Newswise — Recent advances in wearable electronics have been focused on miniaturization and flexibility. With the growing demand for devices that can be attached to the skin or bend freely, conventional batteries are challenged by their lack of mechanical flexibility. Consequently, fiber-shaped energy storage devices that can be deformed into various shapess are emerging as promising next-generation power source. However, the low ionic conductivity of solid-state electrolytes- essential components in these devices-remains a major barrier to commercialization.
A collaborative research team comprising Nam Dong Kim and Yongho Joo of the Center for Functional Composite Materials Research at the Jeonbuk Branch of the Korea Institute of Science and Technology (KIST, President Sang-Rok Oh) and Professor Jinwoo Lee of the Korea Advanced Institute of Science and Technology (KAIST, President Kwang-Hyung Lee) has announced the development of a polymer electrolyte with dramatically improved ionic conductivity usingonly a small amount of additives.
To address the biggest problem of conventional solid electrolytes – low ionic conductivity – the team focused on a special organic molecule called 4-hydroxy TEMPO (HyTEMPO) This molecule maintains a stable free-radical structure while being highly responsive to external stimuli, making it a versatile functional material. By adding a small amount of this organic molecule to the polymer electrolyte, the reserachers achieved significantly improved ionic mobility even in the solid state. As a result, the ionic conductivity increased to 3.2 mS/cm, approximately 17 times higher than before.
These organic molecules act like highways within the polymer matrix, clearing blocked pathway to enable rapid ion transport. Moreover, they no only enhance ionic mobility, but also improve the device’s energy storage and delivery performanceachieving a storage capacity of 25.4 Wh/kg and output power of 25 kW/kg. These results demonstrate that high-performance energy storage devices can be realized using only fiber-shaped electrodes, without the need for additional active materials.
It also demonstrated excellent flexibility and durability. In practical tests, it maintained 91% of its performance even after more than 8,000 bending cycles, and showed virtually no performance losswhen knotted, confirming its suitability for wearable devices. The newly developed high-ionic-conductivity polymer electrolyte is expected to serve as a key material for next-generation, flexible energy storage systems that demand safety, flexibility, and energy efficiency, offering a promising solution to the energy challenges of wearable electronics.
“We were able to dramatically enhance ionic conductivity through a simple additive approach without the need for complex process,” said Nam Dong Kim, principal researcher at KIST. “This research is expected to establish itself as a fundamental technology that can drive the development of a flexible and safe solid-state electrolyte-based energy storage industry.” Co-researcher Yongho Joo, senior researcher at KIST, added, “By effectively leveraging the unique electronic structure of radical polymers and their rapid redox reaction characteristics, we have overcome the limitations of conventional electrolytes,” . “We will continue our effortsto further improve their performance in the future.”
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KIST was established in 1966 as the first government-funded research institute in Korea. KIST now strives to solve national and social challenges and secure growth engines through leading and innovative research. For more information, please visit KIST’s website at https://www.kist.re.kr/eng/index.do
This research was supported by the Ministry of Science and ICT (Minister Yoo Sang-im) and the Ministry of Trade, Industry and Energy (Minister Ahn Duk-geun) through the KIST Major Project, the Nanoconnect Project of the Korea Research Foundation (RS-2024-00433159), the Mid-Career Researcher Support Project (RS-2023-00208313), and the Industrial Materials Source Technology Development Project of the Korea Institute of Industrial Technology Planning and Evaluation (RS-2023-00257573). The results of the research were published in the latest issue of the international journal Nano-Micro Letters (IF 36.3, JCR field 1.4%).