DGIST develops next-generation “polymer electrolyte” that quadruples power generation efficiency!

□ Professor Ju-Hyuck Lee’s research team in the Department of Energy Science and Engineering at DGIST (President Kunwoo Lee), in collaboration with Wonho Lee’s team at Kumoh National Institute of Technology, has presented the world’s first design strategy for precisely controlling “polarity,” the key property of triboelectric energy-harvesting materials. The key to this study lies in structurally tuning the polarity direction through polymer electrolytes, achieving enhanced long-term durability.

□ This triboelectric energy-harvesting technology generates electricity through friction, garnering attention for its ability to produce power without batteries. However, conventional ionic-liquid-based materials have faced challenges in commercialization due to issues such as leakage, environmental instability, and limited durability.

□ To tackle these limitations, the research team designed a “polymer electrolyte” in which ions are anchored to polymer chains, and proposed a new platform concept that enables precise control of triboelectric polarity in the desired direction using this material. This approach not only enhances output performance but also provides greater flexibility in material design.

□ The research team synthesized a series of polymer electrolytes with either cationic or anionic characteristics and comparatively analyzed their performance. The results indicated that the cationic polymer P(MA-A⁺20)TFSI⁻ exhibited an output voltage of 83V, approximately twice that of the conventional material (PMA), while the anionic polymer P(S-S⁻10)Na⁺ achieved 34V, which is four times higher than that of the conventional material (PS). These experiments demonstrated that the triboelectric polarity (positive/negative) can be tuned according to the polymer structure, and that the output performance can be further adjusted by controlling the ionic composition ratio.

□ In addition, the ion-anchored structure within the polymer chains minimized charge loss caused by unnecessary ion migration and ensured excellent thermal stability, maintaining stable output for over a week, even at 60℃. In contrast, the conventional polymer-ionic liquid mixture (PMMA+10IL) exhibited approximately 27% output degradation under the same conditions. This result clearly demonstrates the superiority of the polymer electrolyte-based material.

□ Professor Ju-Hyuck Lee of DGIST stated, “This study goes beyond merely improving performance and is significant in that it presents a new concept for controlling triboelectric polarity through polymer structure design. We expect this approach to provide a new direction for the development of next-generation energy-harvesting devices.”

□ This research was supported by the Ministry of Science and ICT and the National Research Foundation of Korea under the “Nano Future Material Source Technology Development Program.” The findings[1] were published as the cover article in the October issue of Advanced Materials (IF: 27.4), a world-renowned journal in materials science.

[1] Co-first authors: Dr. Hyeonseo Joo (Ph.D. at DGIST, Ph.D. candidate at the time of the study), Sujin Park (Researcher at Kumoh National Institute of Technology, M.S. candidate at the time of the study)