A kind of preparation method of composite lithium cobalt oxide cathode material doped with rare earth elements

Abstract

The invention relates to a preparation method for a rare earth element doped composite lithium cobalt oxide cathode material. The chemical formula of the rare earth element doped composite lithium cobalt oxide is aLiNi1-x-y-zALxCoyNdzO2-LiCoO2, wherein a is equal to 0.5-0.6; x is equal to 0.3-0.4; y is equal to 0.2-0.3; z is equal to 0.02-0.045. The preparation method comprises the following steps: (1) raw materials are weighed; (2) the raw materials are prepared into solutions respectively and subjected to reacting, seasoning, solid-liquid separating, washing, drying, sintering and oxidating to obtain a neodymium (Nd) doped composite lithium cobalt oxide precursor; (3) the neodymium doped composite lithium cobalt oxide precursor and the weighed oxalic acid lithium are mixed and subjected to secondary sintering, temperature reduction treating, smashing and screen separating to obtain a product. According to the rare earth element doped composite lithium cobalt oxide cathode material prepared by the invention, based on the foundation that the particle diameter is improved by a ternary material formed by nickel, cobalt and aluminum mixture, rare earth element Nd is further doped for modifying; therefore, the activity and stability of the materials are further improved; the combination of a wet process and a dry process is adopted in the preparation process; the tap density of the materials is further improved.

Description

Technical field [0001] The invention relates to a preparation method of a composite lithium cobalt oxide cathode material doped with rare earth elements. Background technique [0002] Lithium-ion battery is a new type of power source, it has many advantages such as high voltage, large capacity, safety and environmental protection, so it is widely used in the field of secondary batteries. Lithium batteries are mainly composed of positive electrode materials, negative electrode materials, separators and electrolytes, etc. The positive electrode materials account for more than 40% of the total cost of lithium batteries, and the performance of positive electrode materials directly affects the various performance indicators of lithium batteries, so Lithium battery cathode materials occupy a core position in lithium batteries. At present, lithium battery cathode materials that have been marketed include lithium cobaltate, multi-component materials, lithium manganate and lithium i...

AI Technical Summary

Problems solved by technology

However, in the process of evaluating large-grain lithium cobalt oxide materials, it was found that when the particle size increases, the electrochemical activity of the positive electrode material will decrease, which is manifested as a significant deterioration in cycle performance and rate discharge performance.

[0004] When the particle size of the previous lithium cobalt oxide is below 10 microns, its electrochemical performance is good and its cycle performance is excellent, but its compaction density is low, which cannot meet the increasing demand for energy density.

Although lithium cobalt oxide with a particle size of more than 10 microns can increase the volumetric energy density of the battery, its cycle performance cannot meet market demand due to its poor electrochemical activity.