• Carbon letters
• /
• 제11권2호
• /
• pp.127-130
• /
• 2010

Boron doped fullerene $C_{60}$ ($B:C_{60}$) films were prepared by the thermal evaporation of $C_{60}$ powder using argon plasma treatment. The morphology and structural characteristics of the thin films were investigated by scanning electron microscope (SEM), Fourier transform infra-red spectroscopy (FTIR) and x-ray photo electron spectroscopy (XPS). The electrochemical application of the boron doped fullerene film as a coating layer for silicon anodes in lithium ion batteries was also investigated. Cyclic voltammetry (CV) measurements were applied to the $B:C_{60}$ coated silicon electrodes at a scan rate of $0.05\;mVs^{-1}$. The CV results show that the $B:C_{60}$ coating layer act as a passivation layer with respect to the insertion and extraction of lithium ions into the silicon film electrode.

• 대한기계학회논문집B
• /
• 제37권7호
• /
• pp.665-667
• /
• 2013

리튬이온 전지의 양극은 다양한 종류의 전이금속재료로 구성되며, 전지의 성능은 양극을 구성하는 금속재료에 의해 많은 영향을 받는다. 이는, 양극 내부에서 리튬이온의 확산 및 상전이 양상이 재료마다 서로 다르게 나타나기 때문이다. 따라서, 충방전 시 양극 내부 리튬이온의 확산 및 상전이를 이해하는 것은 고용량, 고전압 리튬 이차전지를 설계하기 위해 필수적이다. 본 연구에서는 phase field model을 바탕으로 양극 내부의 리튬이온 확산 및 상전이 과정을 분석한다.

• Nuclear Engineering and Technology
• /
• 제55권10호
• /
• pp.3665-3676
• /
• 2023

The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)₃^-.

• 한국수소및신에너지학회논문집
• /
• 제26권5호
• /
• pp.416-422
• /
• 2015

Lithium Ion capacitor (LIC) is a new storage device which combines high power density and high energy density compared to conventional supercapacitors. LIC is capable of storing approximately 5.10 times more energy than conventional EDLCs and also have the benefits of high power and long cycle-life. In this study, LICs are assembled with activated carbon (AC) cathode and pre-doped graphite anode. Cathode material of natural graphite and artificial graphite kinds of MAGE-E3 was selected as the experiment proceeds. Super-P as a conductive agent and PTFE was used as binder, with the graphite: conductive agent: binder of 85: 10: 5 ratio of the negative electrode was prepared. Lithium doping condition of current density of $2mA/cm^2$ to $1mA/cm^2$, and was conducted by varying the doping. Results Analysis of Inductively Coupled Plasma Spectrometer (ICP) was used and a $1mA/cm^2$ current density, $2mA/cm^2$, when more than 1.5% of lithium ions was confirmed that contained. In addition, lithium ion doping to 0.005 V at 10, 20 and $30^{\circ}C$ temperature varying the voltage variation was confirmed, $20^{\circ}C$ cell from the low internal resistance of $4.9{\Omega}$ was confirmed.

• 전기화학회지
• /
• 제25권2호
• /
• pp.51-68
• /
• 2022

리튬금속전지는 높은 에너지 밀도를 구현시킬 수 있음에도 불구하고, 단락, 낮은 쿨롱 효율, 용량 손실, 사이클 성능 감소 등의 문제를 초래하는 덴드라이트 성장을 억제시키는 기술은 아직 학술연구 단계에 머물러 있다. 본 논문에서는 최근까지 발표된 리튬금속전극에서 덴드라이트 성장을 억제시킬 수 있는 방법을 4가지로 분류하여 분석해보았다. 즉, 리튬금속전극의 부피 팽창에 대응할 수 있는 유연한 SEI (solid electrolyte interface) 층, 덴드라이트 성장을 물리적으로 억제시킬 수 있는 SEI 지지층, 균일한 리튬 확산을 유도하여 리튬 성장을 조절하는 SHES (self-healing electrostatic shield) 메커니즘, 그리고 리튬의 균일한 전착을 유도하는 마이크로패터닝 등에 대해 연구된 사례들의 장단점을 분석하여, 리튬금속전극의 실용화 연구에 도움을 주고자 한다.

• 폴리머
• /
• 제33권5호
• /
• pp.509-513
• /
• 2009

키토산/피브로인 블렌드의 구조와 물성에 미치는 브롬화 리튬의 효과를 고찰하기 위하여, 브롬화 리튬을 함유한 용액으로 성형한 키토산/피브로인 블렌드 필름과 성형 시 브롬화 리튬을 제거한 블렌드 필름의 구조적 특성을 조사하였다. 키토산/피브로인 블렌드는 용해된 브롬/리튬이온과 더불어 복합체를 형성하였고, 0.6 mol/L의 LiBr 농도에서 X-선 회절에 의한 복합체의 결정성을 보였으며, 이온 농도가 증가할수록 결정성은 감소되었다. 복합체 용액으로부터 고화 시중화 및 삼투작용으로 브롬화 리튬을 제거한 블렌드 필름의 결정은 키토산의 수화형 결정상을 형성하였으며, 브롬화 리튬을 처리하지 않은 것에 비하여 결정성이 크게 증가하였다. 복합체에 의한 블렌드 필름은 자중의 수십 배의 물을 흡수하여 수화겔을 형성하였다.

• 한국재료학회지
• /
• 제14권9호
• /
• pp.627-633
• /
• 2004

Lithium titanate whiske($Li_{x}Ti_{4}O_9$) was prepared by an ion-exchange reaction. To this end, the initial material, potassium tetratitanate ($K_{2}Ti_{4}O_9{\cdot}nH_{2}O$) was prepared by calcination of a mixture of $K_{2}CO_3\;and\;TiO_2$ with a molar ratio of 2.8 at $1050^{\circ}C$ for 3 h, followed by boiling water treatment of the calcined products for 10 h. Fibrous potassium tetratitanate could be transformed into layered hydrous titanium dioxide ($H_{2}Ti_{4}O_9{\cdot}nH_{2}O$) through an exchange of $K^{+}\;with\;H^{+}$ using 0.075 M HCl. Also, lithium titanate whisker was finally prepared as $Li^{+}\;and\;H^{+}$ ions were exchanged by adding 20 mL of a mixture solution of LiOH and $LiNO_3$ to 1g whisker and stirring for $5\~15$ days. The average length and diameter of the $Li_{x}Ti_{4}O_9$ whiskers were $10\~20{\mu}m\;and\;1\~3{\mu}m$, respectively.

• Applied Science and Convergence Technology
• /
• 제23권1호
• /
• pp.14-26
• /
• 2014

Copper is an important component from coin metal to electronic wire, integrated circuit, and to lithium battery. Copper oxides, mainly including $Cu_2O$ and CuO, are important semiconductors for the wide applications in solar cell, catalysis, lithium-ion battery, and sensor. Due to their low cost, low toxicity, and easy synthesis, copper oxides have received much research interest in recent year. Herein, we review the crystallization of copper oxides by designing various chemical reaction routes, for example, the synthesis of $Cu_2O$ by reduction route, the oxidation of copper to $Cu_2O$ or CuO, the chemical transformation of $Cu_2O$ to CuO, the chemical precipitation of CuO. In the designed reaction system, ligands, pH, inorganic ions, temperature were used to control both chemical reactions and the crystallization processes, which finally determined the phases, morphologies and sizes of copper oxides. Furthermore, copper oxides with different structures as electrode materials for lithium-ion batteries were also reviewed. This review presents a simple route to study the reaction-crystallization-performance relationship of Cu-based materials, which can be extended to other inorganic oxides.

• Carbon letters
• /
• 제27권
• /
• pp.98-107
• /
• 2018

Free-standing electrodes of CuO nanorods in carbon nanotubes (CNTs) are developed by synthesizing porous CuO nanorods throughout CNT webs. The electrochemical performance of the free-standing electrodes is evaluated for their use in flexible lithium ion batteries (LIBs). The electrodes comprising CuO@CNT nanocomposites (NCs) were characterized by charge-discharge testing, cyclic voltammetry, and impedance measurement. These structures are capable of accommodating a high number of lithium ions as well as increasing stability; thus, an increase of capacity in long-term cycling and a good rate capability is achieved. We demonstrate a simple process of fabricating free-standing electrodes of CuO@CNT NCs that can be utilized in flexible LIBs with high performance in terms of capacity and cycling stability.

• E2M - 전기 전자와 첨단 소재
• /
• 제11권11호
• /
• pp.9-17
• /
• 1998

The dependence of the ionic conductivity on the B-site ion substitution in (Li0.5La0.5)Ti1-xMxO3 (M=Sn, Zr, Mn, Ge) system has been studied. Same valence state and various electronic configuration and ionic radius of Sn4+, Zr4+, Mn4+ and Ge4+(4d10(0.69$\AA$), 4p6(0.72$\AA$), 3d10(0.54$\AA$) and 3d3(0.54$\AA$), respectively) induced the various crystallographic variaton with substitutions. So it was possibleto investigate the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic factor which influence the ionic conduction by observing the dependence of the conductivity on the crystallographic variations. We found that the conductivity increased with decreasing the radii of B-site ions or vice versa and octahedron distortion disturb the ion conduction. The reason for this reciprocal proportion of conductivity on the radius of B-site ions has been examined on the base of the interatomic bond strength change due to the cation substitutions. The results were good in agreement with the experimental results. Therefore it could be concluded that the interatomic bond strength change due to the cation substitutions may be the one of major factors influencing the lithium ion conductivity in perovskite(Li0.5La0.5) TiO3system.