Preparation method of modified lithium nickel manganese oxide cathode material

A technology of lithium nickel manganese oxide and positive electrode materials, which is applied in the field of preparation of modified lithium nickel manganese oxide positive electrode materials, and can solve the problem of inability to form SEI film to isolate electrolyte and carbon materials, lower cycle performance of negative electrode materials, and difficulty in controlling environmental moisture, etc. problems, to achieve the effects of improving chemical stability, reducing contact, improving rate performance and cycle stability performance

Active Publication Date: 2017-07-04
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the high potential of the positive electrode means that the reducibility of the negative electrode region is enhanced, which also leads to changes in the kinetics of SEI film formation on the surface of lithium nickel manganese oxide matched with graphite negative electrodes, and cannot form an effective SEI film to isolate the electrolyte and carbon materials. , resulting in a significant decrease in the cycle performance of the anode material
In addition, due to the difficult control of environmental moisture in the production process of lithium nickel manganese oxide batteries, the moisture content inside the battery is too high, which in turn causes a chain electrochemical reaction, promotes the decomposition of the electrolyte, and releases a large amount of gas
Especially after the lithium nickel manganese oxide battery is stored at high temperature, a large amount of gas will accumulate inside the battery, and the expansion phenomenon of the battery is very obvious, which seriously restricts the performance of the battery

Method used

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  • Preparation method of modified lithium nickel manganese oxide cathode material
  • Preparation method of modified lithium nickel manganese oxide cathode material
  • Preparation method of modified lithium nickel manganese oxide cathode material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Weigh out lithium carbonate, nickel acetate and manganese acetate according to the molar ratio of Li:Ni:Mn element 1.05:0.5:1.5, and then according to Ce 0.95 Fe 0.05 O 2 And LiNi 0.5 Mn 1.5 O 4 The theoretical synthesis mass ratio is 0.01:1, weighing Ce 0.95 Fe 0.05 O 2 , Will Ce 0.95 Fe 0.05 O 2 After mixing with lithium carbonate, nickel acetate, and manganese acetate, add deionized water for ball milling dispersion to obtain Ce 0.95 Fe 0.05 O 2 Coated LiNi 0.5 Mn 1.5 O 4 The precursor of the material.

[0023] (2) The precursor of step (1) is vacuum dried and then calcined at a constant temperature of 700°C for 20 hours in an air atmosphere, and then naturally cooled to obtain Ce 0.95 Fe 0.05 O 2 Coated LiNi 0.5 Mn 1.5 O 4 The modified lithium nickel manganate cathode material.

[0024] With reference to the drawings, Example 1 is used to illustrate the phase characterization and electrochemical performance of the modified lithium nickel manganate material prepared by ...

Embodiment 2

[0028] (1) Weigh lithium hydroxide, nickel sulfate and manganese sulfate according to the molar ratio of Li:Ni:Mn of lithium nickel manganate to 1.05:0.5:1.5, and then according to Ce 0.9 Fe 0.1 O 2 And LiNi 0.5 Mn 1.5 O 4 The theoretical synthesis mass ratio is 0.05:1, weighing Ce 0.9 Fe 0.1 O 2 , Will Ce 0.9 Fe 0.1 O 2 After mixing with lithium hydroxide, nickel sulfate and manganese sulfate, add absolute ethanol for ball milling dispersion to obtain Ce 0.9 Fe 0.1 O 2 Coated LiNi 0.5 Mn 1.5 O 4 The precursor of the material.

[0029] (2) The precursor of step (1) is vacuum dried, then calcined at a constant temperature of 800°C for 15 hours in an air atmosphere, and then cooled naturally to obtain Ce 0.9 Fe 0.1 O 2 Coated LiNi 0.5 Mn 1.5 O 4 The modified lithium nickel manganate cathode material.

[0030] The modified lithium nickel manganate cathode material synthesized in Example 2 has a capacity retention rate of 98.21% after 50 cycles of cycles.

Embodiment 3

[0032] (1) Weigh lithium acetate, nickel nitrate and manganese nitrate according to the molar ratio of Li:Ni:Mn of lithium nickel manganese oxide to 1.05:0.5:1.5, and then according to Ce 0.9 Fe 0.1 O 2 And LiNi 0.5 Mn 1.5 O 4 Theoretical synthesis mass ratio is 0.07:1 to weigh Ce 0.9 Fe 0.1 O 2 , Will Ce 0.9 Fe 0.1 O 2 After mixing with lithium acetate, nickel nitrate and manganese nitrate, add ethylene glycol for ball milling dispersion to obtain Ce 0.9 Fe 0.1 O 2 Coated LiNi 0.5 Mn 1.5 O 4 The precursor of the material.

[0033] (2) The precursor of step (1) is vacuum dried and then calcined at a constant temperature of 900°C for 10 hours in an air atmosphere, and then naturally cooled to obtain Ce 0.9 Fe 0.1 O 2 Coated LiNi 0.5 Mn 1.5 O 4 The modified lithium nickel manganate cathode material.

[0034] The modified lithium nickel manganate cathode material synthesized in Example 3 has a capacity retention rate of 98.34% after 50 cycles of cycles.

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Abstract

The invention discloses a preparation method of a modified lithium nickel manganese oxide cathode material. The preparation method comprises the following steps: at first, mixing cerium-iron composite compounds with lithium salts, nickel salts, and manganese salts, carrying out ball milling to disperse the mixture, carrying out vacuum drying to obtain a cerium-iron composite compound coated precursor of a lithium nickel manganese oxide material; burning the precursor for 5 to 20 hours at a constant temperature of 700 to 1000 DEG C in air atmosphere, and naturally cooling the precursor to obtain the modified lithium nickel manganese oxide cathode material. The cerium-iron composite compound is coated on the surface of lithium nickel manganese oxide, a stable protective layer is formed, the contact between electrolyte and lithium nickel manganese oxide is reduced, the oxidation and degradation of electrolyte on the anode surface are reduced, thus the chemical stability of the anode material in a cell system is improved, and at the same time, the circulation performance is enhanced.

Description

Technical field [0001] The invention belongs to the field of lithium battery materials, and specifically relates to a method for preparing a modified lithium nickel manganate cathode material. Background technique [0002] As a secondary energy source, lithium-ion batteries have the advantages of high specific energy, long cycle life and stable discharge performance. In recent years, with the popularization of electric vehicles under the national new energy strategy and soaring oil prices, lithium-ion batteries and related fields With rapid development, there are still many technical problems in the current lithium-ion battery system that need to be broken through, such as low energy density, high cost, and poor safety performance. [0003] Spinel lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O 4 ) Is developed on the basis of lithium manganate, with good cycle performance, a reversible capacity of 146.7mAh / g, and a discharge platform up to 4.7V, which is considered to be the mos...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M4/628H01M10/0525H01M2004/028Y02E60/10
Inventor 沈中宇刘兴亮汪涛
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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