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 (I-sc) and output voltage (V-o) of the PPCa-TENG can reach 52.04 mu A 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.

In view of the increasing energy shortage and environmental pollution, the collection of friction charges to achieve the conversion of various natural energies and provide in-situ cathodic protection for metals is a significant challenge. Here, we designed a dual device-structure TENG composite array with the triboelectric layer of linear siloxane-modified polyurethane (PU) coating. This array could achieve a comprehensive collection for multiple forms of nature energy and cathodic protection of metals in multi-weather conditions. For one thing, the wave-mode TENG based on tanker structure could collect wave energy and showed the output performance with a short-circuit current of 15.5 µA. For another hing, the droplet-mode TENG based on arc-shaped surface structure could collect raindrop kinetic energy and showed the output performance with a short-circuit current of 16.3 µA. Notably, the parallel array of wave-mode TENG (W-TENG) and droplet-mode TENG (D-TENG) could simultaneously collect wave energy and raindrop kinetic energy, which showed a short-circuit current of 30.7 µA. Besides, a self-powered a cathodic protection system powered by the dual structure TENG array is assembled and the open-circuit potential drop of the carbon steel connected with the TENG array is about 450 mV. Compared with cathodic protection system powered by single structure TENG, the composite array could provide more effective corrosion resistance for marine equipment in rainy weather. Due to the characteristic for comprehensive collection of nature energy, the anti-corrosion system supplied by TENG parallel array possesses great application potential in the all-weather corrosion protection of metal machinery under complex marine conditions.

Given the security issues caused by electrostatic discharge in electron devices, triboelectrification has attracted extensive attention as a new energy-generation and -collection method. However, high output impedance and low current density will hinder its further development and limit many practical applications. Here, we report an effective method to circumvent these limitations by introducing a vacuum environment into relative movements. By combining discharge, the tribocurrent has two or three orders of magnitude enhancement during different triboelectrification processes. In traditional devices, the vacuum sliding triboelectric nanogenerator (VS-TENG) exhibits an ultrahigh average power of 173.8 W m(-2) Hz(-1) and sets a record of the triboelectrification driven by rotate mode. By shrinking the vacuum environment into a vacuum silicon tube, the current density of conventional TENGs can span from the microamp to the milliamp level. This work develops a universal strategy to enhance the output performance in energy harvesting.

With the increasing demand for carbon neutrality, the development of renewable and recycle green energy has attracted wide attention from researchers. A novel self-healing triboelectric nanogenerator (TENG) was constructed by applying a linear silicone-modified polyurethane (PU) coating as a triboelectric layer, which was obtained by reacting hydroxypropyl silicone oil and hexamethylene diisocyanate under the catalysis of Sn. The linear self-healing coating as the friction electrode could effectively alleviate the damages of TENG devices during long-term energy harvesting. When the triboelectric layer of the TENG device shows abrasion, the broken silicone-modified polyurethane polymer chains would gradually be cross-linked again through hydrogen bonding to achieve a self-healing effect. The entire self-healing process of the friction coating could be completed in 30 min at room temperature. The PU-based self-healing TENG exhibits an evident and stable output performance with a short-circuit current of 31.9 μA and output voltage of 517.5 V after multiple cutting-healing cycles, which could light 480 commercial LEDs. Besides, a self-powered cathodic protection system supplied by the self-healing TENG was constructed, which could transfer negative triboelectric charges to the protected metal surface to achieve an anti-corrosion effect by harvesting mechanical energy. Due to the self-healing characteristics of the TENG device as the power supply part, this intelligent system possesses great application potential in the long-term corrosion protection of multiple metal application industries, such as the marine industry.

Surface charge density greatly influences triboelectric properties and tribological behavior. Given the limitations of current techniques for regulating surface charge, a novel plasma-irradiation-based surface treatment was used to enhance the triboelectric properties and optimize the tribological behavior of polyimide (PI) films. An in-situ two-step Ar+O2 reactive ion etching (RIE) plasma treatment was used to etch the surface of the PI films to enhance the triboelectric performance of PI-PA11-based triboelectric nanogenerators (TENGs). The generation of granular nanostructures on the PI film surface enhanced the effective contact area between triboelectric layers. The C-O and CO content was also greatly increased, improving the electron affinity of the PI films. At the same time, to obtain a fully antistatic PI surface in a PI-PVDF-based TENG, the optimal irradiation time was calculated. In addition, to control the tribological behavior, the surface charge of PI film was successfully eliminated by a one-step Ar plasma irradiation, and the regulation of the coefficient of friction was realized, which significantly improved the friction stability and wear resistance of the material. This new approach can find wide applications in energy harvesting, industrial production, electronic circuit, and other applications.

In this paper, a new type of ice-based triboelectric nanogenerator (ICE-TENG) has been fabricated to harvest energy in cold weather. Ice is a preferred material for designing TENGs in cold winter, alpine or snowy mountain regions because of its cleanness, environmental protection, abundant reserves, low friction, and self-healing properties. The short-circuit current and voltage can achieve 2.4 µA and 48 V with 4 mm thickness of ice layer, 30 N loadings, and 5 Hz contact frequency, which can be useful in some practical applications such as lighting LEDs and charging capacitors. The ICE-TENG possesses excellent stability and can reach an output power of 35 µW under 20 MΩ loading resistance. The coefficient of friction between ice and other friction pairs is negligible, and it can even become super-slippery with the coefficient of friction below 0.008. Thus, the wear of the friction pairs is small, which can help TENG to have a long working life. Besides, due to the rapid phase change of ice, the ICE-TENG exhibits a commendable self-healing ability and maintains the original output performance after several damage and repair processes. To simulate the practical applications, a single electrode ICE-TENG driven by walking has been designed for harvesting energy on the ice surface. Because of the difference in electric output before and after the ice fragmentation, the ICE-TENGs are designed to construct a warning system to remind the danger when the ice surface suddenly shatters. Moreover, such ICE-TENGs are capable of lighting "ICE" LEDs and powering an electric watch with footsteps. This illustrates a promising potential in self-powered systems such as danger warning, charge shortage, and energy harvesting.

Solid-liquid triboelectric nanogenerators (SL-TENGs) have shown promising prospects in energy harvesting and application from water resources. However, the low contact separation speed, small contact area, and long contacting time during solid-liquid electrification severely limit their output properties and further applications. Here, by leveraging the rheological properties of gas-liquid two-phase flow and the Venturi-like design, we circumvent these limitations and develop a previously unknown gas-liquid two-phase flow-based TENG (GL-TENG) that can achieve ultrahigh voltage and volumetric charge density of 3789 volts and 859 millicoulombs per cubic meter, respectively. With a high-power output of 143.6 kilowatts per cubic meter, a 24-watt commercial lamp can be directly lighted by a continuous-flow GL-TENG device. The high performance displayed SL-TENGs in this work provides a promising strategy for the practical application of solid-liquid TENGs in energy harvesting and sensing applications.

Triboelectrification typically occurs in the friction process. In this study, we investigated the effect of liquid lubricants of various polarities on triboelectrification in a friction pair consisting of a steel ball and polyvinylidene fluoride blocks. The results revealed that alkanes and alkenes enhanced triboelectrification. On addition of PAO 4, the friction coefficient reduced considerably, and the short-circuit current could be output stably for a long time. With the increase in the viscosity of PAO, the triboelectric signal gradually decreased. This study revealed that the appropriate lubricant and the quantity of liquid can increase the size of the triboelectric signal to achieve a stable output for a long time.

A novel self-powered fabric composition detection system has been developed from F-TENGs modified by different functional groups.

Intelligent and highly precise control of liquid-solid triboelectricity is of great significance for energy collection and electrostatic prevention. However, most of the traditional methods are irreversible and complex, greatly limiting their applicability. Here, a reversible thermosensitive liquid-solid triboelectric nanogenerator (L-S TENG) is assembled based on P(NIPAM-MMA) (PNM) copolymer for tunable triboelectrification. Through temperature regulation, the conformation between acylamino and isopropyl groups changes with the interfacial wettability and triboelectricity of PNM. When the temperature rises from 20 to 60 °C, the contact angle of PNM rises from 22.49° to 82.08°, and the output of the PNM-based L-S TENG shows a 27-fold increase. In addition, this transformation is reversible and repeatable with excellent durability for up to 60 days. Other organic liquids, such as glycol, exhibit positive response to temperature for this PNM-based L-S TENG. Polymers including polymethylmethacrylic, polytetrafluoroethylene, and polyimide are verified to not have such thermo-sensitivity properties. In addition, a droplet-based wireless warning system based on PNM is designed and actuated for monitoring specific temperature. The introduction of thermal PNM not only provides new material for reversible manipulation of L-S TENG, but also provides a new method for designing highly sensitive temperature warning sensors.

Electrostatic charges can accumulate on insulator surfaces under contact electrification, resulting in hazardous conditions. Despite significant progress in eliminating charges of contact electrification, there are still several limitations, including the need to dope other materials, which can alter their original properties, and the difficulties of fabrication. Here, a new post-treatment antistatic strategy is demonstrated to significantly reduce the accumulation of static charge by controlling the spatial distribution of tribopositive and tribonegative regions. On-site interface charge neutralization between tribopositive and tribonegative regions leads to rapid charge decay, without conductive spraying or grounding, which is especially useful in some extreme scenarios, such as the aerospace industry and the electronics industry. By using this surface engineering strategy, finished materials can be easily retrofit into antistatic materials, which will open up promising possibilities for antistatic polymers in a wide range of applications.

Dynamic metal–semiconductor Schottky contact interfaces suffer from wear even in low-friction direct-current triboelectric nanogenerators (DC-TENGs), which may affect their working stability and limit their practical applications. In this study, the mechanism and relationship between triboelectrification and tribological characteristics of the metal–semiconductor heterojunction interface with a ball-on-flat configuration under a high contact pressure were systematically studied to simultaneously obtain the high triboelectric output and low wear rate of the tribological-behaviour-controlled DC TENG (TCDC-TENG). The working mechanism of the TCDC-TENG could be attributed to the tribovoltaic effect. An increased normal load and sliding frequency enhanced the triboelectric output while increasing the wear loss of the TCDC-TENG. Furthermore, both the triboelectric output and wear loss per unit time increased with the increase in the applied friction power, which was a product of the coefficient of friction (CoF), normal load ( F N ), and sliding speed ( v ). By adding polyalphaolefin SpectraSyn 4 as a lubricant, the CoF was lowered from 0.76 to 0.16, and the wear loss considerably decreased by 99.5% after 20,000 cycles of reciprocating sliding, while maintaining almost constant DC output voltage. This study not only presents the strong correlation between triboelectrification and tribology characteristics based on the tribovoltaic effect but also provides a new strategy for the semiconductor-based DC-TENGs for achieving a stable DC triboelectric output and wear resistance.

Harvesting energy from ambient environment has been considered as a promising strategy for driving portable electronic devices in a sustainable way. A wind driven triboelectric-electromagnetic hybrid nanogenerator has been fabricated to convert wind energy into electricity. It is composed of an electromagnetic generator (EMG) and a triboelectric nanogenerator (TENG) with the output power of 35 and 0.32 mW, respectively when the wind speed is 5 m/s. Generally, TENG shows a low current output with a high voltage output characteristic, on the contrary the EMG shows a high current output and a low voltage output. This hybrid nanogenerator overcomes these problems and exhibits comprehensive and efficient performance on scavenging energy. Moreover, in view of the output performance and charging ability of the hybrid nanogenerator, it shows high stability, making it suitable for charging capacitors or batteries and driving portable electronics sustainably. A new structure of integrated TENG and EMG was designed to harvest wind energy, which shows potential applications in portable and small device power supply system, especially in the areas of remote mountains, deserts, islands, etc., as emergency power supply.

Friction and triboelectrification originate from the relative motion simultaneously at the interface. Charge accumulation becomes a considerable phenomenon when insulator occurs in the friction pair. A modified equipment was fabricated to explore the relationship between charge accumulation and tribological behavior in a ball-on-disc friction system. The electropositive nylon and electronegative PVC were utilized to investigate the effect of positive and negative tribocharges on the friction and wear. Loading and sliding speed were varied to probe the effect of external conditions on charge accumulation. Ionizing blower and grounding conductor were utilized to change the charge accumulation on the polymer surface. By comparing the three friction processes, the tribological behavior had a strong relationship with charge accumulation and it could be optimized by eliminating tribocharges. The friction pair showed excellent friction reduction, anti-wear performance, and good stability when there is no charge accumulation at the friction interface. Besides, the COF could be controlled by adjusting charge accumulation due to the interfacial coulombic force. This experiment not only demonstrate the closely relationship between tribology and triboelectricity, but also provided a new strategy to regulate the tribological behavior for different requirements at the interface.

Ice formation is a common phenomenon that brings security risks in numerous fields. A superhydrophobic surface can greatly delay icing time due to its liquid repellence feature, but it fails under cold and humid conditions. In this work, a photo‐thermal@electro‐thermal superhydrophobic coating (PESC) consisting of electric‐conductive carbon nanotubes (ECNTs) and fluoro‐modified polyacrylate is constructed by means of spray to realize both anti‐icing and de‐icing simultaneously. Traditional ECNTs not only provide hierarchical micro‐nano structures to construct superhydrophobic surfaces for anti‐icing, but also guarantee de‐icing capacity because of solar‐thermal and electric‐thermal effects. In warm daytime, enough heat is generated by solar‐thermal conversion to keep the temperature of the coating surface above zero to achieve anti‐icing and de‐icing. On a cloudy day or extremely cold day, the coating also can stay warm to prevent icing, owing to photo‐thermal and electric‐thermal dual effects. And during the cold nighttime, the coating is heated to prevent icing after it is electrified as a result of electric‐thermal effects. The PESC system can reduce electricity consumption from the maximum, fulfilling eco‐friendly and energy saving concepts. This functional superhydrophobic coating with anti‐icing and swift de‐icing performance may have broad application prospects in the power industry.

Regulated triboelectrification has attracted considerable research attention due to its potential applications in harvesting energy and importance in antistatic protection. Irradiation is an effective and stable modification method due to its adjustable and uniform irradiation parameters. Moreover, atomic oxygen (AO) irradiation is an important component in the low earth orbit, which is a considerable factor for promoting triboelectric nanogenerators (TENGs) in the outer space. AO irradiation was utilized to manipulate the surface structure and chemical composition to regulate electrical properties. AO irradiation can increase electron-donating groups and enhance electrical positivity of polydimethylsiloxane (PDMS) films due to the transition from Si-C bonds to Si-O bonds. Therefore, different trends of polytetrafluoroethylene (PTFE) and polystyrene (PS) were caused by their TENG composition with irradiated PDMS. Tribocharge cross-over polarity and charge generation were prevented completely in PS- and PDMS-based TENGs by adjusting the irradiation time to 4.1 h. Short-circuit current enhanced from 5 to 22 μA and the output voltage increased from 160 to 760 V when PDMS films in PTFE- and PDMS-based TENGs were subjected to AO irradiation for 6 h. This study demonstrated that AO irradiation can manipulate triboelectric properties of silica-based materials, which are potential components for harvesting energy and preventing electrostatic hazard in the outer space.

A new self-healing triboelectric nanogenerator (TENG) was fabricated by combining a temperature responsive polymer material of polycaprolactone (PCL) with flexible silver nanowires (Ag NWs), which could cope with the damages of TENGs in the long-term use of energy harvesting. Two different structured TENGs were designed to investigate their properties of self-recovery of the friction surfaces and conducting layers. When the top surface of the friction electrode is damaged, the healable PCL polymer will intenerate by heating and flow to the wound to realize the self-healing purpose. If the conductive layer at the bottom of the TENG electrode is also damaged, PCL will also drive the Ag NW network at the bottom of the electrode to move for healing during the heating process. This type of self-healing TENGs with a sandwich structure can exhibit a stable and high output performance with an output voltage of 800 V and a short-circuit current of 30 μA after several cutting-healing cycles, which can easily light up 372 commercial light-emitting diodes. This work proposes a simple and effective method to design a self-healing TENG, which has a widespread application prospect to prolong the life of TENGs for restoring the loss of output caused by rapid and repeated cutting.

A new photoanode of Al2O3 anchored carbon quantum dots/TiO2 nanorods (Al/C/TNRs) was constructed for efficient photocathodic protection of Q235 carbon steel (CS) by hydrothermal treatment and ALD process. The Al/C/TNRs photoanode achieved a photocurrent density of 2.28 mA/cm2 under simulated sunlight (AM 1.5 G), and could maintain for 7 days nearly without decay. Potential of Q235 CS was negatively shifted by 620 mV after coupling with Al/C/TNRs in 3.5 wt% NaCl solution, and could maintain more than 7 h. The high and stable photoelectrochemical performances of Al/C/TNRs indicate potential photocathodic protection for Q235 CS in marine environment.

As a kind of environmental dissipative energy, acoustic energy is common but difficult to collect and utilize effectively owing to its low energy density and special acoustic state. In this work, a new type of triboelectric nanogenerator (TENG) based on porous foam copper with sandwich-like friction pairs is designed to harvest sound energy efficiently from the environment. The sound-driven TENG is mainly composed of Cu foam, polyvinylidene fluoride (PVDF) nanofibers and nylon fabric, in which the Cu foam is used as a sound collector, conductor and amplifier, as well as the friction layer and conductive layer of the TENG. The thin and light PVDF nanofiber membrane and nylon fabric are used as vibration membranes, which are easy to generate vibration under weak sound to harvest the sound energy under wideband frequencies. This sound-driven TENG shows high triboelectric output performance with a maximum current density up to 25.01 mA/m(2) and a charging rate of 20.91 mu C/s with a charging transformation efficiency up to 59.85%, which can light up 384 LEDs and drive an electrochromic device for reversible color changing. Importantly, the sound-driven TENG has good working stability. It can work continuously for 7 days under loudspeaker driving without decay. This type of sound-driven TENG has potential application in the field of audio frequency analysis, noise detection, energy supply and presents promising potential to be a self-powered system in the electrochemical industry.

By taking the advantage of the wide surface area of reduced graphene oxide (rGO), a type of carbon/metal hybrids composed by rGO coated with silver nanoparticles (Ag–rGO) has been synthesized via an easy chemical coating method. Then the Ag–rGO hybrids are filled into polyacrylate (PA) as elelctrically conductive fillers to survey the application of the hybrids in polymer based composites. Compatible research indicates the hybrids could evenly disperse in PA with a Methyl Ethyl Ketone (2-MEK) enviroment for a long period. Property measurements suggest that the Ag–rGO dual fillers have greatly improved the electrical conductivity of PA matrix, enabling the conductive of the Ag–rGO/PA composites to rise more than ten orders while reducing the main bonding performance of the composites. With 10.0 wt% of Ag–rGO hybrids, the composites exhibited optimized electrically conducting and mechanical properties, which were 2.40 × 10−2 S/cm of conductivity, 0.62 KN/m of 180°peel strength and 0.67 MPa of shear strength. The great effect on PA is caused by the electrical conducting of nano-scaled Ag particles and the intermolecular forces between rGO and PA.