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Preparation method of porous metal doped lithium manganate/graphene lithium battery positive electrode material

A technology of lithium heteromanganate and porous metal, which is applied in the field of electrochemistry, can solve the problems of unfavorable electrode reaction pulverization, difficulty in controlling the uniformity of the carbon layer, and limited inhibition, so as to inhibit the dissolution of manganese and improve electrochemical stability performance, excellent rate performance and cycle performance

Inactive Publication Date: 2015-12-30
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The technical solution published in this patent uses glucose as a carbon source to improve the conductivity of the material, but glucose needs to undergo a high-temperature carbonization process, which requires 450-600 ° C, and the uniformity of the carbon layer formed after carbonization is difficult to control. Difficulty in LiM 0.2 mn 1.8 o 4 A stable three-dimensional conductive network is formed between the particles, and the formed carbon layer is relatively brittle, which is of great importance to LiM 0.2 mn 1.8 o 4 Nanoparticles have a limited inhibitory effect on the volume change during charge and discharge, which is not conducive to reducing the pulverization phenomenon in the electrode reaction, which is also not conducive to reducing the impedance, so further improvement is needed

Method used

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  • Preparation method of porous metal doped lithium manganate/graphene lithium battery positive electrode material

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Experimental program
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Effect test

Embodiment 1

[0031] In the first step, the polymer P123 with a molar mass of 5800 was dissolved in an appropriate amount of absolute ethanol, and stirred continuously at room temperature to obtain 20 mL of P123 gel with a uniform dispersion concentration of 0.05 g / mL.

[0032] In the second step, solid Mn(NO 3 ) 2 4H 2 O, LiNO 3 , Fe(NO 3 ) 3 9H 2 O is added in a molar ratio of 9:5:1, LiNO 3 The amount is 0.05mol.

[0033] In the third step, the above mixture was magnetically stirred at a medium speed for 12 h at room temperature.

[0034] In the fourth step, the uniformly mixed sol is air-dried at 60° C. for 24 hours in an air-blast drying oven.

[0035] In the fifth step, the dried mixture is heated in a muffle furnace at 2° C. / min to 500° C. in an air atmosphere, and kept for 2 hours.

[0036] Step 6: Add 1g NaNO3 and 2g flake graphite to 40ml of concentrated sulfuric acid solution; add 3g of potassium permanganate, heat up to 10°C, stir for 1h; heat up to 35°C, keep for 1h; ad...

Embodiment 2

[0043] In the first step, the polymer P123 with a molar mass of 5800 was dissolved in an appropriate amount of absolute ethanol, and stirred continuously at room temperature to obtain 20 mL of P123 gel with a uniform dispersion concentration of 0.08 g / mL.

[0044] In the second step, solid Mn(NO 3 ) 2 4H 2 O, LiNO 3 , Fe(NO 3 ) 3 9H 2 O is added in a molar ratio of 9:5:1, LiNO 3 The amount is 0.1mol.

[0045] In the third step, the above mixture was magnetically stirred at a medium speed for 16 h at room temperature.

[0046] In the fourth step, the uniformly mixed sol was air-dried at 70° C. for 36 hours in an air-blast drying oven.

[0047] In the fifth step, the dried mixture is heated in a muffle furnace at 3° C. / min to 600° C. in an air atmosphere, and kept for 3 hours.

[0048] Step 6: Add 1.5g NaNO3 and 3g flake graphite to 60ml of concentrated sulfuric acid solution; add 6g of potassium permanganate, heat up to 10°C, stir for 1h; heat up to 35°C, keep for 1h; ...

Embodiment 3

[0054] In the first step, the polymer P123 with a molar mass of 5800 was dissolved in an appropriate amount of absolute ethanol, and stirred continuously at room temperature to obtain 20 mL of P123 gel with a uniform dispersion concentration of 0.1 g / mL.

[0055] In the second step, solid Mn(NO 3 ) 2 4H 2 O, LiNO 3 , Fe(NO 3 ) 3 9H 2 O is added in a molar ratio of 9:5:1, LiNO 3 The amount is 0.5mol.

[0056] In the third step, the above mixture was magnetically stirred at a medium speed for 24 h at room temperature.

[0057] In the fourth step, the uniformly mixed sol is air-dried at 80° C. for 48 hours in an air-blast drying oven.

[0058] In the fifth step, the dried mixture is heated up to 700° C. in a muffle furnace at 5° C. / min in an air atmosphere, and kept for 4 hours.

[0059] Step 6: Add 2g NaNO3 and 4g flake graphite to 60ml of concentrated sulfuric acid solution; add 9g of potassium permanganate, heat up to 15°C, stir for 1h; heat up to 35°C, keep for 1h; a...

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Abstract

The invention relates to a preparation method of a porous metal doped lithium manganate / graphene lithium battery positive electrode material. The method includes the steps that 1, a sol-gel method is adopted for preparing a precursor of porous LiM0.2Mn1.8O4, and the precursor is put into a muffle furnace to be calcined at constant temperature to obtain porous LiM0.2Mn1.8O4; 2, graphene oxide is taken and added into deionized water to prepare a graphene oxide solution with the mass concentration of 0.05-0.1 g / mL; 3, porous LiM0.2Mn1.8O4 is put into the graphene oxide solution, the mixture is subjected to magnetic stirring, ultrasonic dispersion and drying and then transferred into a tube furnace to be calcined at constant temperature, and the porous metal doped lithium manganate / graphene lithium battery positive electrode material is obtained. Compared with the prior art, the preparation method is simple, and the raw materials are easy to get; the prepared material is good in crystallinity and uniform in particle size, and the size is about 30 nm; serving as a lithium battery positive electrode material, the prepared material is good in electrochemical stability, high in specific discharge capacity and good in rate performance and cycle performance.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and relates to a preparation method of a porous metal-doped lithium manganate / graphene lithium battery cathode material. Background technique [0002] Among the cathode materials for lithium-ion batteries, lithium manganate is one of the more promising materials. Compared with traditional cathode materials such as lithium cobalt oxide, lithium manganate has abundant resources, low cost, no pollution, good safety, and good rate performance. It is an ideal positive electrode material for power batteries, but lithium manganate will dissolve Mn and the Jahn-Teller effect during charging and discharging, which will cause deformation of the crystal lattice and unstable lattice structure, resulting in partial loss of electrical activity. The capacity drops, especially at high temperature (>55 °C) and the cycle performance is poor. [0003] To solve the above problem, LiMn 2 o 4 In the sys...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/505H01M4/62H01M10/0525B82Y30/00
CPCB82Y30/00H01M4/362H01M4/505H01M4/625H01M4/628H01M10/0525Y02E60/10
Inventor 朱申敏石一杉宾珩朱呈岭李尧张荻
Owner SHANGHAI JIAO TONG UNIV
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