https://scholar.dgist.ac.kr/handle/20.500.11750/10154 Wed, 10 Jun 2026 23:25:48 GMT 2026-06-10T23:25:48Z https://scholar.dgist.ac.kr/handle/20.500.11750/60412 Title: Quantitative Analysis of Ionic Channel Network Variation in Nafion Under Continuous Annealing Using Current-Sensing Atomic Force Microscopy Author(s): Kwon, Osung; Son, Byungrak Abstract: Proton exchange membranes (PEMs) are essential for PEM fuel cells, with proton conductivity arising from the hydration-induced ionic channel network. PEM performance can be enhanced through pretreatments, such as annealing, which reconstruct the ionic channels. This study investigates the ionic channel network variation in Nafion 212 under continuous annealing at 90 degrees C using current-sensing atomic force microscopy (CSAFM). A nanoscale PEM fuel cell was formed with a Pt-coated CSAFM tip and Pt-coated Nafion surface. Topography and surface roughness analyses revealed geometrical changes from annealing. Current-sensing images and histograms qualitatively assessed local conductance and ionic channel distribution. The ionic channel network density was quantitatively evaluated using the number of protons moving through the ionic channel network (NPMI), derived from CSAFM and electrodynamics principles. NPMI directly reflects ionic channel density. From the unannealed state to 60 h, NPMI increased linearly at 1 & times; 104 h-1, indicating enhanced channel formation. Beyond 60 h, NPMI decreased linearly at 1.9 & times; 105 h-1, reflecting progressive network degradation. As the ionic channel network increases, the number of protons reaching the membrane surface also increases, whereas in the opposite case it decreases. Thus, NPMI becomes evaluation criterion for ionic channel network density. These findings systematically link nanoscale structural changes to ionic channel reconstruction and proton transport in Nafion 212, providing insight into PEM performance evolution under thermal treatment. Thu, 30 Apr 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60412 2026-04-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60363 Title: Fluorinated ether-anchored solid polymer electrolyte for lithium metal batteries for low-temperature adaptability Author(s): Lee, Yuri; Jeon, Injun; Kim Ji Hoon; Kim Jongmin; Lee Sang Uck; Chun Sang-Eun; Kim Jae Hyun Abstract: Solid polymer electrolytes (SPEs) are promising for safe and scalable all-solid-state lithium batteries, but lowtemperature ionic transport and interfacial instability limit their practical use. Here, we present a fluorinatedether (FE)-anchored polymer electrolyte (FAPE) based on a PEGDME semi-interpenetrating network, designed to overcome these challenges. FE units anchor onto ether chains via C- H & sdot;& sdot;& sdot;O interaction, suppressing crystallization, weakening Li*-EO coordination, and promoting formation of inorganic-rich, anion-derived interphases. FAPE exhibits high ionic conductivity down to -20 degrees C, intrinsic nonflammability, and an expanded electrochemical stability window. Lithium metal cells with FAPE demonstrate enhanced Coulombic efficiency, extended cycling stability, and higher critical current densities compared to conventional PEGDME-based SPEs. Full cells and prototype pouch cells retain high capacities under both ambient and sub-zero temperatures, highlighting their practical applicability. This molecular anchoring strategy provides a versatile platform to tailor solvation structure and interphase chemistry, enabling wide-temperature, safe, and durable operation in high-energy solidstate lithium metal batteries. Thu, 30 Apr 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60363 2026-04-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60268 Title: Tag interference based mobile object tracking with passive UHF RFID system Author(s): Choi, Jae Sung; Kang, Won Seok; Son, Chan Sik; Son, Byung Rak; Lee, Dong Ha Abstract: This paper proposes a novel method that enables location sensing for a mobile object by utilizing deployed passive UHF Radio Frequency Identification (RFID) tags and a stationary RFID reader. In order to estimate the mobile object location, the proposed method utilizes the second order under damped system based tag to tag interference model. The empirical study using RFID systems and a mobile robot verifies the effectiveness and performance of the proposed method. © Springer-Verlag Berlin Heidelberg 2015. Wed, 31 Dec 2014 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60268 2014-12-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60226 Title: Interface-Stabilized and Fire-Resistant Composite Polymer Electrolyte for Safe and Durable All-Solid-State Lithium Batteries Author(s): Jamal, Hasan; Khan, Firoz; Kim, Suin; Alzahrani, Atif; Kim, Jae Hyun Abstract: The multifaceted composition of the solid electrolyte interface (SEI), the low Li-ion conductivity, and the fire hazard sensitivity of poly(ethylene oxide) (PEO)-based solid-state-electrolytes (SSEs) restrict them from being used in cutting-edge all-solid-state lithium-metal batteries (SS-LMBs). Here, a multifunctional solid composite polymer electrolyte (SMB-CPE) was developed by using silica mesoball fillers, offering simultaneous improvements in ionic transport, interfacial stability, and thermal protection. The presence of fillers enabled the segmental motion of the polymer chains, thereby reducing the activation energy for Li-ion diffusion and empowering more efficient Li-ion transportation that exhibited Li-ion conductivity of 6.37 x 10(-3) S cm(-1) at 60 degrees C. Furthermore, the critical current density dramatically doubled it when compared to the unfilled system. Notably, the symmetric [Li/SMB-CPE/Li] cell showed excellent galvanostatic Li plating and stripping, exhibiting stability for 2000 h at 200 mu A cm(-2). However, full-cell configurations with LiFePO4 delivered an initial discharge capacity of similar to 150 mAh g(-1) at 1 C and retained 81.5% capacity after 1000 cycles. Moreover, postcombustion studies reveal that the filler enhanced carbonization and suppressed the formation of hazardous byproducts. The formation of C-O, C=O, CF3, LiF, and high-oxidation-state sulfur and nitrogen species was significantly lessened, suggesting mitigation of exothermic and toxic degradation pathways. Wed, 31 Dec 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60226 2025-12-31T15:00:00Z