Preparation method of oxide-coated double-element co-doped high-nickel ternary positive electrode material

Abstract

The invention discloses a preparation method of an oxide-coated double-element co-doped high-nickel ternary positive electrode material, which comprises the following steps: firstly, mixing a high-nickel ternary precursor material with a doped element salt containing an X element, a doped element salt containing a Y element and a lithium salt to prepare a double-element co-doped high-nickel ternary material; and then dispersing and mixing the double-element co-doped high-nickel ternary material and a metal organic salt which is easy to hydrolyze, drying and calcining to prepare the oxide-coated double-element co-doped high-nickel ternary positive electrode material. The surface of the high-nickel ternary positive electrode material co-doped with two elements is coated with a layer of compact and uniform oxide passivation film, so that the capacity of the high-nickel ternary positive electrode material can be improved, and the water absorption condition of the high-nickel ternary positive electrode material is improved; and moreover, the direct contact between the active material and the electrolyte can be prevented, so that the dissolution of cobalt and manganese in the electrolyte is reduced, and the capacity retention ratio and the cycling stability are well improved.

Description

technical field [0001] The invention relates to the field of lithium-ion battery manufacturing, in particular to a method for preparing an oxide-coated dual-element co-doped high-nickel ternary positive electrode material. Background technique [0002] In recent years, lithium-ion batteries have attracted widespread attention from all walks of life due to their high specific energy, long cycle life, small self-discharge, safety and reliability, and environmental protection. They are widely used in electronic products such as mobile phones, notebook computers, and digital cameras. , At the same time, lithium-ion batteries are also energy storage power sources for electric vehicle power and solar renewable energy. Among them, high-nickel ternary materials in power vehicles are considered to be the most cost-effective cathode materials for power batteries due to their high capacity and high energy density. [0003] The cycle performance of high-nickel ternary materials is not ...

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Problems solved by technology

[0003] The cycle performance of high-nickel ternary materials is not ideal under high voltage. The capacity attenuation is mainly caused by the dissolution of cobalt and manganese in it under high voltage. The hydrofluoric acid in the electrolyte will react with cobalt and manganese. Cobalt and manganese will dissolve, resulting in unstable structure and loss of capacity; in addition, the capacity of high-nickel materials will gradually increase with the increase of nickel content, but this will lead to a series of problems, the most important of which is that the material is easy to Absorb water, thereby generating residual alkali on the surface, which will affect the processing performance and electrochemical performance of the material

[0004] Electrochimica Acta 54 (2009) 3851–3856, Magnesium-Al co-doped high-nickel Li[Ni 0.8 co 0.1 mn 0.1 ]O 2 Material, the structure of the high-nickel ternary material after doping has not changed, and after doping magnesium and aluminum, it replaces the position of manganese in the original structure, choose the appropriate co-doping ratio, when the doping ratio When both are 0.1%, the capacity is only reduced from 201mAh / g to 197.7mAh / g, and the cycle is well improved. The 70-week cycle capacity retention rate after modification is 91%, while that of the unmodified one is only 83% after 70 weeks. % capacity retention, this doping method has improved the cycle stability of high-nickel materials very well, but this method still has not solved the situation that high-nickel materials are easy to absorb water, and is not easy for industrial production

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