Jung, Arum Lee, Michael J. Lee, Seung Woo Cho, Jinhan Son, Jeong Gon Yeom, Bongjun 2024-01-12T02:34:25Z 2024-01-12T02:34:25Z 2022-11-24 2022-12 1613-6810 https://pubs.kist.re.kr/handle/201004/75895 The growth of lithium (Li) dendrites reduces the lifespan of Li-metal batteries and causes safety issues. Herein, hierarchically porous aramid nanofiber separators capable of effectively suppressing the Li dendrite growth while maintaining highly stable cycle performances at high charge/discharge rates are reported. A two-step solvent exchange process combined with reprotonation-mediated self-assembly is utilized to control the bimodal porous structure of the separators. In particular, when ethanol and water are used sequentially, aramid nanofibers form hierarchical porous structures containing nanopores in macroporous polymer frameworks to yield a mechanically robust membrane with high porosity of 97% or more. The optimized samples exhibit high ionic conductivities of 1.87-4.04 mS cm(-1) and high Li-ion transference numbers of 0.77-0.84 because of the ultrahigh porosity and selective affinity to anions. Li-metal symmetric cells do not show any noticeable presence of dendrites after 100 cycles, and they operate stably for more than 1500 cycles even under extreme conditions with a high current density of >20 mA cm(-2). In addition, the LiFePO4/Li full cell retains 86.3% of its capacity after 1000 cycles at a charge rate of 30 C. English Wiley - V C H Verlag GmbbH & Co. Phase Separation-Controlled Assembly of Hierarchically Porous Aramid Nanofiber Films for High-speed Lithium-Metal Batteries Article 10.1002/smll.202205355 1 Small, v.18, no.52, pp.2205355 Small 18 52 2205355 N scie scopus 000878796200001 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article TRANSFERENCE NUMBER ELECTROLYTES ANODES CHALLENGES CARBONATE BEHAVIOR SAFE aramid nanofibers fast charging and discharging lithium dendrite growth lithium metal batteries porous separators