Professor Joon Sung Ahn from the Department of Electronics and Mechanical Convergence Engineering at Korea University's Sejong Campus (Vice President Young Kim) and his research team have developed a cutting-edge energy storage solution for next-generation wearable electronic devices: Fiber Supercapacitors (FSs).

 

This research follows their previous achievement in March, where they were the first in the world to develop a manufacturing technology for metal/ceramic nanoribbon yarns for smart textiles. The current study was conducted in collaboration with Dr. Yong Rok Jung from the Korea Atomic Energy Research Institute, Professor In Kyu Park from the Department of Mechanical Engineering at KAIST, Professor Sang Wook Kim from the Department of Materials Science and Engineering at KAIST, and Dr. Jun Ho Jung from the Korea Institute of Machinery and Materials.

 

△(From left to right) Professor Joon Sung Ahn from the Department of Electronics and Mechanical Convergence Engineering at Korea University’s Sejong Campus, Associate Research Professor Suchithra Padmajan Sasikala from the Department of Materials Science and Engineering at KAIST, Dr. Yong Rok Jung from the Korea Atomic Energy Research Institute, Dr. Jun Ho Jung from the Korea Institute of Machinery and Materials, Professor Sang Wook Kim from the Department of Materials Science and Engineering at KAIST, and Professor In Kyu Park from the Department of Mechanical Engineering at KAIST.

 

The research team successfully developed ultra-high-performance supercapacitors by using nanoribbon yarns based on Transition Metal Oxides (TMOs) through a physical deposition method, overcoming the limitations of conventional chemical deposition techniques.

 

The related research paper was published online in July 2024 in Advanced Fiber Materials (Impact Factor 17.2, JCR 1.7%, JIF Rank 1/29 in Materials Sciences-Textiles), the top international journal in the field of materials science and textiles. Professor Joon Sung Ahn from Korea University’s Sejong Campus, Associate Research Professor Suchithra Padmajan Sasikala from KAIST, and Dr. Yong Rok Jung from the Korea Atomic Energy Research Institute contributed as co-first authors.

 

Fiber supercapacitors, with their flexibility and lightweight properties, are emerging as an efficient energy storage solution for wearable electronic devices. They hold significant potential for various applications, including healthcare, environmental monitoring, and the defense industry.

 

Traditional fiber supercapacitors typically utilize Electric Double-Layer Capacitor (EDLC) materials such as Carbon Nanotube (CNT) fibers or Graphene Fibers (GF), which possess high electrical conductivity. However, these materials have limitations in terms of electrochemical activity and energy density. Recent research has focused on incorporating pseudocapacitor materials to enhance fiber supercapacitor performance.

 

Transition Metal Oxides, known for their pseudocapacitive properties, exhibit high energy density, high capacitance, and rapid redox reactions. However, current manufacturing methods relying on chemical deposition lead to undesirable material structures and require adhesives for fixing pseudocapacitor materials, limiting their electrochemical performance.

 

To address these challenges, the research team developed nanoribbon fibers by physically depositing transition metal oxides using a nanomold process. This method allows for the creation of fiber structures on a large scale by lifting the nanoribbons from the substrate through selective oxygen plasma etching. The process enables direct deposition of transition metal oxides onto nickel electrodes without adhesives, achieving high energy/power density and excellent electrochemical stability.

 

Additionally, the team developed an asymmetric supercapacitor by combining the transition metal oxide nanoribbon fibers with graphene fibers. This supercapacitor exhibited the highest performance among existing fiber-based supercapacitors, showcasing its potential as a world-leading wearable energy storage device.

 

The team also demonstrated that the fiber-based triboelectric nanogenerator, developed in their previous research, could harvest electrical energy from human movements and store it in the fiber supercapacitor to power wearable pressure sensors and flexible light-emitting diodes (LEDs). This integrated system for energy harvesting, storage, and utilization in fibers was revealed for the first time globally and is expected to significantly contribute to the realization of future smart textiles.

 

Professor Joon Sung Ahn, who led the research, stated, “This study demonstrates that nanoribbon fibers based on metals and transition metal oxides can achieve both high electrochemical performance and mechanical flexibility. This represents a groundbreaking advancement beyond the limitations of traditional organic-based smart textile materials.”

 

Professors In Kyu Park, Sang Wook Kim, and Jun Ho Jung, who guided the research, added, “This research opens a new chapter in nanostructure fabrication technology and provides a crucial foundation for establishing global leadership in smart textile technology. It is expected to contribute significantly not only to the development of high-performance energy storage devices but also to various electronic devices, promoting advancements in smart textiles, the Internet of Things (IoT), and wearable electronics.”

 

This research was supported by the Ministry of Science and ICT through the National Research Foundation of Korea (NRF) under the Mid-career Researcher Program (2021R1A2C3008742), the Leader Researcher Program (Creative Research Center for Multidimensional Nanostructure Control, 2015R1A3A2033061), the Ministry of SMEs and Startups under the University-Industry Collabo R&D Program (RS-2024-00428937), and the Ministry of Trade, Industry and Energy under the Development of 30nm-Class Inline UV Nanoimprinter for Nano-Optical Device Patterning Project (20018235).