• Journal of the Korean Electrochemical Society
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• v.11 no.4
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• pp.242-255
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• 2008

In lithium-ion batteries(LIB), the development of electrolytes had mainly focused on the characteristics of lithium cobalt oxide($LiCoO_2$) cathode and graphite anode materials since the commercialization in 1991. Various studies on compatibility between electrode and electrolytes had been actively developed on their interface. Since then, as they try to adopt silicon and tin as anode materials and three components(Ni, Mn, Co), spinel, olivine as cathode materials for advanced lithium batteries, conventional electrolyte materials are facing a lot of challenges. In particular, requirements for electrolytes performance become harsh and complicated as safety problems are seriously emphasized. In this report, we summarized the research trend of electrolyte materials for the electrode materials of lithium rechargeable batteries.

• The Korean Journal of Mycology
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• v.26 no.1 s.84
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• pp.8-15
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• 1998

The present research was undertaken to investigate the activity of ligninolytic enzymes and the decolorization capability of some dyes with Irpex zonatus BN2, isolated from nature and identified. For the assay of enzyme activities, the isolate did not produce lignin peroxidase (LiP) and veratryl alcohol oxidase (VAO), but laccase and manganese dependent peroxidase (MnP). While the activity for MnP was low $(61.6\;nmol/mg{\cdot}protein)$, its laccase activity was very high $(1185.9\;nmol/mg{\cdot}protein)$. Moreover, laccase had appeared earlier than MnP. When the isolate was incubated with each dye for 10 days, the decolorization rates of azo dyes, such as orange II, orange G, tropaeolin O and congo red were 98.0%, 97.4%, 99.0% and 95.3%, respectively. In case of heterocyclic dyes, eosin Y, toludine blue, methyl blue and azur B were 97.4 %, 98.7%, 99.9% and 94.0% respectively. Finally the results of triphenylmethane dye such as basic fuchsin, malachite green and crystal violet were 98.5%, 95.7% and 99.4%, respectively. The results suggest that laccase of Irpex zonatus BN2 should be played an important role in the decolorization of the dyes.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.63
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• pp.101-110
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• 2001

This study is concern with the design of experiment planning for quality improvement in flow shop manufacturing system. In this study, the procedure of two stage experiment planning are proposed and applied to the manufacturing process of Li/$MnO_2$ batteries. The result of in this paper is that, compared with the current process conditions, 52% of the insulation inspection process, 81.6% of the first premier discharge process, 98.5% of the second premier discharge process, 84.7% of O.C.V./C.C.V. process, and 86.2% of voltage inspection process are decreased. After a given period of time, the life of the batteries extends to 75 hours, which means the 15% improvement in capacity. In case that the proposed methods are applied to the process Improvements of the flow shop manufacturing system, the much effected in experimental cost- saving and quality improvement.

• Resources Recycling
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• v.30 no.6
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• pp.28-35
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• 2021

An experiment was conducted to separate or recover Co and Ni using Cyanex 301 from process by-products and waste resources containing Co and Ni. To separate and recover Co and Ni from simulated leaching solutions, 10 v/v% Cyanex 301 was used as an extractant in this study; Li was not extracted. At equilibrium pH 1.5 and a phase ratio (A/O) of 1.0, 0.44% of Mg and 11.57% of Mn were extracted, and more than 99% of Co and Ni were extracted. McCabe-Thiele diagram analysis confirmed that more than 99.9% of Co and Ni could be extracted simultaneously through two-stage extraction with an extraction phase ratio (A/O) of 2. It was possible to extract Mg and Mn simultaneously through the scrubbing process. In the scrubbing process, more than 99% of Mg and 87% of Mn were scrubbed using 0.05 M of H₂SO₄, and 99.9% of Mg and more than 80% of Mn were scrubbed using 0.05 M of HCl. In the stripping process, 93% of Co and 5% of Ni were stripped selectively by 3.0 M of H₂SO₄. However, when 8.0 M of HCl was used as a stripping solution, more than 99.9% of Co and more than 90% of Ni were stripped simultaneously.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.9
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• pp.756-760
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• 2007

Flame retardant(FR) properties were investigated with tricredyl phosphate(TCP) and tris(pentafluorophenyl)phosphine(TFPP) as additives for lithium-ion batteries. Thermal stability was improved with additives in $Li/LiNi\frac{1}{3}Mn\frac{1}{3}Co\frac{1}{3}O_2$ cells comparing to non-additive electrolytes. Oxygen evolution reaction of the cathode material was delayed to up $55^{\circ}C$, from $275^{\circ}C\;to\;330^{\circ}C$. Electrolytes with the 1 wt.% additives provided good FR properties while the resonable battery performance is maintained.

• Resources Recycling
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• v.28 no.5
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• pp.60-67
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• 2019

A valuable metal recovery from waste resources such as spent rechargeable secondary batteries is of critical issues because of a sharp increase in the amount of waste resources. In this context, it is necessary to research not only recycling waste lithium-ion batteries (LIBs), but also reusing valuable metals (e.g., Li, Co, Ni, Mn etc.) recovered from waste LIBs. In particular, the lithium hydroxide ($LiOH{\cdot}xH_2O$), which is of precursors that can be prepared by the recovery of Li in waste LIBs, can be reused as a catalyst, a carbon dioxide absorbent, and again as a precursor for cathode materials of LIB. However, most studies of recycling the waste LIBs have been focused on the preparation of lithium carbonate with a recovery of Li. Herein, we show the preparation of high purity lithium hydroxide powder along with the precipitation process, and the systematic study to find an optimum condition is also carried out. The lithium carbonate, which is recovered from waste LIBs, was used as starting materials for synthesis of lithium hydroxide. The optimum precipitation conditions for the preparation of LiOH were found as follows: based on stirring, reaction temperature $90^{\circ}C$, reaction time 3 hr, precursor ratio 1:1. To synthesize uniform and high purity lithium hydroxide, 2-step precipitation process was additionally performed, and consequently, high purity $LiOH{\cdot}xH_2O$ powder was obtained.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.137-138
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• 2017

본 논문에서는 각형 형태의 120Ah 고용량 배터리 ($LiNiMnCoO_2$; NMC)의 내부 파라미터 추출을 통해 배터리 관리 시스템(battery management system;BMS)에 중요한 팩터로 0.1C 및 0.25C 방전 조건에서 확장칼만필터(extended Kalman fileter;EKF) 기반으로 SOC(state-of-charge)를 추정하였다.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.384-388
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• 2013

Fluorine-doping on the $Li_{1+x}Mn_{1.9-x}Al_{0.1}O_4$ spinel cathode materials is found to alter crystal shape, and enhance initial interfacial reactivity and solid electrolyte interphase (SEI) formation, leading to improved initial coulombic efficiency in the voltage region of 3.3-4.3 V vs. Li/$Li^+$ in the room temperature electrolyte of 1 M $LiPF_6$/EC:EMC. SEM imaging reveals that the facetting on higher surface energy plane of (101) is additionally developed at the edges of an octahedron that is predominantly grown with the most thermodynamically stable (111) plane, which enhances interfacial reactivity. Fluorine-doping also increases the amount of interfacially reactive $Mn^{3+}$ on both bulk and surface for charge neutrality. Enhanced interfacial reactivity by fluorine-doping attributes instant formation of a stable SEI layer and improved initial cyclic efficiency. The data contribute to a basic understanding of the impacts of composition on material properties and cycling behavior of spinel-based cathode materials for lithium-ion batteries.

• Journal of Magnetics
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• v.17 no.4
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• pp.255-260
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• 2012

In this study, we determine that the electron paramagnetic resonance line-width (EPRLW) is axially symmetric about the c-axis and analyze the spin Hamiltonian with an isotopic g-factor of 1.9920 at a frequency of 9.5 GHz. It should be noted that the electron paramagnetic resonance signals are Lorentzian. Our findings show that the EPRLW decreases exponentially with an increase in the temperature; i.e., its temperature dependence in the range 300-400 K obeys Arrhenius behavior, this kind of temperature dependence indicates an off-center a motional narrowing of the spectrum when $Mn^{2+}$ impurity ions substitute for $Nb^{5+}$ ions. The specific heats follow a linear dependence suggesting a simple Debye $T^3$ behavior.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.37.1-37.1
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• 2010

The multi-component olivine cathode material, $LiMn_{1/3}Fe_{1/3}Co_{1/3}PO_4$, was prepared via a novel coprecipitation method of the mixed transition metal oxalate, $Mn_{1/3}Fe_{1/3}Co_{1/3}(C_2O_4){\cdot}2H_2O$. The stoichiometric ratio and distribution of transition metals in the oxalate, therefore, in the olivine product, was affected sensitively by the environments in the coprecipitation process, while they are the important factors in determining the electrochemical property of electrode materials with multiple transition metals. The effect of the pH, atmosphere, temperature, and aging time was investigated thoroughly with respect to the atomic ratio of transition metals, phase purity, and morphology of the mixed transition metal oxalate. The electrochemical activity of each transition metal in the olivine synthesized through this method clearly was enhanced as indicated in the cyclic voltammetry (CV) and galvanostatic charge/discharge measurement. Three distinctive contributions from Mn, Fe, and Co redox couples were detected reversibly in multiple charge and discharge processes. The first discharge capacity at the C/5 rate was $140.5\;mAh\;g^{-1}$ with good cycle retention. The rate capability test showed that the high capacity still is retained even at the 4C and 6C rates with 102 and $81\;mAh\;g^{-1}$, respectively.