阅读说明：本技术 一种高容量富锂三元正极材料的制备方法 (Preparation method of high-capacity lithium-rich ternary cathode material ) 是由 刘杰 张扬 何瑶 陈令 郑胜军 王德齐 于 2019-08-16 设计创作，主要内容包括：本发明公开一种高容量富锂三元材料正极的制备方法,该方法具体为将可溶性的Ni、Co、Mn和Li盐溶解于去离子水中,充分溶解得到澄清溶液A；将柠檬酸溶解于去离子水,磁力搅拌使其充分溶解,得到澄清透明溶液B；将B溶液逐滴滴入溶液A中直至滴完,制成溶液C；然后用氨水溶液调节溶液C的pH值为5-7,制成溶液D；将溶液D蒸发浓缩得溶胶,继续蒸发浓缩得湿凝胶；将湿凝胶冷冻并干燥；得到蓬松干凝胶；将蓬松干凝胶研磨成粗粉末；将粉末预烧,再进行煅烧,冷却至室温,得到富锂三元材料。本发明将生成的基本粒子通过液氮快速冷冻以防止粒子的团聚而导致分散不均。制得的材料颗粒均匀,分散性较好,可制得高容量、高能量密度、优循环性能的正极材料。(The invention discloses a preparation method of a high-capacity lithium-rich ternary material anode, which comprises the steps of dissolving soluble Ni, Co, Mn and Li salts in deionized water, and fully dissolving to obtain a clear solution A; dissolving citric acid in deionized water, and magnetically stirring to fully dissolve the citric acid to obtain a clear transparent solution B; dropwise adding the solution B into the solution A until the solution A is completely added to prepare a solution C; then, adjusting the pH value of the solution C to 5-7 by using an ammonia water solution to prepare a solution D; evaporating and concentrating the solution D to obtain sol, and continuing to evaporate and concentrate to obtain wet gel; freezing and drying the wet gel; obtaining fluffy dry gel; grinding the fluffy dry gel into coarse powder; and pre-burning the powder, then calcining, and cooling to room temperature to obtain the lithium-rich ternary material. The invention quickly freezes the generated basic particles by liquid nitrogen to prevent the particles from agglomerating to cause uneven dispersion. The prepared material has uniform particles and better dispersibility, and can be used for preparing the anode material with high capacity, high energy density and excellent cycle performance.)

1. A preparation method of a high-capacity lithium-rich ternary material anode is characterized by comprising the following steps:

(1) dissolving soluble Ni, Co, Mn and Li salts in deionized water, and fully dissolving the soluble Ni, Co, Mn and Li salts by magnetic stirring to obtain a clear solution A;

(2) dissolving citric acid in deionized water, and magnetically stirring to fully dissolve the citric acid to obtain a clear transparent solution B;

(3) dropwise adding the solution B into the solution A until the solution A is completely added to prepare a solution C;

(4) then, adjusting the pH value of the solution C to 5-7 by using an ammonia water solution to prepare a solution D;

(5) evaporating and concentrating the solution D to obtain sol, and continuing to evaporate and concentrate to obtain wet gel;

(6) freezing the wet gel, and drying in a freeze dryer;

(7) obtaining fluffy xerogel, namely a lithium-rich ternary material precursor;

(8) grinding the fluffy dry gel into coarse powder;

(9) and putting the obtained powder into a muffle furnace for presintering at 450 ℃, calcining at 900 ℃, and cooling to room temperature to obtain the lithium-rich ternary material.

2. The method for preparing the high-capacity lithium-rich ternary material positive electrode according to claim 1, wherein in the step (1), the Ni, Co, Mn and Li salt is soluble acetate, nitrate or sulfate.

3. The method of claim 1, wherein the molar ratio of the Ni, Co, Mn, and Li salts is 0.13:0.13:0.54: 1.2.

4. The method for preparing the high-capacity lithium-rich ternary material positive electrode according to claim 1, wherein the rotation speed of magnetic stirring is 500 r/min.

5. The method for preparing the high-capacity lithium-rich ternary material positive electrode according to claim 1, wherein in the step (2), the molar ratio of citric acid to the total amount of the Ni, Co, Mn and Li salts is 1.5: 1.

6. The preparation method of the high-capacity lithium-rich ternary material positive electrode according to claim 1, wherein in the step (5), the evaporation and concentration conditions are that the water bath temperature is 80 ℃ and the magnetic stirring speed is 500 r/min.

7. The method for preparing the high-capacity lithium-rich ternary material positive electrode according to claim 1, wherein in the step (6), the wet gel is frozen by liquid nitrogen; the freeze drying comprises the following steps: drying the material precursor by sublimation of a solvent; and (5) setting the vacuum degree parameter to be 0.0010mba and carrying out vacuum drying for 48 hours by using a freeze dryer.

8. The preparation method of the high-capacity lithium-rich ternary material positive electrode according to claim 1, wherein in the step (9), the high-capacity lithium-rich ternary material positive electrode is calcined in a muffle furnace at 450 ℃ for 4 hours and then calcined at 900 ℃ for 12 hours.

Technical Field

The invention relates to a preparation method of a high-capacity lithium-rich ternary cathode material, belonging to the field of lithium ion battery materials.

Background

The lithium-rich manganese-based layered oxide can be represented by xLi₂MnO₃-(1-x)LiMO₂(M ═ Ni, Co, Mn). M.M.Thackeray et al proposed a strategy to enhance layered LiNi_xCo_yMn_1-x-yO₂Structural stability and electrochemical performance of materials using structurally compatible Li₂MnO₃As stable LiNi_xCo_yMn_1-x-yO₂The component (c). The lithium-rich manganese-based material has the charge-discharge capacity of more than 250mAh/g between 2.0 and 4.8V. The lithium-rich manganese-based layered oxide has the advantages of good thermal stability, wide charge-discharge voltage window, low cost and the like, and is considered to be one of the positive electrode materials of the high-performance lithium ion battery with the most application prospect in recent years.

The existing lithium-rich ternary cathode material preparation method has the defects that: in the traditional sol-gel preparation process, the precipitated basic particles are easy to agglomerate to form secondary particles with large particle size, so that dispersion is uneven, and the lithium ions are not favorably deintercalated in the material. The freeze-drying method can just keep the uniform state of the solution through the freezing and sublimation processes to obtain the precursor mixed at the atomic level, thereby greatly improving the electrochemical performance of the material.

Disclosure of Invention

The invention aims to provide a preparation method of a high-capacity lithium-rich ternary cathode material.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a preparation method of a high-capacity lithium-rich ternary material anode comprises the following steps:

(1) dissolving soluble Ni, Co, Mn and Li salts in deionized water, and fully dissolving the soluble Ni, Co, Mn and Li salts by magnetic stirring to obtain a clear solution A;

(2) dissolving citric acid in deionized water, and magnetically stirring to fully dissolve the citric acid to obtain a clear transparent solution B;

(3) dropwise adding the solution B into the solution A until the solution A is completely added to prepare a solution C;

(4) then, adjusting the pH value of the solution C to 5-7 by using an ammonia water solution to prepare a solution D;

(5) evaporating and concentrating the solution D to obtain sol, and continuing to evaporate and concentrate to obtain wet gel;

(6) freezing the wet gel, and drying in a freeze dryer;

(7) obtaining fluffy xerogel, namely a lithium-rich ternary material precursor;

(8) grinding the fluffy dry gel into coarse powder;

(9) and putting the obtained powder into a muffle furnace for presintering at 450 ℃, calcining at 900 ℃, and cooling to room temperature to obtain the lithium-rich ternary material.

Further, in the step (1), the Ni, Co, Mn and Li salt is soluble acetate, nitrate or sulfate;

further, the molar ratio of the Ni, Co, Mn and Li salts is 0.13:0.13:0.54: 1.2;

further, the rotating speed of magnetic stirring is 500 r/min;

further, in the step (2), the molar ratio of citric acid to the total amount of Ni, Co, Mn and Li salts is 1.5: 1;

further, in the step (5), the conditions of evaporation and concentration are that the water bath temperature is 80 ℃, and the magnetic stirring rotating speed is 500 r/min;

further, in the step (6), the wet gel is frozen by liquid nitrogen; the freeze drying comprises the following steps: drying the material precursor by sublimation of a solvent; a freeze drier, setting a vacuum degree parameter of 0.0010mba, and vacuum drying for 48 hours;

further, in the step (9), the pre-sintering is carried out for 4 hours at 450 ℃ in a muffle furnace, and then the calcination is carried out for 12 hours at 900 ℃.

Compared with the prior art, the invention has the following remarkable advantages:

1. the invention quickly freezes the generated basic particles through liquid nitrogen to prevent the particles from agglomerating to cause uneven dispersion; 2. the material prepared by the invention has uniform particles and good dispersibility, and can be used for preparing the anode material with high capacity, high energy density and excellent cycle performance.

Drawings

Fig. 1 is an SEM image of a lithium-rich ternary material of example 1.

Fig. 2 is an SEM image of a comparative example lithium-rich ternary material.

FIG. 3 is a graph of the charge and discharge curves of the lithium-rich ternary material of example 1.

Fig. 4 is a charge-discharge curve diagram of a comparative example lithium-rich ternary material.

Detailed Description

The invention will be further described with reference to the following figures and specific examples: