Seung-Taek Myung

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Lithium-excess manganese layered oxides, which are commonly described by the chemical formula zLi(2)MnO(3)-(1-z)LiMeO(2) (Me = Co, Ni, Mn, etc.), are of great importance as positive electrode materials for rechargeable lithium batteries. In this Article, Li(x)Co(0.13)Ni(0.13)Mn(0.54)O(2-δ) samples are prepared from Li(1.2)Ni(0.13)Co(0.13)Mn(0.54)O(2) (or(More)
We propose a feasibility of Co-free Ni-rich Li(Ni(1-x)Mn(x))O2 layer compound. Li(Ni(1-x)Mn(x))O2 (0.1 ≤ x ≤ 0.5) have been synthesized by a coprecipitation method. Rietveld refinement of X-ray diffraction and microscopic studies reveal dense and spherical secondary particles of highly crystalline phase with low cation mixing over the whole compositions,(More)
Layered lithium nickel-rich oxides, Li[Ni(1-x)M(x)]O(2) (M=metal), have attracted significant interest as the cathode material for rechargeable lithium batteries owing to their high capacity, excellent rate capability and low cost. However, their low thermal-abuse tolerance and poor cycle life, especially at elevated temperature, prohibit their use in(More)
Nickel-rich layered lithium transition-metal oxides, LiNi(1-x)M(x)O(2) (M = transition metal), have been under intense investigation as high-energy cathode materials for rechargeable lithium batteries because of their high specific capacity and relatively low cost. However, the commercial deployment of nickel-rich oxides has been severely hindered by their(More)
For the first time, we report the electrochemical activity of anatase TiO2 nanorods in a Na cell. The anatase TiO2 nanorods were synthesized by a hydrothermal method, and their surfaces were coated by carbon to improve the electric conductivity through carbonization of pitch at 700 °C for 2 h in Ar flow. The resulting structure does not change before and(More)
Past efforts have used various carbon sources to coat LiFePO 4 particles. These sources include sucrose, [ 10–14 ] poly(ethylene glycol), [ 15 , 16 ] citric acid, [ 17 ] poly(vinyl alcohol), [ 18 , 19 ] and ascorbic acid. [ 20 ] An important step ahead was marked by Xie et al., [ 21 ] who showed that real success in terms of improving LiFePO 4(More)
While much research effort has been devoted to the development of advanced lithium-ion batteries for renewal energy storage applications, the sodium-ion battery is also of considerable interest because sodium is one of the most abundant elements in the Earth's crust. In this work, we report a sodium-ion battery based on a carbon-coated Fe3O4 anode,(More)
The high capacity of Ni-rich Li[Ni(1-x)M(x)]O(2) (M = Co, Mn) is very attractive, if the structural instability and thermal properties are improved. Li[Ni(0.5)Mn(0.5)]O(2) has good thermal and structural stabilities, but it has a low capacity and rate capability relative to the Ni-rich Li[Ni(1-x)M(x)]O(2). We synthesized a spherical core-shell structure(More)
In recent years, gasoline prices have risen in real terms to levels not seen since the early 1980s. [ 1 ] As a result, demand has increased signifi cantly for a high-performance battery to power hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and all-electric vehicles (EVs). At present, the total worldwide sales of HEVs based on(More)
We have successfully synthesized a spherical core-shell structure based on Li[(Ni0.8Co0.2)0.8(Ni0.5Mn0.5)0.2]O2 via a coprecipitation route. According to the careful examination by scanning electron microscopy (SEM), transmission electron microscopy energy-dispersive spectroscopy (TEM-EDS), and X-ray diffraction (XRD), it was found that the core-shell(More)