• Clean Technology
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• v.20 no.4
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• pp.433-438
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• 2014

There is an increasing interest in the development of rechargeable batteries suitable for use in both hybrid electric vehicles and energy storage systems that require higher charge & discharge rates, bigger battery sizes and increased safety of the batteries. Spinel-type lithium titanium oxide ($Li_4Ti_5O_{12}$) as a potential anode for lithium ion batteries has many advantages. It is a zero-strain materials and it experiences no structural change during the charge/discharge precess. Thus, it has long cycle life due to its structural integrity. It also offers a stable operation voltage of approximately 1.55 V versus $Li^+/Li$, above the reduction potential of most organic electrolyte. In this study, Ru added $Li_4Ti_5O_{12}$ composites were synthesized by solid state process. The characteristics of active material were investigated with TGA-DTA, XRD, SEM and charge/discharge test. The capacity was reduced when Ru was added, however, the polarization decreased. The capacity rate of $Li_4Ti_5O_{12}$ with Ru (3%, 4%) addition was reduced during the charge/discharge precess with 10 C-rate as a high current density.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.430-435
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• 2017

$Li_4Ti_5O_{12}$ (LTO) is an anode material for lithium ion battery, and the cycle performance is very good. The volume change of LTO during insertion and deinsertion of lithium ion is very small, so the cyclibility is very high. In this experiment graphene and CNT was added to increase the low conductivity of LTO which is the weak point of LTO. When graphene was located on the surface of LTO the conductivity did not increase so much because of the nano size LTO. Addition of CNT increased the conductivity because of the formation of the conducting network between LTO particle and the graphene. Carbon material addition was changed before and after the LTO manufacturing, and the capacity and the cyclibility was compared.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.798-803
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• 2018

In order to use Si as an anode material for lithium-ion battery, the particle size was controlled to less than $0.5{\mu}m$ and carbon was coated on the surface with the thickness less than 10 nm. The carbon fiber was grown on the Si surface with 50~150 wt%, and the carbon coating was carried out once again. The Si composite material was mixed with dissimilar metals to increase the conductivity, and graphite was mixed to improve cyclic life characteristics. The physical and electrochemical characteristics of composite materials were measured with XRD, SEM, TEM and coin cell. The discharge capacity of Si/PC/CNF/PC was lower than that of Si/PC (Pyrolytic Carbon)/CNF (Carbon Nano Fiber). However, the cyclic life of Si/PC/CNF/PC was higher. Initial discharge capacity of 1512 mA h g-1 at 0.2 C rate and initial efficiency of 78% were shown. It also showed a capacity retention of 94% in 10 cycles.

• Resources Recycling
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• v.31 no.6
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• pp.81-91
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• 2022

The use of lithium-ion batteries increases significantly with the rapid spread of electronic devices and electric vehicle and thereby an increase in the amount of waste batteries is expected in the near future. Therefore, studies are continuously being conducted to recover various resources of cathode active material (Ni, Co, Mn, Li) from waste battery. In order to recover the cathode active material, black mass is generally recovered from waste battery. The general process of recovering black mass is a waste battery collection - discharge - dismantling - crushing - classification process. This study focus on the crushing/classification process among the processes. Specifically, the particle size distribution of various samples at each crushing/classification step were evaluated, and the particle shape of each particle fraction was analyzed with a microscope and SEM (Scanning Electron Microscopy)-EDS(Energy Dispersive Spectrometer). As a result, among the black mass particle, fine particle less than 74 ㎛ was the mixture of cathode and anode active material which are properly liberated from the current metals. However, coarse particle larger than 100 ㎛ was present in a form in which the current metal and active material were combined. In addition, this study developed a PBM(Population Balance Model) system that can simulate two-species mixture sample with two different crushing properties. Using developed model, the breakage parameters of two species was derived and predictive performance of breakage distribution was verified.

• Journal of the Korean Electrochemical Society
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• v.19 no.4
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• pp.129-133
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• 2016

In this study, a polymer-carbon composite material is prepared for environmental-friendly organic anode. On poly(styrenesulfonate)(PSS)-carbon composite anode, the carbon is coated by PSS as a core-shell structure and the PSS-carbon composite anode has $524mAh\;g^{-1}$ theoretical capacity with <0.6V voltage. Moreover, the PSS-carbon composite anode shows $519.6mAh\;g^{-1}$, $461.2mAh\;g^{-1}$, $411.8mAh\;g^{-1}$ and $315.9mAh\;g^{-1}$ discharge capacities at 0.1, 0.5, 1 and 10 C, respectively, and stable cycle performance up to 30 cycles. The PSS-carbon composite anode, containing polystyrene and sulfonate functional groups, is suitable for high electrochemical properties organic rechargeable battery.

• Journal of Energy Engineering
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• v.3 no.1
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• pp.77-83
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• 1994

아연-산화은 2차전지는 높은 에너지 밀도의 이점을 가진 반면, 짧은 사이클수명(설계 및 사용방법에 따라 10∼200 사이클)을 가진 단점이 있다. 산화은 전극의 비싼 가격 때문에 높은 에너지 밀도가 요구되는 분야에서 제한적으로 사용되고 있다. 본 논문은 수중운동체계의 추진용으로 사용하기 위한 신뢰성이 높은 아연-산화은 전지의 개발을 다루었다. 고율방전에서 양극 활물질의 양에 따른 전압 특성과 음극활물질의 첨가제에 따른 사이클 수명 비교 시험을 실시하였다. 본 연구결과 우수한 전압 특성과 고율방전에서10회 이상의 사이클 수명을 갖는 아연-산화은 2차전지를 개발하였다.

• Journal of the Korean Electrochemical Society
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• v.23 no.4
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• pp.105-112
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• 2020

Transition metal oxide, which undergoes a conversion reaction in the negative electrode material for a lithium-ion batteries, has a high specific capacity, but still has several critical problems. In this study, manganese pyrophosphate (Mn₂P₂O₇), nickel pyrophosphate (Ni₂P₂O₇), and carbon composite materials with pyrophosphates as novel negative electrode materials instead of transition metal oxide, are synthesized through simple solid-state reaction. The initial reversible capacity of Mn₂P₂O₇ and Ni₂P₂O₇ are 333 and 340 mAh g^-1, and when the composite materials are composed with carbon, the reversible capacity increases to 433 and 387 mAh g^-1, respectively. The initial Coulombic efficiency is also improved by about 10%. The Mn₂P₂O₇ and carbon composite material has the highest initial capacity and efficiency, and has the best cycle performance. Mn₂P₂O₇ containing polyanion, has a lower specific capacity due to the large mass of polyanion compared to MnO (manganese oxide). However, since Mn₂P₂O₇ shows a voltage curve with a slope, the charging (lithiation) voltage increases from 0.51 to 0.57 V (vs. Li/Li⁺), and the discharge (delithiation) voltage decreases from 1.15 to 1.01 V (vs. Li/Li⁺). Therefore, the voltage efficiency of the cell is improved because the voltage difference between charging and discharging is greatly reduced from 0.64 to 0.44 V, and the operating voltage of the full cell increases because the negative electrode potential is lowered during the discharging process.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.31-35
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• 2001

The phase forming ability and formation enthalpies(${\Delta}H$) of Si-M(M = Ti, Cu, Ni, Zr) compound alloys were predicted by Miedema's model. The silicon compound alloys were synthesized by mechanical alloying and then characterized for the phase formation by X -ray diffraction. The electrochemical properties as the anode materials for lithium ion batteries were investigated using a galvanostatic method. It appears that the electrochemical characteristics of Si-M alloys can be predicted from the thermodynamic criteria for the phase formation using the Miedema's model.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.83-91
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• 2016

We studied the effect of battery deep cycle according to the way of active materials formation and the creation condition of electrode material, 3BS ($3PbO{\cdot}PbSO_4{\cdot}H_2O$) and 4BS ($4PbO{\cdot}PbSO_4$), in order to develop the batteries for Idle Stop & Go system. During the curing with active materials of anode and cathode, we found that the final creased active material was deformed by temperature control and it effects the durability of batteries. AGM battery and Flooded battery with 3BS active materials have excellent initial performance. And AGM battery with 4BS active materials shows the lower performance relatively. To compare and analyze of the formation efficiency of active materials, we tested the formation chagging steps with 3 steps and 9 steps differently. The results are that AGM battery with 4BS active materials is better on initial performance than AGM battery with 3BS. After the comparison of durability by DOD 17.5% life test, AGM battery is more suitable than flooded battery for the ISG system which needs the frequent deep cycle. In conclusion, AGM battery is the most suitable for ISG system and the life performance shows 80% difference according to the way of formation and curing of AGM batteries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04a
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• pp.27-30
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• 2004

Different types of hybrid negative materials on pitch based carbon and natural graphite for lithium ion batteries were studied. Two types of active materials were prepared, that is, pitch based graphite carbon, and pitch based carbon impregnating natural graphite. The specific capacity, capacity recovery in high temperature condition, and other electrochemical properties were achieved for these materials. We found that addition of natural graphite type to the pitch based carbon can significant1y improve the specific capacity and interfacial resistance. However, use of natural graphite will cause a serious capacity loss in the high temperature condition owing to its increasing interface resistance. The specific capacity ranged from 321 to 348 mAh/g and the maximum specific capacity was obtained in the case of pitch based carbon impregnating natural graphite.