Water is one of the most sustainable resources in the world, offering an abundance of hydro energy. Getting a large amount of electricity through conventional water energy harvesting is expensive, with complex mechanisms and bulky installation systems. In the case of the small amount of energy for some portable electronic devices and sensor systems, water droplet harvesting as a sustainable energy resource has become a forward‐looking step to meet the future demand for green energy. The ultimate demand for green energy in the future requires all the possible sustainable energy sources surrounding human society. The emerging potential of water droplet‐driven energy‐harvesting nanogenerators can meet a significant portion of the green energy demand. In this review, the recent developments in droplets‐driven nanogenerators for effective energy scavenging is summarized. It also includes an extensive discussion about the device structures from the material selection and output performance aspects. This review also gives a brief discussion on the applications of droplet‐based nanogenerators and outlines the future possibilities via the current improvement in designs and fabrication strategies that have been introduced by the field.

Water Droplet‐Based Nanogenerators

Energy harvesting from the ambient environment can be a beneficial and promising source for powering micro- and nanodevices. Triboelectric nanogenerator (TENG) technology has been proved to be a simple and cost-effective method to harness ambient mechanical energy. The performance of the TENG device mainly depends on the careful selection of the material pair. So far, metals and polymer materials have dominated TENG technology. Recently, there have been few reports on metal–organic framework (MoF)-based TENGs. MoFs are very interesting and offer excellent chemical and thermal stability, besides their unique properties, such as tunable pore size and high surface area. Herein, we report a zeolitic imidazole framework (ZIF-67)-based TENG device for self-powered device applications. We used ZIF-67 as one tribolayer, and PET and PMMA as opposite tribolayers. The output performance of the TENG device fabricated with the PMMA/ZIF-67 pair showed values of 300 V, 47.5 µA, and 593 mW/m2 of open-circuit voltage, short-circuit current, and power density, respectively. To the best of our knowledge, these are the highest reported values so far for ZIF-67-based TENG devices. The fabricated TENG device lit up 250 LEDs and was employed to explore different self-powered device applications.

/pdf/zif-67-metal-organic-framework-based-triboelectric-3s691en6.pdf

ZIF-67-Metal–Organic-Framework-Based Triboelectric Nanogenerator for Self-Powered Devices

Small-scale electronic devices need self-powering technology, and one way to do that is to use mechanical energy harvesters. These devices can turn ambient mechanical energy into electricity. Triboelectric nanogenerators (TENGs) are the best choice for converting mechanical energy into electrical energy, but they have a problem in converting ultra-low vibrations in the environment. Traditional TENGs with solid frictional layers are not well-suited for this purpose. To address this limitation, liquid-solid (L-S) TENGs have emerged, which can capture ultra-low vibrational frequencies due to their fluidic nature. Despite this advantage, L-S TENGs exhibit lower energy conversion efficiency than their solid counterparts, and they cannot be used in hybrid energy harvesting. New research has started using ferrofluids in TENGs to address these issues. The resulting ferrofluid-solid based (FF-S) TENGs have showcased a promising outcome by replacing the liquid component with ferrofluids. These systems have demonstrated their capability to capture ultra-low vibrational frequencies effectively and are also used for hybrid energy harvesting. In the current review, we present a comprehensive overview of diverse designs, operational mechanisms, and applications of FF-S TENGs. Furthermore, we delve into the potential opportunities and prospects for integrating FF-S TENGs into practical applications. 

Advances in Ferrofluid-Based Triboelectric Nanogenerators: Design, Performance, and Prospects for Energy Harvesting Applications

Advances in liquid-solid triboelectric nanogenerators and its applications

Triboelectric nanogenerators (TENGs) are emerging as a form of sustainable and renewable technology for harvesting wasted mechanical energy in nature, such as motion, waves, wind, and vibrations. TENG devices generate electricity through the cyclic working principle of contact and separation of tribo-material couples. This technology is used in outstanding applications in energy generation, human care, medicinal, biomedical, and industrial applications. TENG devices can be applied in many practical applications, such as portable power, self-powered sensors, electronics, and electric consumption devices. With TENG energy technologies, significant energy issues can be reduced or even solved in the near future, such as reducing gas emissions, increasing environmental protection, and improving human health. The performance of TENGs can be enhanced by utilizing materials with a significant contrast in their triboelectrical characteristics or by implementing advanced structural designs. This review comprehensively examines the recent advancements in TENG technologies for harnessing mechanical waste energy sources, with a primary focus on their sustainability and renewable energy attributes. It also delves into topics such as optimizing tribo-surface structures to enhance output performance, implementing energy storage systems to ensure stable operation and prolonged usage, exploring energy collection systems for efficient management of harvested energy, and highlighting practical applications of TENG in various contexts. The results indicate that TENG technologies have the potential to be widely applied in sustainable energy generation, renewable energy, industry, and human care in the near future.

Advances in Triboelectric Nanogenerators for Sustainable and Renewable Energy: Working Mechanism, Tribo-Surface Structure, Energy Storage-Collection System, and Applications

This study aimed to develop a simple but effective mechanical-to-electrical energy conversion for harvesting hydrokinetic energy based on triboelectric nanogenerator (TENG) technology. Here, a direct-current fluid-flow-based TENG is reported as a potential solution to solve the inconvenience of directly powering electronic devices where direct-current (DC) power is required. The falling of a water droplet (about 1.06 mL) from an elastomeric pipe can generate an open-circuit voltage of ~35 V, short-circuit current of 3.7 µA, and peak power of 57.6 µW by passing through a separated electrode. Notably, the electrical responses have the distinct characteristics of pulsed direct current. The ability to generate DC outputs enables the TENG to directly drive electronic devices. Our experimental results prove that this TENG can act as a power source to directly light up 50 light-emitting diodes without requiring a rectifier, and, also, the produced electric energy was demonstrated that can be stored directly in a capacitor to power commercial temperature and humidity IoT sensors. Furthermore, the device shows a greatly varied output voltage based on the droplet flow rate, with a linearity R2 = 0.998. This work highlights a promising potential for applications in harvesting hydrokinetic energy and self-powered sensors and systems.

/pdf/a-direct-current-triboelectric-nanogenerator-energy-14pg5ohi.pdf

A Direct-Current Triboelectric Nanogenerator Energy Harvesting System Based on Water Electrification for Self-Powered Electronics

Recently, there has been a growing need for sensors that can operate autonomously without requiring an external power source. This is especially important in applications where conventional power sources, such as batteries, are impractical or difficult to replace. Self-powered sensors have emerged as a promising solution to this challenge, offering a range of benefits such as low cost, high stability, and environmental friendliness. One of the most promising self-powered sensor technologies is the L–S TENG, which stands for liquid–solid triboelectric nanogenerator. This technology works by harnessing the mechanical energy generated by external stimuli such as pressure, touch, or vibration, and converting it into electrical energy that can be used to power sensors and other electronic devices. Therefore, self-powered sensors based on L–S TENGs—which provide numerous benefits such as rapid responses, portability, cost-effectiveness, and miniaturization—are critical for increasing living standards and optimizing industrial processes. In this review paper, the working principle with three basic modes is first briefly introduced. After that, the parameters that affect L–S TENGs are reviewed based on the properties of the liquid and solid phases. With different working principles, L–S TENGs have been used to design many structures that function as self-powered sensors for pressure/force change, liquid flow motion, concentration, and chemical detection or biochemical sensing. Moreover, the continuous output signal of a TENG plays an important role in the functioning of real-time sensors that is vital for the growth of the Internet of Things.

/pdf/recent-progress-in-self-powered-sensors-based-on-liquid-3dxltxe8.pdf

Recent Progress in Self-Powered Sensors Based on Liquid–Solid Triboelectric Nanogenerators

In order to meet the growing demand for sustainable and renewable energy, significant processes have been achieved in the energy harvesting field in recent years. Due to its strong polarity property and superior mechanical characteristics, polyvinylidene fluoride (PVDF) serves as the most attractive material for a liquid-solid triboelectric nanogenerator (LS-TENG). PVDF-based TENG has come a long way thus far. Hence, we developed a high-performance magnetoelectric (ME) nanocomposite membrane made of PVDF and CoFe2O4 nanoparticles for application in the triboelectric layer of the LS-TENG device. Due to the large magnetic anisotropy of CoFe2O4, a strong interaction between the electromagnetic phase and the crystalline phase could well be established. Moreover, a chemical technique is used to introduce 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) with a reasonably extended fluoride chain to increase the dispersion of CoFe2O4 nanoparticles in the PVDF. Thus, the crystalline β phase of the membrane increased to 77.7% with 10 wt.% CoFe2O4 and reached a maximum value of 85.4% with 10 wt.% CoFe2O4@POTS in PVDF matrix, indicating an increase in polarity property and dielectric constant of the nanocomposite membrane. Besides, the CoFe2O4/PVDF-based TENG also delivers a power density of 1.62 W/m2, which is 2.7 higher than the pure PVDF-based TENG. This work demonstrates a novel technique for increasing the β phase of the CoFe2O4/PVDF nanocomposite membrane, which could also improve the LS-TENG output performance for real-life applications in energy harvesting.

/pdf/driving-the-polyvinylidene-fluoride-crystallization-via-cs04ph5r.pdf

Driving the Polyvinylidene Fluoride Crystallization via Surface Functionalization of Ferromagnetic Nanoparticles for Liquid-Solid Triboelectric Nanogenerator Enhancement

Pulsating flow, a common term in industrial and medical contexts, necessitates precise water flow measurement for evaluating hydrodynamic system performance. Addressing challenges in measurement technologies, particularly for pulsating flow, we propose a flowing liquid-based triboelectric nanogenerator (FL-TENG). To generate sufficient energy for a self-powered device, we employed a fluorinated functionalized technique on a polyvinylidene fluoride (PVDF) membrane to enhance the performance of FL-TENG. The results attained a maximum instantaneous power density of 50.6 µW/cm2, and the energy output proved adequate to illuminate 10 white LEDs. Regression analysis depicting the dependence of the output electrical signals on water flow revealed a strong linear relationship between the voltage and flow rate with high sensitivity. A high correlation coefficient R2 within the range from 0.951 to 0.998 indicates precise measurement accuracy for the proposed FL-TENG. Furthermore, the measured time interval between two voltage peaks precisely corresponds to the period of pulsating flow, demonstrating that the output voltage can effectively sense pulsating flow based on voltage and the time interval between two voltage peaks. This work highlights the utility of FL-TENG as a self-powered pulsating flow rate sensor.

Flowing Liquid-Based Triboelectric Nanogenerator Performance Enhancement with Functionalized Polyvinylidene Fluoride Membrane for Self-Powered Pulsating Flow Sensing Application

This work develops a cellulose-based electric generator that offers a new method for harvesting mechanical energy in the presence of water based on the triboelectric effect and the charging effect between two metals with different work functions. This design consists of two dissimilar electrodes located on a dielectric substrate and a movable cellulose sponge wetted by water. The device is capable to produce a maximum instantaneous short-circuit current of 60 μA/cm2 and an induced voltage of 0.5 V with direct-current characteristics. The ability to generate DC outputs enables DC-CEG directly charge a capacitor without requiring a rectifier. This finding declares a great potential application of DC-CEG as a power source to run electronic devices.

DC Output Cellulose-Based Electric Generator Based On Materials Work Functions

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Q. Nguyen

Author Tools

Chat about Author