- Develops a high-performance nanogenerator based on vanadium MXene-functionalized composite nanofibers ？

- Develops a battery-free pressure sensor for real-time monitoring of human activity and posture in wearable devices -

- Paper published in the internationally renowned journal Nano Energy by Elsevier (IF: 17.6) -

Professor Jae-young Park's research team (Department of Electronic Engineering) successfully developed a wearable battery-free sensor that can monitor human activity and posture in real-time, using a fluoropolymer composite nanofiber material functionalized with vanadium MXene (V2CTX-MXene), which has high electronegativity, as well as a breathable, high-performance triboelectric nanogenerator.

 (left) Professor Jae-young Park and Dr. Omar (right)

Recently, wearable sensors have gained attention as a key technology in various applications, including electronic skin, robotics, healthcare and medical systems, and human-machine interfaces. However, the power supply issue for operating these sensors remains a significant challenge that must be addressed for their commercialization. As a solution to this issue, research on eco-friendly, battery-free wearable sensors using triboelectric nanogenerators to monitor various human activities and biometric information in real-time without the need for a power supply is actively underway.

The research team successfully developed a V2CTX@poly(vinylidene fluoride-co-hexafluoropropylene) composite nanofiber mat with high electronegativity, stability, and flexibility using electrospinning technology, and significantly enhanced the performance of the triboelectric nanogenerator using this material. By utilizing the abundant functional groups (-F, -O, and -OH) on the surface of vanadium MXene, the electronegativity was increased. A microcapacitor network was formed in the polymer matrix, improving dielectric properties along with electron trapping capacity, while significantly reducing charge loss.

The triboelectric nanogenerator, fabricated by combining the nanofiber mat of polyethylene oxide (PEO), which has high electropositivity, demonstrated a high power density of 18.2W/m², which is 3.5 times higher than that of a nanogenerator based on pure PVDF-HFP nanofibers. The nanogenerator, fabricated using a nanofiber mat, exhibited excellent breathability, making it highly wearable and stable. The energy harvested from various human activities provided enough electricity to power commercial electronic devices such as stopwatches and thermohygrometers. Additionally, the battery-free wearable pressure sensor, with a high sensitivity of 25.17 VkPa^-1 (1~42 kPa), was successfully used to demonstrate real-time monitoring of various human activities and postures, including walking, running, jumping, sitting, and cycling. The nanogenerator-based battery-free sensor developed by the research team is expected to be widely utilized and applied in electronic skin, robotics, human-machine interfaces, and various wearable medical and healthcare devices.

This research was funded by the government (Ministry of Science and ICT) through the National Research Foundation of Korea's support for mid-career researchers (NRF-2020R1A2C2012820) and the Ministry of Trade, Industry, and Energy's Industrial Technology Innovation Program (RS-2022-00154983, Development of Autonomous Power Sensor Platform for Low-Power Sensors and Actuation). The research results were published in Nano Energy (IF: 17.6), one of the world's leading journals in energy materials and devices by Elsevier. https://doi.org/10.1016/j.nanoen.2024.109787

<Key performance of the triboelectric nanogenerator and battery-free pressure sensor based on vanadium MXene-functionalized fluoropolymer composite nanofiber mat, and examples of self-powered human activity and posture monitoring applications>