Flexible Layered-Graphene Charge Modulation for Highly Stable Triboelectric Nanogenerator

The continuous quest to enhance the output performance of triboelectric nanogenerators (TENGs) based on the surface charge density of the tribolayer has motivated researchers to harvest mechanical energy efficiently. Most of the previous work focused on the enhancement of negative triboelectric charges. The enhancement of charge density over positive tribolayer has been less investigated. In this work, we developed a layer-by-layer assembled multilayer graphene-based TENG to enhance the charge density by creatively introducing a charge trapping layer (CTL) Al2O3 in between the positive triboelectric layer and conducting electrode to construct an attractive flexible TENG. Based on the experimental results, the optimized three layers of graphene TENG (3L-Gr-TENG) with CTL showed a 30-fold enhancement in output power compared to its counterpart, 3L-Gr-TENG without CTL. This remarkably enhanced performance can be ascribed to the synergistic effect between the optimized graphene layers with high dielectric CTL. Moreover, the device exhibited outstanding stability after continuous operation of > 2000 cycles. Additionally, the device was capable of powering 20 green LEDs and sufficient to power an electronic timer with rectifying circuits. This research provides a new insight to improve the charge density of Gr-TENGs as energy harvesters for next-generation flexible electronics.

Download Full-text

Boosting output performance of sliding mode triboelectric nanogenerator by charge space-accumulation effect

Nature Communications ◽

10.1038/s41467-020-18086-4 ◽

2020 ◽

Vol 11 (1) ◽

Cited By ~ 6

Author(s):

Wencong He ◽

Wenlin Liu ◽

Jie Chen ◽

Zhao Wang ◽

Yike Liu ◽

...

Keyword(s):

Charge Density ◽

Sliding Mode ◽

Mechanical Energy ◽

Low Frequency ◽

Deep Understanding ◽

Triboelectric Nanogenerator ◽

Ambient Conditions ◽

Output Performance ◽

Charge Space ◽

Air Breakdown

Abstract The sliding mode triboelectric nanogenerator (S-TENG) is an effective technology for in-plane low-frequency mechanical energy harvesting. However, as surface modification of tribo-materials and charge excitation strategies are not well applicable for this mode, output performance promotion of S-TENG has no breakthrough recently. Herein, we propose a new strategy by designing shielding layer and alternative blank-tribo-area enabled charge space-accumulation (CSA) for enormously improving the charge density of S-TENG. It is found that the shielding layer prevents the air breakdown on the interface of tribo-layers effectively and the blank-tribo-area with charge dissipation on its surface of tribo-material promotes charge accumulation. The charge space-accumulation mechanism is analyzed theoretically and verified by experiments. The charge density of CSA-S-TENG achieves a 2.3 fold enhancement (1.63 mC m−2) of normal S-TENG in ambient conditions. This work provides a deep understanding of the working mechanism of S-TENG and an effective strategy for promoting its output performance.

Download Full-text

Triboelectric nanogenerators as new energy technology and self-powered sensors – Principles, problems and perspectives

Faraday Discussions ◽

10.1039/c4fd00159a ◽

2014 ◽

Vol 176 ◽

pp. 447-458 ◽

Cited By ~ 590

Author(s):

Zhong Lin Wang

Keyword(s):

Energy Harvesting ◽

Charge Density ◽

Energy Conversion ◽

Daily Life ◽

Mechanical Energy ◽

Ocean Waves ◽

Human Motion ◽

Triboelectric Nanogenerator ◽

Standard Material ◽

Self Powered

Triboelectrification is one of the most common effects in our daily life, but it is usually taken as a negative effect with very limited positive applications. Here, we invented a triboelectric nanogenerator (TENG) based on organic materials that is used to convert mechanical energy into electricity. The TENG is based on the conjunction of triboelectrification and electrostatic induction, and it utilizes the most common materials available in our daily life, such as papers, fabrics, PTFE, PDMS, Al, PVCetc.In this short review, we first introduce the four most fundamental modes of TENG, based on which a range of applications have been demonstrated. The area power density reaches 1200 W m−2, volume density reaches 490 kW m−3, and an energy conversion efficiency of ∼50–85% has been demonstrated. The TENG can be applied to harvest all kinds of mechanical energy that is available in our daily life, such as human motion, walking, vibration, mechanical triggering, rotation energy, wind, a moving automobile, flowing water, rain drops, tide and ocean waves. Therefore, it is a new paradigm for energy harvesting. Furthermore, TENG can be a sensor that directly converts a mechanical triggering into a self-generated electric signal for detection of motion, vibration, mechanical stimuli, physical touching, and biological movement. After a summary of TENG for micro-scale energy harvesting, mega-scale energy harvesting, and self-powered systems, we will present a set of questions that need to be discussed and explored for applications of the TENG. Lastly, since the energy conversion efficiencies for each mode can be different although the materials are the same, depending on the triggering conditions and design geometry. But one common factor that determines the performance of all the TENGs is the charge density on the two surfaces, the saturation value of which may independent of the triggering configurations of the TENG. Therefore, the triboelectric charge density or the relative charge density in reference to a standard material (such as polytetrafluoroethylene (PTFE)) can be taken as a measuring matrix for characterizing the performance of the material for the TENG.

Download Full-text

Flexible and Wearable PDMS-Based Triboelectric Nanogenerator for Self-Powered Tactile Sensing

Nanomaterials ◽

10.3390/nano9091304 ◽

2019 ◽

Vol 9 (9) ◽

pp. 1304 ◽

Cited By ~ 4

Author(s):

Jie Wang ◽

Shuo Qian ◽

Junbin Yu ◽

Qiang Zhang ◽

Zhongyun Yuan ◽

...

Keyword(s):

Human Body ◽

Flexible Electronics ◽

Mechanical Energy ◽

Electric Energy ◽

Green Light ◽

Triboelectric Nanogenerator ◽

Good Sensitivity ◽

Pdms Film ◽

Compact Size ◽

Self Powered

Flexible electronics devices with tactile perception can sense the mechanical property data of the environment and the human body, and they present a huge potential in the human health system. In particular, the introduction of ultra-flexible and self-powered characteristics to tactile sensors can effectively reduce the problems caused by rigid batteries. Herein, we report a triboelectric nanogenerator (TENG), mainly consisting of an ultra-flexible polydimethylsiloxane (PDMS) film with micro-pyramid-structure and sputtered aluminum electrodes, which achieves highly conformal contact with skin and the self-powered detection of human body motions. The flexible polyethylene terephthalate (PET) film was selected as spacer layer, which made the sensor work in the contact-separation mode and endowed the perfect coupling of triboelectrification and electrostatic induction. Moreover, the controllable and uniform micro-structure PDMS film was fabricated by using the micro-electro-mechanical system (MEMS) manufacturing process, bringing a good sensitivity and high output performance to the device. The developed TENG can directly convert mechanical energy into electric energy and light up 110 green Light-Emitting Diodes (LEDs). Furthermore, the TENG-based sensor displays good sensitivity (2.54 V/kPa), excellent linearity (R2 = 0.99522) and good stability (over 30,000 cycles). By virtue of the compact size, great electrical properties, and great mechanical properties, the developed sensor can be conformally attached to human skin to monitor joint movements, presenting a promising application in wearable tactile devices. We believe that the ultra-flexible and self-powered tactile TENG-based sensor could have tremendous application in wearable electrons.

Download Full-text

Predicting the Output of a Triboelectric Energy Harvester Undergoing Mechanical Pressure

Volume 2: Modeling, Simulation and Control; Bio-Inspired Smart Materials and Systems; Energy Harvesting ◽

10.1115/smasis2016-9157 ◽

2016 ◽

Author(s):

Danial Sharifi Kia ◽

Shahrzad Towfighian ◽

Congrui Jin

Keyword(s):

Theoretical Model ◽

Charge Density ◽

Surface Charge ◽

Surface Charge Density ◽

Mechanical Energy ◽

High Energy ◽

Interfacial Structure ◽

Triboelectric Nanogenerator ◽

Contact Behavior ◽

Interfacial Structures

Energy harvesting using a triboelectric nanogenerator (TENG) has been a major area of research in the recent years in order to harvest mechanical energy in different scales. High energy conversion efficiency, broad range of application in different systems and relatively easy fabrication process are among the factors demonstrating essential needs for TENG technology development. Performance of a TENG could be affected by many factors such as the frequency of vibration and the surface charge density. As a key factor in improving the power output of TENGs, surface charge density could be modified by the selection of proper charging materials and by increasing the contact area between the tribo-pairs. Although there have been numerous studies analyzing the performance of different tribo-pairs and different interfacial structures for a TENG, a systematical analysis of the contact phenomena between the interfacial structures in order to investigate the effects of different surface properties and structures such as, surface roughness, dielectric properties or the presence of nanostructures is still not available. In the current study, systematical numerical simulations have been performed on the adhesive contact behavior of the macro/nanostructures at the TENG interface. An interaction potential has been used to represent the adhesive interactions while surface deformations are coupled using half-space Green’s function. Furthermore, effects of the deformation of the interfacial structure on the performance and output of the TENG has been investigated by developing a theoretical model for a vertical-contact-mode TENG using a mass-spring system to represent the motion of the moving electrode. Coupling the theoretical model to the instantaneous deformation of the interfacial structure, real-time output of the TENG in terms of short-circuit voltage and open-circuit current has been studied in response to a predefined pressure input. The results of the current study demonstrate the effects of the deformation of the interfacial structure on the output characteristics of TENGs during the transition between partial-contact to full-contact modes. Numerical simulation results represent acceptable correlations with previously reported experimental data. The simulation package developed in this study is capable of simulating the contact behavior of the interfacial structure and predicting the deformed geometry.

Download Full-text

High performance floating self-excited sliding triboelectric nanogenerator for micro mechanical energy harvesting

Nature Communications ◽

10.1038/s41467-021-25047-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Li Long ◽

Wenlin Liu ◽

Zhao Wang ◽

Wencong He ◽

Gui Li ◽

...

Keyword(s):

Charge Density ◽

High Performance ◽

Mechanical Energy ◽

Triboelectric Nanogenerator ◽

Maximum Charge ◽

Charge Decay ◽

Air Breakdown ◽

Weak Wind ◽

Breakdown Model ◽

High Output

AbstractNon-contact triboelectric nanogenerator (TENG) enabled for both high conversion efficiency and durability is appropriate to harvest random micro energy owing to the advantage of low driving force. However, the low output (<10 μC m−2) of non-contact TENG caused by the drastic charge decay limits its application. Here, we propose a floating self-excited sliding TENG (FSS-TENG) by a self-excited amplification between rotator and stator to achieve self-increased charge density, and the air breakdown model of non-contact TENG is given for a maximum charge density. The charge density up to 71.53 μC m−2 is achieved, 5.46 times as that of the traditional floating TENG. Besides, the high output enables it to continuously power small electronics at 3 m s−1 weak wind. This work provides an effective strategy to address the low output of floating sliding TENG, and can be easily adapted to capture the varied micro mechanical energies anywhere.

Download Full-text

Rationally patterned electrode of direct-current triboelectric nanogenerators for ultrahigh effective surface charge density

10.21203/rs.3.rs-49397/v1 ◽

2020 ◽

Author(s):

Zhihao Zhao ◽

Yejing Dai ◽

Di Liu ◽

Linglin Zhou ◽

Shaoxin Li ◽

...

Keyword(s):

Energy Harvesting ◽

Charge Density ◽

Surface Charge ◽

Direct Current ◽

Surface Charge Density ◽

Large Scale ◽

Mechanical Energy ◽

Triboelectric Nanogenerator ◽

Electrode Structure ◽

Effective Surface

Abstract As a new-era of energy harvesting technology, triboelectric nanogenerator (TENG) has been invented to convert randomly distributed mechanical energy into electric power for Internet of Things (IoTs) and artificial intelligence (AI) applications. Enhancement of the triboelectric charge density is crucial for its large-scale commercialization. Here, a microstructure-designed direct-current TENG (MDC-TENG) with rationally patterned electrode structure is presented to enhance its effective surface charge density by increasing the efficiency of contact electrification, which achieves a record high charge density of ~5.4 mC m-2 (more than 2 times of the best value reported). The MDC-TENG realizes both the miniaturized device and high output performance. Meanwhile, its effective charge density can be further improved as the device size increases. Our work not only provides a miniaturization strategy of TENG for the application in IoTs and AI as energy supply or self-powered sensor, but also presents a paradigm shift of the large-scale energy harvesting by TENGs.

Download Full-text

A Tubular Flexible Triboelectric Nanogenerator with a Superhydrophobic Surface for Human Motion Detecting

Sensors ◽

10.3390/s21113634 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3634

Author(s):

Jianwei Wang ◽

Zhizhen Zhao ◽

Xiangwen Zeng ◽

Xiyu Liu ◽

Youfan Hu

Keyword(s):

Energy Harvesting ◽

Flexible Electronics ◽

Superhydrophobic Surface ◽

Mechanical Energy ◽

Construction Material ◽

Human Motion ◽

Triboelectric Nanogenerator ◽

Free Standing ◽

Self Powered ◽

Human Motion Monitoring

The triboelectric nanogenerator (TENG) is a newly arisen technology for mechanical energy harvesting from the environment, such as raindrops, wind, tides, and so on. It has attracted widespread attention in flexible electronics to serve as self-powered sensors and energy-harvesting devices because of its flexibility, durability, adaptability, and multi-functionalities. In this work, we fabricated a tubular flexible triboelectric nanogenerator (TF-TENG) with energy harvesting and human motion monitoring capabilities by employing polydimethylsiloxane (PDMS) as construction material, and fluorinated ethylene propylene (FEP) films coated with Cu as the triboelectric layer and electrode, serving in a free-standing mode. The tube structure has excellent stretchability that can be stretched up to 400%. Modifying the FEP films to obtain a superhydrophobic surface, the output performance of TF-TENG was increased by at least 100% compared to an untreated one. Finally, as the output of TF-TENG is sensitive to swing angle and frequency, demonstration of real-time monitoring of human motion state was realized when a TF-TENG was worn on the wrist.

Download Full-text