Abstract: Disclosed herein is a cathode active material based on lithium nickel oxide represented by Formula 1, wherein the lithium nickel oxide has a nickel content of at least 40% among overall transition metals and is coated with a polymer having a melting point of 80 to 300° C. at a surface thereof. A lithium secondary battery having the disclosed cathode active material has advantages of not deteriorating electrical conductivity while maintaining high temperature stability, so as to efficiently provide high charge capacity.

Abstract: Disclosed herein is a lithium secondary cell including 20 to 100 wt. % of lithium transition metal oxide represented by a formula of Li1+zNibMncMe1?(b+c)O2, relative to a total amount of a cathode active material, as well as an electrolyte consisting of a lithium salt and a non-aqueous solvent, wherein a first additive to form a protective film (that is, a solid electrolyte interface film: SEI film) over a surface of an anode active material and a second additive to form another SEI film over the surface of the anode active material while inactivating impurities contained in the cathode active material are included in the electrolyte.

Abstract: Disclosed is a lithium-containing metal composite oxide comprising paramagnetic and diamagnetic metals, which satisfies any one of the following conditions: (a) the ratio of intensity between a main peak of 0±10 ppm (Io PPm) and a main peak of 240±140 ppm (I240 pPm), Uoppm/124o PPm), is less than 0.117·Z wherein Z is the ratio of moles of the diamagnetic metal to moles of lithium; (b) the ratio of line width between the main peak of 0±10 ppm (Io PPm) and the main peak of 240+140 ppm (I24o PPm), (W24o PPm/WO ppm), is less than 21.45; and (c) both the conditions (a) and (b), the peaks being obtained according to the 7Li—NMR measurement conditions and means disclosed herein. Also, an electrode comprising the lithium-containing metal composite oxide, and an electrochemical device comprising the electrode are disclosed.

Abstract: Disclosed is a method for preparing a lithium-metal composite oxide, the method comprising the steps of: (a) mixing an aqueous solution of one or more transition metal-containing precursor compounds with an alkalifying agent and a lithium precursor compound to precipitate hydroxides of the transition metals; (b) mixing the mixture of step (a) with water under supercritical or subcritical conditions to synthesize a lithium-metal composite oxide, and drying the lithium-metal composite oxide; and (c) subjecting the dried lithium-metal composite oxide either to calcination or to granulation and then calcination. Also disclosed are an electrode comprising the lithium-metal composite oxide, and an electrochemical device comprising the electrode. In the disclosed invention, a lithium-metal composite oxide synthesized based on the prior supercritical hydrothermal synthesis method is subjected either to calcination or to granulation and then calcination.

Abstract: Disclosed is a secondary battery. The secondary battery includes a battery can serving as a positive electrode terminal or a negative electrode terminal of the secondary battery, an electrically conductive substrate provided at an outer portion of the battery can, and a nonconductive film interposed between the battery can and the electrically conductive substrate in order to insulate the electrically conductive substrate from the battery can, wherein the electrically conductive substrate is electrically connected to an electrode terminal having polarity opposite to that of the battery can. Safety of the secondary battery is ensured even if the secondary battery is subject to external parameters, such as penetration of a sharp tool (e.g. a nail or a drill tip), pressing force of a tool (e.g. a nipper), external impact, and exposure to the high temperature.

Abstract: Disclosed is a lithium secondary battery, which is low in capacity loss after overdischarge, having excellent capacity restorability after overdischarge and shows an effect of preventing a battery from swelling at a high temperature.

Abstract: Disclosed is a compound represented by the following formula 1. A lithium secondary battery using the same compound as electrode active material, preferably as cathode active material, is also disclosed. LiMP1-xAxO4??[Formula 1] wherein M is a transition metal, A is an element having an oxidation number of +4 or less and 0<x<1. The electrode active material comprising a compound represented by the formula of LiMP1-xAxO4 shows excellent conductivity and charge/discharge capacity compared to LiMPO4.

Abstract: Disclosed is an anode active material, comprising: (a) a carbonaceous material; and (b) a carbide coating layer partially or totally formed on a surface of the carbonaceous material, the carbide coating layer comprising at least one element selected from the group consisting of metals and metalloids. An anode obtained by using the anode active material and an electrochemical device comprising the anode are also disclosed. The carbonaceous material comprises a coating layer of metal-/metalloid-carbide obtained by treating it at high temperature under inert atmosphere, wherein the coating layer has increased interfacial boding force to the carbonaceous material and thus shows minimized reactivity to lithium. The carbonaceous material as anode active material can minimize the irreversible anode capacity needed for the formation of an SEI film during the first charge/discharge cycle, thereby providing high capacity, high efficiency and significantly improved anode qualities.

Abstract: An object of the present invention is to provide the device for protecting a secondary battery safely from overvoltage and overheating caused by the overcharge by using simple safety device, which provides a contacted safety device which connects between a constant voltage element showing a discharge characteristic in the state of overvoltage and a MIT (metal insulator transition) element showing a discharge characteristic in the state of overheating. Each of the constant voltage element and the MIT element are connected in parallel between a cathode lead and an anode lead of the secondary battery.

Abstract: Disclosed herein is a cathode active material for a lithium secondary battery, in particular, including a lithium transition metal oxide with a layered crystalline structure in which the transition metal includes a transition metal mixture of Ni, Mn and Co, and an average oxidation number of all transition metals other than lithium is more than +3, and specific conditions represented by the following formulae (1) and (2), 1.1<m(Ni)/m(Mn)<1.5 and 0.4<m(Ni2+)/m(Mn4+)<1, are satisfied. The inventive cathode active material has a more uniform and stable layered structure by controlling the oxidation number of transition metals contained in a transition metal oxide layer to form the layered structure, compared to conventional substances. Accordingly, the active material exhibits improved overall electrochemical characteristics including battery capacity and, in particular, excellent high rate charge-discharge features.

Abstract: Disclosed is a secondary battery having a constant-voltage device for preventing the secondary battery from being excessively overcharged. The breakdown voltage of the constant-voltage device is lower than the explosion or ignition voltage of the secondary battery, so the discharge operation may occur before the secondary battery is exploded or ignited even if the voltage of the secondary battery rises above the overcharge voltage, thereby protecting the secondary battery from explosion or ignition. The leakage current value of the constant-voltage device is less than 0.05% of the capacity value of the secondary battery under the maximum charge voltage of the secondary battery, or the breakdown voltage of the constant-voltage device is higher than the maximum charge voltage of the secondary battery. Thus, the constant-voltage device rarely generates the leakage current even if the secondary battery has been charged with the maximum charge voltage.

Abstract: Disclosed is a method for regulating terminal voltage of a cathode during overdischarge. Also disclosed is a lithium secondary battery, which is low in capacity loss after overdischarge, having excellent capacity restorability after overdischarge and shows an effect of preventing a battery from swelling at a high temperature.

Abstract: Disclosed are a safety element for a battery, which is provided with material having a Metal-Insulator Transition (MIT) characteristic where resistance abruptly drops at or above a certain temperature, and a battery with such a safety element. This battery with an MIT safety element is turned into a stable discharged state when it is exposed to an elevated temperature or a battery temperature rises due to external impact, so that it can ensure its safety.

Abstract: Disclosed is an anode active material, comprising: (a) a carbonaceous material; and (b) a carbide coating layer partially or totally formed on a surface of the carbonaceous material, the carbide coating layer comprising at least one element selected from the group consisting of metals and metalloids. An anode obtained by using the anode active material and an electrochemical device comprising the anode are also disclosed. The carbonaceous material comprises a coating layer of metal-/metalloid-carbide obtained by treating it at high temperature under inert atmosphere, wherein the coating layer has increased interfacial boding force to the carbonaceous material and thus shows minimized reactivity to lithium. The carbonaceous material as anode active material can minimize the irreversible anode capacity needed for the formation of an SEI film during the first charge/discharge cycle, thereby providing high capacity, high efficiency and significantly improved anode qualities.

Abstract: Disclosed is an anode active material, comprising: (a) a carbonaceous material; and (b) a carbide coating layer partially or totally formed on a surface of the carbonaceous material, the carbide coating layer comprising at least one element selected from the group consisting of metals and metalloids. An anode obtained by using the anode active material and an electrochemical device comprising the anode are also disclosed. The carbonaceous material comprises a coating layer of metal-/metalloid-carbide obtained by treating it at high temperature under inert atmosphere, wherein the coating layer has increased interfacial boding force to the carbonaceous material and thus shows minimized reactivity to lithium. The carbonaceous material as anode active material can minimize the irreversible anode capacity needed for the formation of an SEI film during the first charge/discharge cycle, thereby providing high capacity, high efficiency and significantly improved anode qualities.

Abstract: The present invention relates to an apparatus for protecting a secondary battery by preventing overcharge of the secondary battery. The apparatus for protecting a secondary battery includes: a secondary battery; a power supply, connected with both electrode terminals of the secondary battery, for providing a charging voltage and a charging current to the secondary battery to charge the secondary battery; and a secondary battery protection unit for shorting the power supply thereby to stop charging the secondary battery if a charging voltage of the secondary battery is above a predetermined voltage.