Abstract: Disclosed is a method for preparing an electrochemical device, comprising the steps of: charging an electrochemical device using an electrode active material having a gas generation plateau potential in a charging period to an extent exceeding the plateau potential; and degassing the electrochemical device. An electrochemical device, which comprises an electrode active material having a gas generation plateau potential in a charging period, and is charged to an extent exceeding the plateau potential and then degassed, is also 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 method for preparing an electrochemical device, comprising the steps of: charging an electrochemical device using an electrode active material having a gas generation plateau potential in a charging period to an extent exceeding the plateau potential; and degassing the electrochemical device. An electrochemical device, which comprises an electrode active material having a gas generation plateau potential in a charging period, and is charged to an extent exceeding the plateau potential and then degassed, is also disclosed.

Abstract: Disclosed is a method for preparing an electrochemical device, comprising the steps of: charging an electrochemical device using an electrode active material having a gas generation plateau potential in a charging period to an extent exceeding the plateau potential; and degassing the electrochemical device. An electrochemical device, which comprises an electrode active material having a gas generation plateau potential in a charging period, and is charged to an extent exceeding the plateau potential and then degassed, is also disclosed. Some electrode active materials provide high capacity but cannot be applied to a high-capacity battery due to the gas generation. This is because a battery using such electrode active materials should be charged to an extent exceeding the gas generation plateau potential in order to realize a high capacity. To solve the problems caused by the gas generation, the battery is charged to an extent exceeding the plateau potential, and then degassed.

Abstract: The present invention relates to 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 (I0ppm) and a main peak of 240±140 ppm (I240ppm), (I0ppm/I240ppm), 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 (I0ppm) and the main peak of 240±140 ppm (I240ppm), (W240ppm/W0ppm), is less than 21.45; and (c) both the conditions (a) and (b). The peaks of the lithium-containing metal composite oxide are obtained according to the 7Li—NMR measurement conditions and means disclosed herein.

Abstract: The invention provides an anion-deficient lithium transition-metal phosphate as an electrode-active material, which is represented by the chemical formula Li1?xM(PO4)1?y (0?x?0.15, 0?y?0.05). The invention provides a method for preparing said Li1?xM(PO4)1?y, which comprises preparing a precursor of lithium transition-metal phosphate; mixing said precursor with water under reaction conditions of 200˜700 and 180˜550 bar to produce an anion-deficient lithium transition-metal phosphate; and calcining, or granulating and calcining the resultant compound. The invention also provides electrochemical devices employing said Li1?xM(PO4)1?y as an electrode-active material.

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 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 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.