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Method for synthesizing spherical gradient lithium-rich anode material

A lithium-rich positive electrode material and synthesis method technology, applied in battery electrodes, electrical components, circuits, etc., can solve problems such as low tap density, harsh hydrothermal synthesis method, and poor rate performance

Inactive Publication Date: 2011-04-13
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Lithium-rich materials usually synthesized by co-precipitation and sol-gel methods maintain a high cycle specific capacity, but their size is small, the tap density is low and the rate performance is poor; in recent years, many nanostructured materials The synthesis of lithium-rich cathode materials has received great attention, among which Li 0.88 [Li 0.18 co 0.33 mn 0.49 ]O 2 Nanowires and Li[Ni] synthesized by hydrothermal template method 0.25 Li 0.15 mn 0.6 Although ]O2 nanowires have very superior cycle specific capacity and high rate performance, the hydrothermal synthesis method is relatively harsh, and the size of the material is small (<100nm), which is not suitable for commercial production, and the size of the nanomaterial is relatively large. The specific surface area and the electrolyte have more side reactions at high potentials

Method used

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  • Method for synthesizing spherical gradient lithium-rich anode material
  • Method for synthesizing spherical gradient lithium-rich anode material
  • Method for synthesizing spherical gradient lithium-rich anode material

Examples

Experimental program
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Embodiment 1

[0030] 1. In order to coat manganese on the surface of the existing commercial spherical precursor [Ni0.4Co0.2Mn0.4](OH)2, use manganese sulfate as manganese source, according to MnSO4: [Ni0.4Co0.2Mn0. 4] (OH) 2 (Molar ratio)=0.2:0.8, weigh the existing commercial spherical precursor [Ni 0.4 co 0.2 mn 0.4 ](OH) 2 and manganese sulfate, add deionized water to form a suspension, and then stir in a 60°C water bath;

[0031] Weigh the existing commercial spherical precursor [Ni 0.4 co 0.2 mn 0.4 ](OH) 2 After adding manganese sulfate, add deionized water to dissolve, the concentration of the cationic solution is 0.05mol / L, ultrasonically disperse for 1-2h, and place it in a 60°C water bath and stir for 1-2h.

[0032] 2. Prepare 0.05mol / L NaCO 3 solution, the Na with a peristaltic pump 2 CO 3 The solution was added dropwise to the MnSO in 1 4 In the solution, a certain drop rate is controlled so that Na 2 CO 3 solution with Mn adsorbed on the surface of the precursor ...

Embodiment 2

[0039] 1-3 steps are the same as embodiment 1;

[0040] 4. Mix the spherical precursor with a dry coating obtained in step 3 with lithium hydroxide at a molar ratio of 1:1.25 and grind them in an agate mortar for 1 hour. Place it in a tube furnace and heat treat at 450°C for 3 hours, then slowly heat up for 25 hours at 800°C for 12 hours to obtain the desired material.

[0041] It can be seen from the morphology that the sample obtained at 800°C is a solid spherical particle with a diameter of about 10 μm. From the EDS energy spectrum to the concentration distribution of Mn element in the particle, it can be concluded that the concentration of Mn element in the sample treated at 800°C is along the The particle diameter gradually decreases from the outside to the inside, showing a certain gradient, but the difference between the surface Mn ion concentration and the internal concentration is slightly lower than that of the sample at 750 °C.

[0042] X-ray diffraction (XRD) anal...

Embodiment 3

[0045] 1-3 steps are the same as embodiment 1;

[0046] 4. Mix the spherical precursor with a dry coating obtained in step 3 with lithium hydroxide at a molar ratio of 1:1.25 and grind them in an agate mortar for 1 hour. Place it in a tube furnace and heat-treat at 450°C for 3 hours, then heat-treat at 850°C for 15 hours after 28 hours of slow temperature rise to obtain the desired material.

[0047] It can be seen from the morphology that the sample obtained at 850°C is a solid spherical particle with a diameter of about 10 μm. From the EDS energy spectrum to the concentration distribution of Mn element in the particle, it can be concluded that the concentration of Mn element in the sample treated at 850°C is along the The gradient of the particle diameter from the outside to the inside is not obvious, and the surface Mn ion concentration is almost equal to the internal concentration. This shows that the increase of sintering temperature makes the distribution of Mn element ...

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Abstract

The invention discloses a method for synthesizing a spherical gradient lithium-rich anode material, which comprises the following steps of: adding deionized water into MnSO4 and [Ni0.4Co0.2Mn0.4](OH)2 in a molar ratio of x:1-x to form suspension, and dripping 0.025 to 0.1mol / L NaCO3 solution into the suspension in a 60 DEG C water bath to form a compact manganese carbonate precipitate layer; filtering, washing, and drying at the temperature of between 80 and 120 DEG C; and uniformly mixing precursor particles and lithium hydroxide in a molar ratio of 1:1.15-1.45, performing heat treatment in air at the temperature of between 400 and 500 DEG C for 3 to 5 hours, raising the temperature for 22 to 32 hours, and sintering at the temperature of between 750 and 900 DEG C for 12 to 15 hours. The material synthesized by the method has certain Mn concentration gradient, improves the tap density of lithium-rich materials, has high cyclical stability and specific capacity, and keeps high rate performance.

Description

technical field [0001] The invention relates to a method for synthesizing a spherical gradient lithium-rich positive electrode material, which belongs to the field of lithium ion battery positive electrode materials and electrochemistry. Background technique [0002] Traditional cathode material LiCoO 2 Low capacity, high cost; LiNiO 2 The synthesis conditions are harsh and the reversibility is not good; easy-to-synthesize spinel-shaped cathode material LiMn 2 o 4 There is a problem of large capacity fading at high temperature; and the cheap olivine-shaped material LiFePO 4 Its further development is hindered by its low ionic and electronic conductivity. Therefore, it is of great significance to choose lithium-rich cathode materials with high capacity and relatively low price and cycle stability. These materials can exhibit unusual electrochemical properties, such as high specific capacity, excellent cycling ability, and novel electrochemical charge-discharge mechanisms...

Claims

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Application Information

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IPC IPC(8): H01M4/1391H01M4/505
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 赵煜娟孙召琴冯海兰孙少瑞
Owner BEIJING UNIV OF TECH
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