Lithium-rich positive electrode material surface modification method, positive electrode containing surface-modified lithium-rich positive electrode material, and lithium ion battery

A lithium-rich positive electrode material, lithium-ion battery technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of poor cycle performance and rate performance, low Coulombic efficiency and rate performance, and insignificant improvement in electrical performance, etc. Achieve environmental friendliness, improve electrical performance, and increase the effect of the first discharge specific capacity

Inactive Publication Date: 2015-09-09
GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

However, the low Coulombic efficiency, rate performance and cycle performance of lithium-rich cathode materials seriously hinder their large-scale application.
A.Manthiram et al. (US 7678503B2) reported a method for coating the surface of lithium-rich cathode materials with oxides, the oxides involved include Al 2 o 3 , CeO 2 , ZrO 2 , ZnO and SiO 2 , through oxide coating, the first discharge capacity and Coulombic efficiency of the material are improved, but the electrical properties of the coated material are not significantly improved at high rates.
S.H.Kang et al. (Chem.Mater., 2008, 20, 6095-6106) used dilute nitric acid solution to surface-treat lithium-rich cathode materials, which reduced the irreversible capacity loss in the first cycle and improved the Discharge specific capacity, but the acid treatment destroys the structure of the positive electrode material, resulting in poor cycle performance and rate performance

Method used

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  • Lithium-rich positive electrode material surface modification method, positive electrode containing surface-modified lithium-rich positive electrode material, and lithium ion battery
  • Lithium-rich positive electrode material surface modification method, positive electrode containing surface-modified lithium-rich positive electrode material, and lithium ion battery
  • Lithium-rich positive electrode material surface modification method, positive electrode containing surface-modified lithium-rich positive electrode material, and lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Weigh the composition as 0.6Li 2 O 0.8Mn 0.675 Ni 0.1625 co 0.1625 o1.75 30.00 g of the lithium-rich cathode material was dispersed in 500 mL of 0.01 mol / L hydrochloric acid solution, heated and stirred at 80° C. for 5 h, and evaporated to dryness. The dried powder was heat treated at 200°C and kept for 10h. The obtained powder was washed with deionized water, filtered with suction and dried, and dispersed in 2.68g of Al(NO 3 ) 3 in aqueous solution (with coating AlF 3 Calculated, its relative lithium-rich cathode material addition is 2wt%), continue to stir, add ammonia water dropwise to make the slurry pH = 7, NH 4 An aqueous solution of F (0.79 g) was added to the above slurry, the stirring was continued for 6 h, and the slurry was dried at 100°C. Afterwards, the powder was heat-treated at 450°C under an argon atmosphere, kept for 8 hours, and cooled with the furnace. The obtained powder is ground and passed through a 300-mesh sieve to finally obtain a surfac...

Embodiment 2

[0030] Weigh the composition as 0.6Li 2 O 0.8Mn 0.7 Ni 0.2 co 0.1 o 1.75 30.00g of lithium-rich cathode material, dispersed in 500mL of 10 -6 mol / L sulfuric acid solution, heated and stirred at 70°C for 6 hours, and evaporated to dryness. The dried powder is heat treated at 400°C and kept for 10h. The obtained powder was washed with deionized water, suction filtered and dried, and then dispersed in dissolved 0.67g Al(NO 3 ) 3 in aqueous solution (with coating AlF 3 Calculated, its relative addition amount of lithium-rich cathode material is 0.5wt%), continuous stirring, dripping ammonia water to make the slurry pH = 7, NH 4 F (0.20g) aqueous solution was added to the above slurry, and the stirring reaction was continued for 6h, and the slurry was dried at 100°C. Afterwards, the powder was heat-treated at 450°C under an argon atmosphere, kept for 8 hours, and cooled with the furnace. The obtained powder is ground and passed through a 300-mesh sieve to finally obtain a...

Embodiment 3

[0032] Weigh the composition as 0.6Li 2 O 0.8Mn 0.675 Ni 0.1625 co 0.1625 o 1.75 30.00g of lithium-rich cathode material, dispersed in 500mL of 10 -6 mol / L nitric acid solution, heated and stirred at 90°C for 5h, and evaporated to dryness. The dried powder was heat-treated at 500°C and kept for 10 hours. The obtained powder was washed with deionized water, filtered with suction and dried, and then dispersed in dissolved 0.44gSr(NO 3 ) 2 in aqueous solution (with coating SrF 2 Calculated, its relative addition amount of lithium-rich positive electrode material is 1wt%), continuous stirring, dripping ammonia water to make the slurry pH = 7, NH 4 An aqueous solution of F (0.15 g) was added to the above slurry, the stirring was continued for 4 h, and the slurry was dried at 100°C. Afterwards, the powder was heat-treated at 550°C under an argon atmosphere, kept for 8 hours, and cooled with the furnace. The obtained powder is ground and passed through a 300-mesh sieve to f...

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Abstract

The present invention discloses a lithium-rich positive electrode material surface modification method, a positive electrode containing the surface-modified lithium-rich positive electrode material, and a lithium ion battery, wherein the chemical formula of the lithium-rich positive electrode material is xLi2O.yMOb, wherein M is at least one selected from Mn, Ni, Co, Al, Cr, Fe, Ti, Mg and Cu, the ratio of x to y is more than 0.51 and is less than 0.95, and b is more than or equal to 1 and is less than or equal to 2. The surface modification method comprises at least three steps: 1) adding the lithium-rich positive electrode material to an aqueous solution with the pH value of less than or equal to 7, and continuously stirring to obtain a slurry; 2) drying the stirred slurry, and carrying out a heat treatment to obtain powder; and 3) dispersing the powder in a solution containing cladding ionic fluorine, adjusting the pH value of the slurry to 6-9, carrying out a precipitation reaction, drying the slurry after the reaction, and carrying out a heat treatment to obtain the surface-modified lithium-rich positive electrode material. With the method of the present invention, various electrical properties of the material can be comprehensively improved, and the material can meet the development requirements of high power electronic devices. According to the present invention, the process is simple, the cost is low, and the method is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a surface modification method of a lithium-rich positive electrode material, a positive electrode containing the surface-modified lithium-rich positive electrode material and a lithium ion battery, belonging to the field of lithium ion battery positive electrode materials. Background technique [0002] With the deterioration of the current environment and the shortage of energy, lithium-ion batteries have attracted widespread attention as a new generation of energy. Lithium-ion batteries are widely used in the main power supply of portable electronic products such as mobile phones and notebook computers, but they want to apply them in electric vehicles. In the field, batteries are required to have high energy density and reliable safety, and the key factor limiting the development of batteries is the positive electrode material of batteries. [0003] Currently widely used cathode materials for lithium-ion batteries include lith...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/485H01M4/505H01M4/525
CPCY02E60/10
Inventor 尹艳萍庄卫东庞国耀沈雪玲卢世刚黄倩
Owner GENERAL RESEARCH INSTITUTE FOR NONFERROUS METALS BEIJNG
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