Lithium cobalt oxide positive electrode material of lithium ion battery with voltage of 4.45 V or above and preparation method of lithium cobalt oxide positive electrode material

Abstract

The invention discloses a lithium cobalt oxide positive electrode material of a lithium ion battery with the voltage of 4.45 V or above. The lithium cobalt oxide positive electrode material comprisesa lithium cobalt oxide matrix (Mg, Ti and Al doped lithium cobalt oxide) and a coating layer (M and N doped lithium cobalt oxide) coating the surface of the matrix. The preparation method comprises the following steps that: (1) a Li source, a Co source, MgO, TiO2 and Al2O3 are uniformly mixed, an obtained mixture is sintered, jet milling is performed on a sintered product, so that a matrix lithiumcobalt oxide can be obtained; and (2) the matrix lithium cobalt oxide, CoCO3 containing doped metal elements M and N, and a Li source are uniformly mixed, secondary constant-temperature sintering isperformed, and sieving is performed, and the lithium cobalt oxide positive electrode material is obtained. The lithium cobalt oxide positive electrode material disclosed by the invention is assembledinto a whole battery; a test under the condition of 25 DEG C shows that the first discharge capacity of the battery of 4.5 V is not lower than 191mAh / g and the efficiency of the battery is not lower than 92.0%; and a test under the condition of 45 DEG C shows that the capacity retention ratio of the battery after 500 cycles under 4.48 V is not lower than 80.0%, and the capacity retention ratio ofthe battery after 350 cycles under 4.5 V is not lower than 80.0%.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials, and in particular relates to a lithium cobalt oxide positive electrode material for a lithium ion battery above 4.45V and a preparation method thereof. Background technique [0002] With the continuous development of lithium-ion battery technology, the battery system puts forward higher requirements for the four major components, namely, positive electrode material, negative electrode material, separator and electrolyte, and gradually moves from low-end to high-end. At present, lithium-ion batteries are mainly divided into two categories: 3C digital and power, because lithium cobalt oxide material has excellent energy density, cycle performance and high and low temperature performance, and is an irreplaceable positive electrode material in 3C digital lithium-ion batteries. Since the mass production of 4.45V lithium cobaltate has been realized, it can basically meet the needs of more t...

AI Technical Summary

Problems solved by technology

Although the above technical means can achieve the technical effect of improving structural stability and improving material cycle performance, purely inert substances and LiVPO without capacity activity 4 F coating will inevitably block lithium ions from coming out and intercalating during charging and discharging, which will affect the capacity of the positive electrode material itself.

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