Abstract: Disclosed is a lithium secondary battery comprising a cathode including a lithium-containing transition metal oxide, an anode including a carbon-based material, and a non-aqueous electrolyte with addition of a compound of formula (1). Incorporation of the compound (1) into the electrolyte significantly improves the high-temperature performance and cycle life characteristics of the battery.

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 electrolyte for a secondary battery comprising an electrolyte salt and an electrolyte solvent, the electrolyte comprising both a lactam-based compound and a sulfinyl group-containing compound. Also, disclosed is an electrode having a solid electrolyte interface (SEI) film partially or totally formed on a surface thereof, the SEI film being formed by electrical reduction of the above compounds. Further, a secondary battery comprising the electrolyte and/or the electrode is disclosed.

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 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 secondary battery including (i) a cathode; (ii) an anode; (iii) a separator; and (iv) a gel polymer electrolyte composition including an electrolyte solvent, an electrolyte salt, and a polymerizable monomer, wherein a polymerization initiator is coated or added on at least one battery device element in contact with the gel polymer electrolyte composition. Also, the secondary battery including a cathode, an anode, a separator, and a gel polymer electrolyte is manufactured by the steps of: coating or adding a polymerization initiator on/to at least one battery device element in contact with the gel polymer electrolyte; inserting the cathode, the anode, and the separator into a battery case; and forming the gel polymer electrolyte by injecting a gel polymer electrolyte composition including an electrolyte solvent, an electrolyte salt, and a polymerizable monomer into the battery case, and carrying out polymerization.

Abstract: Disclosed is a non-aqueous electrolyte comprising: a first acrylate compound having one or two acryl groups; a second acrylate compound having three or more acryl groups; an electrolyte salt; and an organic solvent. Also, disclosed is an electrode comprising a coating layer formed partially or totally on a surface thereof, the coating layer comprising: (i) a reduced form of a first acrylate compound having one or two acryl groups; and (ii) a reduced form of a second acrylate compound having three or more acryl groups. Further, disclosed in an electrochemical device comprising a cathode, an anode, a separator and a non-aqueous electrolyte, wherein (i) the non-aqueous electrolyte is the above non-aqueous electrolyte; and/or (ii) the cathode and/or the anode is the above electrode.

Abstract: Disclosed is a composition for a gel polymer electrolyte, the composition comprising: (i) a cyclic compound as a first crosslinking agent, the cyclic compound containing a cyclic group at the center thereof and having at least three double bonds at the end thereof; (ii) a linear or branched compound as a second crosslinking agent, the linear or branched compound containing an oxyalkylene group at the center thereof and having at least two (meth)acryl groups at the end thereof; (iii) an electrolyte solvent; (iv) an electrolyte salt; and (v) a polymerization initiator. Also, disclosed are a gel polymer electrolyte formed by polymerizing the composition for a gel polymer electrolyte, and an electrochemical device comprising the gel polymer electrolyte.

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 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 electrolyte for a secondary battery comprising an electrolyte salt and an electrolyte solvent, the electrolyte further comprising both a cyclic diester compound and a sulfinyl group-containing compound. Also, disclosed is an electrode having a solid electrolyte interface (SEI) film partially or totally formed on a surface thereof, the SEI film being formed by electrical reduction of the above compounds. Further, a secondary battery comprising the electrolyte and/or the electrode is disclosed.

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.

Abstract: Disclosed is an additive for a non-aqueous electrolyte, which is a compound having a double bond and at least two cyano groups, the two cyano groups being in a trans-formation to the double bond. Also, a non-aqueous electrolyte comprising the additive and an electrochemical device comprising the non-aqueous electrolyte are also disclosed. Further, an electrode comprising the cyano group-containing compound and an electrochemical device comprising the electrode are disclosed.

Abstract: Disclosed is an electrolyte for a secondary battery comprising an electrolyte salt and an electrolyte solvent, the electrolyte further comprising a lactam-based compound substituted with an electron withdrawing group (EWG) at the nitrogen position thereof. The electrolyte allows formation of a firm and dense SEI film on the surface of an anode, minimizes irreversible oxidative decomposition at a cathode, and thus can provide a battery with significantly improved lifespan, stability and high temperature characteristics.

Abstract: Disclosed are nonaqueous electrolyte additives, which can improve the safety of a battery upon overcharge of the battery without reducing the performance of the battery, as well as a nonaqueous electrolyte comprising the additives, and a lithium secondary battery comprising the nonaqueous electrolyte. More particularly, disclosed are a nonaqueous electrolyte comprising both fluorobiphenyl and fluorotoluene as additives, and a lithium secondary battery comprising the nonaqueous electrolyte.

Abstract: Disclosed is an electrolyte for batteries, comprising: (a) an electrolyte salt; (b) an organic solvent; (c) a first compound having an oxidation initiation voltage (vs. Li/Li+) higher than the operating voltage of a cathode; and (d) a second reversible compound having an oxidation initiation voltage higher than the operating voltage of the cathode, but lower than the oxidation initiation voltage of the first compound. Also disclosed is a lithium secondary battery comprising said electrolyte. In the lithium secondary battery, two compounds having different safety improvement actions at a voltage higher than the operating voltage of the cathode are used in combination as electrolyte components. Thus, the safety of the secondary battery in an overcharged state can be ensured, and at the same time, the deterioration of the battery can be prevented from occurring when it is repeatedly cycled, continuously charged and stored at high temperature for a long time.

Abstract: Disclosed is negative electrode active material for lithium ion batteries and a method for manufacturing the same. The active material includes a crystalline carbon core; and an amorphous or turbostratic carbon shell evenly covering the crystalline carbon core, the carbon shell having a thickness of 10-2000 Å. The method includes the steps of chemically combining a crystalline carbon and an amorphous carbon precursor; removing remaining amorphous carbon precursor not reacted in the chemical combination; and heat-treating a chemical combination material of graphite and the amorphous carbon precursor obtained in the chemical combination.

Abstract: A negative active material for a lithium secondary battery which is capable of improving packing density and has good high-rate charge/discharge and cycle life characteristics is provided. The negative active material includes a crystalline carbon core and an amorphous carbon shell. Alternatively, the negative active material includes secondary particles prepared by gathering at least one crystalline carbon primary particle. A surface of the secondary particles is coated with an amorphous carbon and the secondary particles has a substantially spherical form. The negative active material has two exothermic peak of the differential thermal analysis at 1000° C. or less. A lithium secondary battery using the negative active material can use propylene carbonate for an organic solvent of an electrolyte.