Modified high-nickel positive electrode material coated with fast ion conductor and preparation method of modified high-nickel positive electrode material

Abstract

The invention discloses a modified high-nickel positive electrode material coated with a fast ion conductor and a preparation method of the modified high-nickel positive electrode material. The high-nickel positive electrode material comprises a substrate, wherein the substrate is a compound LiNi<1-x-y>Co<x>Mn<y>M<z>O<2> shown in a formula I, in the formula I, x is more than 0 but less than or equal to 0.20, y is more than 0 but less than or equal to 0.20, z is more than 0 but less than or equal to 0.1, and M is arbitrary one or more of elements of Al, Mg, Ti, Zr, Mn, Ni, Sn, Co, Zn, W, Mo, Ru, Ca, Sr, Ba, B, Y, V and Nb. The preparation method comprises the following steps of washing and drying the high-nickel positive electrode material, uniformly mixing the high-nickel positive electrode material and an appropriate amount of coating agent, and performing sintering and sieving to obtain the modified high-nickel positive electrode material coated with the fast ion conductor. The fastion conductor is coated by washing and surface drying methods, the alkali amount of a surface of the positive electrode material is reduced, side reaction of the material and an electrolyte is reduced, and the high-temperature stability and the safety of the material are improved; and by doping and coating the surface with the fast ion conductor, the energy density, the rate performance and the cycle property of the material are improved, and the long cycle lifetime of a battery is finally prolonged.

Description

technical field [0001] The invention relates to the field of positive electrode materials for lithium ion batteries, in particular to a fast ion conductor-coated modified high-nickel positive electrode material and a preparation method thereof. Background technique [0002] High-nickel cathode material LiNi for lithium-ion batteries 1-x-y co x mn y o 2 (0<x≤0.20, 0<y≤0.20) Compared with lithium cobalt oxide cathode materials, it has the advantages of high specific capacity and low price, and can significantly increase the battery capacity without increasing the positive and negative active materials of lithium batteries. , is one of the most promising cathode materials, and is currently widely used in portable electronic products such as mobile phones and computers, as well as various green vehicles and other fields. However, due to the similar radii of Li and Ni ions, lithium-nickel mixing is prone to occur during preparation and use, resulting in defects in the c...

AI Technical Summary

Problems solved by technology

However, due to the similar radii of Li and Ni ions, lithium-nickel mixing is prone to occur during preparation and use, resulting in defects in the crystal structure, which in turn leads to high irreversible capacity for the first time in high-nickel cathode materials, rapid cycle decay at high voltages, and low rate performance. Bad question

At the same time, due to the low reactivity of the high-nickel cathode material, the prepared material has high residual lithium, which in turn leads to high alkalinity of the material, and the "jelly" phenomenon is prone to occur when making the pole piece, which affects the processing performance of the pole piece

In addition, the residual lithium of high-nickel cathode materials will have side reactions with the electrolyte, which is prone to safety problems such as large gas production, battery swelling, and explosion under high-temperature conditions, which greatly limits the widespread use of high-nickel cathode materials.

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