Here, we explore why TENGs are poised to play a major role in powering next-generation sensor networks and enabling self-powered, sustainable sensor technologies.
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The widespread integration of sensors, pivotal in ushering in the new era of 5G and the Internet of Things (IoT), faces a critical bottleneck—dependence on batteries and wired power sources. However, triboelectric nanogenerators (TENGs) offer a promising solution, harnessing ambient mechanical energy to power sensors wirelessly.
The sensors industry has expanded rapidly, with sensor technologies now integrated across consumer electronics, transportation, infrastructure, industrial automation, environmental monitoring, and more. Global sensor industry revenue is expected to grow from $200 billion in 2022 to over $410 billion by 2030. However, most sensors today rely on batteries or wired power connections, limiting their application scope and long-term sustainability.
Triboelectric nanogenerators (TENGs) have emerged as a promising technology that can convert ambient mechanical energy into usable electrical energy through simple, low-cost components. Their energy harvesting capacity and simple integration with sensor systems make TENGs well-positioned to enable self-powered, sustainable sensors across industries.
The Working Principle of TENGs
TENGs rely on the triboelectric effect and electrostatic induction to convert ambient mechanical energy into electrical energy. The triboelectric effect causes certain materials to gain or lose electrons when they come into contact. For example, when the glass comes into contact with plastic, triboelectric charging causes the transfer of electrons from the plastic to the glass surface, causing the glass to acquire a negative polarity and the plastic to acquire a positive polarity.
As the materials separate, the opposite charges accumulated on their surfaces create a potential difference that can drive electron flow through an external load resistor connected between electrodes attached to the back of each material.
Alternating the contact and separation continuously leads to electron flow back and forth between the electrodes. This oscillatory motion induces electron flow, generating alternating current, and with rectifiers, TENGs efficiently convert this into continuous, low-power output, ideal for powering sensors, data transmission, and electronics.
How TENGs are Transforming the Sensor Industry?
The simple, versatile design of TENGs makes them well-suited as long-lasting power sources for low-power electronics like sensors or IoT devices, which may require between 10-100 microwatts of energy. This energy harvesting capacity perfectly positions TENGs to enable self-powered sensor networks for infrastructure monitoring, industrial automation, environmental sensing or even healthcare applications.
Compared to traditional batteries, TENGs provide sustainable, maintenance-free energy without the need for replacement or recharging cycles. Their low fabrication costs using accessible materials and their lightweight nature enable easy integration with sensors and wearable technology. Importantly, triboelectric output scales with the extent of applied mechanical force, making TENGs adaptable and scalable energy sources.
TENGs are compatible with various potential energy sources such as vibration, motion, temperature fluctuations, wind, and flowing liquids. Applications range from roadside networks harnessing vehicle motion for citywide air quality monitoring to wearable TENGs using body movements for remote health tracking. This versatility enables seamless integration with sensor networks in smart cities, transportation, agriculture, factories, and supply chain applications.
Biomechanical Monitoring in Healthcare
TENG-powered biosensors are advancing remote patient monitoring through portable or implantable self-powered devices, facilitating early diagnosis and intervention. Applications include energy-autonomous pacemakers, hearing aids, and electronic skin patches, harnessing biomechanical energy from natural physiological processes for vital sign tracking and transmission.
Recent developments, such as the smart wearable sensor (SWS) with TENG technology, demonstrate the potential for diverse biometric health monitoring applications, including fall-down alarms and sleep tracking, showcasing the versatility and effectiveness of TENGs in the healthcare sector.Top of Form
Industrial Automation
The growing demand for industrial sensor networks, projected to reach over $4 billion by 2025, emphasizes the need for reliable and efficient solutions. Self-powered wireless sensor systems offer a transformative approach, using factory vibrations as an input energy source through TENGs. This innovation enhances energy efficiency in manufacturing, process industries, and energy plants, eliminating the need for sensor wiring or battery expenses.
TENGs power self-powered ammonia leakage sensors, support real-time food quality monitoring in cold supply chains, and contribute to gas sensing systems for CO and NH3, acting as remote leak alarms in gas pipelines.
Environmental Monitoring
Leveraging natural forms of kinetic energy like wind, vibration and fluid flow, TENGs can facilitate continuous, self-powered data collection from distributed sensor networks, even in remote locations for agricultural, meteorological and seismic monitoring applications. In marine environmental monitoring, TENG-activated devices, such as oscillating rotary switch mechanisms (SR-TENG) and multi-tiered TENGs, harness mechanical energy from ocean waves to enable self-powered wireless sensor nodes.
Maintenance visits to periodically replace batteries in such extensive networks also become avoidable by deploying TENG-enabled sensors.
Reducing the Environmental and Economic Impact of the Sensor Industry
On the one hand, self-powered sensors decrease electronic waste related to depleted sensor batteries that contain toxic compounds such as lithium, cadmium, and lead, which require careful disposal. TENG constituent materials, such as polymers, oxides, and flip-chip-mounted silicon, are relatively environmentally benign, exhibiting a seven times lower carbon footprint than battery materials.
On the other hand, avoiding recurring battery costs throughout the long functional periods of sensors provides a return on investment while enhancing productivity through uninterrupted operation.
Therefore, TENG integration supports the sensors industry’s broader shift toward clean, renewable sensor power sources with lower carbon footprint and toxic waste generation in alignment with ESG initiatives around sustainability.
Challenges and Future Developments
While triboelectric output has steadily improved over the past decade owing to advances in materials like Teflon, MoS2, graphene, silicone rubber and breakthroughs in structural engineering, the voltage levels generated remain modest. They are not ideal for high-performance applications and are prone to wear and tear, requiring suitable packaging to protect them from environmental factors.
Ongoing research on TENGs aims to optimize materials, explore new triboelectric pairs, and enhance energy generation through hybridization with solar cells or piezoelectrics. This advancement could expand their application to equipment monitoring in wind farms, underwater exploration systems, real-time food supply chain tracking and rapid health diagnostics in disaster response. Moreover, integrating data transmission and artificial intelligence on sensor data will further evolve self-powered wireless sensor networks for smarter, more predictive, and more efficient operations.
References and Further Reading
Li, Y., et al. (2023). Recent progress in self-powered wireless sensors and systems based on TENG. Sensors, 23(3), p.1329. doi.org/10.3390/s23031329
Li, R., et al. (2021). Smart wearable sensors based on triboelectric nanogenerator for personal healthcare monitoring. Micromachines, 12(4), p.352. doi.org/10.3390/mi12040352
Wang, N., et al. (2023). Innovative Technology for Self‐Powered Sensors: Triboelectric Nanogenerators. Advanced Sensor Research, 2(5), p.2200058. doi.org/10.1002/adsr.202200058
Cao, X., et al. (2023). Multidiscipline applications of triboelectric nanogenerators for the intelligent era of Internet of Things. Nano-Micro Letters, 15(1), p.14. doi.org/10.1007/s40820-022-00981-8
Ikimi .O. (2021). The Future’s in the Friction: How “TENGs” Show Promise in Self-powered Sensors. [Online]. Available at: https://www.allaboutcircuits.com/news/futures-in-the-friction-how-tengs-show-promise-self-powered-sensors/
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