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Atmospheric moisture accelerates the triboelectric charge transport and dissipation in the triboelectric nanogenerator (TENG). However, the output of polyvinyl alcohol (PVA)‐based humidity‐resistant TENG is still limited under high humidity and suffers from the swelling problem in practical application. In this paper, a swelling‐ and humidity‐resistant high‐performance TENG using a polyacrylonitrile/polyvinyl alcohol‐calcium chloride (PAN/PVA‐CaCl2) composite film (PPCa‐TENG) is designed for seawater desalination. The PAN/PVA‐CaCl2 composite films exhibit superior water uptake speed, swelling resistance, and mechanical and tribological properties compared with other prepared membranes at high relative humidity (RH). The maximum short‐circuit current (Isc) and output voltage (Vo) of the PPCa‐TENG can reach 52.04 µA and 941 V at 75% RH, respectively, with increasing the power of PVA‐based TENG by about 17.39 times. The Kelvin probe force microscopy (KPFM) results suggest that the PAN/PVA‐CaCl2 composite film demonstrates a higher tribopositivity. Furthermore, the PPCa‐TENG is applied as an effective, economical power source for seawater desalination, with an energy consumption of only 0.19 kWh m−3. This number is remarkably lower than that of desalination powered by conventional direct‐current power supplies reported in previous work. This paper provides a feasible, effective method for the design of the TENG with high performance under high‐humidity conditions. [ABSTRACT FROM AUTHOR]

With the increasing popularity of artificial intelligence, wearable and functional fabric triboelectric nanogenerators (F-TENGs) have an increasingly prominent role in human activities. Here, a new self-powered fabric composition detection system with high sensitivity and responsivity has been developed from F-TENGs modified by different functional groups. The power unit and group analysis system were successfully integrated into one device. Groups with different electronegativity were grafted onto the silk surface, and this silk was applied as the friction electrode to assemble TENG devices. The TENG with the original silk electrode exhibits a stable output performance with a short-circuit current of 11.8 μA and an output voltage of 49.8 V, while the corresponding short-circuit current and output voltage would gradually decrease with the increase of electronegativity for the grafted groups. This variation trend has resulted from different contributions of different functional groups to contact electrification of silks. Meanwhile, the group analysis system exhibits good sensitivity and selectivity for common functional groups with different electronegativity. This work provides a novel strategy to fabricate the fabric composition analysis system, which possesses tremendous application potential to collect human motion energy for detecting group types without any additional power supplies. [ABSTRACT FROM AUTHOR]

Wetting is often perceived as an intrinsic surface property of materials, but determining its evolution is complicated by its complex dependence on roughness across the scales. The Wenzel (W) state, where liquids have intimate contact with the rough surfaces, and the Cassie–Baxter (CB) state, where liquids sit onto air pockets formed between asperities, are only two states among the plethora of wetting behaviors. Furthermore, transitions from the CB to the Wenzel state dictate completely different surface performance, such as anti‐contamination, anti‐icing, drag reduction etc.; however, little is known about how transition occurs during time between the several wetting modes. In this paper, wetting dynamics can be accurately quantified and tracked using solid–liquid triboelectrification. Theoretical underpinning reveals how surface micro‐/nano‐geometries regulate stability/infiltration, also demonstrating the generality of the authors' theoretical approach in understanding wetting transitions. It can clarify the functioning behavior of materials in real environment. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) is a new type of device that can convert mechanical energy in the environment into electrical energy. Since its wide range of energy sources, high energy conversion efficiency and wide application range, it has become a hot spot in the energy field. However, the shortcomings of the high internal resistance, the low output current and power density have seriously affected the further applications of TENGs. This review is aimed to introduce the recent advanced methods and applications of controlling the interface contact electrification of TENGs, and identify and discuss the key issues that deserve additional studies. This paper delineates the advanced methods and applications of enhancing the electrical output of TENG and looks forward to the application prospects of TENG in other fields. [ABSTRACT FROM AUTHOR]

In tribology, maintaining good lubrication of friction pairs is an important technical means to reduce wear and failure, which is very important but difficult to monitor the lubrication state of friction pairs. In this paper, when measuring the thickness and shape of the lubricating oil film by the ball-disk elastohydrodynamic oil film measuring instrument, a current amplifier is integrated to measure the electrical signal generated during the friction process. By monitoring the change of lubricating oil film, the change of ball-disk friction force, and the change of triboelectric signal during the friction process in real time, the relationship between the tribological behavior and the triboelectric behavior of the friction pair is explored. The experimental results show that under the conditions of limited oil supply, different rotational speeds and different lubricating oil viscosities, the time of the discharge phenomenon of the steel ball corresponds one-to-one with the time when the friction pair starts to wear under oil-scarce lubrication. The discharge occurs due to the electric charge breaking through the air in the micro-gap of the wear scar. The results demonstrate that the formation of the oil-depleted state has an important influence on the triboelectric process. Based on the relationship between the two, the state of the lubricating oil can be reflected in real time by using the triboelectric signal, which provides a reliable method for the real-time monitoring of the lubrication state. [Display omitted] • Triboelectric charges generated by friction breaks down air and causes a discharge. • The current discharge advances as the rotation speed increases. • Lubricating oils with higher viscosity are more prone to discharge. • A depleted oil status early warning sensing system is designed based on triboelectric signals. • The triboelectric sensor can provide real-time warning for oil starvation. [ABSTRACT FROM AUTHOR]

Controlling liquid–solid triboelectrification is highly demanded in a wide range of applications, from electrostatic prevention to energy collection and utilization. Except for traditional unidirectional and irreversible ways, smart approaches are required urgently. Here, a novel temperature response liquid–solid triboelectric nanogenerator (TENG) is reported on the basis of a polycaprolactone (PCL) covered fluorinated alumina for tunable triboelectrification. The PCL conformation is regulated by temperature to endow the substrate controllable surface component and interfacial wettability to manipulate the liquid–solid triboelectricity flexibly. As the temperature rises from 20 to 40 °C, the short circuit current and the open‐circuit voltage of the PCL‐based TENG are reduced by more than 40 times. When the temperature drops to 20 °C, the electrical output can return to its original level again. Moreover, after one month, the electrical signal is still reversible and stable. In addition to water, the electrical output of organic liquid, such as ethylene glycol, also responds well to temperature. This work initially provides a new strategy for achieving the customizable manipulation of liquid–solid triboelectrification by polymer surface reorganization, gives a new idea for in situ monitoring the interfacial wettability changes, and configures the reconstruction of amphiphilic polymer using triboelectricity. [ABSTRACT FROM AUTHOR]

Maintaining the condition of the friction pair is an important measure to reduce mechanical failure. This paper integrates a vacuum elastohydrodynamic oil film measurement device and a current amplifier to simultaneously observe the optical interference image, friction coefficient and triboelectric signal during the friction process. In a high vacuum environment, the discharge phenomenon of steel balls corresponds to the time when the friction pair wears. Changes in the friction state in high vacuum environments have a significant impact on triboelectricity. Based on the relationship between the two, a sensor for real-time monitoring of the friction and wear status of the friction pair is designed, which provides a reliable real-time monitoring method for friction pair monitoring in vacuum machinery. [Display omitted] [ABSTRACT FROM AUTHOR]

• High-humidity invalidity of traditional cathodic protection needs to be further improved. • A novel wind-driven and humidity-resistant TENG is designed to constitute the self-powered CP system. • High-humidity wind energy collection and in situ cathodic protection are achieved. • The protected metal gets an obvious open-circuit potential drop, which is 590 mV. The triboelectric nanogenerator (TENG) is a novel energy harvesting strategy to convert various types of mechanical energy into electrical energy through the synergistic effect of triboelectrification and electrostatic induction. A hydrophobic polytetrafluoroethylene (PTFE) flexible film was introduced to establish a wind-driven TENG as the power supply for a self-powered cathodic protection (CP) system. The PTFE flexible film was used as the friction layer with polyvinyl alcohol (PVA) film to generate charges. The developed triboelectric charges were transferred to the cathodic protection system. The PTFE-based flexible TENG exhibits enhanced output performance with an optimized short current of 29.72 μA, an output voltage of 695.18 V, and an optimized power of 1.74 mW at 95% RH (Relative Humidity). Besides, through the external connection to the protected metal, the PTFE-based flexible TENG established the power supply of the self-powered anticorrosion system. In the electrochemical measurements, an apparent open-circuit potential drop (OCP) of 590 mV was achieved for the carbon steel connected with the wind-driven TENG, and the charge transfer resistance was also significantly reduced. Due to the high performance of the flexible TENG under high humidity, this smart self-powered system could effectively collect wind energy in the marine environment and prevent metal corrosion in marine facilities by converting wind power. The self-powered cathodic protection system provided a novel and efficient strategy for harvesting and converting abundant wind energy in high humidity condition, by which the in situ corrosion protection of metals in the marine environment was achieved.Prime Novelty Statement: Wind energy collection and corrosion prevention from high humidity environments basing on flexible TENG. [Display omitted] [ABSTRACT FROM AUTHOR]