Search

Energy harvesting plays an important role in developing power-independent electronics such as wearables, implantable devices, monitoring networks, and robotics. The triboelectric nanogenerator (TENG), a novel promising energy-harvesting technology, has attracted increasing attention across a broad range of applications from self-powered sensing to implantable medical devices to blue energy. However, a comprehensive review associated with the TENG-based hybrid energy system is lacking. Here, we systematically summarize the recent advances in the TENG-based hybrid energy-harvesting system with a focus on the concept designs and significant applications of the hybrid devices in various fields. The major hybridization designs through unique combinations of electromagnetic nanogenerators (NGs), piezoelectric NGs, solar cells, and thermo-/pyroelectric NGs with TENGs are discussed in detail for self-charging power units, self-powered biomedical systems, wearable electronics, environment-monitoring systems, and blue energy-harvesting facilities. We finally discuss the major challenges and perspectives for the future development of hybrid energy-harvesting systems.

The development of stretchable electronics requires the invention of compatible high-performance power sources, such as stretchable supercapacitors and batteries. In this work, two-dimensional (2D) titanium carbide (Ti3C2Tx) MXene is being explored for flexible and printed energy storage devices by fabrication of a robust, stretchable high-performance supercapacitor with reduced graphene oxide (RGO) to create a composite electrode. The Ti3C2Tx/RGO composite electrode combines the superior electrochemical and mechanical properties of Ti3C2Txand the mechanical robustness of RGO resulting from strong nanosheet interactions, larger nanoflake size, and mechanical flexibility. It is found that the Ti3C2Tx/RGO composite electrodes with 50 wt % RGO incorporated prove to mitigate cracks generated under large strains. The composite electrodes exhibit a large capacitance of 49 mF/cm2(∼490 F/cm3and ∼140 F/g) and good electrochemical and mechanical stability when subjected to cyclic uniaxial (300%) or biaxial (200% × 200%) strains. The as-assembled symmetric supercapacitor demonstrates a specific capacitance of 18.6 mF/cm2(∼90 F/cm3and ∼29 F/g) and a stretchability of up to 300%. The developed approach offers an alternative strategy to fabricate stretchable MXene-based energy storage devices and can be extended to other members of the large MXene family.

Harvesting ocean wave energy is a killer application of triboelectric nanogenerator (TENG) for advantages in simple mechanism, high power density and high efficiency at low frequency. Here we report a self-powered intelligent buoy system (SIBS), in which a high-output multilayered TENG is used for water wave energy harvesting. With a power management module, the output voltage can be converted and regulated as a steady DC voltage of 2.5 V for the operations of a microprogrammed control unit (MCU), several micro sensors and a transmitter. With the intelligent monitoring mechanism of the MCU, the harvested energy can be deployed for each sensor with different priority and data transmission cycle, and the SIBS can be at standby and active status by itself at different energy levels. At a wave frequency of 2 Hz, the SIBS can provide an average output power density of 13.2 mW/m2and realize sustainable and autonomous wireless sensing for acceleration, magnetic intensity and temperature in range of 15 m, with amount of 19 bytes every 30 s. The SIBS has first demonstrated a complete TENG-based micro-energy solution for self-powered intelligent system, including energy harvesting, management, deployment and utilization, with an unattended manner and infinite lifetime. As a significant milestone for the TENG, this work has provided a universal platform for self-powered wireless sensor network nodes and exhibited broad prospects in internet of things, big data, artificial intelligence and blue energy.

Water wave energy is regarded as one of the most prospective renewable energy sources, while most of it has not been utilized for numerous technology defects. As a new energy technology, triboelectric nanogenerator (TENG) has been widely utilized for low frequency and random mechanical energy harvesting, which is very suitable for scavenging water wave energy. In this paper, we present a torus structured triboelectric nanogenerator (TS-TENG) which consists of an inner ball and a torus shell. Triggered by water waves, the ball revolves in the torus shell for triboelectric power generation, and the TS-TENG can harvest random wave energy from all directions. Moreover, to scavenge large-scale water wave energy, the TS-TENG array is fabricated and presented as a power source for persistently powering electronic devices and charging a battery or capacitor. With an agitation frequency of 2 Hz and an oscillation angle of 5°, the TS-TENG is expected to give a maximum peak power density of 0.21 W/m2. Take advantage of low-cost, environment-friendly and easy- implement, the development of the TS-TENG is of great significance for harvesting large-scale ocean wave energy and other potential applications in blue energy.

Piezoelectric organic–inorganic lead halide perovskites have recently attracted much attention in the field of optoelectronic devices. However, their piezoelectric properties as a possible way to modulate device performances have rarely been reported. Here, we study experimentally a photodetector based on CH3NH3PbI3(MAPbI3) single crystals, whose performance is effectively modulated viaan emerging effect—the piezo-phototronic effect, which is to use the piezoelectric polarization charges to tune the optoelectronic processes at the interface. A piezoelectric coefficient of 10.81 pm/V of the CH3NH3PbI3single crystal is obtained. Under 680 nm laser illumination with a power density of 3.641 mW/cm2and at an external bias of 2 V, compared to the case without straining, the light current of the photodetector is enhanced by ∼120% when a 43.48 kPa compressive pressure is applied. The response speed of the photocurrent is 3 and 2 times faster than the cases without applying pressure for the light-on and light-off states, respectively. This work proves that the performance of the photodetector based on MAPbI3single crystals can be effectively enhanced by the piezo-phototronic effect, providing a good method for optimizing the performance of future perovskite-based optoelectronic devices.

Because silicon transistors are rapidly approaching their scaling limit due to short-channel effects, alternative technologies are urgently needed for next-generation electronics. Here, we demonstrate ultrathin ZnO piezotronic transistors with a ∼2 nm channel length using inner-crystal self-generated out-of-plane piezopotential as the gate voltage to control the carrier transport. This design removes the need for external gate electrodes that are challenging at nanometer scale. These ultrathin devices exhibit a strong piezotronic effect and excellent pressure-switching characteristics. By directly converting mechanical drives into electrical control signals, ultrathin piezotronic devices could be used as active nanodevices to construct the next generation of electromechanical devices for human–machine interfacing, energy harvesting, and self-powered nanosystems.

Triboelectric nanogenerator (TENG) has been developed as an effective way to harvest mechanical energy, which is expected for application in mechanical components. In this study, we report a kind of flexure hinges based triboelectric nanogenerator (FH-TENG) by 3D printing with great structural integration and stability. Based on the flexure hinges as a mechanical elastomer, the FH-TENG can convert mechanical energy into electricity by utilizing the contact electrification between fluorinated ethylene propylene and copper films. For a two-layer FH-TENG, it can deliver a maximal output voltage of 191 V and an instantaneous output power of 64μWon the external load of 210MΩat a frequency of 0.8 Hz and a force of ∼20 N. The output performances of the FH-TENGs with different layers, areas, minimum thicknesses and radii of the flexure hinges substrate are also systematically studied and discussed. Furthermore, as an alternative design, the FH-TENG has been integrated into a bearing pedestal, which can not only harvest mechanical energy from the shaft radial movement, but also be applied as a self-powered axis deviation sensor. This work has provided potential applications of the TENG for mechanical energy harvesting and self-powered damage monitoring in mechanical systems.

The physical filtration mechanism of a traditional face mask has a low removal efficiency of ultrafine particulates in the size range of 10–1000 nm, which are badly harmful to human health. Herein, a novel self-powered electrostatic adsorption face mask (SEA-FM) based on the poly(vinylidene fluoride) electrospun nanofiber film (PVDF-ESNF) and a triboelectric nanogenerator (TENG) driven by respiration (R-TENG) is developed. The ultrafine particulates are electrostatically adsorbed by the PVDF-ESNF, and the R-TENG can continually provide electrostatic charges in this adsorption process by respiration. On the basis of the R-TENG, the SEA-FM shows that the removal efficiency of coarse and fine particulates is higher than 99.2 wt % and the removal efficiency of ultrafine particulates is still as high as 86.9 wt % after continually wearing for 240 min and a 30-day interval. This work has proposed as a new method of wearable air filtration and may have great prospects in human health, self-powered electronics, and wearable devices.

Mechanical energy in a rolling tire is strong and stable, but it is always wasted and there is no effective means for harvesting. Herein, we demonstrate an array of compressible hexagonal-structured triboelectric nanogenerators (CH-TENGs) for harvesting the mechanical energy from a rolling tire. The CH-TENG units can be stacked in parallel connections and fixed in a rubber tire. The energy harvesting performances are systematically investigated and the maximum instantaneous power is 1.9 mW with the CH-TENG in 8 units, a weight load of 10 N and a speed of 2.51 m/s. The CH-TENGs have stable and durable characteristics for a 30-day continuous work and can drive a wireless tire pressure sensor once every 14 min when the moving speed is 2.51 m/s and weight load is 10 N. On the basis of the measured output power of the CH-TENG, it is expected to produce at least 1.2 W for a standard tire with the CH-TENG in 500 units and the running speed of 100 km/h. This work not only provides a promising solution to harvest the wasted mechanical energy from rolling tires, but also demonstrates the potential applications of the CH-TENG in sustainable automotive electronics.

Effective power management has always been the difficulty and bottleneck for practicability of triboelectric nanogenerator (TENG). Here we propose a universal power management strategy for TENG by maximizing energy transfer, direct current (DC) buck conversion, and self-management mechanism. With the implemented power management module (PMM), about 85% energy can be autonomously released from the TENG and output as a steady and continuous DC voltage on the load resistance. The DC component and ripple have been systematically investigated with different circuit parameters. At a low frequency of 1Hz with the PMM, the matched impedance of the TENG has been converted from 35MΩ to 1MΩ at 80% efficiency, and the stored energy has been dramatically improved in charging a capacitor. The universality of this strategy has been greatly demonstrated by various TENGs with the PMM for harvesting human kinetic and environmental mechanical energy. The universal power management strategy for TENG is promising for a complete micro-energy solution in powering wearable electronics and industrial wireless networks. With the new coupling mode of triboelectricity and semiconductor in the PMM, the tribotronics has been extended and a new branch of power-tribotronics is proposed for manageable triboelectric power by electronics.

Realizing active interaction with external environment/stimuli is a great challenge for current electronics. In this paper, a tribotronic tuning diode (TTD) is proposed by coupling a variable capacitance diode and a triboelectric nanogenerator in free-standing sliding mode. When the friction layer is sliding on the device surface for electrification, a reverse bias voltage is created and applied to the diode for tuning the junction capacitance. When the sliding distance increases from 0 to 25 mm, the capacitance of the TTD decreases from about 39 to 8 pF. The proposed TTD has been integrated into analog circuits and exhibited excellent performances in frequency modulation, phase shift, and filtering by sliding a finger. This work has demonstrated tunable diode and active analog signal modulation by tribotronics, which has great potential to replace ordinary variable capacitance diodes in various practical applications such as signal processing, electronic tuning circuits, precise tuning circuits, active sensor networks, electronic communications, remote controls, flexible electronics, etc.

Flexible and transparent electronics have attracted wide attention for electronic skin, wearable sensors and man-machine interactive interfacing. In this paper, a novel flexible transparent tribotronic transistor (FTT) is developed by coupling an organic thin film transistor (OTFT) and a triboelectric nanogenerator (TENG) in free-standing sliding mode. The carrier transport between drain and source can be modulated by the sliding-induced electrostatic potential of the TENG instead of the conventional gate voltage. With the sliding distance increases from 0 to 7mm, the reverse drain current is almost linearly increased from 2 to 22 μA. The FTT has excellent performances in stability and durability in different bending modes and radius. The optical transmittance of the device is about 71.6% in the visible wavelength range from 400 to 800nm. Moreover, the FTT is used for active modulation of conventional electronics, in which the luminance, magnetism, sound and micro-motion can be modulated by sliding a finger. This work has provided a new way to actively modulate conventional electronics, and demonstrated the practicability of tribotronics for human-machine interaction.

Water wave energy is considered a promising renewable energy source, while currently little has been exploited due to a number of unsolved challenges for present technologies. The triboelectric nanogenerator (TENG), as an emerging energy harvesting technology, shows particular advantages in transforming low frequency mechanical energy into electricity, providing new opportunities for harvesting water wave energy. In this work, an integrated triboelectric nanogenerator array device based on air-driven membrane structures is demonstrated. With novel designs of a spring-levitated oscillator structure and a mechanism to use air pressure to transfer and distribute harvested water wave energy, the device can drive a series of integrated TENG units effectively and simultaneously. While operating at low frequency near the resonant frequency of about 2.9Hz, the device integrating 38 TENG units shows high output of transferred charges per cycle of 15μC, short-circuit current of 187μA and optimized peak power density of 13.23Wm−3. The device can easily integrates large-scale high-density TENG arrays in one package, as can greatly augment the output, providing a promising route to effectively harvest water wave energy for various practical applications.

The push for green and eco-friendly materials has intensified, driven by the mounting environmental concerns associated with traditional petroleum-based products. As land resources shrink and space for development narrows, marine biomaterials have emerged as a promising alternative over the past decades. Well-known for their vast availability, outstanding biocompatibility, impressive biodegradability, and minimal toxicity, marine biomaterials present an ideal foundation for developing eco-friendly triboelectric nanogenerators (TENGs). In this review, we present the evolution of TENGs based on marine biomaterials, from their core working principles to their multifaceted applications. We begin by elucidating the operational modes and foundational principles of TENGs. Next, we highlight the intrinsic qualities and advantages of marine biomaterials commonly utilized in TENG designs. Additionally, we discuss approaches adopted to amplify the efficacy of TENGs derived from marine biomaterials. A synthesis of documented applications of these TENGs from existing literature is then presented. We finally discuss the existing challenges and future directions in marine biomaterial-inspired TENGs.

Smart packaging plays a crucial role in safeguarding products, monitoring their quality, and ensuring supply chain efficiency during distribution and transportation. However, the extensive use of sensors in smart packaging systems requires a sustainable power supply for long-term monitoring. Unfortunately, portable batteries may not meet the needs for next-generation smart packaging as they have a limited lifetime, are heavy, and may cause environmental pollution after use. To address this issue, we propose a self-powered integrated smart packaging system driven by a novel desiccant-based triboelectric nanogenerator (D-TENG). The D-TENG is designed using a contact-separation mode and includes a paperboard-based honeycomb frame, two PTFE/Cu triboelectric layers, and desiccants stored in the honeycomb holes as the freestanding triboelectric material. We systematically investigate the significant parameters affecting the energy harvesting performance of the D-TENG, including the type of desiccants, frame height, number of honeycomb holes, frequency and amplitude of external excitation, and device orientation with the vibration direction. Furthermore, we demonstrate a self-powered integrated smart packaging system based on the D-TENGs that harvests vibration energy to power sensors integrated into the package. This research provides a practical strategy to continuously monitor the status and quality of packaged products throughout the supply chain for an extended period, reducing food waste and ensuring a complete record of logistics history in vaccine delivery.

Large-scale tactile sensor arrays are of great importance in flexible electronics, human–robot interaction, and medical monitoring. In this paper, a flexible 10 × 10 tribotronic transistor array (TTA) is developed as an active tactile sensing system by incorporating field-effect transistor units and triboelectric nanogenerators into a polyimide substrate. The drain–source current of each tribotronic transistor can be individually modulated by the corresponding external contact, which has induced a local electrostatic potential to act as the conventional gate voltage. By scaling down the pixel size from 5 × 5 to 0.5 × 0.5 mm2, the sensitivities of single pixels are systematically investigated. The pixels of the TTA show excellent durability, independence, and synchronicity, which are suitable for applications in real-time tactile sensing, motion monitoring, and spatial mapping. The integrated tribotronics provides an unconventional route to realize an active tactile sensing system, with prospective applications in wearable electronics, human–machine interfaces, fingerprint identification, and so on.

Portable and wearable personal electronics and smart security systems are accelerating the development of transparent, flexible, and thin-film electronic devices. Here, we report a transparent and flexible self-charging power film (SCPF) that functions either as a power generator integrated with an energy storage unit or as a self-powered information input matrix. The SCPF possesses the capability of harvesting mechanical energy from finger motions, based on the coupling between the contact electrification and electrostatic induction effects, and meanwhile storing the generated energy. Under the fast finger sliding, the film can be charged from 0 to 2.5 V within 2094 s and discharge at 1 μA for approximately 1630 s. Furthermore, the film is able to identify personal characteristics during a sliding motion by recording the electric signals related to the person’s individual bioelectricity, applied pressing force, sliding speed, and so on, which shows its potential applications in security systems in touchpad technology.

Wind energy has played a reasonable proportion in the current energy structure, extracting energy from wind sources attracts extensive attention in the era of global carbon neutrality. However, traditional wind turbine based on electromagnetic generator are not economic in some cases, the new technology demand for complementing conventional approaches is proposed. Recently, the emerging triboelectric nanogenerator (TENG) technology based on the coupling of contact electrification and electrostatic induction have been widely researched and utilized to scavenge wind energy, with the advantages of high efficiency, low cost and portability. Here, the recent advances of wind harvesters based on TENG are reviewed, where the material, structure design, power management and the developed strategies to optimize the performance of TENG-based wind harvesting system are summarized. Meanwhile, the hybridization of TENG with other types of energy harvesting techniques is discussed. Finally, the application, outlook and challenge in the growth of TENG-based wind harvester are outlined.

Multifunctional tactile sensors that can mimic the sensory capabilities of human skin to perceive various external static and dynamic stimuli are essential to interact with the environment and humans for wearable electronics and soft intelligent robotics. Here, inspired by human skin, we report a textile-based tactile sensor capable of multifunctional sensing for personalized healthcare monitoring and soft robotic control. The tactile sensor consists of a triboelectric nanogenerator sensing layer to mimic the function of fast adapting (FA) mechanoreceptors and a piezoresistive sensing layer to achieve the functionality of slow adapting (SA) mechanoreceptors. The tactile sensor has been demonstrated to be able to recognize voice and monitor physiological signals and human motions in a real-time manner. Combined with a machine learning framework, the tactile sensor is able to percept surface textures and material types with high accuracy. It is also demonstrated as an effective human-machine interface for the control of assistive robotics.

There is a tremendous interest to harvest ocean wave energy due to its promising advantages of high-power density, wide distribution, independence of time of day, weather or seasons, and sustainability. However, most of the current energy harvesters or converters based on electromagnetic generators are suffering from unsatisfactory efficiency at low ocean wave triggering frequency and have the drawbacks of complex design, high cost and ease of corrosion in seawater. In this work, we report a matryoshka-inspired hierarchically structured triboelectric nanogenerator (HS-TENG) by nest-assembling multiple shells with decreasing sizes for effectively harvesting low-frequency wave energies with low-cost, high power density and high efficiency. As a proof-of-concept, we have fabricated a three-hierarchical-level HS-TENG by nesting three spherical acrylic shells filled with polytetrafluoroethylene (PTFE) balls into the gap spaces between the neighboring shells. The important factors that may affect the energy harvesting performance of the HS-TENG are studied, including the size and number of moving balls, the diameter of the holding shell, the amplitude and frequency of wave actuation, as well as the orientation angle between wave motion direction and electrode gap. It is demonstrated that the HS-TENG has superior output performance over the traditional single ball TENG (SB-TENG), with a maximum output peak power of 544 μW at a low frequency of 2 Hz, more than 6.5 times of that obtained by a SB-TENG with the same size, capable of driving different wearable electronics. Based on the optimized design, we further demonstrate that a HS-TENG network formed by a 3 × 3 device array can directly lighten dozens of light-emitting diodes and power an electronic thermometer for monitoring water condition, indicating its capability in effectively harvesting water wave energy for potential large-scale deployment in the ocean. This study provides an innovative hierarchical structure that can effectively improve the output performance of TENGs and paves the way for developing next-generation high-performance TENGs for blue energy harvesting.