Cobalt-free precursor for lithium ion battery, positive electrode material and preparation methods of cobalt-free precursor and positive electrode material

Abstract

The invention discloses a cobalt-free precursor for a lithium ion battery, the chemical formula of the precursor is NixMn1-x (OH) 2, 0.75 < = x < = 0.85, the particle size is 12-18 [mu] m, and the cross-sectional morphology of the particles is divergent from the center of a circle to the circumference. The invention also discloses a preparation method of the cobalt free precursor for lithium ion battery and a positive electrode material. According to the preparation method disclosed by the invention, the core-shell cobalt-free precursor with a divergent structure can be obtained, the nickel content of the inner core is higher than that of the outer shell, and the manganese content of the inner core is lower than that of the outer shell, so that a structure of which the inner core is high-nickel and low-manganese and the outer shell is high-manganese and low-nickel is formed; the high nickel of the inner core can improve the specific capacity of the material, the high manganese of the outer shell can provide smooth transition of Li < + >, and the divergent structure of the inner core particles provides a Li < + > transmission channel to accelerate de-intercalation of Li < + > and improve the rate capability of the material, so that the problem of poor rate capability caused by Co deficiency is solved; higher specific capacity, cycling stability and thermal stability can be obtained by using the precursor to prepare the positive electrode material.

Description

technical field [0001] The invention relates to the field of positive electrode materials for lithium ion batteries, in particular to a cobalt-free precursor for lithium ion batteries, positive electrode materials and a preparation method thereof. Background technique [0002] With the rapid development of lithium-ion batteries, the nickel-cobalt-manganese ternary cathode material with high specific capacity is the goal that the new energy industry is constantly pursuing. In numerous LiNi x co y mn 1-x-y o 2 (NCM) layered materials, usually LiNi 0.8 mn 0.1 co 0.1 o 2 Discharging at 3.8V can provide an average of more than 200mAh g -1 Therefore, it has become a ternary material that has attracted more attention. But despite this, high-nickel cathode materials are hindered in market applications due to the disadvantages of poor cycle performance and rate performance. These disadvantages are mainly due to the random arrangement of the primary particles, resulting in d...

AI Technical Summary

Problems solved by technology

However, in the ternary cathode material, the introduction of Co element greatly increases the manufacturing cost of the material, but because Co resources are very scarce and relatively concentrated, the price of Co fluctuates greatly. Therefore, it is necessary to reduce and remove Co in the ternary cathode material. Co is an inevitable trend for large-scale use of new energy vehicles. How to remove Co without affecting the stability and rate performance of ternary cathode materials is the focus of research.

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