Triboelectric Energy Harvesting Research Articles

Toward Self-Powered Load Imbalance Detection for Instrumented Knee Implants Using Quadrant Triboelectric Energy Harvesters

Toward Self-Powered Load Imbalance Detection for Instrumented Knee Implants Using Quadrant Triboelectric Energy Harvesters

Sustainable Biopolymers in Eco-Friendly Triboelectric Energy Harvesting.

Biopolymer-based triboelectric nanogenerators (B-TENGs) represent an innovative fusion of eco-friendly, sustainable energy-harvesting technology with renewable and environmentally benign biopolymer material. This integration not only introduces novel pathways for advancing green energy solutions but also offers a critical approach to addressing contemporary environmental challenges and fostering sustainable progress. Over the past few years, B-TENGs have seen rapid and remarkable growth in the realm of biopolymers, device architecture, and their applications (e.g., implantable power source, electronic medicine, human anatomical and physiological movements monitoring sensors, etc.). In this review article, the promising developments in harnessing triboelectric biopolymers are encapsulated, enumerate their representative applications, evaluate the pros and cons of these biopolymers, highlight key challenges for future research, and offer strategic recommendations for innovating and realizing advanced B-TENGs.

MnO2 Nanowires with Sub-10nm Thick Conjugated Microporous Polymers as Synergistic Triboelectric Materials.

MnO2 nanowires coated with conjugated microporous polymers (CMP) are applied as triboelectric energy harvesting materials. The tribopositive performance of the CMP shells is enhanced with the assistance of MnO2 nanowires (MnO2 NW), likely due to cationic charge transfer from the tribopositive CMP layers to the surface Mn2+ and Mn3+ species of MnO2 NW. This is supported by model studies. The MnO2@CMP-2 with sub-10nm thick CMP layers shows promising triboelectric output voltages up to 576V and a maximum power density of 1.31mWcm-2. Spring-assisted triboelectric nanogenerators fabricated with MnO2@CMP-2/PVP-3 films are used as power supplies to operate electronic devices.

Achieving Ultrahigh Efficiency of Triboelectric Nanogenerator Energy Harvesting Systems via Hybrid Electronic‐Spark Power Management

AbstractSignificant efforts are devoted to optimizing the efficiency of triboelectric energy harvesting systems, particularly through the design of an advanced power management system (PMS) for Triboelectric Nanoenerators (TENGs). A critical aspect of PMS is the design and control of switches. However, existing switches face significant limitations. For spark switches, precise control cannot be achieved, and electronic switches can only operate at voltages below several hundred volts which is limited by the risk of electrical breakdown. To address these limitations, a hybrid electronic‐spark switch power management system (HESS) is proposed. HESS changes the connection of capacitors from parallel to series by deploying a maximum voltage tracking switch components at the peak voltage point, resulting in a much‐elevated voltage level to activate the spark switch. This approach achieves precise control of the spark switch for the first time and significantly reduces the operating voltage of electronic switches. Through simulation and experimental verification, HESS achieves the control at a voltage level of 1.8 kV for spark switch, with an electrical component breakdown voltage of only 450 V. The power density of the HESS is 29.8 mW Hz−1 m−2, which is a new record for electronic switches.

A Mussel-Inspired and Recyclable Coating with Integrated Daytime Radiative Cooling and Triboelectric Energy Harvesting for Intelligent and Sustainable Buildings.

Carbon neutrality necessitates new technologies for renewable energy utilization, active regulation of heat exchange, and material recycling to promote green and intelligent building development. Currently, the integration of these functions and characteristics into a single coating material presents a significant challenge. Here, we demonstrate a novel triboelectric and radiative cooling coating with mussel-inspired architectures, fabricated using cellulose nanofibers and Mica-TiO2 as a functional mortar and brick, respectively. The abundant polar groups and specific surface area of cellulose nanofibers enable a high accumulation of induced electrostatic charges, allowing the coating to act as a tribolayer to generate triboelectric outputs. The regularly layered arrangement of Mica-TiO2 endows fire resistance to the coating, which exhibits self-extinguishing properties and maintains 45% of its original electrical output even after direct exposure to flame for 20 s. Additionally, the created multilayered stacking morphology, as well as intense group vibrations of Mica-TiO2, facilitates high reflectivity (Rsolar = 0.9) and long-wave infrared emissivity (ϵLWIR = 0.94), achieving a daytime subambient temperature drop of 5.3 °C. Notably, the coating can be recycled easily while maintaining its triboelectric, radiative cooling, and fire-resistant properties. This work provides an innovative strategy for unifying triboelectric and radiative cooling functions, as well as recyclability, into a single coating material, offering new insights for future sustainable and energy-efficient buildings.

A self-integration via dual-active mode structural-SC-TENG energy device for electrochemical energy storage and triboelectric energy harvesting

The structural supercapacitor with triboelectric nanogenerator (structural-SC-TENG) is a remarkable integrated energy device utilized for clean energy storage and harvesting. Here, we demonstrated the structural-SC-TENG device based on a multifunctional storage and harvester using dual-functional MoO3 grown on a carbon cloth electrode (CC) via hydrothermal technique and physiochemical characterization revealed the formation of an orthorhombic phase of MoO3. The FE-SEM morphological analysis confirms that the cubes-like peals were uniformly decorated on the CC surface in an upward and downward direction. The dual-functional MoO3 grown on the CC electrode was used for the construction of the supercapacitor and TENG device which will act as a charge-storing electrode in the supercapacitor and charge-sharing electrode in TENG. The constructed MoO3 SSC provides an excellent device capacitance of 97.86 F g−1, energy density of 40.50 Wh kg−1, and a high-power density of 28,125 W kg−1 with remarkable cyclic life modeled/predicted via time series analysis (TSA) technique. On the other side, the TENG device constructed using MoO3 on CC as the positive electrode (confirmed through KPFM analysis) and PDMS as the negative electrode exhibited a better electrical response with a high voltage and current of 55 V and 0.19 μA and delivered a peak power of 4.17 μW. This type of integrated device is splendid and possibly be used for self-powered sensors, smart IoTs, self-charging power systems, low-power electronics, and various indoor/outdoor environments.

Utilization of the easy electron-losing capacity of dog fur waste for green energy devices and self-powered smart pet care systems

The present global energy shortage and climate crisis can be addressed by embracing recycling, reuse, and recovery; for example, this can be achieved by methodically utilizing the problematic wastes for energy harvesting. This research describes a novel approach for recovery and reutilization of waste material by incorporating dog fur waste into a triboelectric energy harvester; this was accomplished via a simple, inexpensive, and eco-friendly chemical processing to turn this problematic waste into a high-performance tribolayer. Due to the complications of operating practical devices with dog fur in its natural form, the dog fur waste was transformed for the first time into a uniform thin-film-based high-performance positive tribolayer. The optimization of the fabrication of the dog fur film featured hexagonal pyramid nanostructures, and a novel tribopair was selected and consisted of the dog fur-based film and a Teflon film; these films have very large differences in electron affinities. Based on this optimization and selection, we achieved an outstanding output voltage, current, and power density of 2021.46 V, 109.84 μA and 24,669.957 μWcm−2, respectively, along with appreciable mechanical stability during continuous operation up to 10,000 cycles. Our research demonstrates the potential for integration of green electronics and self-powered human-pet interaction systems while providing a sustainable approach to a circular bioeconomy.

Study on dynamics and power generation performance coupling of galloping-based triboelectric nanogenerator for harvesting broadband wind energy

In order to innovate the wind energy harvesting method based on galloping and improve galloping-based triboelectric nanogenerator wind energy harvesting performance, a galloping-based square cylinder triboelectric nanogenerator (GSC-TENG) is proposed in this work. The GSC-TENG consists of a square cylinder bluff body, a triboelectrification embedded in the bluff body, a cantilever beam and a base. The response of the aerodynamics and power generation performance of the GSC-TENG with a high mass ratio (m*=526.6) to the system damping ratio (0.0106, 0.0304 and 0.0568) and wind speed (0.6–12.4 m/s) are studied through CFD simulation and wind tunnel test. The critical wind speed, amplitude and power generation performance of systems with different damping ratios are analyzed in detail, and the wind speed range corresponding to the maximum amplitude is determined. By increasing the stiffness and damping ratio of the system, the output performance under high wind speed conditions can be enhanced and stabilized. Compared with the GSC-TENG with damping ratio 0.0106, the output power of the GSC-TENG with damping ratio 0.0568 at the wind speed of 4.0 m/s is enhanced by 141 times, which is up to 62.25 W/m3. To harness a broadband wind energy, a novel galloping-based TENG is introduced. Analyzing the dynamic characteristics of square cylinder bluff body with different damping ratios is of significant meaning to the design and improve of the galloping-based triboelectric wind energy harvester.

Flexible PMN-PT/rGO/PVDF-TrFE based composites for triboelectric and piezoelectric energy harvesting

Flexible piezoelectric nanogenerator (PENG) and triboelectric nanogenerators (TENG) have gained prodigious attention due to the increasing demand of nano and micro energy for driving of miniaturized electronic devices, sensors, and various internet of things. The key challenges that are currently in focus are material selection and simple fabrication techniques for improved electrical performance along with good mechanical properties and flexibility. Herein, a ferroelectric polymer, poly(vinylidenefluoride-co-trifluoroethyne) (PVDF-TrFE), is chosen as a flexible material due to its promising prospect for energy harvesting. To improve the performance, a ceramic material, 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN-PT), with very high piezoelectric properties has been selected as the reinforcement. Further, reduced graphene oxide has been added as a conducting filler to promote charge conduction. A remarkable enhancement in output voltage of nearly 3 fold is achieved in PVDF-TrFE/PMN-PT (PP) polymer composite as compared to the base polymer PVDF-TrFE (P) TENG device. Furthermore, the PVDF-TrFE/rGO/PMN-PT (PPR) as a PENG illustrates a great improvement in output current of the order of 2 as compared to the pristine polymer. The maximum output voltage as shown by the TENG is 200 V and the maximum current that is shown by the PENG is 30 µA. Therefore, the fabricated PMN-PT based PVDF-TrFE nanogenerators have an immense prospect for applications in self-powered systems.

Quenched PVDF/PMMA Porous Matrix for Triboelectric Energy Harvesting and Sensing

Quenched <scp>PVDF</scp>/<scp>PMMA</scp> Porous Matrix for Triboelectric Energy Harvesting and Sensing

Smart Lanceolate Surface with Fast Fog-Digesting Performance for Triboelectric Energy Harvesting.

Utilizing the ubiquitous fog in nature to create decentralized energy-harvesting devices, free from geographical and hydrological constraints, presents an opportunity to foster sustainable power generation. Extracting electrical energy from fog relies heavily on fog-digesting performance. Improving the efficiency of fogwater utilization remains a formidable challenge for existing fogwater energy-harvesting technologies. Inspired by the water-harvesting behavior of Tillandsia leaves, a smart lanceolate surface is developed to harvest triboelectric energy by rapidly digesting fog. Such a surface exhibits capabilities in fog management, encompassing precise fog capture, transportation, and critical droplet separation. Specifically, fog droplets condense at hydrophilic sites of acylated cellulose ester, subsequently migrating toward the rear under Laplace pressure, thereby producing energy as they traverse through the tail end. Such architecture yields a brief voltage restoration period (with an average of 9.36 s), can rush the capacitor to 11.59 V within 20 s, and achieves a water-digestion rate of up to 71.05 kg/m2 h. This biomimetic approach enhances the water-digestion efficacy of the atmospheric water energy apparatus and offers perspectives on mitigating deficiencies in power resources.

Self-adaptive rotational electromagnetic energy generation as an alternative to triboelectric and piezoelectric transductions

Triboelectric and piezoelectric energy harvesters can hardly power most microelectronic systems. Rotational electromagnetic harvesters are very promising alternatives, but their performance is highly dependent on the varying mechanical sources. This study presents an innovative approach to significantly increase the performance of rotational harvesters, based on dynamic coil switching strategies for optimization of the coil connection architecture during energy generation. Both analytical and experimental validations of the concept of self-adaptive rotational harvester were carried out. The adaptive harvester was able to provide an average power increase of 63.3% and 79.5% when compared to a non-adaptive 16-coil harvester for harmonic translation and harmonic swaying excitations, respectively, and 83.5% and 87.2% when compared to a non-adaptive 8-coil harvester. The estimated energy conversion efficiency was also enhanced from ~80% to 90%. This study unravels an emerging technological approach to power a wide range of applications that cannot be powered by other vibrationally driven harvesters.

Ethylcellulose and bismuth sodium titanate-barium zirconate titanate (BNT-BZT) composite fibers for triboelectric energy harvesting

Green cellulose and toxic-free/rare earth-free nanomaterials are promising towards the development of triboelectric nanogenerators (TENGs) as energy harvesters for sustainable electronics. In this study, ethylcellulose (EC) and bismuth sodium titanate-barium zirconate titanate (BNT-BZT) are used as raw materials. An EC and BNT-BZT composite fiber mat was prepared by electrospinning and used as a positive triboelectric layer in a friction nanogenerator, while fluorinated ethylene propylene (FEP) was used as a negative triboelectric layer. After optimizing the electrospinning parameters and characterizing the materials, the developed TENG output power was studied as a function of the BNT-BZT doping concentration in the EC. At 2 wt% of doping, the output voltage of the TENG has a 3-fold increase compared with that obtained with a pure EC mat as the positive triboelectric layer. In addition, the TENG showed good output performance and operating stability after exposure to high temperature (70 ºC) and relative humidity (90 %). The maximum output power density of 134 μW/cm2 was obtained at a load resistance of 210 MΩ, showing good prospects in powering Internet of Things (IoT) sensor nodes.

Robust PVA-MWCNTs-based triboelectric energy harvesting device: Self-powered smart-door technology

Triboelectric nanogenerators (TENGs) are emerging as promising solutions for mechanical energy harvesting from various environmental sources, offering a pathway toward self-sufficient power generation. The present research demonstrates the feasibility and effectiveness of the polyvinyl alcohol (PVA)-multi-walled carbon nanotubes (MWCNTs) composite as a tribopositive material for designing robust TENG. Through comprehensive evaluations, the dispersion of MWCNTs in PVA is confirmed. MWCNTs-based TENGs are fabricated in a vertical contact-separate configuration for harnessing mechanical energy effectively. The device's performance metrics including output voltage, current, power generation, and durability, are investigated. The device with 1.6 wt% MWCNTs fillers exhibits a performance enhancement in voltage and current. The optimized MWCNTs-based TENG attains its maximum power of 542 μW at 30 MΩ load resistance, showcasing its potential for powering small-scale electronics. Furthermore, possible applications and implications of integrating self-powered smart-door systems are demonstrated. This can be implemented in various real-world scenarios, such as residential buildings, commercial establishments, and public facilities.

Piezoelectric-triboelectric energy harvester with elastic double-side stoppers

An impact-based piezoelectric and triboelectric energy harvester with elastic double-side stoppers for wideband operation and efficient energy capture is proposed. The coupled nonlinear governing equations of the energy harvesting system are derived based on Hertz's contact model. The dynamic behavior of the energy harvester is enriched from linear to nonlinear regime by introducing stoppers to broaden the energy harvesting frequency range. The dynamic mechanism and energy harvesting performance of the harvester are explored through frequency sweeps, which identify comprehensive dynamic states and evaluate the energy harvesting performance. The time history diagram, phase diagram, Poincaré mapping and bifurcation diagram are used to discuss the single-period, double-period, multi-period and chaotic period vibrations of the energy harvester. Detailed parametric studies investigate the effects of the initial gap, mass ratio, stopper stiffness and excitation amplitude on the voltage and power output. Four models with different stoppers are compared to identify the best energy harvesting performance. Results show that compared with the cantilever without stopper, the proposed model with elastic double-side stoppers significantly broadens the resonance frequency region by 172.5 %, and increases the output cumulative voltage by 0.89 V. A maximum voltage of 1.2 V with a 0.6-V-bandwidth of 6.9 Hz is achieved when the energy harvester is actuated at 0.8 g acceleration. The RMS voltage of triboelectric nanogenerator is highest at 25 Hz, reaching 1.99 V, and the peak-to-peak output voltage reaches 15.59 V.

The investigation of the energy harvesting performance using electrospun PTFE/PVDF based on a triboelectric assembly

This work presents an investigation into the energy harvesting performance of a combination of polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) materials prepared using a one-step electrospinning technique. Before electrospinning, different percentages of the 1 micron PTFE powder were added to a PVDF precursor. The surface morphology of the electrospun PTFE/PVDF fibre was investigated using a scanning electron microscope and tunnelling electron microscope. The structure was investigated using Fourier-transform infrared spectroscopy and x-ray diffraction analysis (XRD). A highly porous structure was observed with a mix of the α- and β-phase PVDF. The amount of β-phase was found to reduce when increasing the percentage of PTFE. The maximum amount of PTFE that could be added and still be successfully electrospun was 20%. This percentage showed the highest energy harvesting performance of the different PTFE/PVDF combinations. Electrospun fibres with different percentages of PTFE were deployed in a triboelectric energy harvester operating in the contact separation mode and the open circuit voltage and short circuit current were obtained at frequencies of 4–9 Hz. The 20% PTFE fibre showed 4 (51–202 V) and 7 times (1.3–9.04 µA) the voltage and current output respectively when compared with the 100% PVDF fibre. The V oc and I sc were measured for different load resistances from 1 kΩ to 6 GΩ and achieved a maximum power density of 348.5 mW m−2 with a 10 MΩ resistance. The energy stored in capacitors 0.1, 0.47, 1, and 10 µF from a book shaped PTFE/PVDF energy harvester were 1.0, 16.7, 41.2 and 136.8 µJ, respectively. The electrospun fibre is compatible with wearable and e-textile applications as it is breathable and flexible. The electrospun PTFE/PVDF was assembled into shoe insoles to demonstrate energy harvesting performance in a practical application.

A self-powered accelerometer with over-range detection for vibration and shock based on triboelectric-electromagnetic mechanism

Accelerometers based on triboelectric nanogenerators (TENGs) have garnered significant interest in recent years. However, many of these devices lack a self-sustained power supply for autonomous wireless operations and a mechanism for over-range detection. Additionally, theoretical investigations on the sensitivity of TENG-based accelerometers are scarce. In this work, a novel self-powered accelerometer for vibration and shock integrating a freestanding triboelectric-layer-based TENG (FT-TENG), two contact-separation TENGs (CS-TENGs) and an electromagnetic generator (EMG) is proposed and then investigated through both numerical simulations and experimental demonstrations. The EMG is used for vibration energy harvesting, exhibiting an impressive power output of 4.11 mW under a vibration acceleration of 12 m/s2. The FT-TENG and the CS-TENGs work for acceleration sensing and over-range detection respectively. Under vibration, the sensitivity and measurement range are related to the frequency of excitation, and the proposed accelerometer has the maximum sensitivity (0.75 V s2/m) at its natural frequency. For shock events, the sensitivity of the accelerometer is dominated by the shock duration in a short-duration range, which is estimated to be 0.12 V s2/m under a shock duration of 0.03 s. This work not only contributes to the understanding of TENGs adopted for sensing but also creates potential applications of triboelectric and electromagnetic energy harvesting and provides a feasible design for autonomous wireless sensor nodes.

Energizing geriatric healthcare: A triboelectric energy harvester with self-powered morse code generator and IoT-Enabled remote sensing tactile patch

Self-powered tactile sensors unleash a diverse array of distinctive interaction techniques and other possibilities in the contemporary world of small-scale electronics. In many circumstances of information exchange, the touch sensor is a fundamental and crucial human-machine interface (HMI). Rapid advancements in portable, wearable, and Internet of Things technologies demand a tactile sensing system to be thin, flexible, effective, self-powered, and secure. Triboelectric nanogenerator (TENG) based touch sensors are the future of flexible and self-powered sensors. Triboelectric nanogenerator based sensors exhibit excellent material compatibility and can produce substantial electrical signals even when frequencies are low and forces are moderate; this motivates researchers to develop self-powered triboelectric sensors. Here, we have proposed a skin-conforming and flexible tactile sensor with a micro-patterned dielectric surface, driven by a stencil-printed activated carbon electrode (Printed carbon PC-TENG). The device performance has been enhanced through the optimization of its output, achieved by analysing its structure using Finite Element Analysis in conjunction with the electrostatic module of COMSOL Multiphysics. The fabricated device produces a voltage in an open circuit measuring 242V along with a power density of 14.69 μW/cm2 in single electrode mode. Further, it can be employed as an energy harvester, demonstrated through energizing LEDs, LCD, Wristwatches, and digital ring counter. The proposed TENG can also serve as an international Morse code generator and self-powered sensor for IoT-enabled remote-sensing finger patches, providing medical assistance to geriatric and bedridden patients.

Agricultural waste rice husk/poly(vinylidene fluoride) composite: a wearable triboelectric energy harvester for real-time smart IoT applications

Agricultural waste rice husk/poly(vinylidene fluoride) composite: a wearable triboelectric energy harvester for real-time smart IoT applications

A generalized model for a triboelectric nanogenerator energy harvesting system

A triboelectric nanogenerator (TENG) energy harvesting system involves at least three components: the mechanical source that inputs mechanical energy to drive TENGs, the TENG device itself as an energy converter, and an external electrical circuit that output the energy from TENGs. Multiple theoretical models have been developed for structural optimization design and maximum power output, yet there has been less emphasis on dynamic modelling of the entire energy harvesting system. This work presents attempts to establish such system-level models that encompass both mechanical and electrical systems. Special consideration is paid to the dynamic contact problem in this generalized model, since dynamic response of impacts can significantly affect the electric outputs. To address contact constraint problems, the penalty function method is utilized to handle non-smoothness and discontinuity. Subsequently, this research specifies how to improve the maximum energy conversion efficiency, and suggest optimal executive strategies for maximizing the energy output through a thorough parametric study. The anticipated outcome is that the generalized model will not only guide optimization design and predict the dynamic characteristics of the energy harvesting system but also assess the potential feasibility of mechanical energy harvesting technology across diverse application domains.