Abstract: A method of preparing a positive electrode active material for a secondary battery includes preparing a lithium composite transition metal oxide which includes nickel, cobalt, and manganese and contains 60 mol % or more of the nickel among all metals except lithium, adding a moisture absorbent and the lithium composite transition metal oxide into an atomic layer deposition (ALD) reactor, and adding a coating metal precursor into the atomic layer deposition (ALD) reactor and forming a metal oxide coating layer on surfaces of particles of the lithium composite transition metal oxide by atomic layer deposition (ALD).

Abstract: A positive electrode active material for a lithium secondary battery has a mixture of microparticles having a predetermined average particle size (D50) and macroparticles having a larger average particle size (D50) than the microparticles. The microparticles have the average particle size (D50) of 1 to 10 ?m and are at least one selected from the group consisting of particles having a carbon material coating layer on all or part of a surface of primary macroparticles having an average particle size (D50) of 1 ?m or more, particles having a carbon material coating layer on all or part of a surface of secondary particles formed by agglomeration of the primary macroparticles, and a mixture thereof. The macroparticles are secondary particles having an average particle size (D50) of 5 to 20 ?m formed by agglomeration of primary microparticles having a smaller average particle size (D50) than the primary macroparticles.

Abstract: A positive electrode for a lithium secondary battery includes a positive electrode collector, a first positive electrode active material layer formed on the positive electrode collector and includes a first positive electrode active material, and a second positive electrode active material layer formed on the first positive electrode active material layer and includes a second positive electrode active material. The first positive electrode active material and the second positive electrode active material include a lithium nickel-cobalt-based oxide in which an amount of nickel among total metallic components excluding lithium is 80 atm % or more, the first positive electrode active material has a molar ratio of nickel to cobalt of 18 or more, and the second positive electrode active material has a molar ratio of nickel to cobalt of less than 18.

Abstract: An electrode includes an electrode active material, wherein the electrode active material layer includes an electrode active material, polyvinylidene fluoride, and a conductive agent, wherein the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure is included in an amount of 0.01 wt % to 0.5 wt % in the electrode active material layer. A secondary battery including the same, and a method of preparing the electrode are also provided.

Abstract: A positive electrode active material for a lithium secondary battery comprising lithium transition metal oxide particles having a core-shell structure which includes a core portion and a shell portion disposed on a surface of the core portion. Wherein, the average crystallite size of the core portion is smaller than an average crystallite size of the shell portion and an amount of nickel among total transition metals included in the core portion and the shell portion is 80 atm % or more. A positive electrode active material, which suppresses decomposition of an electrolyte solution and occurrence of micro cracks of the positive electrode active material during charge and discharge by forming an average crystallite size of a core portion of the high-nickel positive electrode active material smaller than an average crystallite size of a shell portion, and a method of preparing the same.

Abstract: The present invention relates to a test socket heating module and a device test apparatus including the same, and more particularly, to a test socket heating module for performing a high-temperature test on a device, and a device test apparatus including the same. The present invention discloses a test socket heating module (200) including: a support plate (210) installed to be spaced apart a distance from a bottom surface of a test board (100) which is provided with one or more test sockets (20) for performing a test on a device (10) mounted on the test sockets; and one or more heater units (220) which are coupled to the support plate (210) between the test board (100) and the support plate (210), and heat the corresponding test sockets (20), respectively.

Abstract: Methods, devices, and systems are provided herein related to a connection management server connected to a signaling server, a push server, at least one home device, and at least two smart devices. The connection management server includes a connection management request receiver for receiving a video call connection request or a user switching request. A connection management request transmitter is also included for transmitting a connection state releasing request to the home device and the first smart device, for transmitting a video call push notification transmission request to the push server upon the video call connection request, and for transmitting a user switching push notification transmission request to the push server upon the user switching request. A group manager is also included for managing, in a group, smart device identity corresponding to a push notification sent from the push server.

Abstract: Methods, devices, and systems are provided herein related to a connection management server connected to a signaling server, a push server, at least one home device, and at least two smart devices. The connection management server includes a connection management request receiver for receiving a video call connection request or a user switching request. A connection management request transmitter is also included for transmitting a connection state releasing request to the home device and the first smart device, for transmitting a video call push notification transmission request to the push server upon the video call connection request, and for transmitting a user switching push notification transmission request to the push server upon the user switching request. A group manager is also included for managing, in a group, smart device identity corresponding to a push notification sent from the push server.