A preparation method of nanowire-like lithium-rich manganese-based positive electrode material

A lithium-rich manganese-based, cathode material technology, applied in battery electrodes, structural parts, electrical components, etc., can solve problems such as poor electronic conductivity and ionic conductivity, large first-round irreversible capacity, and increased irreversible capacity. Achieve the effect of improving electrochemical performance, alleviating the drop of the discharge voltage platform, and facilitating insertion and extraction.

Active Publication Date: 2019-06-11
SHANGHAI UNIVERSITY OF ELECTRIC POWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the lithium-rich layered cathode material for lithium-ion batteries is 0.5Li 2 MnO 3 0.5LiNi 1 / 3 co 1 / 3 mn 1 / 3 o 2 It has a high discharge specific capacity unparalleled by other materials, but its practical application still faces a series of challenges: (1) Large irreversible capacity in the first cycle
Due to the existence of the first-cycle activation process of lithium-rich materials, part of the lithium released during the first-cycle charging process cannot be re-intercalated into the layered unit cell, resulting in a part of irreversible capacity. In addition, side reactions will occur between the electrode and the electrolyte under high voltage. , will increase the value of the irreversible capacity
(2) Discharge rate difference
Due to the poor electronic conductivity and ion conductivity of lithium-rich manganese-based layered materials, the discharge rate under high current discharge is poor.
(3) Voltage drop phenomenon during charging and discharging
However, due to the obvious agglomeration of materials, the irreversible capacity in the first cycle still exists.

Method used

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  • A preparation method of nanowire-like lithium-rich manganese-based positive electrode material
  • A preparation method of nanowire-like lithium-rich manganese-based positive electrode material
  • A preparation method of nanowire-like lithium-rich manganese-based positive electrode material

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Experimental program
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Effect test

Embodiment 1

[0039] 1) 1.736g MnSO 4 , 3.936g KMnO 4 Soluble in deionized water, configured as Mn 2+ The concentration is 0.4~0.6mol·L -1 (choose 0.5mol L in the present embodiment -1 ), after stirring for 1 hour, transfer the mixed solution into a sealed polytetrafluoroethylene reactor at room temperature, raise the temperature to 160° C., and react for 24 hours.

[0040] After the temperature of the reaction kettle was cooled to room temperature, the precipitate was filtered, and washed alternately with deionized water and absolute ethanol for 3 to 4 times. Dry the washed solid particles at 80°C for 6 hours, and the brown powder after grinding is α-MnO 2 Nanowires.

[0041] 2) soluble 0.09459g cobalt nitrate (Co(NO 3 ) 2 ·6H 2 O), 0.09451g nickel nitrate (Ni(NO 3 ) 2 ·6H 2 O), 0.1258g lithium hydroxide (LiOH·H 2 O) (5% excess lithium hydroxide) was dissolved in a mixed solution of deionized water and absolute ethanol (the volume ratio was 1:1), and ultrasonically dissolved fo...

Embodiment 2

[0058] 1) soluble 0.08095g cobalt acetate (Co(CH 3 COO) 2 4H 2 O), 0.08087g nickel acetate (Ni(CH 3 COO) 2 4H 2 O), 0.3229g lithium acetate (LiCH 3 COO·2H 2 O) (5% excess lithium acetate) was dissolved in a mixed solution of deionized water and absolute ethanol (the volume ratio was 1:1), and ultrasonically dissolved for 20 minutes to obtain solution A.

[0059] 2) the α-MnO prepared in step 1) in Example 1 2 Nanowires are uniformly dispersed in a mixed solution of ethanol and deionized water (the volume ratio is 1:1) to obtain dispersion B; wherein, the molar ratio of Li, Ni, Co, and Mn metal ions is 1.2:0.13:0.13 :0.54. At room temperature, use a peristaltic pump to add the solution A to the dispersion B dropwise at a constant speed, control the dropping rate to 0.1ml / min, and the rotation speed to 500r / min. After reacting for 4 hours, the cloudy liquid was dried at 80° C. to obtain a dark brown powder.

[0060] 3) Put the dark brown powder obtained in step 2) into...

Embodiment 3

[0062] 1) soluble 0.08095g cobalt acetate (Co(CH 3 COO) 2 4H 2 O), 0.08087g nickel acetate (Ni(CH 3 COO) 2 4H 2 O), 0.3229g lithium acetate (LiCH 3 COO·2H 2 O) (5% excess lithium acetate) was dissolved in a mixed solution of deionized water and absolute ethanol (the volume ratio was 1:1), and ultrasonically dissolved for 20 minutes to obtain solution A.

[0063] 2) the α-MnO prepared in step 1) in Example 1 2 Nanowires are uniformly dispersed in a mixed solution of ethanol and deionized water (the volume ratio is 1:1) to obtain dispersion B; wherein, the molar ratio of Li, Ni, Co, and Mn metal ions is 1.2:0.13:0.13 :0.54. Under the condition of water bath, the temperature is controlled at 60°C, and the solution A is added dropwise to the dispersion B at a constant speed with a peristaltic pump. The dropping rate is controlled to be 0.1ml / min, and the rotation speed is 500r / min. After reacting for 4 hours, the cloudy liquid was dried at 80° C. to obtain a dark brown po...

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Abstract

The invention relates to a method for preparing nanowire-shaped lithium-rich manganese-based anode materials. The method includes steps of (1), dissolving soluble cobalt salt, nickel salt and lithium salt in mixed solvents to obtain solution A; (2), dissolving nanowire-shaped alpha-MnO2 in mixed solvents to obtain dispersion liquid B; (3), adding the solution A into the dispersion liquid B drop by drop, carrying out stirring reaction, separating reaction products after the reaction is completely carried out, and washing and drying the reaction products to obtain solid powder; (4), calcining and cooling the solid powder obtained at the step (3) to obtain the nanowire-shaped lithium-rich manganese-based anode materials. Compared with the prior art, the method has the advantages that processes for preparing the nanowire-shaped lithium-rich manganese-based anode materials are relatively simple, the lithium-rich manganese-based anode materials are in the shapes of nanowires and are excellent in electrochemical performance, and the like.

Description

technical field [0001] The invention relates to the field of positive electrode materials for lithium ion batteries, in particular to a preparation method of a nanowire-shaped lithium-rich manganese-based positive electrode material. Background technique [0002] As a new type of chemical power source, lithium-ion battery is one of the most promising energy storage devices so far because it is superior to traditional chemical power sources in terms of energy density, cycle life, safety performance, and environmental friendliness. Argonne National Laboratory in the United States first applied for a patent for lithium-rich layered cathode materials in 2001. Its theoretical specific capacity exceeds 300mAh / g, its actual available capacity is greater than 200mAh / g, and its energy density is greater than 300Wh / kg. As far as the current development situation is concerned, the lithium-rich layered cathode material for lithium-ion batteries is 0.5Li 2 MnO 3 0.5LiNi 1 / 3 co 1 / 3 mn...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/505H01M4/525H01M4/131H01M4/1391H01M10/0525
CPCH01M4/131H01M4/1391H01M4/505H01M4/525H01M10/0525Y02E60/10
Inventor 徐群杰常幸萍闵宇霖刘新暖袁小磊
Owner SHANGHAI UNIVERSITY OF ELECTRIC POWER
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