• Resources Recycling
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• v.30 no.6
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• pp.43-52
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• 2021

In this study, the optimal nitration process for selective lithium leaching from powder of a spent battery cell (LiNi_xCo_yMn_zO₂, LiCoO₂) was studied using Taguchi method. The nitration process is a method of selective lithium leaching that involves converting non-lithium nitric compounds into oxides via nitric acid leaching and roasting. The influence of pretreatment temperature, nitric acid concentration, amount of nitric acid, and roasting temperature were evaluated. The signal-to-noise ratio and analysis of variance of the results were determined using L₁₆(4⁴) orthogonal arrays. The findings indicated that the roasting temperature followed by the nitric acid concentration, pretreatment temperature, and amount of nitric acid used had the greatest impact on the lithium leaching ratio. Following detailed experiments, the optimal conditions were found to be 10 h of pretreatment at 700℃ with 2 ml/g of 10 M nitric acid leaching followed by 10 h of roasting at 275℃. Under these conditions, the overall recovery of lithium exceeded 80%. X-ray diffraction (XRD) analysis of the leaching residue in deionized water after roasting of lithium nitrate and other nitrate compounds was performed. This was done to determine the cause of rapid decrease in lithium leaching rate above a roasting temperature of 400℃. The results confirmed that lithium manganese oxide was formed from lithium nitrate and manganese nitrate at these temperatures, and that it did not leach in deionized water. XRD analysis was also used to confirm the recovery of pure LiNO₃ from the solution that was leached during the nitration process. This was carried out by evaporating and concentrating the leached solution through solid-liquid separation.

• Journal of Electrochemical Science and Technology
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• v.13 no.3
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• pp.407-415
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• 2022

Surface coating of cathodes is an essential process for all-solid-state batteries (ASSBs) based on sulfide electrolytes as it efficiently suppresses interfacial reactions between oxide cathodes and sulfide electrolytes. Based on computational calculations, Li₃PO₄ has been suggested as a promising coating material because of its higher stability with sulfides and its optimal ionic conductivity. However, it has hardly been applied to the coating of ASSBs due to the absence of a suitable coating process, including the selection of source material that is compatible with ASSBs. In this study, polyphosphoric acid (PPA) and (NH₄)₂HPO₄ were used as source materials for preparing a Li₃PO₄ coating for ASSBs, and the properties of the coating layer and coated cathodes were compared. The Li₃PO₄ layer fabricated using the (NH₄)₂HPO₄ source was rough and inhomogeneous, which is not suitable for the protection of the cathodes. Moreover, the water-based coating solution with the (NH₄)₂HPO₄ source can deteriorate the electrochemical performance of high-Ni cathodes that are vulnerable to water. In contrast, when an alcohol-based solvent was used, the PPA source enabled the formation of a thin and homogeneous coating layer on the cathode surface. As a consequence, the ASSBs containing the Li₃PO₄-coated cathode prepared by the PPA source exhibited significantly enhanced discharge and rate capabilities compared to ASSBs containing a pristine cathode or Li₃PO₄-coated cathode prepared by the (NH₄)₂HPO₄ source.

• Journal of the Mineralogical Society of Korea
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• v.4 no.1
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• pp.1-10
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• 1991

Tosudite from the Sungsan mine, Korea is an alteration product of rhyolitic tuff in the cretaceous Hwangsan Formation. It is associated with illite, dickite, nacrite or quartz and also found in the cavities of black claystone. X-ray diffraction and chemical analyses show that the Sungsan tosudite is a lithium-bearing aluminous 1:1 regularly interstratified mineral of di, dioctahedral chlorite and smectite. Its structural formula is $(K_{0.73}Na_{0.02}Ca_{0.07})(Si1_{13.23}Al_{2.77})(Li_{0.52}Mg_{0.08}Mn_{0.01)Fe^{3+}_{0.07}Al_{12.33})O_{40}(OH)_{20}$ and it suggests that Sungsan tosudite consists of regularly interstratified Li-donbassite and beidellite. DTA and TG curves as well as IR absorption data also support such a result. Temperature of formation of tosudite is inferred to be between $110{\circ}$ and $270{\circ}C$.

• Korean Journal of Materials Research
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• v.21 no.2
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• pp.73-77
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• 2011

Specific heat of a crystal is the sum of electronic specific heat, which is the specific heat of conduction electrons, and lattice specific heat, which is the specific heat of the lattice. Since properties such as crystal structure and Debye temperature do not change even in the superconducting state, the lattice specific heat may remain unchanged between the normal and the superconducting state. The difference of specific heat between the normal and superconducting state may be caused only by the electronic specific heat difference between the normal and superconducting states. Critical temperature, at which transition occurs, becomes lower than $T_{c0}$ under the influence of a magnetic field. It is well known that specific heat also changes abruptly at this critical temperature, but magnetic field dependence of jump of specific heat has not yet been developed theoretically. In this paper, specific heat jump of superconducting crystals at low temperature is derived as an explicit function of applied magnetic field H by using the thermodynamic relations of A. C. Rose-Innes and E. H. Rhoderick. The derived specific heat jump is compared with experimental data for superconducting crystals of $MgCNi_3$, $LiTi_2O_4$ and $Nd_{0.5}Ca_{0.5}MnO_3$. Our specific heat jump function well explains the jump up or down phenomena of superconducting crystals.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.10
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• pp.4761-4767
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• 2016

Objective: The use of Shamma (smokeless tobacco) by certain groups is giving rise to health problems, including cancer, in parts of Saudi Arabia. Our objective was to determine metals levels in Shamma using inductively coupled plasma mass spectrometry (ICP-MS). Methods: Thirty-three samples of Shamma (smokeless tobacco) were collected, comprising four types: brown Shamma (n = 14.0), red Shamma (n = 9.0), white Shamma (n = 4.0), and yellow Shamma (n = 6.0). All samples were collected randomly from Shamma users in the city of Najran. Levels of 11 elements (Al, As, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, and Zn) were determined by ICP-MS. Results: A mixed standard (20 ppb) of all elements was used for quality control, and average recoveries ranged from 74.7% to 112.2%. The highest average concentrations were found in the following order: Al ($598.8-812.2{\mu}g/g$), Mn ($51.0-80.6{\mu}g/g$), and Ni ($23.2-53.3{\mu}g/g$) in all four Shamma types. The lowest concentrations were for As ($0.7-1.0{\mu}g/g$) and Cd ($0.0-0.06{\mu}g/g$). Conclusions: The colour of each Shamma type reflects additives mixed into the tobacco. Cr and Cu were showed significant differences (P < 0.05) among Shamma types. Moreover, Pb levels are higher in red and yellow Shamma, which could be due to use (PbCrO4) as yellow colouring agent and lead tetroxide, Pb3O4 as a red colouring agent. The findings from this study can be used to raise public awareness about the safety and health effects of Shamma, which is clearly a source of oral exposure to metals.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.219-221
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• 2018

ESS용 NCM계 $LIB(Li[Ni_xCo_yMn_z]O_2)$의 양극 전이금속 설계인자 조성비(x:y:z)를 5:2:3, 6:2:2로 달리하여 제작한 전지를 사용하여 C-rate별 방전시험을 통한 기본성능평가를 진행하였고, 가속열화 시험을 통한 수명특성을 분석하였다. EIS(Electrochemical Impedance Spectroscopy) 실험을 통하여 전지의 임피던스를 확인하였고, 열화되지 않은(Fresh) 전지와 열화된(Aging) 전지의 SOC(State-of-Charge)별 임피던스 특성을 비교 분석하였다.

• Journal of Microbiology and Biotechnology
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• v.26 no.11
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• pp.1881-1890
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• 2016

Manganese superoxide dismutase (MnSOD) is a vital enzyme that protects cells from free radicals through eliminating superoxide radicals ($O^{2-}$). Hirudin, a kind of small active peptide molecule, is one of the strongest anticoagulants that can effectively cure thrombus diseases. In this study, we fused Hirudin to the C terminus of human MnSOD with the GGGGS linker to generate a novel dual-feature fusion protein, denoted as hMnSOD-Hirudin. The hMnSOD-Hirudin gene fragment was cloned into the pET15b (SmaI, CIAP) vector, forming a recombinant pET15b-hMnSOD-Hirudin plasmid, and then was transferred into Escherichia coli strain Rosetta-gami for expression. SDS-PAGE was used to detect the fusion protein, which was expected to be about 30 kDa upon IPTG induction. Furthermore, the hMnSOD-Hirudin protein was heavily detected as a soluble form in the supernatant. The purification rate observed after Ni NTA affinity chromatography was above 95%. The hMnSOD-Hirudin protein yield reached 67.25 mg per liter of bacterial culture. The identity of the purified protein was confirmed by western blotting. The hMnSOD-Hirudin protein activity assay evinced that the antioxidation activity of the hMnSOD-Hirudin protein obtained was $2,444.0{\pm}96.0U/mg$, and the anticoagulant activity of the hMnSOD-Hirudin protein was $599.0{\pm}35.0ATU/mg$. In addition, in vitro bioactivity assay showed that the hMnSOD-Hirudin protein had no or little cytotoxicity in H9c2, HK-2, and H9 (human $CD_4{^+}$, T cell) cell lines. Transwell migration assay and invasion assay showed that the hMnSOD-Hirudin protein could suppress human lung cancer 95-D cell metastasis and invasion in vitro.

• Journal of Electrochemical Science and Technology
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• v.8 no.2
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• pp.162-168
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• 2017

$LiNi_xCo_yMn_zO_2$ cathode materials have been the focus of much attention because of their high specific capacity. However, because of the poor interfacial stability between cathodes and electrolytes, the cycling performance of these materials fades rapidly, especially at high temperatures. In the present paper, we propose the use of tris(trimethylsilyl) phosphate (TMSPO), which contains phosphate and silyl functional groups, as a functional additive in electrolytes. The addition of TMSPO resulted in the formation of cathode electrolyte interphase (CEI) layers on the surfaces of the cathodes and effectively suppressed electrolyte decomposition reactions, even at high temperatures. As a result, cells cycled with TMSPO exhibited remarkable capacity, which remained after 50 cycles (82.0%), compared to cells cycled without TMSPO (64.6%).

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.40-46
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• 2024

Among the electrode manufacturing processes for lithium-ion batteries, the drying process is crucial for production speed and process cost. Particularly, as the loading level of the electrode increases to enhance the energy density of the battery, optimizing process conditions for electrode drying becomes more critical. In this study, we compared the drying time and electrochemical performance of the positive electrode prepared at different drying temperatures. LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622) was used as the active material and manufactured under various drying temperature conditions ranging from 120 ℃ to 210 ℃ at loading levels of 2.5 and 4.5 mAh cm^-2. The physical and electrochemical properties of the electrodes were compared. As the loading level of the electrode increases, the drying time of the electrode also increases, but this time can be reduced by increasing the drying temperature. The drying temperature used in manufacturing the NCM622 positive electrode does not significantly affect the electrochemical performance but drying above 210 ℃ resulted in an increase in the volume resistivity of the electrode and a decrease in electrochemical performance. Accordingly, in the manufacture of high-loading electrodes, the drying temperature was increased to 190 ℃ to shorten the electrode manufacturing time without a loss of performance.

• Journal of Society of Preventive Korean Medicine
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• v.3 no.2
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• pp.151-170
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• 1999

This study was to investigate the metal accumulation from SipJeonDaeBo-Decoction to rat blood of Sprague Dawley. 1. There were no significance in body weight, water dose feed ingestion quantity, liver, kidney, brain, bone weights between the control and the experimental groups. Under the experiment with drinking waters was no metal ${\sim}\;0.65mg/L$ detected. Metal level within feed found 0.0001-376.983mg/kg. 2. In the pack of SipJeonDaeBo-decoction, there detected no metal ${\sim}2.086mg/L$ 3. After P.O(per os) SipJeonDaeBo-decoction, As is detected $2.390{\pm}0.812mg/kg$ in blood; Cd $0.001{\pm}0.001mg/kg$, Co $0.003{\pm}0.001mg/kg$, Cr $0.432{\pm}0.234mg/kg$, Cu $1.013{\pm}0.373mg/kg$, Fe $426.293{\pm}114.842mg/kg$, no Hg, Mn $0.109{\pm}0.082mg/kg$, Ni $0.122{\pm}0.068mg/kg$, Zn $3.584{\pm}1.270mg/kg$. 4. The concentration of Hazardous heavy metal (As, Cd, Co, Cr, Hg, Ni, Pb) within blood control group is searched $0.488{\pm}0.138\;mg/l$; experiment I group $0.432{\pm}0.080mg/l$, experiment II group $0.588{\pm}0.213mg/l$. In the concentration of non hazardous heavy metal(Cu, Fe, Mn, Zn) control group $101.409{\pm}6.832mg/l$; experiment I group $96.062{\pm}5.732\;mg/l$, experiment II group $125.139{\pm}044.820mg/l$. 5. Correlation among every metal in blood Zn and Cr was 0.87956 ; Cd and As -0.02316, Pb and As -0.08738, Ni and As 0.07824, Mn and As 0.07824, Mn and Cd 0.04999. Briefly under the injection of SipJeonDaeBo-decoction, this study was defined within safety in blood level by P.O. during 10 days.