Kim, Jeong-Gil Ko, Jaehyoung Lim, Hyung-Kyu Jo, Yerin Yu, Hayoung Kim, Min Woo Kim, Min Ji Jeong, Hyeon Su Lee, Jinwoo Joo, Yongho Kim, Nam Dong 2025-04-09T08:01:17Z 2025-04-09T08:01:17Z 2025-04-09 2025-03 2311-6706 https://pubs.kist.re.kr/handle/201004/152213 Fiber-shaped energy storage devices (FSESDs) with exceptional flexibility for wearable power sources should be applied with solid electrolytes over liquid electrolytes due to short circuits and leakage issue during deformation. Among the solid options, polymer electrolytes are particularly preferred due to their robustness and flexibility, although their low ionic conductivity remains a significant challenge. Here, we present a redox polymer electrolyte (HT_RPE) with 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (HT) as a multi-functional additive. HT acts as a plasticizer that transforms the glassy state into the rubbery state for improved chain mobility and provides distinctive ion conduction pathway by the self-exchange reaction between radical and oxidized species. These synergetic effects lead to high ionic conductivity (73.5 mS cm−1) based on a lower activation energy of 0.13 eV than other redox additives. Moreover, HT_RPE with a pseudocapacitive characteristic by HT enables an outstanding electrochemical performance of the symmetric FSESDs using carbon-based fiber electrodes (energy density of 25.4 W h kg−1 at a power density of 25,000 W kg−1) without typical active materials, along with excellent stability (capacitance retention of 91.2% after 8,000 bending cycles). This work highlights a versatile HT_RPE that utilizes the unique functionality of HT for both the high ionic conductivity and improved energy storage capability, providing a promising pathway for next-generation flexible energy storage devices. English Shanghai Jiao Tong University Press Organic Radical-Boosted Ionic Conductivity in Redox Polymer Electrolyte for Advanced Fiber-Shaped Energy Storage Devices Article 10.1007/s40820-025-01700-9 1 Nano-Micro Letters, v.17, no.1 Nano-Micro Letters 17 1 Y scie scopus 001444877900001 2-s2.0-105000067277 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Science & Technology - Other Topics Materials Science Physics Article SOLID-STATE DENSITY LIQUID MECHANISM Redox polymer electrolyte Hydroxy-TEMPO Ionic conductivity Self-exchange reaction Fiber-shaped energy storage devices