High-nickel positive electrode material and preparation method and application thereof

Abstract

The invention relates to a high-nickel positive electrode material as well as a preparation method and application thereof. The high-nickel positive electrode material is of a core-shell structure, the structures of a core material and a shell material are respectively shown as a formula I and a formula II, M is a metal element, 0.6<=b<=1, a molar ratio of the core material to the shell material is 1:a, and 0<a<=1. The high-nickel positive electrode material of a core-shell structure is formed through in-situ growth on the surface of the high-nickel positive electrode raw material. On one hand, the high-nickel positive electrode material can be prepared into a positive electrode piece at a time, the energy density of the battery is improved by generating a lithium supplementing effect on a negative electrode through the shell material during charging, no additional lithium supplementing material is needed, the process is simple, and the lithium supplementing effect is good; and on the other hand, a protective layer can be formed on the surface of the high-nickel positive electrode material after the battery obtained by utilizing the high-nickel positive electrode material is charged for the first time, so that the stability and the safety of the battery are improved.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a high-nickel positive electrode material and its preparation method and application, in particular to a high-nickel positive electrode material capable of replenishing lithium on the negative electrode and its preparation method and application. Background technique [0002] New energy vehicles have four main requirements for lithium-ion power batteries, namely high energy density, long calendar life, high safety performance and low manufacturing cost. At present, power batteries have begun to use high-nickel ternary cathode materials (NCM or NCA) with a specific capacity of more than 205mAh / g, and the energy density of the single battery made is higher than 300Wh / kg. New energy vehicles equipped with high specific energy and high nickel system power batteries can have a cruising range of more than 500km. The use of high-nickel cathode materials meets the development requir...

AI Technical Summary

Problems solved by technology

The first method is to use lithium metal to replenish lithium on the negative electrode. Since lithium metal and water will react violently, the water content in the operating environment is required to be extremely low, which has certain safety risks.

The second method is to use a high-concentration electrolyte to replenish lithium on the negative electrode, because it will consume lithium ions in the electrolyte, which will eventually affect the power performance of the battery

However, due to the need for conventional positive electrode materials (lithium cobaltate, lithium manganese oxide, lithium nickelate, lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminate, lithium-rich manganese-based positive electrode materials, etc.) and The positive electrode lithium supplement materials are separately pulped, coated, and dried, which increases the difficulty of making the electrode sheet

In addition, due to the positive electrode lithium supplement material Li 2 NiO 2 Materials with relatively high hardness and a median particle size of less than 3 μm are limited by the capacity of crushing equipment, making it difficult to achieve large-scale industrial production

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