separated from the target material, which in this study is lithium aluminate. The results show that the method is effective, and lithium aluminate can be successfully enriched. Full article

Triboelectric separation has recently been investigated as a novel process for dry enrichment and separation of protein of various crops like wheat flour. The triboelectric effect allows for the separation of starch and protein particles in an electric field based on their different charging behavior despite having a similar density and size distribution. Particles are triboelectrically charged in a charging section before being separated in an electric field based on their polarity. While the charging section is crucial, the influence of process parameters remains largely unexplored. Thus, the influence of the charging sections’ dimensions and the particle concentration as process key parameters was investigated experimentally. Varying the length (0, 105, and 210 mm) showed that the protein shift increases with the length (max. 0.53%) during separation. Varying the diameter (6, 8, and 10 mm) influenced the charging behavior, resulting in an increase in protein accumulation on the negative electrode as the diameter decreased. Varying the mass flow of flour (40, 80, 160, and 320 g·h⁻¹) also affected the separability, leading to a maximum protein shift of 0.61%. Based on the observed results, it is hypothesized that the electrostatic agglomeration behavior of oppositely charged particles is directly affected by alterations in machine parameters. These agglomerates have a charge-to-mass ratio that is too low for separation in the electric field. Full article

Triboelectric nanogenerators (TENGs) are a promising technique for harvesting environmental energy that is based on electrostatic induction and contact electrification. This is a method that uses every relative motion between two electrodes to convert mechanical energy into electrical energy. Several modes of TENGs are designed based on various relative motions between electrode pairs. As TENGs are a surface phenomenon, properties such as the structure of the electrodes are key parameters that affect their performance. In this paper, in order to identify the best pattern designed adapted to the TENG mode, the effect of surface structures in each mode is investigated numerically. To achieve the best performance of the micro-patterned electrode, a comparative study has been conducted on the four TENG modes under the same conditions. To reach this goal, micro-patterned shapes such as pyramid, spherical, and cube structures are designed, and the open circuit voltage is calculated and compared to a flat surface. The results show that surface modification has a significant role in TENG’s performance. Based on this study, by using a cube-patterned electrode instead of a flat electrode, the output voltage increases from 233 V to 384 V in sliding mode. Also, by applying the spherical pattern, the output voltage is 1.7 times higher than a flat electrode in contact-separation mode. In the case of investigating TENG pattern structure, the results show that the electrical outputs of the patterned layer depend on the mode. The spherical pattern has a higher impact in contact-separation mode compared to the cube pattern. Meanwhile, in sliding mode, the cube pattern has a greater effect. This work provides a hint for designing an effective pattern on electrodes for a particular mode to enhance TENG performance. Full article

In this study, a two-dimensional separation of microparticles based on their settling velocity and triboelectric charge ability is achieved using an air classifier for size fractionation and simultaneous charging, followed by an electrostatic separator. In the first part, considerations for enhancing particle classification with high sharpness and low-pressure drops are discussed through improvements in blade design investigated with CFD simulations and validated experimentally. Blades with extended lengths towards the center of the classifier prevent the formation of high-velocity vortices, thereby minimizing the back-mixing of particles and enhancing separation sharpness. This approach also reduces pressure drops associated with these flow vortices. In the second part of the study, the modified blades within the classifier are utilized for two-dimensional separation. Powders from two different materials are fed into the classification system, where particles become triboelectrically charged, mainly through collisions with the walls of the classification system components. Coarse particles are rejected at the wheel and exit the classifier, while differently charged fine particles of the two materials are directed into an electrostatic separator for material sorting. An enrichment of approximately 25–35% for both materials has been achieved on the electrodes of the separator. Full article