A Swing Self-Regulated Triboelectric Nanogenerator for High-Entropy Ocean Breaking Waves Energy Harvesting

Multidirectional irregular breaking wave is the most prominent feature of the ocean surface and bears tremendous amounts of sustainable high-entropy energy. However, the commercial utilization and harvesting efficiency are very limited low due to its low-frequency and low-amplitude. Here, a swing self-regulated triboelectric nanogenerator (SSR-TENG) is proposed, which can convert collected low-grade breaking waves energy into electrical energy by regulating the oscillation frequency and resonance effect. Benefiting from simple and efficient structural strategy, SSR-TENG outputs a peak power of 0.14 mW under wave height range of 6–11 cm, that the open-circuit voltage, short-circuit current and transferred charge increases is 5.8, 4, and 3.7 times compared to without self-regulated design, respectively. This work gives a practical solution to the problems faced by harvesting high-entropy ocean breaking waves energy, which exhibits large potential for building the self-powered ocean assessment and meteorology system in the future.     

Segmented Swing-Structured Fur-Based Triboelectric Nanogenerator for Harvesting Blue Energy toward Marine Environmental Applications

Reducing carbon emissions to realize carbon neutrality is crucial to the environmental protection, and developing clean and renewable energy sources is an effective means to achieve this goal. Triboelectric nanogenerators (TENGs) provide a promising energy technology for converting the abundant renewable ocean wave energy on the earth surface. In this work, a segmented swing-structured fur-based TENG (SSF-TENG) is designed and fabricated to harvest low frequency water wave energy. The introduction of soft and dense rabbit furs reduces the frictional resistance and material wear, and the design and optimization of segmented structures further enhance the output performance of TENG. The use of ultra-lubricated bearings makes the SSF-TENG achieve an extended period of energy harvesting of more than 5 min after one triggering, with a total energy conversion efficiency of up to 23.6%. Under the real water wave triggering, the SSF-TENG can deliver a maximum peak power of 6.2 mW and an average power of 0.74 mW. Furthermore, through effective water wave energy harvesting by the SSF-TENG or array, self-powered marine environmental applications are successfully demonstrated, which establishes a solid foundation for large-scale blue energy harvesting and realization of smart oceans.     

3D Stack Integrated Triboelectric Nanogenerator for Harvesting Vibration Energy

The applications of a single‐layer triboelectric nanogenerator (TENG) may be challenged by its lower output current, and a possible solution is to use three‐dimensional (3D) integrated multilayered TENGs. However, the most important point is to synchronize the outputs of all the TENGs so that the instantaneous output power can be maximized. Here, a multi‐layered stacked TENG is reported as a cost‐effective, simple, and robust approach for harvesting ambient vibration energy. With superior synchronization, the 3D‐TENG produces a short‐circuit current as high as 1.14 mA, and an open‐circuit voltage up to 303 V with a remarkable peak power density of 104.6 W m^?2. As a direct power source, it is capable of simultaneously lighting up 20 spot lights (0.6 W ea.) as well as a white G16 globe light. Furthermore, compared with the state‐of‐the‐art vibration energy harvesters, the 3D‐TENG has an extremely wide working bandwidth up to 36 Hz in low frequency range. In addition, with specific dimensional design, the 3D‐TENG is successfully equipped inside a ball with a diameter of 3 inches, using which 32 commercial LEDs are simultaneously lighted up via hand shaking, exhibiting great potential of scavenging the abundant but wasted kinetic energy when people play basketball, football, baseball, and so on.     

A Self-Healing Triboelectric Nanogenerator Based on Feathers for Sensing and Energy Harvesting

A useful direction to solve the energy problem is the effective repeated use of biomaterial for mechanical energy collection and sensing applications. Here, a feather-based single-electrode triboelectric nanogenerator (F-STENG) by only sputtering copper atoms on the feathers are presented. The feather of F-STENG, as a natural material, has environmental friendliness, which is different from the polymer materials of other triboelectric nanogenerators. F-STENG has super durability due to its feather structure self-healing property. The device has a high output voltage of 90 V and an output current of 3.5 µA. After breaking and self-healing lots of times, the output performance is also 80% of the original. F-STENG has a high sensitivity to temperature, humidity, and wind speed, and the sensitivity is 0.50 V °C⁻¹, -0.98 V RH⁻¹, and 1.67 μA m⁻¹ s⁻¹. The output power of F-STENG is 0.62 mW g⁻¹, which can realize global positioning and photographing to solve the module energy consumption problem. F-STENG provides an effective way for the application of self-powered sensors and equipment in military, industrial, transportation, and daily life.     

A Multi-Layer Stacked Triboelectric Nanogenerator Based on a Rotation-to-Translation Mechanism for Fluid Energy Harvesting and Environmental Protection

Energy shortage and environmental degradation are two important challenges facing humanity. Here, a multi-layer stacked triboelectric nanogenerator (MLS-TENG) based on a rotation-to-translation mechanism is reported for fluid energy harvesting and environmental protection. The mechanism transforms fluid-induced rotation into a reciprocal translation of the MLS-TENG, enabling the conversion of fluid energy into electrical energy. In addition, benefiting from a multi-layer stacked structural design, the open-circuit voltage is increased from 860 to 2410 V and an efficient energy harvesting rate of 2 mJ min⁻¹ is obtained in an actual river. Furthermore, with the assistance of the MLS-TENG, a self-powered wireless temperature and humidity monitoring system and a metal anticorrosion system are successfully established. Ambient monitoring data can be transmitted continuously at an interval of 49.7 s, and the corrosion rate of steel is significantly slowed down. This study provides guidance for efficient harvesting of ambient fluid energy, with promising applications in environmental monitoring and protection.     

Lightweight Triboelectric Nanogenerator for Energy Harvesting and Sensing Tiny Mechanical Motion

Triboelectric nanogenerators (TENGs) have shown exciting applications in mechanical energy harvesting and self‐powered sensing. Aiming at commercial applications, cost reduction and simplification of TENG structures are of great interest. In this work, a lightweight TENG based on the integration of polymer nanowires and a carbon sponge, which serves both as the substrate and an electrode, are reported. Because of the low density of the carbon sponge and the filmy nanowires, the device exhibits a total mass of less than 0.1 g for a volume of 12.5 cm³ and it produces a short‐circuit current of 6 μA, open‐circuit voltage of 75 V, and a maximum output power of 0.28 W kg^?1 under light finger tapping. The device can linearly measure the acceleration at a detection limit down to 0.25 m s^?2 and for a detection range from 0.25 m s^?2 to 10.0 m s^?2.     

Dielectric Modulated Glass Fiber Fabric-Based Single Electrode Triboelectric Nanogenerator for Efficient Biomechanical Energy Harvesting

Single-electrode triboelectric nanogenerators (SE-TENGs) are versatile tools for energy harvesting with simple structures and great practicability. However, low output performance hinders SE-TENGs in applications as portable power sources. Herein, a novel SE-TENG that utilizes glass fiber fabric (GFF) as tribo-materials, along with an inorganic ferroelectric film for the dielectric layer is proposed. The GFF is first shown to be a promising tribo-material for its highly positive tribo-polarity and unique chemical/mechanical/durable properties. Meanwhile, an inorganic dielectric film with high dielectric constant is introduced between the GFF and Al electrode for enhancing the charge trapping capability. Owing to the synergistic effect of optimized triboelectrification and dielectric properties, the specific designed SE-TENG delivers an open-circuit voltage of 1640 V and a short-circuit current density of 59.05 mA m⁻², which are superior to most reported SE-TENGs. With a maximum instantaneous power of 11.30 mW, the device can light up 1350 light-emitting diodes, charge a 47 µF capacitor into 10 V in 421 s, and power up a digital watch even without additional control circuits. This work provides new insights in designing high-performance SE-TENGs and facilitates their application in biomechanical energy harvesting and portable power sources.     

Triboelectric Nanogenerator Boosts Smart Green Tires

Tires are important parts in creating a great transportation system because they can significantly improve the overall system safety and fuel/power efficiency. The latter is especially important for the mileage of electric vehicles due to the limited electrical storage capacity. Here, green energy tires are designed by incorporating silica tread rubber with triboelectric nanogenerators (TENGs). On the one hand, the silica‐based tread compound sharply cuts off the rolling resistance, improves fuel efficiency and reduces CO₂ emissions, and provides all‐around traction without compromising braking. On the other hand, TENG converts frictional energy into electricity without changing the process of traditional tire production, which is able to be used for powering the electronics for automobile safety and automeasuring of tire pressure. The most important point lies in that TENG helps harness static electricity, which at present hinders the large‐scale application of silica‐filled green tires. Interestingly, it is also able to measure tire pressure and road condition from the changes in the output electrical signals, which thus leads to the smart applications of green energy tire in road/tire condition monitoring.     

Triboelectric Nanogenerator for Harvesting Vibration Energy in Full Space and as Self‐Powered Acceleration Sensor

A spherical three‐dimensional triboelectric nanogenerator (3D‐TENG) with a single electrode is designed, consisting of an outer transparent shell and an inner polyfluoroalkoxy (PFA) ball. Based on the coupling of triboelectric effect and electrostatic effect, the rationally developed 3D‐TENG can effectively scavenge ambient vibration energy in full space by working at a hybridization of both the contact‐separation mode and the sliding mode, resulting in the electron transfer between the Al electrode and the ground. By systematically investigating the output performance of the device vibrating under different frequencies and along different directions, the TENG can deliver a maximal output voltage of 57 V, a maximal output current of 2.3 μA, and a corresponding output power of 128 μW on a load of 100 MΩ, which can be used to directly drive tens of green light‐emitting diodes. Moreover, the TENG is utilized to design the self‐powered acceleration sensor with detection sensitivity of 15.56 V g^‐1. This work opens up many potential applications of single‐electrode based TENGs for ambient vibration energy harvesting techniques in full space and the self‐powered vibration sensor systems.     

Tunable Anisotropic Structural Aramid Triboelectric Aerogels Enabled by Magnetic Manipulation

Material designs for wearable sensors are increasingly important due to variable application scenarios and environmental disturbances. The high temperatures pose a significant challenge to the performance of sensing materials. The reasonable anisotropic structure in materials is recognized as a promising approach to address this challenge. Precise control of the orientation of the material remains difficult, owing to the entropy effect. In this work, a tunable anisotropic triboelectric aerogel via an in situ coupled magnetic alignment and protonation reduction strategy is demonstrated. The designed orientation with a fitting degree of 98% can effectively suppress electron thermionic emission, which enables the surface charge density to reach 75 µC m⁻² at 300 °C. Such a perfect coordination between self-powered sensing and thermostability innovates multifunctional wearable sensing design at high temperatures, allowing aramid-based aerogel to be a candidate for advanced sensing materials for applications in the military and aerospace fields.     

Harvesting Multidirectional Breeze Energy and Self-Powered Intelligent Fire Detection Systems Based on Triboelectric Nanogenerator and Fluid-Dynamic Modeling

Fire warning and monitoring are very important for public safety and environmental protection. However, most of the proposed wind energy conversion devices based on triboelectric nanogenerator (TENG) only work for unidirectional and high-speed wind and face the challenge of fatigue damage and even failure caused by cyclic stress. Moreover, TENG guided by the theory of fluid dynamics needs further exploration. Herein, a flow-induced vibration effect based TENG (F-TENG) for continuously capturing and monitoring multidirectional breeze (1.8–4.3 m s⁻¹) is developed to build a self-powered intelligent fire detection system (SIFDS). A dynamic model is proposed to study the intrinsic interaction between the electrical properties of F-TENG and wind. Since the model optimized F-TENG is more adaptable to wind characteristics, it delivers better performance and higher durability compared with previous studies. Relying on the dynamic model and combining the relationship between F-TENG's electrical output and wind characteristics, a self-powered visual wind sensing system is obtained. F-TENG successfully drives some electronic devices to monitor environmental information, which is expected to provide data for SIFDS to reduce fire hazards. This study can provide an in-depth understanding of the electromechanical conversion mechanism and large-scale capture and utilization of breeze energy.     

A Nonmetallic Stretchable Nylon‐Modified High Performance Triboelectric Nanogenerator for Energy Harvesting

As a new energy harvesting strategy, triboelectric nanogenerators which have a broad application prospect in collecting environmental energy, human body mechanical energy, and supplying power for low‐power electronic devices, have attracted extensive attention. However, technology challenges still exist in the stretchability for the preparation of some high‐performance triboelectric materials. In this work, a new strategy for nonmetallic nylon‐modified triboelectric nanogenerators (NM‐TENGs) is reported. Nylon is introduced as a high performance friction material to enhance the output performance of the stretchable TENG. The uniform matrix reduces the difficulty of heterogeneous integration and enhances the structural strength. The open‐circuit voltage (V_OC) and short‐circuit current (I_SC) of NM‐TENG can reach up to 1.17 kV and 138 µA, respectively. The instantaneous power density reaches 11.2 W m^?2 and the rectified output can directly light ≈480 LEDs. The transferred charge density is ≈100 µC m^?2 in one cycle when charging the capacitor. In addition, a low‐power electronic clock can be driven directly by the rectified signal without additional circuits. NM‐TENG also has high enough strain rate and can be attached to the human body for energy harvesting effectively. This work provides a new idea for fabrication of stretchable TENGs and demonstrates their potential application.     

Self-Healable Triboelectric Nanogenerators: Marriage between Self-Healing Polymer Chemistry and Triboelectric Devices

Based on the triboelectrification and electrostatic induction coupling, triboelectric nanogenerators (TENGs) can convert mechanical energy into electrical energy, showing a promising potential in the fields of micro/nano energy and self-powered sensors applications. However, the devices are prone to malfunction due to fatigue and damage, limiting their development and applications. In this review, according to the working modes and operational malfunctions as well as the possible solutions, it is proposed that a robust TENG device can be constructed from three perspectives: self-healing friction layers, self-healing electrodes, and self-healing whole devices. Based on the structure, suitable environment, and self-healing materials, the design ideas and fabrication approaches of self-healing TENGs in recent years are summarized in detail. Finally, the development of self-healing TENGs in energy harvesting and self-powered sensors is outlined. It is the wish to provide insights and guidance for the application design of self-healing TENGs in the future.     

Increase Output Energy and Operation Frequency of a Triboelectric Nanogenerator by Two Grounded Electrodes Approach

Triboelectric nanogenerator (TENG) generally operates using two‐electrodes to form a closed outer circuit loop without directly contacting ground. Here, a newly designed TENG, the two electrodes of which are grounded for doubling the energy output and the operation frequency, is introduced. The TENG operates in two modes: two‐channel mode in which the two electrodes are simultaneously connected to the ground, and single‐channel mode in which the two electrodes are alternately connected to the ground through a self‐triggered vibrating switch. Both modes doubles the total charges to be transported compared to the traditional ungrounded TENG. For the single‐channel TENG, about 30 current peaks with an output frequency of 50 Hz are generated in a single cycle at a motion triggering frequency of 2 Hz. The output energy at a load lower than 10 MΩ of the single‐channel TENG is enhanced, and the enhancing ratio is more than 100 at a load of 100 kΩ. The two electrodes grounded TENG provides a new strategy for effective use of the energy harvested from our living environment.     

Acid and Alkali-Resistant Textile Triboelectric Nanogenerator as a Smart Protective Suit for Liquid Energy Harvesting and Self-Powered Monitoring in High-Risk Environments

Industrialization and anthropogenic activities are expected and unavoidable to consummate the current resources of humankind, which also lead to accidents in the laboratory, chemical plants, or other high risk areas that cause severe burns, or even casualties. Increased casualties in such accidents are due to inappropriate safety measures and prevention. Here, a smart anti-chemical protective suit with a bio-motion energy harvesting and self-powered safety monitoring system is demonstrated, which can protect the body from chemical harm, detect sudden chemical spills, monitor human real-time living signals, and trigger alarms in an emergency. Particularly, a fabric triboelectric nanogenerator (F-TENG), which is fabricated by the all-fiber single-electrode triboelectric nanogenerator yarn (SETY), works as the basic elements of the intelligent suit. The SETY with core-shell structured design shows a high sensitivity to the corrosive liquids including acids and alkalis. Furthermore, the working principle of the yarn based nanogenerator that is powered by contacting with acid liquid droplets is demonstrated for the first time. In addition, discretionary thickness, permeability, and any other functionalities are also achieved by taking advantage of the fabric structure. This self-powered smart anti-chemical protective suit equipped with a real time monitoring system will benefit the wearer who works in a very high-risk environment.     

A Flexible Multifunctional Triboelectric Nanogenerator Based on MXene/PVA Hydrogel

Triboelectric nanogenerators (TENGs) represent an emerging technology in energy harvesting, medical treatment, and information technology. Flexible, portable, and self-powered electronic devices based on TENGs are much desired, whereas the complex preparation processes and high cost of traditional flexible electrodes hinder their practical applications. Here, an MXene/polyvinyl alcohol (PVA) hydrogel TENG (MH-TENG) is presented with simple fabrication, high output performance, and versatile applications. The doping of MXene nanosheets promotes the crosslinking of the PVA hydrogel and improves the stretchability of the composite hydrogel. The MXene nanosheets also form microchannels on surfaces, which not only enhances the conductivity of the hydrogel by improving the transport of ions but also generates an extra triboelectric output via a streaming vibration potential mechanism. The measured open-circuit voltage of the MH-TENG reaches up to 230 V even in a single-electrode mode. The MH-TENG can be stretched up to 200% of the original length and demonstrates a monotonical increasing relationship between the stretchable length and the short-circuit voltage. By utilizing the MH-TENG's outstanding stretchable property and ultrahigh sensitivity to mechanical stimuli, applications in wearable movement monitoring, high-precision written stroke recognition, and low-frequency mechanical energy harvesting are demonstrated.     

Humidity Sustained Wearable Pouch‐Type Triboelectric Nanogenerator for Harvesting Mechanical Energy from Human Activities

Triboelectric nanogenerators (TENGs) are gaining much research interest recently owing to their facile and cost‐effective device structure. However, the effect of relative humidity (in moisture atmosphere) on the output performance still needs to be resolved. Herein, a pouch‐type TENG is proposed to significantly reduce the effect of relative humidity on its electrical output and a stable performance is also attained in a humid environment. In this regard, a dielectric and dielectric materials‐based TENG (DD‐TENG) is first developed using nanoarchitecture polydimethylsiloxane (NA‐PDMS) and multiwalled carbon nanotube/nylon composite layers as a triboelectric material with the negative and positive tendencies, respectively. The NA‐PDMS and nylon composite layers play a key role in increasing the surface contact area and surface charge density between the dielectric/triboelectric materials as well as the output performance of DD‐TENG. However, the DD‐TENG device exhibits a stable and high output performance with the effective output power density of ≈25.35 W m^?2. Additionally, the performance of the pouch‐type DD‐TENG device is not almost affected even though the relative humidity is increased from 35 to 81%, while it is dramatically decreased for the nonpouch‐type device. Finally, the pouch‐type DD‐TENG is employed as a wearable device to effectively harvest the mechanical energy from daily human activities.     

Flexible Sponge-Based Nanogenerator for Energy Harvesting from Land and Water Transportation

Triboelectric nanogenerator (TENG) devices with high robustness are promising in collecting powerful energy. In this study, highly elastic and pressure-resistance sponge fabricated TENG capable of adapting to high strength impact in land and water transportation and scalable for any shape is demonstrated for harvesting wave energy and mechanical energy. The polydimethylsiloxane sponge prepared by sacrificial template method has interconnected network and large size ratio of cavity-wall suitable for contact and separation. The operation modes of self-contact and extra-contact collaborating with MXene in electron transfer provide options for different operating conditions. The polydopamine-MXene modification of the sponge enables higher output due to the combination of the electronegativity, excellent adhesion, and antioxidant ability. Sponges are used to collect mechanical energy and applied for TENG-powered cathodic protection, making the 304 stainless steel (304 SS, Φ = 2 mm) electrode enter a thermodynamic stable state. What's more, the work also tries the universal strategies of program monitoring wave in the water tank and harvests the mechanical energy created by cars and passers-by, which enrich the applications of sponge TENG.     

Achieving High-Efficiency Wind Energy Harvesting Triboelectric Nanogenerator by Coupling Soft Contact,Charge Space Accumulation,and Charge Dissipation Design

To enhance the durability of a triboelectric nanogenerator (TENG), soft contact is an effective approach due to its flexible and elastic contact mode. However, soft contact is hard to obtain with a large charge density by triboelectrification, resulting in low power output. Herein, a novel blade soft contact TENG (BSC-TENG), coupling flexible functional blades with shielded electrodes on the rotor, charge accumulation, and charge dissipation design on the stator, is proposed. Extra polishing blades and debris storage grooves are adopted in the BSC-TENG to further ensure high durability. A remarkable charge density of 328 µC m⁻² is achieved, setting a new record for soft contact TENGs. Besides, the output charge remains at 100% even after 200 000 cycles. The wind-driven BSC-TENG not only can power 3840 green LEDs and 80 parallel hygrothermometers but also can drive electronic devices for smart farms, establishing self-powered sensing systems. This work provides a novel strategy for enhancing soft contact TENG output and durability.     

Liquid‐Metal Electrode for High‐Performance Triboelectric Nanogenerator at an Instantaneous Energy Conversion Efficiency of 70.6%

Harvesting ambient mechanical energy is a key technology for realizing self‐powered electronics, which has tremendous applications in wireless sensing networks, implantable devices, portable electronics, etc. The currently reported triboelectric nanogenerator (TENG) mainly uses solid materials, so that the contact between the two layers cannot be 100% with considering the roughness of the surfaces, which greatly reduces the total charge density that can be transferred and thus the total energy conversion efficiency. In this work, a liquid‐metal‐based triboelectric nanogenerator (LM‐TENG) is developed for high power generation through conversion of mechanical energy, which allows a total contact between the metal and the dielectric. Due to that the liquid–solid contact induces large contacting surface and its shape adaptive with the polymer thin films, the LM‐TENG exhibits a high output charge density of 430 μC m^?2, which is four to five times of that using a solid thin film electrode. And its power density reaches 6.7 W m^?2 and 133 kW m^?3. More importantly, the instantaneous energy conversion efficiency is demonstrated to be as high as 70.6%. This provides a new approach for improving the performance of the TENG for special applications. Furthermore, the liquid easily fluctuates, which makes the LM‐TENG inherently suitable for vibration energy harvesting.