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The term fatty keratopathy is used to describe the phenomenon of fat deposition caused by corneal neovascularization, which will severely affect the eye’s beauty and vision. The purpose of this study was to establish a New Zealand white rabbit animal model of fatty keratopathy, that is, the establishment of an animal model of fatty keratopathy. The goal was achieved by the combination of a corneal neovascularization animal model and a hyperlipidemia animal model. Two groups were created according to the experimental sequence. The first group initially induced a corneal neovascularization pattern and later induced a hyperlipidemia pattern, and the second group followed the opposite sequence. The results of the two groups showed that all the significant crystalline deposits of the cornea were visible. So the animal models of fatty keratopathy were successfully established in both groups.

The triboelectric nanogenerator (TENG) holds significant potential for applications in energy harvesting and environment monitoring. However, a notable challenge lies in developing a combined system capable of efficiently harvesting energy and providing real‐time self‐powered sensing. Here, a combined wind energy harvesting and speed sensing (EHSS) system is constructed based on a noncontact electricity‐induced constant‐voltage TENG (EICV‐TENG) that achieves constant output by coupling two different phases and incorporates a parasitic sensing module in a single phase. Through the optimization of system integration, the EICV‐TENG achieves a current density of 28.7 mA m−2 and an average power density of 0.26 W m−2 Hz−1. With an optimal power management, the energy output efficiency of the EICV‐TENG reaches up to 96%. And EICV‐TENG can stably power 32 commercial hygrothermographs connected in parallel with the PMC at a wind speed of 7 m s−1. In addition, the EHSS system demonstrates excellent real‐time sensing performance based on the correlation between the peak number of pulse output in a single phase and wind speeds. This work contributes to the advancement of TENG technology for a combined energy harvesting and self‐powered sensing system in the context of the Internet of Things (IoTs). [ABSTRACT FROM AUTHOR]

The emerging tribovoltaic nanogenerators (TVNGs) has garnered considerable attention in recent years owing to its higher power density, but it is still limited by unstable output, mismatched impedance, and lower charging speed. Herein, a power‐managed GaN‐based TVNG is first proposed and a self‐powered wireless temperature monitoring system (SWTMS) is developed. The energy backflow from transition capacitor to TVNG is effectively suppressed by applying a high‐voltage‐resistant diode. Benefiting from the combination of the maximum power point tracking (MPPT and the buck converter, an autonomous power management unit (PMU) is designed. The internal impedance of TVNG with PMU decreases by ten times and the charging speed of capacitor increases by 7.18 times compared to those without PMU. Moreover, 100 LEDs and six parallel thermohygrometers can be constantly powered. The wireless temperature monitoring in industrial environments without external power supply is demonstrated through the developed SWTMS. This work proposes an effective power management strategy for TVNG with high output voltage, which exhibits great potential to promote the development of self‐powered sensors and Industrial Internet of Things (IIoT). [ABSTRACT FROM AUTHOR]

Accurate measurement of complicated multiphase flow is crucial to the safety and efficiency of petroleum and chemical industrial facilities. However, the existing multiphase flow detection techniques are not applicable to pipelines in remote regions including deserts or deep seas, due to the high cost of providing a stable power supply. Herein, a self‐powered multiphase flow sensor, composed of a liquid‐driven triboelectric nanogenerator (TENG) ‐based signal generator, a ring‐type transmitter, and a string‐type receiver, is proposed. Theoretical modeling of displacement current between transmitter and receiver implies that the received current signal can accurately reflect the wetting state of the receiver, validated by a combined experimental (accuracy above 97%) and simulation study. Coupling with a quantitative analysis algorithm, a multiphase flow detection system with numerous receiver measurement points is developed to precisely monitor various flow parameters, including slug frequency (one point), slug length (two points), and flow pattern (four points), which is verified by spontaneous high‐speed camera recordings of water–air flow. The present work provides a paradigm‐shift way to develop a self‐powered, inexpensive, and accurate technique to detect multiphase flow at remote industrial facilities. [ABSTRACT FROM AUTHOR]

Charge generation and charge decay are two essential factors that determine the surface charge density of a triboelectric nanogenerator (TENG). However, research mainly focuses on boosting charge generation, and little attention is paid to suppressing charge decay. Here, a strategy of suppressing charge decay, including the air breakdown and dielectric charge leakage, of TENG with high surface charge density (HCD‐TENG) is proposed by utilizing a dual dielectric layer. A series of parameters of different dielectric materials are tested with the assistance of a charge excitation TENG (CE‐TENG) to reveal the relationships between charge generation, air breakdown, and dielectric charge leakage in the atmospheric environment. Further, the phenomenon of dielectric charge leakage limiting the maximum output of TENG prior to air breakdown is observed for the first time. With the simultaneous suppression of the air breakdown and dielectric charge leakage, the output of TENG is enhanced to 2.2 mC m−2. This work not only provides new insight into the performance optimization and material selection of TENG, but also provides significant guidance for obtaining high‐output TENG in the future. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have received intense attention due to their broad application prospects in the new era of internet of things (IoTs) as distributed power sources and self‐powered sensors. Advanced materials are vital components for TENGs, which decide their comprehensive performance and application scenarios, opening up the opportunity to develop efficient TENGs and expand their potential applications. In this review, a systematic and comprehensive overview of the advanced materials for TENGs is presented, including materials classifications, fabrication methods, and the properties required for applications. In particular, the triboelectric, friction, and dielectric performance of advanced materials is focused upon and their roles in designing the TENGs are analyzed. The recent progress of advanced materials used in TENGs for mechanical energy harvesting and self‐powered sensors is also summarized. Finally, an overview of the emerging challenges, strategies, and opportunities for research and development of advanced materials for TENGs is provided. [ABSTRACT FROM AUTHOR]

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. Arising from contact electrification and electrostatic breakdown, DC triboelectric nanogenerators are a promising solution to the air breakdown bottleneck in conventional TENGs. Here, authors reveal and regulate three discharge domains enhancing the device output power by an order of magnitude. [ABSTRACT FROM AUTHOR]

With the intrinsic characters of high voltage and low current, triboelectric nanogenerators (TENGs) serving as green high voltage (HV) power source exhibit excellent practicability and safety compared to traditional HV power sources. To further simplify the TENG‐based HV power source system, a single electrode mode TENG (SE‐TENG) with simple wiring is first employed to generate ultra‐high voltage power in this work. By optimizing surface charge density and the thickness of packing layer between the primary electrode and reference electrode, a record value of 12.7 kV is achieved for SE‐TENGs. Furthermore, a calculation method based on a capacitance model is proposed to accurately measure the open voltage of TENG with a wide range (over 10 kV). The SE‐TENG‐based HV power source is successfully applied to power electronics and generates negative air ions for air cleaning. This work significantly simplifies TENG‐based HV power sources, and is expected to enrich the diversity of high‐voltage applications based on the reach of existing technologies. [ABSTRACT FROM AUTHOR]

Triboelectric 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. [ABSTRACT FROM AUTHOR]

As a new technology for high‐entropy energy harvesting, a triboelectric nanogenerator (TENG) has broad applications in sensor networks and internet of things as a power source, but its average power density is limited by the fixed low‐frequency output. Here, a frequency‐multiplication TENG based on intrinsic high frequency of tuning fork is proposed which enables converting low‐frequency mechanical energy into high‐frequency electric energy. A tuning‐fork TENG is used to systematically study the effects of intrinsic frequency, dielectric's thickness, and gap distance on its electric performance, and a total transferred charges of 4.3 µC and an average power density of 9.42 mW m–2 are realized at the triggering frequency of 0.2 Hz, which are 71 times and 5.7 times than that of the single‐cycle output of conventional contact‐separation TENG, respectively. Moreover, the crest factor also decreases from 3.5 to around 1.5. Then, a homemade tuning fork‐like TENG is reasonably designed for harvesting ambient wind energy, achieving an average power density of 20.02 mW m–2 at a wind speed of 7 m s–1. Specially, its impedance resistance is independent of the mechanical triggering frequency, simplifying the back‐end power management circuit design. Therefore, the frequency‐multiplication TENG shows a great potential for efficient distributed energy harvesting. [ABSTRACT FROM AUTHOR]

The emerging direct‐current triboelectric nanogenerator (DC‐TENG) does not need to be rectified and is not restricted by a dielectric breakdown compared with an alternating current TENG (AC‐TENG). Furthermore, the charge density of the DC‐TENG reaches an ultrahigh level far beyond that of the AC‐TENG based on a rational design. However, there are always some electrons remaining on the surface of the dielectric after the breakdown process in the DC‐TENG, and therefore a low charge utilization is obtained. Herein, a simple and universal method is proposed through a double‐layer structure design, that is, a triboelectric layer as the friction layer and an electret layer charged through a surface treatment as the field‐enhancing layer to further improve the output performance of the DC‐TENG, which is inspired by the fable "The Crow and the Pitcher." Owing to the external field‐enhancing breakdown effect, a double improvement in the breakdown efficiency and output charge density is obtained compared with a conventional DC‐TENG. Moreover, a nearly constant output current has been demonstrated for directly powering electronics without a rectifier. This study provides a universal method for optimizing the output performance of a DC‐TENG. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) that can efficiently harvest ubiquitous mechanical energy provide a promising technology for the energy supply of intelligent electronic devices. However, the issues of low durability induced by wear and moisture sensibility of TENGs greatly limit their practical applications. Here, a no‐wear dual‐capacitor enhancement system (DCES) to simultaneously improve the service lifetime and electric performance of TENGs in a high humidity environment is proposed. The combination of low charge injection from lightly touched TENG and charge transfer in no‐wear DCES can synchronously realize ultralow material wear and charge pumping up. Therefore, the dual‐capacitor‐enhanced TENG (DCE‐TENG) achieves a long service life of at least 1 000 000 cycles with 15‐fold enhancement of matched average power. Furthermore, owing to the humidity resistance of DCES, the output performance of DCE‐TENG remains 95% of the initial value in 90% humidity. This work is expected to promote the commercial applications of TENGs. [ABSTRACT FROM AUTHOR]

The sliding‐mode triboelectric nanogenerator (TENG) exhibits higher charge transfer efficiency for extracting mechanical energy than the contact–separation mode TENG, but the energy loss induced by air breakdown as well as the inferior durability seriously limits its practical applications. Here, an effective strategy via interface liquid lubrication is proposed for enhancing output performance of both sliding‐mode alternative current TENG (AC‐TENG) and direct current TENG (DC‐TENG). Due to the improved breakdown field strength requirement and reduced electrostatic field strength in the microgap between the triboelectric layer and electrode, interface liquid lubrication suppresses the interfacial electrostatic breakdown and reduces charge loss after the triboelectrification process, and thus more electrostatic charges are harvested by the AC‐TENG via electrostatic induction and the DC‐TENG via electrostatic breakdown. The maximum output power density of the lubricated sliding‐mode TENG is enhanced by more than 50% (3.45 W m−2 Hz−1) compared to the device without lubrication, and shows excellent durability over more than 500 000 operation cycles. This work provides an effective approach to improve the electric performance and durability of sliding‐mode AC‐TENG and DC‐TENG, which further promotes the practical applications of TENGs. [ABSTRACT FROM AUTHOR]

Harvesting mechanical energy through triboelectric nanogenerators (TENGs) for effectively purifying water, self‐powered wastewater treatment system presents a promising solution to address both energy and environmental crises. However, issues such as side‐discharge and wear, resulting from interfacial charge transfer, seriously hinder the output and durability of TENGs, and then reduce the efficiency of self‐powered wastewater treatment. Here, an interface charge regulation technique is introduced that simultaneously boosts both output performance and durability of TENG, enabling a greater efficiency in self‐powered wastewater treatment. The interface charge regulation method, suppressing side‐discharge around electrodes with an innovative insulator design as well as boosting charge density through secondary collection, fully utilizes surface charges for power output and results in minimum wear by reducing the interface electrostatic force. Surface charge density of 0.8 mC m−2 between the Ethyl tetrafluoro ethylene and copper (µ = 0.35), with a threefold enhancement under ambient conditions, and durability of 500 000 cycles (a 12.5‐fold enhancement) are achieved. Furthermore, the removal efficiency for proposed self‐powered sewage filter system is improved onefold, indicating the potential for sustainable and practical applications. [ABSTRACT FROM AUTHOR]

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.

Although electrocoagulation technology has been widely researched in wastewater treatment, high energy consumption and electrode passivation are still the main challenges for its widespread applications. Here, we propose a self-powered electrocoagulation system based on a triboelectric nanogenerator (TENG) with alternating current (AC) outputs to solve these two issues, and thus enhance the removal efficiency of organic pollutants. Compared with the direct current source, the AC power source can reduce the electrode passivation, produce more aluminum hydroxide compounds after consuming an equal amount of charges, and thus improve the degradation efficiency. Moreover, the removal efficiency can be further enhanced by decreasing the frequency AC, in which a 5.7-fold improvement was achieved at 0.2 Hz compared to DC at 1.8 Hz. Inspired by the low frequency of ocean wave water, we developed a self-powered AC-electrocoagulation system to directly drive the electrocoagulation reaction by harvesting water wave energy, which can effectively remove 94.8% of xylenol orange and 98.8% of water-oil emulsion, and thus completely address the problem of energy consumption. This study further promotes the application of self-powered electrochemical systems in treating environmental pollution.

Vibration sensor is very necessary for monitoring the structural health of constructions. However, it is still a major challenge to meet simultaneously real-time monitoring, continuous assessment, and early incident warning in a simple device without a complicated power and analysis system. Here, we report a self-powered vibration sensor system to achieve real-time and continuous detection of the vibration characteristics from a dual-mode triboelectric nanogenerator (AC/DC-TENG), which can produce either alternating current (AC) or direct current (DC) within different operation zones. Within the vibration-safe region, the AC/DC-TENG with AC output not only can continuously assess the vibration characteristics but also can power the signal transmission. More importantly, once the vibration amplitude crosses the danger threshold, the AC converts immediately to DC, meanwhile triggering the alarm system directly to accurately predict the danger of construction. Our self-powered vibration sensor system can serve as a facile tool for accurately monitoring the structural health of constructions.