The triboelectric effect — first documented over a century ago as a classical electrostatic phenomenon — has recently experienced a remarkable transformation, evolving into cutting-edge technology for sustainable energy generation. Once considered a scientific curiosity and limited to simple static electricity demonstrations, this age-old principle has been revolutionized by the advent of triboelectric nanogenerators (TENGs).
TENGs convert mechanical energy into electricity through the transfer of electrons when two different materials come into contact and then separate. This simple process creates a charge imbalance, which generates an electric field through electrostatic induction, inducing a flow of electrons in an external circuit and producing electricity. While other nanogenerators already exist, TENGs are unique because they can translate vibrations as low as 5 Hz into useful energy.
TENGs have, therefore, emerged as a promising technology for sustainable and self-powered systems, capable of converting ubiquitous mechanical energy into electrical energy even at low frequencies. Over the past decade, research has evolved from proof-of-concept devices to diverse, application-oriented innovations in wearables, healthcare, environmental monitoring, and smart electronics.
As of 2024, the global TENG market was valued at approximately $1.2 billion. The market is expected to grow significantly, reaching around $13.6 billion by 2033, representing a compound annual growth rate (CAGR) of nearly 25%. This growth is driven by the potential for TENGs to be used in consumer electronics, healthcare, aerospace and defense, and the automotive industry. As demand for sustainable power sources and advancements of nanotechnology has taken off, TENGs are useful in more applications.
Explosive research growth in barely a decade
The evolution of TENGs since their inception in 2012 has been marked by significant academic interest and technological innovation (see Figure 1). We examined the CAS Content CollectionTM, the largest human-curated collection of scientific publications, covering the period from 2012 to 2025. This analysis revealed a substantial increase in scholarly publications on TENGs, reflecting their growing importance in energy harvesting and self-powered systems.
However, patents (yellow) are growing comparatively less than the growth in journal publications, as TENGs are relatively new and still in the early stages of research rather than commercialization. Research efforts are focused on developing materials for triboelectric layers, optimizing the structure of nanogenerator devices, improving the electrostatic function and output electricity generated by the nanogenerators, and enhancing the stability of device performance.
Dual functionality drives new applications
TENGs utilize materials that are inherently triboelectric-positive or negative in nature, as listed in the triboelectric series. One of TENGs’ most exciting features is their dual functionality; since they can power themselves as standalone devices or act as a power source for other devices, they meet the needs of advanced electronics and emissions-free electricity.
- As self-powered active devices: The triboelectric layer materials are strategically chosen to act as active self-powered devices. In these applications, TENGs convert mechanical stimuli into electrical signals via the output signal’s direct correlation with mechanical stimulus, both in amplitude and frequency. This allows TENGs to deliver real-time, high-resolution data, which makes them ideal for monitoring in wearables, biomedical devices, e-skin, and human-machine interfaces.
- As external power sources: TENGs act as power sources by harvesting ambient mechanical energy to charge energy storage devices such as supercapacitors or micro batteries, which can run low-powered electronics. As energy harvesters/power sources, TENGs are instrumental in powering wearables, portable electronics, Internet of Things (IoT) nodes, and even environmental monitoring systems in remote areas without conventional power sources.
Numerous modes of structural design and optimization
TENGs operate in four distinct modes, each with unique mechanisms for generating electricity (see Figure 2).
- Vertical contact-separation mode: Two materials come into contact and then separate perpendicularly, generating opposite charges on the surfaces. This separation creates a potential difference, driving current through an external circuit. It is ideal for vertical pressing motions.
- Lateral sliding mode: The triboelectric layers slide against each other horizontally, creating a displacement in the contact area, which leads to charge separation and current generation. It is suitable for in-plane motions like swiping, sliding, or twisting.
- Single-electrode mode: One triboelectric layer is grounded, while the other (usually mobile) induces a potential difference as it contacts/separates or slides. It is ideal for freely moving or irregular objects, like human skin or flowing water.
- Freestanding triboelectric-layer mode: A mobile triboelectric layer (not connected to electrodes) moves between two fixed electrodes, inducing charge flow due to changing electrostatic balance. It is effective for rotatory devices, wind/water-driven systems, and engine vibrations.
In addition to these numerous operational modes, TENGs display inherent adaptability across a broad range of energy harvesting scales, from micro to macro-level applications. This versatility arises from these diverse operational modes, their modular design, and the broad choice of materials that can be customized for specific environments and energy sources. As a result, TENGs are being integrated into large-, medium-, and small-scale energy harvesting based on the type of vibrational source (see Figure 3).
Innovative applications from biomedicine to renewable energy
TENGs are versatile, and as advanced electronics and battery energy storage continue to become ubiquitous, their uses will multiply. As seen in Figure 4, our analysis of the CAS Content Collection showed a detailed overview of the current and emerging applications of TENGs, described in more detail below:
Providing power and flexibility for wearables
Wearable devices are electronics worn on the body, often close to the skin to track, analyze, and transmit personal data. These devices have become popular due to their ability to monitor health, fitness, and other biometric data in real time. TENGs can harvest energy from various mechanical movements, such as walking, running, or even subtle body movements. This harvested energy can be used to power wearable devices and create self-powered sensors that monitor various physiological parameters, such as heart rate, respiration, and body temperature. These sensors can also operate without external power sources.
TENGs can be made from flexible materials, making them suitable for integration into clothing and accessories. This flexibility ensures comfort and ease of use for the wearer, and it allows them to be used for environmental monitoring, such as detecting changes in temperature, humidity, and air quality.
Powering body-implantable medical devices
TENGs are emerging as an external powerhouse for body-implantable devices. They can power devices like pacemakers, implantable sensors, and drug delivery systems. These devices harvest biomechanical vibrations from body motions, organ activity, or fluid flow and convert it into usable electric power. Materials that are biocompatible such as PDMS, silicone, or hydrogel composites can be used, and the TENG devices can be scaled down to fit in tight anatomical spaces.
Enabling closed-loop electrostimulations
TENGs are increasingly utilized in closed-loop electrostimulation systems due to their ability to generate electricity from biomechanical activities. They can function as active self-powered biosensors, detecting body motion, neural activity, or mechanical deformation, and convert this biomechanical vibrational energy into electricity for use in electrostimulation. Examples include self-control systems for neurogenic underactive bladder vagus nerve stimulation using gastrointestinal peristalsis energy, pain modulation therapy, and muscle rehabilitation by responsive stimulation based on motion or stress levels.
Triboelectric nanogenerators for human–machine interfaces
Because they are sensitive, self-powered sensors, TENGs enable intuitive and real-time human-machine interfaces (HMIs). Their high sensitivity, flexibility, and scalability makes them suitable for prosthetics, virtual/augmented reality, and interactive surfaces. Some tactile restoration devices using TENGs in patients with nerve injury or soft tissue loss have already entered the market. Recent developments include dual-mode interaction, where TENGs facilitate voice and gesture recognition, enhancing interaction capabilities. Additionally, nanophotonic readout circuits are being used to stabilize and enhance the real-time performance of TENG-based HMIs.
Facilitating ocean energy harvesting
Wave energy harvesting using TENGs has emerged as a promising method for converting low-frequency ocean wave motion into electricity. Key designs include pendulum-based, rolling-sphere, and hybrid systems that convert wave-induced mechanical motion into electrical energy. Applications range from buoys and offshore sensors to hybrid renewable energy systems. While TENGs show potential for decentralized marine energy harvesting, challenges such as scalability and durability in harsh ocean conditions must be addressed.
Hybridization with other nanogenerators for greater reliability
TENGs are excellent for harvesting low-frequency, irregular mechanical energy. However, output can be intermittent, making them less than ideal for all environments when used alone. Hybridizing complementary technologies broadens their energy harvesting spectrum. Hybridization involves combining TENGs with nanogenerators that operate on other mechanisms, such as piezoelectric, thermoelectric, and pyroelectric effects. Additionally, TENGs are hybridized with batteries and supercapacitors, as well as TENG-based uninterrupted power supplies (UPS), to enhance charge storage and supply capabilities.
Multiple materials available for different applications
Since material properties are crucial for boosting the output of TENGs, the choice of materials is central to their performance and application scope. The triboelectric effect is ubiquitous and can occur between any two materials found in nature. For TENG layers, insulators and dielectric materials are commonly used due to their ability to retain the electrostatic charges and prevent dissipation.
Polymers are a primary class of materials chosen as triboelectric layers because many are highly triboelectric positive or negative (based on the triboelectric series), which enhances the charge transfer between contacting surfaces. Polymers’ flexibility also makes them well-suited for stretchable and wearable applications.
Conductive polymer composites like PDOT:PSS and graphene are useful as flexible electrodes and smart textiles, as are 2D materials such as MXenes. Metal-organic frameworks (MOFs) have strong charge induction and charge trapping capabilities, which makes them suitable for TENGs in wearable devices. In our analysis of the CAS Content Collection, we visualized the materials mentioned in TENG-related publications (see Figure 5).
There is also a newly discovered effect on the metal-semiconductor interface known as the tribovoltaic phenomenon, where a direct current is generated by sliding a p-type semiconductor over an m-type semiconductor or a metal surface. This further expands the material horizon for TENGs to the metal-semiconductor interface, p-n semiconductor interface, metal-insulator-semiconductor interface, and metal-insulator-metal interface.
Challenges to widespread usage
Despite their potential, TENGs present key challenges to their wider application, such as energy conversion efficiency, durability, scalability, and limited knowledge of their capabilities. They face competition from established technologies and hurdles with integrating alongside existing systems.
To overcome these challenges, researchers are focusing on:
- Engineering advanced materials with higher triboelectric performance, self-healing properties, and eco-friendliness.
- Hybridizing TENGs with other energy harvesting mechanisms to enhance output.
- Developing scalable manufacturing methods for real-world development.
- Improving power management systems for efficient energy storage and usability
- Using biodegradable and natural polymers for greener solutions.
Powering the future, one contact at a time
From their roots in classical electrostatics to their use as modern energy harvesters, TENGs have made a remarkable transformation. Initially considered a simple by-product of material contact, the triboelectric effect has reemerged as a powerful mechanism for converting ambient mechanical energy into electricity. Over the past decade, the transformation has been fueled by material innovation, design, and interdisciplinary collaboration.
TENGs have evolved from laboratory prototypes to practical devices that have found applications in many sectors. This progress reflects not only the flexibility and efficiency of TENGs but also their adaptability to various scales and environments. It shows their immense potential in addressing real-world energy challenges.
As we move toward a future dominated by smart devices and sustainable energy systems, the unique dual functionality of TENGs — as both energy harvesters and self-powered systems — places them at the forefront of next-generation technologies. Whether embedded in clothing, implanted in biomedical devices or deployed as energy harvesters in remote environments, TENGs offer a pathway toward clean, maintenance-free, and smart electronics.
