A kind of selenium-doped lithium-rich manganese-based positive electrode material and its preparation method and application

A cathode material, lithium-rich manganese-based technology, which is applied in the field of preparation of lithium-rich manganese-based cathode materials, can solve problems such as poor rate performance, capacity and voltage decay, achieves simple preparation process, suppresses capacity decay and voltage drop, and is easy to popularize Effect

Active Publication Date: 2021-06-25
CENT SOUTH UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0007] In view of the above-mentioned defects existing in the lithium-rich manganese-based cathode materials in the prior art, one of the purposes of the present invention is to provide a selenium anion-doped modified anode material with good lattice stability and electrode / electrolyte interface stability. Lithium-rich manganese-based cathode material, which can not only inhibit the loss of lattice oxygen during cycling, but also inhibit the decomposition of electrolyte, thereby alleviating the capacity fading and voltage drop of lithium-rich manganese-based cathode materials during cycling, which can effectively Overcome the problems of poor rate performance, serious capacity and voltage decay in the cycle process of existing cathode materials

Method used

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  • A kind of selenium-doped lithium-rich manganese-based positive electrode material and its preparation method and application
  • A kind of selenium-doped lithium-rich manganese-based positive electrode material and its preparation method and application
  • A kind of selenium-doped lithium-rich manganese-based positive electrode material and its preparation method and application

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preparation example Construction

[0048] Its preparation method comprises the following steps:

[0049] S1. Mix the precursor and the lithium source in a dry environment for 0.5-1 h, and mix them uniformly to obtain a mixture; wherein, the mass excess coefficient of the lithium source is 3-10%; the lithium source is a common lithium-containing compound, including But not limited to lithium carbonate, lithium hydroxide monohydrate, lithium hydroxide, lithium nitrate, etc.; the precursor can be replaced by carbonate, oxalate, acetate or hydroxide of nickel-cobalt-manganese in different proportions;

[0050] S2. Put the mixture obtained in step S1 into a calcination device for calcination treatment under an oxygen atmosphere. After the calcination, cool to room temperature with the furnace to obtain a lithium-rich manganese-based positive electrode material; the calcination adopts a two-stage calcination method: the first The first stage of calcination is calcination at 500~700 ℃ for 5~10 h, and the second stage ...

Embodiment 1

[0058] A method for preparing a lithium-rich manganese-based positive electrode material, comprising the following steps:

[0059] (1) Add 2 g precursor Mn 0.672 Ni 0.164 co 0.164 CO 3 with 1.02 g LiOH·H 2 O was placed in an agate mortar and mixed for 1 h in a dry environment to obtain a mixture precursor;

[0060] (2) Transfer the homogeneous mixture precursor in step (1) to the corundum ark, and then place it in an oxygen atmosphere tube furnace for calcination. The calcination condition is 5 ℃ / min to 500 ℃, and after constant temperature for 5 h, The temperature was raised to 900 °C at 5 °C / min, kept at a constant temperature for 12 h, and cooled to room temperature with the furnace to obtain a lithium-rich manganese-based cathode material sample, which was named LRM.

Embodiment 2

[0062] A preparation method of a selenium-doped lithium-rich manganese-based positive electrode material, comprising the following steps:

[0063] S1. Mix 2 g of the lithium-rich manganese-based positive electrode material prepared in Example 1 with 20 mg of commercial selenium powder for 2 h, transfer the uniformly mixed material to a corundum ark, and then place it in a tube furnace with an argon atmosphere Medium calcination, the calcination condition is 2 ℃ / min heating up to 500 ℃, constant temperature for 5 h, gas flow 2 mL / min;

[0064] S2. Take the sample after calcination in step S1 and add it to 10 mL of carbon disulfide solution at 500 r / min, stir for 5 h, filter and wash with alcohol for 4 times, and vacuum-dry at 120 °C for 12 h to obtain a lithium-rich solution doped with selenium anions. The manganese-based cathode material is named Se-LRM, and electron spectroscopy analysis shows that the mass fraction of selenium is 0.86%.

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Abstract

The invention provides a selenium-doped lithium-rich manganese-based positive electrode material and its preparation method and application. In the structure of the selenium-doped lithium-rich manganese-based material, selenium is distributed in the lithium-rich manganese-based positive electrode material in the form of anions. The general chemical formula of the cathode material is mLi 2 MnO 3‑δ Se 2δ / 3 •(1‑m)LiTMO 2‑δ Se 2δ / 3 , wherein, TM is at least one of Ni, Co and Mn, 0.2≤m≤0.8, 0<δ<2; in terms of mass percentage, the selenium content in the positive electrode material is 0~5%. The cathode material has good lattice stability and electrode / electrolyte interface stability, which can not only inhibit the loss of lattice oxygen during the cycle, but also inhibit the decomposition of the electrolyte, and alleviate the degradation of the lithium-rich manganese-based cathode material during the cycle. Capacity fading and voltage drop effectively overcome the problems of poor rate performance in existing cathode materials. The preparation method of the invention is simple and easy to popularize.

Description

technical field [0001] The invention relates to the field of preparation of lithium-rich manganese-based positive electrode materials, and more specifically, to a selenium-doped lithium-rich manganese-based positive electrode material and a preparation method and application thereof. Background technique [0002] With the development of society, clean and efficient energy storage and conversion has become a research hotspot in the field of energy. As a new type of secondary power supply, lithium-ion batteries have the advantages of high specific energy, no memory effect, long cycle life, and low environmental pollution, injecting fresh blood into the vigorous development of energy networks. Lithium-ion electric vehicles are an important part of the new energy vehicle family. As the "heart" of electric vehicles, high-energy-density lithium-ion power batteries can effectively overcome the problem of "mileage anxiety" in the field of electric vehicles. In recent years, the dem...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/62H01M4/505H01M4/525H01M4/131H01M10/0525C01G53/00B82Y30/00B82Y40/00
CPCB82Y30/00B82Y40/00C01G53/44C01P2002/72C01P2004/03C01P2004/50C01P2004/61C01P2004/62C01P2004/64C01P2006/40H01M4/131H01M4/505H01M4/525H01M4/628H01M10/0525Y02E60/10
Inventor 纪效波陈军侯红帅邹国强
Owner CENT SOUTH UNIV
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