22 results on '"Jungdon Suk"'
Search Results
2. Incorporating Ethylene Oxide Functionalized Inorganic Particles to Solid Polymer Electrolytes for Enhanced Mechanical Stability and Electrochemical Performance
- Author
-
Hyo Won Bae, Jungdon Suk, Ho Seok Park, and Dong Wook Kim
- Subjects
cycle performance ,functionalized aluminum oxide nanoparticles ,lithium polymer batteries ,mechanical strength ,solid polymer electrolytes ,Environmental technology. Sanitary engineering ,TD1-1066 ,Renewable energy sources ,TJ807-830 - Abstract
Solid‐state batteries based on polymer electrolytes attract increasing interest owing to their high feasibility of roll‐to‐roll mass production. However, the mechanical strength of polymer electrolytes is not sufficient to suppress the formation of lithium dendrites, leading to early capacity fading. Many researchers have attempted to reinforce polymer electrolytes by adding inorganic particles, but insufficient compatibility between the particles and electrolytes can cause particles to agglomerate, deteriorating the mechanical stability of the resulting hybrid electrolytes. Herein, surface‐functionalized inorganic particles are used to prepare hybrid polymer electrolytes (HPEs). The surface of aluminum oxide (Al2O3) nanoparticles is chemically modified by an organic material containing an ethylene oxide (EO) group. The EO group on the functionalized Al2O3 (F‐Al2O3) enables uniform dispersion of the nanoparticles in the EO polymer electrolytes and improves the ionic conductivity and electrochemical stability. The nanoindentation measurements show that the hybrid polymer electrolytes with F‐Al2O3 (HPE‐F‐Al2O3) have enhanced stiffness. The electrochemical stability and ionic conductivity of the polymer electrolytes also benefit from incorporating F‐Al2O3. As a result, a lithium polymer battery with Li anode, LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode, and HPE‐F‐Al2O3 electrolyte demonstrates stable long‐term cycling with a capacity retention of up to 87% over 100 cycles.
- Published
- 2023
- Full Text
- View/download PDF
3. Laser Cutting Characteristics on Uncompressed Anode for Lithium-Ion Batteries
- Author
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Dongkyoung Lee and Jungdon Suk
- Subjects
laser cutting ,lithium-ion battery ,absorption coefficient measurement ,uncompressed anode ,multi-physical phenomena ,laser material interaction ,Technology - Abstract
Lithium-ion batteries are actively used for many applications due to many advantages. Although electrodes are important during laser cutting, most laser cutting studies use commercially available electrodes. Thus, effects of electrodes characteristics on laser cutting have not been effectively studied. Since the electrodes’ characteristics can be manipulated in the laboratory, this study uses an uncompressed anode on laser cutting for the first time. Using the lab-made anode, this study identifies laser cutting characteristics of the uncompressed anode. First, the absorption coefficients of graphite and copper in the ultraviolet, visible, and infrared range are measured. The measured absorptivity of the graphite and copper at the wavelength of 1070 nm is 88.25% and 1.92%, respectively. In addition, cutting phenomena can be categorized in five regions: excessive cutting, proper cutting, defective cutting, excessive ablation, and proper ablation. The five regions are composed of a combination of multi-physical phenomena, such as ablation of graphite, melting of copper, evaporation of copper, and explosive boiling of copper. In addition, the top width varies in the order of 10 μm and 1 μm when applying high and low volume energy, respectively. The logarithmic relationship between the melting width and the volume laser energy was found.
- Published
- 2020
- Full Text
- View/download PDF
4. Electrical modification of a composite electrode for room temperature operable polyethylene oxide-based lithium polymer batteries
- Author
-
Balasubramaniyan Rajagopalan, Min Kim, Do Youb Kim, Jungdon Suk, Dong Wook Kim, and Yongku Kang
- Subjects
lithium polymer battery ,composite electrode ,conducting filler ,electrical conductivity ,loading density ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Chemical technology ,TP1-1185 - Abstract
Lithium polymer batteries (LPBs) are considered to be the most promising alternatives to current lithium-ion batteries (LIBs), which have been known to exhibit certain safety issues. However, the relatively poor electrochemical performances of LPBs hinder their practical usage, particularly at high C-rates, moderate temperatures, and/or with high loading densities. Therefore, this study analyzes the use of a novel composite electrode for manufacturing room-temperature operable LPBs with high loading densities. Rapid decay in the rate capabilities of LPBs at high C-rates is found to be attributable to the increased electrical resistance in an electrode. To account for this, this study modified the composite electrode with various conducting fillers. Subsequently, the effect of the type and content of the conducting fillers on the performance of LPBs was systematically investigated using the composite electrode. The incorporation of the conducting fillers in the lithium iron phosphate (LFP) composite electrode was found to effectively reduce the electrical resistance and consequently improve the electrochemical performance of LPBs. Furthermore, LFP composite electrodes with a mixture of structurally different graphene (G) and carbon nanotube (CNT) (1 wt%) were observed to demonstrate synergistic effects on improving the electrochemical performance of LPBs. The results obtained in this study elucidate that the facilitated electrical conduction within a composite electrode is critically important for the performance of LPBs and the expedited diffusion of Li ^+ .
- Published
- 2020
- Full Text
- View/download PDF
5. High‐Performance Lithium‐Oxygen Battery Electrolyte Derived from Optimum Combination of Solvent and Lithium Salt
- Author
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Su Mi Ahn, Jungdon Suk, Do Youb Kim, Yongku Kang, Hwan Kyu Kim, and Dong Wook Kim
- Subjects
lithium nitrate ,lithium oxygen batteries ,NO2−/NO2 redox reaction ,tetramethylene sulfone ,Science - Abstract
Abstract To fabricate a sustainable lithium‐oxygen (Li‐O2) battery, it is crucial to identify an optimum electrolyte. Herein, it is found that tetramethylene sulfone (TMS) and lithium nitrate (LiNO3) form the optimum electrolyte, which greatly reduces the overpotential at charge, exhibits superior oxygen efficiency, and allows stable cycling for 100 cycles. Linear sweep voltammetry (LSV) and differential electrochemical mass spectrometry (DEMS) analyses reveal that neat TMS is stable to oxidative decomposition and exhibit good compatibility with a lithium metal. But, when TMS is combined with typical lithium salts, its performance is far from satisfactory. However, the TMS electrolyte containing LiNO3 exhibits a very low overpotential, which minimizes the side reactions and shows high oxygen efficiency. LSV‐DEMS study confirms that the TMS‐LiNO3 electrolyte efficiently produces NO2−, which initiates a redox shuttle reaction. Interestingly, this NO2−/NO2 redox reaction derived from the LiNO3 salt is not very effective in solvents other than TMS. Compared with other common Li‐O2 solvents, TMS seems optimum solvent for the efficient use of LiNO3 salt. Good compatibility with lithium metal, high dielectric constant, and low donicity of TMS are considered to be highly favorable to an efficient NO2−/NO2 redox reaction, which results in a high‐performance Li‐O2 battery.
- Published
- 2017
- Full Text
- View/download PDF
6. The Effect of Compactness on Laser Cutting of Cathode for Lithium-Ion Batteries Using Continuous Fiber Laser
- Author
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Dongkyoung Lee, Byungmoon Oh, and Jungdon Suk
- Subjects
laser cutting ,lithium-ion battery ,compression ,cathode ,continuous fiber laser ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Lithium-Ion Batteries (LIB) are growing in popularity for many applications. Much research has been focusing on battery performance improvement. However, few studies have overcome the disadvantages of the conventional LIB manufacturing processes. Laser cutting of electrodes has been applied. However, the effect of electrodes’ chemical, physical, and geometrical characteristics on the laser cutting has not been considered. This study proposes the effect of compression of cathode on laser cutting for lithium-ion batteries. The kerf width and top width of the specimens with laser irradiation are measured and the material removal energy is obtained. Observations of SEM photographs and absorptivity measurements are conducted. Increasing volume energies causes logarithmic increases in the kerf and top width. It is observed that the compressed cathode forms a wider kerf width than the uncompressed cathode under the same laser parameters. The top width of the uncompressed cathode is wider than the uncompressed cathode. The compression has a favorable effect on uniform cutting and selective removal of an active electrode.
- Published
- 2019
- Full Text
- View/download PDF
7. Ex‐Situ Raman Microscopic Investigation of the High‐Order Polysulfide Restriction of Encapsulated Sulfur Nanowires
- Author
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Joo‐Hyung Kim, Hye‐Ji Eun, Jihyun Jang, Suyoon Eom, Jou‐Hyeon Ahn, Mihye Wu, Jungdon Suk, and San Moon
- Subjects
Electrochemistry ,Catalysis - Published
- 2023
8. Al2O3 Ceramic/Nanocellulose-Coated Non-Woven Separator for Lithium-Metal Batteries
- Author
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Dong-Min Shin, Hyunsu Son, Ko Un Park, Junyoung Choi, Jungdon Suk, Eun Seck Kang, Dong-Won Kim, and Do Youb Kim
- Subjects
nanocellulose ,Al2O3 ,lithium-metal battery ,safety ,stability ,Materials Chemistry ,Surfaces and Interfaces ,Surfaces, Coatings and Films - Abstract
Separators play an essential role in lithium (Li)-based secondary batteries by preventing direct contact between the two electrodes and providing conduction pathways for Li-ions in the battery cells. However, conventional polyolefin separators exhibit insufficient electrolyte wettability and thermal stability, and in particular, they are vulnerable to Li dendritic growth, which is a significant weakness in Li-metal batteries (LMBs). To improve the safety and electrochemical performance of LMBs, Al2O3 nanoparticles and nanocellulose (NC)-coated non-woven poly(vinylidene fluoride)/polyacrylonitrile separators were fabricated using a simple, water-based blade coating method. The Al2O3/NC-coated separator possessed a reasonably porous structure and a significant number of hydroxyl groups (-OH), which enhanced electrolyte uptake (394.8%) and ionic conductivity (1.493 mS/cm). The coated separator also exhibited reduced thermal shrinkage and alleviated uncontrollable Li dendritic growth compared with a bare separator. Consequently, Li-metal battery cells with a LiNi0.8Co0.1Mn0.1O2 cathode and an Al2O3/NC-coated separator using either liquid or solid polymer electrolytes exhibited improved rate capability, cycle stability, and safety compared with a cell with a bare separator. The present study demonstrates that combining appropriate materials in coatings on separator surfaces can enhance the safety and electrochemical performance of LMBs.
- Published
- 2023
9. Spatial Control of Lithium Deposition by Controlling the Lithiophilicity with Copper(I) Oxide Boundaries
- Author
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Ju Ye Kim, Oh B. Chae, Gukbo Kim, Woo‐Bin Jung, Sungho Choi, Do Youb Kim, San Moon, Jungdon Suk, Yongku Kang, Mihye Wu, and Hee‐Tae Jung
- Subjects
Renewable Energy, Sustainability and the Environment ,General Materials Science ,Environmental Science (miscellaneous) ,Waste Management and Disposal ,Energy (miscellaneous) ,Water Science and Technology - Published
- 2022
10. Stable cycling via absolute intercalation in graphite-based lithium-ion battery incorporated by solidified ether-based polymer electrolyte
- Author
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Kim Hyun Jin, Jin Bae Lee, Do Youb Kim, Yongku Kang, Jungdon Suk, Dong-Wook Kim, and Hae Jin Kim
- Subjects
Battery (electricity) ,Materials science ,Intercalation (chemistry) ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Lithium-ion battery ,0104 chemical sciences ,Anode ,Chemical engineering ,chemistry ,Chemistry (miscellaneous) ,General Materials Science ,Thermal stability ,Lithium ,Graphite ,0210 nano-technology - Abstract
Current lithium-ion batteries are vulnerable to fire accidents and explosions because liquid electrolytes have a low flash point and poor thermal stability. This intrinsic problem has led to an ever-growing interest in solid-state polymer electrolytes with high thermal stability. In this study, a solidified polyether-based polymer electrolyte is incorporated into a graphite/LiFePO4 full-cell battery. A liquid precursor, which is prepared by mixing the bisphenol A ethoxylate diacrylate (BisA) crosslinker and the poly(ethylene glycol) dimethyl ether (PEGDME) plasticizer, first wets the anode and cathode, and is then solidified by in situ thermal crosslinking to produce a solid polymer electrolyte. BisA forms a rigid crosslinked network and PEGDME conducts lithium ions within the network. Analysis results, including in situ X-ray diffraction, show that PEGDME in the polymer electrolyte is co-intercalated with lithium ions into the gallery of the graphite electrode, which causes electrode exfoliation and severe capacity fading. Fluoroethylene carbonate is highly effective to prevent the co-intercalation of lithium–PEGDME complex ions into the graphite, via the formation of a solid electrolyte interphase layer, which leads to the ‘absolute intercalation’ of lithium ions. Consequently, the graphite/LiFePO4 full-cell battery based on the solid polymer electrolyte runs stably at a coulombic efficiency higher than 99% for most cycles and the residual capacity of the cell reaches 80% after 100 cycles.
- Published
- 2021
11. Molten salts approach of metal-organic framework-derived nitrogen-doped porous carbon as sulfur host for lithium-sulfur batteries
- Author
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Dae Kyom Kim, Jin Seul Byun, San Moon, Junyoung Choi, Joon Ha Chang, and Jungdon Suk
- Subjects
History ,Polymers and Plastics ,General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
12. Three-dimensional SnO2 nanoparticles synthesized by joule heating as anode materials for lithium ion batteries
- Author
-
Woo-Bin Jung, Yu Jin Hong, Jeesoo Yoon, San Moon, Sungho Choi, Do Youb Kim, Jungdon Suk, Oh B. Chae, Mihye Wu, and Hee-Tae Jung
- Subjects
General Medicine - Abstract
Tin dioxide (SnO2) is a promising material for use as anodes because of its high theoretical capacity (1,494 mAh g−1). However, a critical limitation is the large change in volume during repeated cycling by pulverization of SnO2, which results in capacity fading. In this study, we enhanced cycle life and reduced capacity fading by introducing the use of three-dimensional SnO2 nanoparticles on carbon nanofibers (CNFs) as an anode material, which is fabricated by simple carbothermal shock through the Joule heating method. Our observations show that the SnO2 nanoparticles are about 50 nm in diameter and are uniformly distributed on CNF, and that the strong connections between SnO2 nanoparticles and CNF are sustained even after repeated cycling. This structural advantage provides high reversible capacity and enhanced cycle performance for over 100 cycles. This study provides insight into the fabrication of anode materials that have strong electric connections between active materials and conductive materials due to the Joule heating method for high-performance lithium ion batteries.
- Published
- 2022
13. Autoxidation in amide-based electrolyte and its suppression for enhanced oxygen efficiency and cycle performance in non-aqueous lithium oxygen battery
- Author
-
Dong Hoon Choi, Jungdon Suk, Do Youb Kim, Dong Hun Lee, Yongku Kang, Dong Wook Kim, and Su Mi Ahn
- Subjects
Battery (electricity) ,Autoxidation ,Lithium nitrate ,Renewable Energy, Sustainability and the Environment ,Vapor pressure ,Inorganic chemistry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Oxygen ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Lithium ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
In spite of several desirable properties such as high stability against superoxide anion and low vapor pressure, N -methyl-2-pyrrolidone (NMP) electrolyte is reported not suitable for use in lithium-oxygen (Li-O 2 ) batteries because of severe degradation upon cycling and low oxygen efficiency. In this work, we find that NMP electrolyte is reactive with O 2 gas in the presence of lithium metal and such O 2 -consuming reaction ( i.e., autoxidation) is a possible cause for the poor performance in Li-O 2 batteries with NMP electrolyte. The autoxidation of NMP is verified by direct measurement of the depletion of O 2 gas in the hermetically sealed symmetric Li/Li cells via in-situ gas pressure analysis. In-situ differential electrochemical mass spectroscopy (DEMS) experiment reveals that the autoxidation resulted in significant O 2 consumption upon discharge, very low O 2 efficiency upon charge, and eventually fast capacity fading. Lithium nitrate (LiNO 3 ), which provides a protective layer on the surface of lithium metal, is employed to suppress the autoxidation, leading to significantly enhanced oxygen efficiency and cycle life.
- Published
- 2017
14. Semi-interpenetrating solid polymer electrolyte based on thiol-ene cross-linker for all-solid-state lithium batteries
- Author
-
Do Youb Kim, Dong Wook Kim, Yu Hwa Lee, Song Yun Cho, Jungdon Suk, Yongku Kang, and Ji Man Kim
- Subjects
chemistry.chemical_classification ,Materials science ,Ethylene oxide ,Renewable Energy, Sustainability and the Environment ,Radical polymerization ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,Polymer ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,Pentaerythritol ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Polymer chemistry ,Lithium ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,0210 nano-technology ,Ethylene glycol - Abstract
We developed highly promising solid polymer electrolytes (SPEs) based on a novel cross-linker containing star-shaped phosphazene with poly(ethylene oxide) (PEO) branches with very high ionic conductivity (7.6 × 10−4 S cm−1), improved mechanical stability, and good electrochemical stability for all-solid-state lithium batteries. In particular, allyl groups were introduced at the ends of the cross-linker in order to overcome the easy self-polymerization of existing cross-linking acrylate end groups. A novel semi-interpenetrating network (semi-IPN) SPE was prepared by in-situ radical polymerization of a precursor solution containing lithium salt, poly(ethylene glycol) dimethyl ether as a plasticizer, and a mixture of pentaerythritol tetrakis(3-mercaptopropionate) and a synthesized hexakis(allyloxy)cyclotriphosphazene (thiol-ene PAL) as the cross-linker. Batteries employing LiFePO4 as the cathode, lithium foil as the anode, and the SPE thin film as the electrolyte were assembled and tested. At ambient temperature, the initial discharge capacity was 147 mAh/g at 0.1 °C and 132 mAh/g at 0.5 °C, and 97% of the capacity was retained at the 100th cycle. All-solid-state pouch-package lithium cells assembled with the SPEs exhibited stable electrochemical performance, even under a severely wrinkled state. These outstanding properties of SPEs based on thiol-ene PAL demonstrate feasibility for practical battery applications with improved reliability and safety.
- Published
- 2016
15. The Effect of Compactness on Laser Cutting of Cathode for Lithium-Ion Batteries Using Continuous Fiber Laser
- Author
-
Jungdon Suk, Dongkyoung Lee, and Byungmoon Oh
- Subjects
Battery (electricity) ,laser cutting ,cathode ,Materials science ,Laser cutting ,chemistry.chemical_element ,02 engineering and technology ,lithium-ion battery ,lcsh:Technology ,01 natural sciences ,Lithium-ion battery ,law.invention ,lcsh:Chemistry ,law ,Fiber laser ,0103 physical sciences ,General Materials Science ,lcsh:QH301-705.5 ,Instrumentation ,010302 applied physics ,Fluid Flow and Transfer Processes ,lcsh:T ,business.industry ,Process Chemistry and Technology ,General Engineering ,021001 nanoscience & nanotechnology ,Laser ,compression ,lcsh:QC1-999 ,Cathode ,Computer Science Applications ,lcsh:Biology (General) ,lcsh:QD1-999 ,chemistry ,lcsh:TA1-2040 ,Electrode ,Optoelectronics ,Lithium ,continuous fiber laser ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,business ,lcsh:Physics - Abstract
Lithium-Ion Batteries (LIB) are growing in popularity for many applications. Much research has been focusing on battery performance improvement. However, few studies have overcome the disadvantages of the conventional LIB manufacturing processes. Laser cutting of electrodes has been applied. However, the effect of electrodes&rsquo, chemical, physical, and geometrical characteristics on the laser cutting has not been considered. This study proposes the effect of compression of cathode on laser cutting for lithium-ion batteries. The kerf width and top width of the specimens with laser irradiation are measured and the material removal energy is obtained. Observations of SEM photographs and absorptivity measurements are conducted. Increasing volume energies causes logarithmic increases in the kerf and top width. It is observed that the compressed cathode forms a wider kerf width than the uncompressed cathode under the same laser parameters. The top width of the uncompressed cathode is wider than the uncompressed cathode. The compression has a favorable effect on uniform cutting and selective removal of an active electrode.
- Published
- 2019
- Full Text
- View/download PDF
16. Correction to Polyelemental Nanoparticles as Catalysts for a Li–O2 Battery
- Author
-
Jihan Kim, Mihye Wu, Ju Ye Kim, Ji-Soo Jang, Yongku Kang, Hyun-Soo Park, Do Youb Kim, Il-Doo Kim, Dong Wook Kim, Woo-Bin Jung, Eunsoo Lim, Hannes Jung, Jungdon Suk, and Sungho Choi
- Subjects
Battery (electricity) ,Materials science ,General Engineering ,General Physics and Astronomy ,Nanoparticle ,General Materials Science ,Nanotechnology ,Catalysis - Published
- 2021
17. Electrical modification of a composite electrode for room temperature operable polyethylene oxide-based lithium polymer batteries
- Author
-
Do Youb Kim, Jungdon Suk, Rajagopalan Balasubramaniyan, Yongku Kang, Min Kim, and Dong Wook Kim
- Subjects
chemistry.chemical_classification ,Materials science ,Polymers and Plastics ,Metals and Alloys ,Lithium polymer battery ,chemistry.chemical_element ,Polymer ,Polyethylene oxide ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Biomaterials ,chemistry ,Electrical resistivity and conductivity ,Composite electrode ,Lithium ,Composite material - Abstract
Lithium polymer batteries (LPBs) are considered to be the most promising alternatives to current lithium-ion batteries (LIBs), which have been known to exhibit certain safety issues. However, the relatively poor electrochemical performances of LPBs hinder their practical usage, particularly at high C-rates, moderate temperatures, and/or with high loading densities. Therefore, this study analyzes the use of a novel composite electrode for manufacturing room-temperature operable LPBs with high loading densities. Rapid decay in the rate capabilities of LPBs at high C-rates is found to be attributable to the increased electrical resistance in an electrode. To account for this, this study modified the composite electrode with various conducting fillers. Subsequently, the effect of the type and content of the conducting fillers on the performance of LPBs was systematically investigated using the composite electrode. The incorporation of the conducting fillers in the lithium iron phosphate (LFP) composite electrode was found to effectively reduce the electrical resistance and consequently improve the electrochemical performance of LPBs. Furthermore, LFP composite electrodes with a mixture of structurally different graphene (G) and carbon nanotube (CNT) (1 wt%) were observed to demonstrate synergistic effects on improving the electrochemical performance of LPBs. The results obtained in this study elucidate that the facilitated electrical conduction within a composite electrode is critically important for the performance of LPBs and the expedited diffusion of Li+.
- Published
- 2020
18. Laser Cutting Characteristics on Uncompressed Anode for Lithium-Ion Batteries
- Author
-
Jungdon Suk and Dongkyoung Lee
- Subjects
laser cutting ,Control and Optimization ,Materials science ,Laser cutting ,Energy Engineering and Power Technology ,chemistry.chemical_element ,uncompressed anode ,lithium-ion battery ,02 engineering and technology ,lcsh:Technology ,01 natural sciences ,Lithium-ion battery ,law.invention ,multi-physical phenomena ,law ,0103 physical sciences ,Graphite ,Electrical and Electronic Engineering ,Composite material ,Absorption (electromagnetic radiation) ,Engineering (miscellaneous) ,010302 applied physics ,lcsh:T ,Renewable Energy, Sustainability and the Environment ,absorption coefficient measurement ,021001 nanoscience & nanotechnology ,Laser ,Copper ,Anode ,chemistry ,Electrode ,0210 nano-technology ,laser material interaction ,Energy (miscellaneous) - Abstract
Lithium-ion batteries are actively used for many applications due to many advantages. Although electrodes are important during laser cutting, most laser cutting studies use commercially available electrodes. Thus, effects of electrodes characteristics on laser cutting have not been effectively studied. Since the electrodes&rsquo, characteristics can be manipulated in the laboratory, this study uses an uncompressed anode on laser cutting for the first time. Using the lab-made anode, this study identifies laser cutting characteristics of the uncompressed anode. First, the absorption coefficients of graphite and copper in the ultraviolet, visible, and infrared range are measured. The measured absorptivity of the graphite and copper at the wavelength of 1070 nm is 88.25% and 1.92%, respectively. In addition, cutting phenomena can be categorized in five regions: excessive cutting, proper cutting, defective cutting, excessive ablation, and proper ablation. The five regions are composed of a combination of multi-physical phenomena, such as ablation of graphite, melting of copper, evaporation of copper, and explosive boiling of copper. In addition, the top width varies in the order of 10 &mu, m and 1 &mu, m when applying high and low volume energy, respectively. The logarithmic relationship between the melting width and the volume laser energy was found.
- Published
- 2020
19. Confinement of sulfur in the micropores of honeycomb-like carbon derived from lignin for lithium-sulfur battery cathode
- Author
-
Hyunjoo Lee, So Hyun Park, Jeong Seok Yeon, Jungdon Suk, and Ho Seok Park
- Subjects
Tafel equation ,Materials science ,Nanoporous ,General Chemical Engineering ,Exchange current density ,Lithium–sulfur battery ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Redox ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Hydrothermal carbonization ,chemistry ,Chemical engineering ,Environmental Chemistry ,0210 nano-technology ,Dissolution ,Polysulfide - Abstract
Nitrogen-incorporated honeycomb-like nanoporous carbons (n-hC) are synthesized through the hydrothermal carbonization of a lignin precursor, subsequent KOH activation, and a post-doping process. The as-obtained n-hC exhibits a large surface area (2071 m2 g−1) and pore volume (1.11 cm3 g−1) and a high N content (3.47%). The n-hC is used as an S-hosting material with a mass loading of 64.1 wt% (S@n-hC) through the in situ redox reaction of Na2S2O3. The S@n-hC achieves a high initial discharge capacity of 1295.5 mAh g−1 at 0.1C and retains 647.2 mAh g−1 after 600 cycles, and shows excellent cycling stability (with the capacity fading of 0.05% per cycle over 900 cycles at 1C). The strong confinement of S in the N-incorporated micropores leads to the electrochemical and thermal stabilization of S, providing different redox environments. The facile and reversible redox kinetics of the S@n-hC are confirmed by deriving the lowest exchange current density and redox charge-transfer resistance from Tafel and Nyquist plots and through the prominent redox and charge/discharge profiles. The improved performance of the S@n-hC is attributed to the S confinement in the micropores, the honeycomb-like hierarchical structure, and the N incorporation for the inhibition of polysulfide dissolution and the efficient utilization of S.
- Published
- 2020
20. Battery Electrolytes: High‐Performance Lithium‐Oxygen Battery Electrolyte Derived from Optimum Combination of Solvent and Lithium Salt (Adv. Sci. 10/2017)
- Author
-
Su Mi Ahn, Dong Wook Kim, Yongku Kang, Do Youb Kim, Jungdon Suk, and Hwan Kyu Kim
- Subjects
chemistry.chemical_classification ,Battery (electricity) ,Lithium nitrate ,Lithium vanadium phosphate battery ,Chemistry ,General Chemical Engineering ,Inorganic chemistry ,General Engineering ,General Physics and Astronomy ,Medicine (miscellaneous) ,Salt (chemistry) ,chemistry.chemical_element ,Electrolyte ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Oxygen ,Solvent ,lithium oxygen batteries ,chemistry.chemical_compound ,tetramethylene sulfone ,Cover Picture ,NO2−/NO2 redox reaction ,General Materials Science ,Lithium ,lithium nitrate - Abstract
The front cover image illustrates a redox shuttle reaction of NO2 −/NO2 molecules with a toroid‐shape lithium peroxide in the lithium oxygen battery for a possible application in electric vehicles. Oxygen gases are recovered from the lithium peroxide during the shuttle reaction, which is efficiently promoted in the solvent with high dielectric constant and good compatibility with lithium metal anode. Detailed mechanism and process are discussed in article number 1700235 by Dong Wook Kim and his colleagues at Korea Research Institute of Chemical Technology.
- Published
- 2017
21. High‐Performance Lithium‐Oxygen Battery Electrolyte Derived from Optimum Combination of Solvent and Lithium Salt
- Author
-
Hwan Kyu Kim, Su Mi Ahn, Do Youb Kim, Yongku Kang, Jungdon Suk, and Dong Wook Kim
- Subjects
General Chemical Engineering ,Inorganic chemistry ,General Physics and Astronomy ,Medicine (miscellaneous) ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,Overpotential ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Oxygen ,Redox ,chemistry.chemical_compound ,tetramethylene sulfone ,NO2−/NO2 redox reaction ,General Materials Science ,Full Paper ,Lithium nitrate ,General Engineering ,Full Papers ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Solvent ,lithium oxygen batteries ,chemistry ,Linear sweep voltammetry ,lithium nitrate ,0210 nano-technology - Abstract
To fabricate a sustainable lithium‐oxygen (Li‐O2) battery, it is crucial to identify an optimum electrolyte. Herein, it is found that tetramethylene sulfone (TMS) and lithium nitrate (LiNO3) form the optimum electrolyte, which greatly reduces the overpotential at charge, exhibits superior oxygen efficiency, and allows stable cycling for 100 cycles. Linear sweep voltammetry (LSV) and differential electrochemical mass spectrometry (DEMS) analyses reveal that neat TMS is stable to oxidative decomposition and exhibit good compatibility with a lithium metal. But, when TMS is combined with typical lithium salts, its performance is far from satisfactory. However, the TMS electrolyte containing LiNO3 exhibits a very low overpotential, which minimizes the side reactions and shows high oxygen efficiency. LSV‐DEMS study confirms that the TMS‐LiNO3 electrolyte efficiently produces NO2 −, which initiates a redox shuttle reaction. Interestingly, this NO2 −/NO2 redox reaction derived from the LiNO3 salt is not very effective in solvents other than TMS. Compared with other common Li‐O2 solvents, TMS seems optimum solvent for the efficient use of LiNO3 salt. Good compatibility with lithium metal, high dielectric constant, and low donicity of TMS are considered to be highly favorable to an efficient NO2 −/NO2 redox reaction, which results in a high‐performance Li‐O2 battery.
- Published
- 2017
22. Ex‐Situ Raman Microscopic Investigation of the High‐Order Polysulfide Restriction of Encapsulated Sulfur Nanowires
- Author
-
Prof. Joo‐Hyung Kim, Hye‐Ji Eun, Prof. Jihyun Jang, Suyoon Eom, Prof. Jou‐Hyeon Ahn, Dr. Mihye Wu, Dr. Jungdon Suk, and Dr. San Moon
- Subjects
lithium-sulfur battery ,lithium polysulfides ,orthorhombic sulfur ,monoclinic sulfur ,Raman spectroscopy ,Industrial electrochemistry ,TP250-261 ,Chemistry ,QD1-999 - Abstract
Abstract Lithium‐sulfur (Li−S) batteries are attracting significant research attention because of their high theoretical energy density (2500 Wh kg−1) and excellent economic feasibility. However, commercialization has proven difficult owing to their low electronic conductivity and the dissolution of lithium polysulfide (Li2Sx; x=1–8). In particular, lithium polysulfide dissolution is known to be caused by high‐order polysulfide generated at the start of the discharge process. Thus, the control of this factor is important because it determines the electrochemical performance of the cell. In this study, three types of sulfur nanocomposites in the orthorhombic, amorphous, and monoclinic phases, were designed and successfully manufactured. The mechanism of polysulfide generation was confirmed to differ according to the location of sulfur on the carbon matrix (inner pores and surfaces) and allotropic form of sulfur (S4–S8) via electrochemical tests. Furthermore, the electrochemical reaction mechanism was identified by tracing the lithium polysulfide species according to the reaction region using ex‐situ Raman spectroscopy. In this research, suppression of the high‐order polysulfide generation reaction by controlling the monoclinic sulfur was represented by a single plateau galvanostatic curve, suggesting a clear strategy for maximizing cycle stability in next‐generation Li−S batteries
- Published
- 2023
- Full Text
- View/download PDF
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