▲ (From left) Professor Jerald Yoo, Dr. Zhuoyue Li, and integrated M.S.-Ph.D. candidates Kyungsoo Park, Donghan Kim, and Gwangjin Kim

Professor Jerald Yoo’s research team in the ECE Department announced that it has developed “SkinECG,” a skin-adhesive wearable healthcare system capable of measuring electrocardiogram signals without a battery.

By combining energy harvesting technology with body-coupled power transfer, the research team proposed a new solution to one of the biggest challenges in the commercialization of wearable devices: power supply.

The research was published on May 1 in Science Advances, an international academic journal published by the American Association for the Advancement of Science (AAAS).

■ Research Background

Wearable healthcare systems are gaining attention as next-generation medical technologies that can measure biological signals in real time through sensors worn on the body and detect early signs of disease. A representative example is the electrocardiography (ECG) sensor. ECG sensors measure electrical signals generated by the heart and are essential for identifying cardiovascular diseases such as arrhythmia.

However, batteries remain a major obstacle to the commercialization and long-term use of wearable devices. Due to their size and weight, batteries reduce wearability, and when they are discharged, biological signal collection may be interrupted. They also require periodic charging and replacement, causing inconvenience for users and making long-term continuous monitoring of biological signals difficult.

To address this issue, previous studies have attempted to apply energy harvesting technology to wearable devices. Energy harvesting converts ambient energy, such as light, heat, and movement, into electricity. However, there has been a mismatch between the location where a wearable sensor must be attached and the location where energy can be efficiently harvested.

For example, ECG sensors are generally attached to the chest, while power-generating devices such as solar cells are more efficient when attached to areas such as the arms or legs, where they can receive sunlight. In other words, the optimal location for generating electricity does not necessarily match the location where biological signals need to be measured.

■ Research Achievements

To overcome this fundamental limitation, Professor Yoo’s research team proposed a new power supply architecture that wirelessly delivers power generated by multiple energy-harvesting devices attached to the human body to a remote ECG sensor. In the paper, this technology is referred to as an Orthogonal Energy Harvesting Network (O-EHN).

SkinECG consists of an ECG sensor, which integrates a flexible circuit board and semiconductor chip on a skin-adhesive hydrocolloid patch, and a multi-energy wireless power supply network that delivers power generated by multiple energy-harvesting devices to the sensor.


▲ Figure 1. Conceptual diagram of battery-free wearable power supply technology

The system operates by converting ambient energy into electricity through one or more energy-harvesting devices and then wirelessly supplying that power to an ECG sensor on the chest through body-coupled power transfer technology. Each power-generating device is designed to transmit power at an orthogonal frequency, allowing the number and placement of devices to be flexibly adjusted while ensuring stable power delivery to the ECG sensor.

Professor Yoo’s team also overcame the limitations of conventional wireless power transfer methods. Conventional approaches transmit power by radiating electromagnetic waves through the air, but when used near the human body, electromagnetic waves may be absorbed or scattered by the body, reducing efficiency. The research team instead focused on transmitting power along the surface of the skin rather than radiating it over a distance.

Using body-coupled powering, the team successfully delivered power generated by devices attached to the body to the ECG sensor on the skin without wires. The system was also designed so that power signals from multiple energy-harvesting devices do not interfere with one another by using distinct frequency channels, enabling stable power delivery to the sensor.

In particular, the research team limited the level of power coupled to the human body to a level comparable to what people are routinely exposed to from surrounding electronic devices and everyday environments. The system was operated under low-power conditions designed with human safety in mind. Through this, the team demonstrated that an ECG sensor can be powered solely by energy harvesting, without batteries or wires.

■ Expected Impact

The development of SkinECG is expected to mark an important turning point in solving the power supply challenge for next-generation wearable healthcare systems.

This technology can also be applied not only to ECG monitoring, but also to long-term monitoring of various biological signals, including electromyography and electroencephalography. Furthermore, it is expected to develop into a foundational technology for addressing power supply challenges in wearable electronics and implantable medical devices.

In addition, because the technology reduces constraints on the number and placement of energy-harvesting devices and can be combined with existing commercial energy harvesting technologies, it offers strong potential for expansion into a wide range of future wearable healthcare devices.

■ Researchers’ Remarks

Professor Yoo explained, “Wearable healthcare devices have faced a fundamental limitation: the location where ambient energy can be effectively harvested and the location where biological signals must be measured are often different. This research addresses that problem by wirelessly delivering power along the surface of the human body.”

He added, “We limited the power level delivered to the human body to a level comparable to everyday exposure, taking safety into account. Through this, we demonstrated that stable power can be supplied to ECG sensors without heavy and bulky batteries. In the future, this technology could be expanded not only into a multimodal digital healthcare platform that powers various biological signal sensors, such as electromyography and electroencephalography sensors, but also into a foundational power supply technology for a wide range of wearable devices.”

■ Researcher Career Path

The first author of the paper, Dr. Zhuoyue Li, received her Ph.D. in February 2026 from the Department of Electrical and Computer Engineering at the National University of Singapore (NUS) under the co-supervision of Professor Jerald Yoo and worked as a visiting researcher at Seoul National University. Co-authors Kyungsoo Park, Donghan Kim, and Gwangjin Kim are conducting research in the field of body area networks (BAN).

This study was conducted as an international joint research project led by Professor Jerald Yoo’s research team at Seoul National University, with participation from the University of Tokyo and the National University of Singapore.


▲ Figure 2. Implementation and demonstration of a battery-free skin-adhesive wearable system
A solar cell-based wireless power supply module (left) and a skin-adhesive ECG sensor (center) were attached to the human body. The team successfully measured ECG signals while wirelessly supplying power without a battery (right).

[Reference]
- Paper/Journal : SkinECG: An orthogonal remote powering wearable skin-like sensor, Science Advances
- DOI : https://doi.org/10.1126/sciadv.aec9803 
- Chosun Ilbo (2026. 05. 20) : Wearable System Developed to Measure ECG Signals Without Batteries

- Hankook Ilbo (2026. 05. 29) : Energy Harvesting, a Solution to the Charging Problem, Could Become Part of Everyday Life Within Five Years

[Contact]

Professor Jerald Yoo / High-Performance Integrated Microsystems Laboratory / 02-880-1776 / jerald@snu.ac.kr

Source: https://ece.snu.ac.kr/ece/news?md=v&bbsidx=57886

Translated by: Changhoon Kang, English Editor of the Department of Electrical and Computer Engineering, changhoon27@snu.ac.kr