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Lithium sodium manganate cathode material and preparation method thereof

A technology of sodium manganate and lithium positive electrode, which is applied in the field of new lithium-ion battery positive electrode materials, can solve the problem of low capacitance of electrode materials, and achieve the effects of environmental friendliness, low production cost and stable structure

Active Publication Date: 2013-05-01
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The present invention aims at LiMnO with layered structure in the prior art 2 The battery material will transform into lithium manganate with a spinel structure with reduced electrochemical activity as the charge and discharge cycle progresses, and the sodium-containing material in the prior art has a defect in the low capacitance of the electrode material of the lithium ion battery, the purpose is to Provide a new lithium sodium manganate positive electrode material with stable structure, large specific capacity, stable cycle capacity, low cost and environmental friendliness

Method used

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  • Lithium sodium manganate cathode material and preparation method thereof
  • Lithium sodium manganate cathode material and preparation method thereof
  • Lithium sodium manganate cathode material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0039] LiOH·H 2 O, NaOH, electrolytic MnO 2 , mixed at a molar ratio of 1:3:4, dispersed in ethanol, placed in a planetary ball mill at a speed of 500 rpm for 4 hours. Then, in an argon atmosphere, the temperature was raised to 600° C. at a rate of 2° C. / min, roasted at a constant temperature for 8 hours, and then cooled naturally with the furnace. The nominal composition of the resulting product is Li 1 / 4 Na 3 / 4 MnO 2 , XRD analysis ( figure 1 ) shows that it has Na 0.7 MnO 2 Structured single-phase compounds. The primary particle size is 100~300nm, with a certain degree of agglomeration ( figure 2 ). Mix it with acetylene black and polyvinylidene fluoride (PVDF) at a mass ratio of 8:1:1, add an appropriate amount of organic solvent N-methylpyrrolidone (NMP) as a dispersant, grind it evenly and coat it on a 0.02mm current collector After being vacuum-dried at 120° C. on an aluminum foil, it was stamped into a positive electrode disc with a diameter of 14 mm. Use m...

Embodiment 2

[0042] LiOH·H 2 O, NaOH, MnCO 3 , mixed at a molar ratio of 1:2:3, dispersed in ethanol, placed in a planetary ball mill at a speed of 600 rpm for 6 hours. Then in an air atmosphere, the temperature was raised to 700° C. at a rate of 1° C. / min, roasted at a constant temperature for 48 hours, and then cooled naturally with the furnace. The nominal composition of the resulting product is Li 1 / 3 Na 2 / 3 MnO 2 . A battery was assembled according to the method of Example 1, and a charge and discharge test was carried out. The results show that the specific capacity of the first discharge is 196mAh / g, and the specific capacity of the second discharge is 241mAh / g. As the cycle progresses, the specific capacity of the 30th discharge is 252mAh / g.

Embodiment 3

[0044] Will Li 2 CO 3 , Na 2 CO 3 , MnCO 3 , mixed at a molar ratio of 1:1:4, dispersed in ethanol, placed in a planetary ball mill at a speed of 600 rpm for 6 hours. Then in an air atmosphere, the temperature was raised to 700° C. at a rate of 1° C. / min, roasted at a constant temperature for 24 hours, and then cooled naturally with the furnace. The nominal composition of the resulting product is Li 1 / 2 Na 1 / 2 MnO 2 , XRD shows that it is a layered material (Na 0.7 MnO 2 phase) and spinel materials (LiMn 2 o 4 )mixture. A battery was assembled according to the method of Example 1, and a charge and discharge test was carried out. The results show that there are multiple platforms on the charge and discharge curve, and the discharge curve has at least four platforms of 4V, 2.9V, 2.7V and 2V, which proves that the material is a mixture of layered materials and spinel materials, and the specific capacity of the first discharge is 196mAh / g, the specific capacity of th...

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Abstract

The invention discloses a lithium sodium manganate cathode material. The lithium sodium manganate cathode material consists of lithium sodium manganate with a layered structure, or sodium manganate with a layered structure, or lithium sodium manganate with a layered structure and a lithium manganate with a spinel structure. A preparation method comprises the following steps: mixing a manganese surface and a sodium surface, or a lithium surface, the manganese surface and the sodium surface and dispersing a mixture in a liquid disperse medium; mixing for 2-8 h through ball milling to obtain a ball-milled material; and putting the ball-milled material in an atmosphere of reducing gas, inert gas or air, roasting the ball-milled material for 6-50 h at 500-1,200DEG C, and cooling the ball-milled material to room temperature to obtain the lithium sodium manganate cathode material. The lithium sodium manganate cathode material is stable in structure, large in specific capacity, stable in cycle capacity, low in cost and environment-friendly; and the preparation method is simple in process, easy to control conditions, low in production cost and low in environment pollution and conducive to large-scale production.

Description

technical field [0001] The invention relates to a lithium sodium manganate cathode material and a preparation method thereof, belonging to the field of novel lithium ion battery cathode materials. Background technique [0002] After more than 20 years of development, lithium-ion batteries have occupied the largest share in the current secondary battery market due to their advantages such as high working voltage, high energy density, long cycle life, low self-discharge rate, and environmental protection. Among them, the positive electrode material, as the key to determine the performance and cost of lithium-ion batteries, has received great attention. [0003] LiMnO 2 The material has always been considered as an ideal cathode material for lithium-ion batteries, and LiCoO 2 In comparison, not only is the price much cheaper, but it is also safe and environmentally friendly. The material has a theoretical specific capacity ratio of LiCoO 2 Slightly higher, there are many ty...

Claims

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Application Information

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IPC IPC(8): H01M4/505C01G45/12
CPCY02E60/122Y02E60/10
Inventor 杜柯胡国荣彭忠东曹雁冰
Owner CENT SOUTH UNIV
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