Method for preparing nanowire-shaped lithium-rich manganese-based anode materials

A lithium-rich manganese-based, positive electrode material technology, applied in the direction of battery electrodes, electrical components, electrochemical generators, etc., can solve the problem of poor electronic conductivity and ion conductivity, large irreversible capacity in the first cycle, and increased irreversible capacity, etc. problems, to achieve the effect of improving electrochemical performance, alleviating the drop of discharge voltage plateau, and facilitating intercalation and extraction

Active Publication Date: 2016-10-26
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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  • Method for preparing nanowire-shaped lithium-rich manganese-based anode materials
  • Method for preparing nanowire-shaped lithium-rich manganese-based anode materials
  • Method for preparing nanowire-shaped lithium-rich manganese-based anode materials

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] 1) Add 1.736g MnSO 4 , 3.936g KMnO 4 Dissolved in deionized water and configured as Mn 2+ The concentration is 0.4~0.6mol·L -1 (In this example, choose 0.5mol·L -1 After stirring for 1 hour, the mixed solution was transferred to a sealed polytetrafluoroethylene reactor at room temperature, the temperature was raised to 160°C, and the reaction was carried out for 24 hours.

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

[0041] 2) The 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) (Lithium hydroxide excess 5%) is dissolved in a mixed solution of deionized water and absolute ethanol (the volume ratio is 1:1), and ultrasonically disso...

Embodiment 2

[0058] 1) The 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) (Lithium acetate excess 5%) is dissolved in a mixed solution of deionized water and absolute ethanol (the volume ratio is 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 The 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 drop solution A into dispersion B at a constant speed, control the dropping rate to be 0.1ml / min and the speed to be 500r / min. After 4 hours of reaction, the turbid liquid was dried at 80°C to obtain a dark brown powder.

[0060] 3) Put the dark brown powder obtained in step 2) into a high-temperature tube fur...

Embodiment 3

[0062] 1) The 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) (Lithium acetate excess 5%) is dissolved in a mixed solution of deionized water and absolute ethanol (the volume ratio is 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 The 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. The temperature is controlled at 60°C under water bath conditions, and solution A is dropped into dispersion B at a constant speed with a peristaltic pump, and the dropping speed is controlled to be 0.1ml / min and the speed is 500r / min. After 4 hours of reaction, the turbid liquid was dried at 80°C to obtain a dark brown powder.

[0064] 3) Put the dark bro...

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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 lithium ion battery cathode materials, in particular to a method for preparing nanowire-shaped lithium-rich manganese-based anode materials. Background technique [0002] As a new type of chemical power source, lithium-ion battery is superior to traditional chemical power sources in terms of energy density, cycle life, safety performance, and environmental friendliness, making it one of the most promising energy storage devices so far. The Argonne National Laboratory in the United States first applied for a lithium-rich layered cathode material patent in 2001. Its theoretical specific capacity exceeds 300mAh / g, the actual usable capacity is greater than 200mAh / g, and the energy density is greater than 300Wh / kg. In terms of current development, 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 excellent cycling ability, good thermal stability, wide ...

Claims

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Application Information

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Patent Type & Authority Applications(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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