Coating modification method for improving performance of rich-lithium manganese-base positive electrode material

A lithium-rich manganese-based, positive electrode material technology, applied in the direction of battery electrodes, electrical components, electrochemical generators, etc., can solve the problems of capacity fading, low initial Coulombic efficiency, poor rate performance, etc., and achieve small voltage drop and low cost , good stability and rate performance

Active Publication Date: 2017-05-31
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The technical problem to be solved by the present invention is to overcome the problems of low first coulombic efficiency, poor rate performance and capacity fading in the cycle process of the lithium-rich manganese-based positive electrode materials used in the existing lithium-ion batt

Method used

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  • Coating modification method for improving performance of rich-lithium manganese-base positive electrode material
  • Coating modification method for improving performance of rich-lithium manganese-base positive electrode material
  • Coating modification method for improving performance of rich-lithium manganese-base positive electrode material

Examples

Experimental program
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Example Embodiment

[0036] Example 1

[0037] The lithium-rich manganese-based positive electrode material containing the praseodymium phosphate coating layer of this embodiment has the chemical formula Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 The outer surface of the layered structure of lithium-rich manganese-based cathode material is coated with praseodymium phosphate; in the example, the coating amount is PrPO 4 / Li[Li 0.2 Mn 0.54 Ni0 .13 Co 0.13 ]O 2 The mass ratio is 3%.

[0038] The preparation method is:

[0039] (1) Prepare the mixture: According to the molecular formula Li[Li 0.2 Mn 0.54 Ni 0.13 Co0 .13 ]O 2 The molar ratio of Mn:Ni:Co=54:13:13 to 5g of the hydroxide precursor and 3.65g of analytical grade LiOH·H 2 O, added to the mixing tank of the ball mill, after grinding and mixing uniformly, the element composition is Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 mixture;

[0040] (2) Sintering and grinding: The element composition obtained in step (1) is Li[Li 0.2 Mn 0.54 Ni 0.13 Co0 .13 ]O 2 The m...

Example Embodiment

[0044] In Example 2, divide by PrPO in step (2) 4 / Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 Except for the different mass ratios, the other experimental steps are the same as in Example 1, where PrPO in Example 2 4 / Li[Li 0.2 Mn 0.54 Ni 0.13 Co 0.13 ]O 2 = 5%,

[0045] XRD pattern analysis

[0046] XRD pattern analysis was performed on the lithium-rich manganese-based cathode material containing the praseodymium phosphate coating layer and the manganese-based layered cathode material obtained in step (2), and the results are as follows figure 1 As shown, the lithium-rich manganese-based positive electrode material containing the praseodymium phosphate coating layer obtained in the embodiment and the lithium-rich manganese-based positive electrode material obtained in step (2) have a pure-phase layered structure with complete crystals. After coating, there is no Affect the crystal form of the material, see figure 1 .

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Abstract

The invention discloses a coating modification method for improving performance of a rich-lithium manganese-base positive electrode material. The rich-lithium manganese-base positive electrode material is arranged in the material, wherein the rich-lithium manganese-base material is Li[LixMn1-x-yMy]O2; praseodymium phosphate is arranged on a surface layer of the material; intermigration of a transition metal ion, a phosphate radical and a praseodymium ion exists in a coating process; and a new phase capable of conducting an ion and an electron is generated on an interface. The method comprises the following specific steps of ultrasonically dispersing the rich-lithium manganese-base material in secondary water or an organic solution to form a disperse and uniform suspension; dissolving praseodymate in the suspension; adding phosphoric acid or phosphate to allow a phosphate radical ion and the praseodymium ion to perform a precipitation reaction on the surface of the rich-lithium manganese-base material; generating an initial coating layer; obtaining slurry comprising the initial coating layer; and finally drying the obtained slurry and then calcinating the slurry to obtain the rich-lithium manganese-base anode composite powder material comprising a praseodymium phosphate coating layer. The rich-lithium manganese-base composite material comprising the praseodymium phosphate coating layer prepared by the method is low in cost, high in capacity, high in first efficiency, low in voltage drop, good in stability and good in rate performance.

Description

[0001] Technical field: [0002] The invention relates to a modification method for improving the performance of lithium-rich manganese-based materials, and belongs to the field of lithium ion batteries. [0003] Background technique: [0004] With the rapid development of portable devices and wearable devices, people's requirements for high specific capacity energy storage devices are getting higher and higher. As the main energy storage and output system of electronic equipment, lithium-ion batteries require high specific capacity, good cycle performance, and high safety. The performance of lithium batteries largely depends on electrode materials and electrolytes. The research and development of negative electrode materials have brought their specific capacity, cycle performance, and rate performance to a high level. Therefore, the positive electrode material restricts the specific capacity of the material. The key factor for further improvement. [0005] Among the traditional cath...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/505H01M4/62H01M10/0525
CPCH01M4/366H01M4/505H01M4/62H01M10/0525Y02E60/10
Inventor 李建玲李继广丁飞翔徐国峰
Owner UNIV OF SCI & TECH BEIJING
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