Electrostatic Breakdown Research Articles

Enhancing CAR-T cell therapy against solid tumor by drug-free triboelectric immunotherapy

Chimeric antigen receptor (CAR) T cell therapy is a highly effective immunotherapy for hematological tumors, but its efficacy against most solid tumors remains challenging. Herein, a novel synergistic combination therapy of drug-free triboelectric immunotherapy and CAR-T cell therapy against solid tumor was proposed. A triboelectric nanogenerator (TENG) that can generate pulsed direct-current by coupling triboelectrification effect and electrostatic breakdown effect was fabricated. The TENG can generate up to 30 pulse direct-current peaks with peak current output ≈35 μA in a single sliding to power the triboelectric immunotherapy. The pulsed direct-current stimulation induced immunogenic cell death of tumor cells (survival rate of 35.9 %), which promoted dendritic cells maturation, accelerated the process of antigen presentation to CAR-T cells and enhanced the systemic adaptive immune response. Furthermore, triboelectric immunotherapy promoted M1-like macrophage polarization, reduced regulatory T cells differentiation and reprogrammed the tumor immunosuppressive microenvironment, which ultimately enhanced the efficacy of CAR-T cells to eradicate nearly 60 % of NALM6 solid tumor mass. Notably, considering that triboelectric immunotherapy is a safe and effective drug-free antitumor strategy, the combined therapy did not increase the burden of double-medication on patients.

Fully Integrated Direct Current Triboelectric Nanogenerators Coupled with Charge Pump and Electric Field Enhancing Effect Enabling Improved Output Performance

AbstractDirect‐current triboelectric nanogenerators (DC‐TENGs) arising from electrostatic breakdown have garnered significant attention due to their advantages of rectification‐free operation, constant current output, and high output power density. Previous studies have primarily concentrated on improving its performance through structural design and parameter optimization, neglecting the potential benefits of external charge excitation. Here, a facile and universal strategy coupling charge pump and electric field enhancing effect with DC‐TENG (CE‐DC‐TENG) is proposed to improve the output performance of DC‐TENG. An alternating current TENG is used as the charge pump. A field‐enhancing conductive layer, which is introduced under the main DC‐TENG, is connected with the pump TENG to accumulate the charge and enhance the electric field for electrostatic breakdown. The effectiveness of this method is demonstrated by linear and rotary sliding mode TENGs. Furthermore, a fully integrated rotary sliding mode CE‐DC‐TENG is designed and fabricated, and it exhibits impressive performance with a 13‐fold higher power density of 1.56 W m−2 compared to conventional DC‐TENG. Moreover, it can directly power small electronics or be combined with a designed power management circuit for more efficient energy conversion. This work presents a new design strategy for improving the performance of DC‐TENG and facilitating its practical applications.

Dynamic interfacial electrostatic energy harvesting via a single wire.

Spontaneously occurred electrostatic breakdown releases enormous energy, but harnessing the energy remains a notable challenge due to its irregularity and instantaneity. Here, we propose a revolutionary method that effectively harvests the energy of dynamic interfacial electrostatic breakdown by simply imbedding a conductive wire (diameter, 25 micrometers) beneath dielectric materials to regulate the originally chaotic and distributed electrostatic energy resulted from contact electrification into aggregation, effectively transforming mechanical energy into electricity. A point-charge physical model is proposed to explain the power generation process and output characteristics, guide structural design, and enhance output performance. Furthermore, a quantified triboelectric series including 72 dielectric material pairs is established for materials choice and optimization. In addition, a high voltage of over 10 kilovolts is achieved using polytetrafluoroethylene and polyethylene terephthalate. This work opens a door for effectively using electrostatic energy, offering promising applications ranging from novel high-voltage power sources, smart clothing, and internet of things.

Spontaneously established reverse electric field to enhance the performance of triboelectric nanogenerators via improving Coulombic efficiency

Mechanical energy harvesting using triboelectric nanogenerators is a highly desirable and sustainable method for the reliable power supply of widely distributed electronics in the new era; however, its practical viability is seriously challenged by the limited performance because of the inevitable side-discharge and low Coulombic-efficiency issues arising from electrostatic breakdown. Here, we report an important progress on these fundamental problems that the spontaneously established reverse electric field between the electrode and triboelectric layer can restrict the side-discharge problem in triboelectric nanogenerators. The demonstration employed by direct-current triboelectric nanogenerators leads to a high Coulombic efficiency (increased from 28.2% to 94.8%) and substantial enhancement of output power. More importantly, we demonstrate this strategy is universal for other mode triboelectric nanogenerators, and a record-high average power density of 6.15 W m−2 Hz−1 is realized. Furthermore, Coulombic efficiency is verified as a new figure-of-merit to quantitatively evaluate the practical performance of triboelectric nanogenerators.

Controlling the residual charge to alleviate the frequency dependence of ternary direct current triboelectric nanogenerators

Recently, the ternary direct current triboelectric nanogenerators (T-DC-TENGs), especially those working in rotation mode, have received much attentions due to their high DC output and superior durability. However, the frequency dependence of T-DC-TENG was largely ignored, which greatly hinders the miniaturization of the device. Because the electron-donating capacity of positive tribo-layer is unequal to the electron-gaining capacity of negative tribo-layer, the number of residual charges on the intermediate triboelectric layer due to not instant dissipation depends on the rotation frequency of T-DC-TENGs. At higher frequency, the more undissipated residual charges will exemplify their effect on the triboelectrification process and limit the output of T-DC-TENGs. Herein, we disclose these residual charges first and then their frequency dependent effect on triboelectrification in T-DC-TENGs. In this study, a charge collecting electrode (CCE) is introduced to construct an electrostatic breakdown T-DC-TENG (EBT-DC-TENG) with greatly reduced frequency dependence. By efficiently reducing the residual charges, the charge density output of EBT-DC-TENG is increased by 51.75% at 90 rpm (from 145.7 to 221.1 μC m−2 r−1) compared with T-DC-TENG without CCE. Furthermore, with the help of its soft property, the less residual charges accumulated polyester fur enables EBT-DC-TENG to maintain 100% output without wear after 10,000 cycles. This EBT-DC-TENG with a better crest factor of 1.028 can continuously power 1200 LEDs in series connection, showing unique advantages in harvesting environmental energy steadily and efficiently. This work also provides a theoretical and practical path for the miniaturization of the rotating mode T-DC-TENG.

An ultra-high voltage (>10 kV) direct-current triboelectric nanogenerator realized by structural and material optimizations

High-voltage power supplies are pivotal in sectors such as agriculture, medicine, and environmental protection. However, conventional high-voltage sources are associated with environmental pollution, cumbersome size, high costs, and significant safety risks due to the accompanying high current. To address these challenges, we propose a high-voltage source that employs a direct-current triboelectric nanogenerator (DC-TENG). Based on contact electrification and electrostatic breakdown effects, the inherent electrostatic charges and minimal fixed capacitance enable the DC-TENG to generate ultra-high voltage with low current effortlessly. To fully harness the potential of this high-voltage technology, a theoretical model encompassing multiple discharge domains is developed and the three main constraints on open-circuit voltage are identified. Guided by the model, the optimized DC-TENG achieves a record output voltage of 10.85 kV through structural and material optimizations, effectively achieving water-oil separation and air purification within 2.5 and 3 minutes, respectively. This research not only fully exploits the high-voltage capabilities of DC-TENG but also offers an eco-friendly, portable, cost-effective, and safe alternative for supplying ultra-high voltage.

A High-Voltage-Specialized Direct-Current Triboelectric Nanogenerator for Air Purification.

Human health and the environment face significant challenges of air pollution, which is predominantly caused by PM2.5 or PM10 particles. Existing control methods often require elevated energy consumption or bulky high-voltage electrical equipment. To overcome these limitations, a self-powered, convenient, and compact direct current high-voltage triboelectric nanogenerator based on triboelectrification and electrostatic breakdown effects is proposed. By optimizing the structure-design of the direct current triboelectric nanogenerator and corresponding output voltage, it can easily achieve an output voltage of over 3kV with a high charge density of 320 µC m-2. A power management circuit is designed to overcome the influence of third domain self-breakdown, optimize 92.5% amplitude of voltage shake, and raise 5% charge utilization ratio. With a device size as tiny as 2.25 cm3, it can continuously drive carbon nanowires to generate negative ions that settle dust within 300 s. This compact, simple, efficient, and safe high-voltage direct current triboelectric nanogenerator represents a promising sustainable solution. It offers efficient dust mitigation, fostering cleaner environments, and enhancing overall health.

High-performance pneumatic solid–liquid triboelectric nanogenerator

In the field of blue energy harvesting, solid-liquid triboelectric nanogenerators (SL-TENG) show significant potential. However, their low output performance in energy applications is limited due to the relatively small contact area and slow separation speed during the friction process. To overcome these limitations, we develop a pneumatic solid-liquid triboelectric nanogenerator (PSL-TENG) with ultrahigh output performance based on pneumatic solid-liquid triboelectrification and electrostatic breakdown. The pneumatic design effectively increases the solid-liquid interface area and the solid-liquid contact and separation rate, which can enhance solid-liquid triboelectrification effect. The synergistic design of the horn and the bent pipe can converge positively charged mist into large droplets, which can enhance electrostatic breakdown effect. This innovative design approach has achieved outstanding output performance, with a peak instantaneous voltage of 6436 V and a peak instantaneous current of 3.05 mA. This exceptional output performance is sufficient to directly power 3000 LED lights or a 55 W commercial lamp. These research achievements provide new insights for SL-TENG in energy harvesting, as significant output can be generated by collecting the inherent charges of liquids themselves.

Design, characterization and installation of the NEXT-100 cathode and electroluminescence regions

NEXT-100 is currently being constructed at the Laboratorio Subterráneo de Canfranc in the Spanish Pyrenees and will search for neutrinoless double beta decay using a high-pressure gaseous time projection chamber (TPC) with 100 kg of xenon. Charge amplification is carried out via electroluminescence (EL) which is the process of accelerating electrons in a high electric field region causing secondary scintillation of the medium proportional to the initial charge. The NEXT-100 EL and cathode regions are made from tensioned hexagonal meshes of 1 m diameter. This paper describes the design, characterization, and installation of these parts for NEXT-100. Simulations of the electric field are performed to model the drift and amplification of ionization electrons produced in the detector under various EL region alignments and rotations. Measurements of the electrostatic breakdown voltage in air characterize performance under high voltage conditions and identify breakdown points. The electrostatic deflection of the mesh is quantified and fit to a first-principles mechanical model. Measurements were performed with both a standalone test EL region and with the NEXT-100 EL region before its installation in the detector. Finally, we describe the parts as installed in NEXT-100, following their deployment in Summer 2023.

Advances of Strategies to Increase the Surface Charge Density of Triboelectric Nanogenerators: A Review.

Triboelectric nanogenerators (TENGs) have manifested a remarkable potential for harvesting environmental energy and have the prospects to be utilized for various uses, for instance, self-powered sensing devices, flexible wearables, and marine corrosion protection. However, the potential for further development of TENGs is restricted on account of their low output power that in turn is determined by their surface charge density. The current review majorly focuses on the selection and optimization of triboelectric materials. Subsequently, various methods capable of enhancing the surface charge density of TENGs, including environmental regulation, charge excitation, charge pumping, electrostatic breakdown, charge trapping, and liquid-solid structure are comprehensively reviewed. Lastly, the review is concluded by highlighting the existing challenges in enhancing the surface charge density of TENGs and exploring potential opportunities for future research endeavors in this area.

Discharge domains regulation and dynamic processes of direct-current triboelectric nanogenerator

Direct-current triboelectric nanogenerators arising from electrostatic breakdown can eliminate the bottleneck problem of air breakdown in conventional triboelectric nanogenerators, offering critical benefits of constant-current output, resistance to electromagnetic interference, and high output power density. Previous understanding is that its output characteristics are described by a capacitor-breakdown model or dictated by one or two discharge domains in direct-current triboelectric nanogenerators. Here, we demonstrate that the former holds only for ideal conditions and the latter cannot fully explain the dynamic process and output performance. We systematically image, define, and regulate three discharge domains in direct-current triboelectric nanogenerators, then a “cask model” is developed to bridge the cascaded-capacitor-breakdown dynamic model in ideal conditions and real outputs. Under its guidance, the output power is increased by an order of magnitude within a wide range of resistive loads. These unexplored discharge domains and optimization methods revolutionize the output performance and potential applications of direct-current triboelectric nanogenerators.

Triboelectric-material-pairs selection for direct-current triboelectric nanogenerators

Direct-current triboelectric nanogenerator (DC-TENG) arising from electrostatic breakdown exhibits unique merits over conventional alternating-current TENGs, such as the constant-current output and high output charge density. The selection of appropriate triboelectric material pair (TMP) is important for improving its performance. Here, we propose a universal strategy for the TMP selection of DC-TENG by simultaneously considering the friction, dielectric and triboelectric performance. Based on assessing five basic parameters in DC-TENG, including the friction coefficient, surface charge density, leakage current, breakdown charge density and breakdown efficiency, it is found that the thermoplastic urethanes (TPU)-ethylene-tetra-fluoro-ethylene (ETFE) pair presents considerable output performance. Finally, a micro-structured DC-TENG with a designed power-management circuit was fabricated to further demonstrate the enhanced performance of DC-TENG with TPU-ETFE as the TMP. This work provides an effective strategy to select appropriate TMPs to optimize the performance of DC-TENG, facilitating its practical applications.

Adjusting Photoresist Curing Temperature to Eliminate Electrostatic Breakdown from Etching Residues

Adjusting Photoresist Curing Temperature to Eliminate Electrostatic Breakdown from Etching Residues

Triboelectric immunotherapy using electrostatic-breakdown induced direct-current

Electrical stimulation is a promising technique for drug-free treatment of complex malignant tumors because it can directly kill tumor cells and induce immunotherapy, avoiding the risk of drug-related side effects, toxicity, adverse reactions, drug dependence, drug resistance, etc. Herein, a drug-free tumor therapy strategy, defined as “Triboelectric Immunotherapy”, is invented to directly damage tumor cells and recruit immune cells by applying pulsed direct-current (DC) generated from a small size fabric DC triboelectric nanogenerator (DC-TENG). The pulsed DC is generated by coupling triboelectrification effect and electrostatic breakdown effect. The electrical stimulation can promote immunogenic cell death (ICD) of 4T1 cells to release damage-associated molecular patterns that attract dendritic cells to aggregate in tumors and present exposed abundant antigens to T cells, activating T cells-mediated adaptive immunity response to further inhibit tumor growth. Importantly, tissue structures such as blood vessels were preserved during electrical stimulation, allowing cytokines to accumulate to the tumor site through blood supply, significantly inhibiting the growth of 4T1 solid tumors and effectively prolonging survival. This work provides a highly efficient, cost-effective and safe solution for miniaturized wearable tumor treatment system.

Enhanced Performance of Series Microexploding Bridge Planar Discharge Switch Integrated With Exploding Foil

To achieve the low energy, miniaturization, and low cost of the exploding bridge foil initiator, single and series microexploding bridge planar discharge switch (MEB-PDS) coplanar and cocathode integrated with exploding bridge foil is fabricated by magnetron sputtering and photolithography forming etching in this work. The maximum electrostatic field strength and breakdown voltage of the MEB-PDS are calculated by multiphysics field theory. The breakdown voltage, conduction performance, MEB electrical explosion performance, and integrated exploding foil initiator (EFI) of the MEB-PDS have been tested. The relationship between breakdown voltages and design parameters, variation law between conduction time and design parameters, operating voltages and trigger voltages, and the matching between operating voltages and trigger voltages of MEB-PDS are analyzed. The results show that the breakdown voltages of single-bridge and three-series MEB-PDS can meet the insulation requirements at the operating voltage. The plasma clouds generated by the three-series MEB-PDS converge and superimpose, which results in its better conduction performance and operating reliability than single MEB-PDS. Based on the optimization of MEB structure parameters, the breakdown voltage of the three-series MEB-PDS is 2.848 kV at a trigger voltage of 0.600 kV. The 50% ignition voltage sensitivity U (50%) of the corresponding integrated exploding foil initiator is 1.191 kV, and the 99.9% ignition voltage sensitivity U (99.9%) is 1.269 kV. Compared with other types of spark gap discharge switches, U (99.9%) is reduced by 11.07%. The trigger voltage of the switch is reduced from ∼1.5 to 0.6 kV.

Spray coagulation as an alternative to argon plasma coagulation for bleeding portal hypertensive gastropathy

Spray coagulation as an alternative to argon plasma coagulation for bleeding portal hypertensive gastropathy

Achieving High‐Performance Triboelectric Nanogenerator by DC Pump Strategy

AbstractTriboelectric nanogenerator (TENG) has been demonstrated as a promising solution for powering widely distributed electronics in the new era of Internet of Things (IoTs), however, high‐performance TENG always relies on tribo‐materials with high triboelectric property. Herein, a simple self‐charge excitation technique that charge injection is directly realized by self‐generated electrostatic breakdown charge instead of voltage‐multiplying circuit is proposed to break through the limitation of triboelectrification. By using the designed electrostatic breakdown charge excitation TENG (EBE‐TENG), the output performance of poor tribo‐material based TENG such as polyethylene (PE) can be enhanced by 5.7 times, which even approximates that of high tribo‐material based TENG such as fluorinated ethylene propylene (FEP). Moreover, electrostatic breakdown charge excitation technique also exhibits a universal applicable ability for other different triboelectric materials. This work not only greatly simplifies the charge excitation system, but also broadens the availability of materials for achieving high‐performance TENG.

A novel hybrid triboelectric nanogenerator based on the mutual boosting effect of electrostatic induction and electrostatic breakdown

A novel hybrid triboelectric nanogenerator integrating AC- and DF-triboelectric nanogenerators is developed, with a switchable dual-output feature, and the mutual boosting effect of electrostatic induction and electrostatic breakdown is identified.

Achieving a highly efficient triboelectric nanogenerator via a charge reversion process

A highly efficient TENG is achieved based on a charge reversion process arising from the electrostatic breakdown effect, which is supported by a modified dielectric capacitance model in theory, to improve the output performance.

Achieving high-efficiency triboelectric nanogenerators by suppressing the electrostatic breakdown effect

Maximizing TENGs’ energy cycle by analyzing the dynamic charge transfer process and suppressing air breakdown.