Preparation method for high-tapping-density modified nickel-cobalt lithium manganate positive material

Abstract

The invention relates to a method for preparing a nickel-cobalt lithium manganatepositive material. The method comprises the following steps: carrying out coprecipitation reaction, drying, carrying out uniform rheological phase mixing, and calcining at high temperature so as to obtain high-tapping-density ball-shaped nickel-cobalt lithium manganate. The positive material prepared by adopting the method has the advantages of uniform element distribution, uniform particle size distribution, high tapping density, small specific surface area and good electrochemical property; a preparation process is simple, and the industrial production is easily realized; and the production cost also can be reduced and the stability of the quality of a product can be improved.

Description

technical field [0001] The invention relates to a preparation method of a positive electrode material of a lithium ion battery, in particular to a preparation method of a high-tap modified nickel-cobalt lithium manganese oxide positive electrode material. technical background [0002] Cathode materials are an important part of determining the performance of lithium-ion batteries. At present, the most mature cathode material LiCoO has been industrialized 2 , the research is relatively mature, and the comprehensive performance is excellent, but the price is expensive, the toxicity is high, and the safety performance is flawed. Especially under the condition of overcharge, the material is unstable and easy to react with the electrolyte, and the application field is greatly affected; in addition, LiCoO 2 Only half of the lithium can be reversibly deintercalated, which limits the increase in the capacity of lithium-ion batteries and cannot meet the needs of electric vehicle powe...

AI Technical Summary

Problems solved by technology

Ternary cathode materials have the advantages of low cost, high specific capacity, high voltage platform, good overshoot resistance, and excellent thermal stability. At present, the methods for synthesizing ternary cathode materials are mainly high-temperature solid-phase method, sol-gel method, Combustion method, molten salt method, but these methods or the preparation process are complicated, or the performance of the prepared material is not good

The ternary positive electrode material reported in Chinese patent CN 101621125A is mostly a spherical shape formed by the aggregation of multiple particles, and the tap density can reach 2.0-2.5g / cm 3 , but it is difficult to further improve

In addition, the particle size of the polycrystalline particles formed by the aggregation of multiple particles is difficult to be uniform, and the particle size distribution is wide. The polycrystalline particles have a large specific surface area, and are easy to absorb moisture when exposed to the air, which affects the performance of the product

In addition, Chinese patents CN 101304090A, CN 102306765A, and CN 1851962A adopt the method of physically and mechanically mixing lithium carbonate and ternary precursors to prepare nickel-cobalt lithium manganese oxide cathode materials through solid-state sintering to reduce costs; however, due to the simple Mechanical and physical mixing will inevitably bring about the inhomogeneity of materials, which will lead to the appearance of impurity phases in the sintered products, causing rapid capacity attenuation, and the reduction of comprehensive electrochemical performance and other defects

In addition, the traditional physical and mechanical mixing process requires strict requirements and control on many important physical indicators of each raw material, such as particle size and morphology, which brings great challenges to actual production and application.

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