Microcrystal graphite used for negative electrode material of lithium battery, and preparation method of microcrystal graphite

A technology of microcrystalline graphite and negative electrode materials, which is applied in the direction of battery electrodes, secondary batteries, hybrid capacitor electrodes, etc., can solve the problems of poor electrical properties of natural microcrystalline graphite, reduce usage, increase specific surface area, and reduce ratio The effect of surface area

Inactive Publication Date: 2018-03-13
HUNAN GUOSHENG GRAPHITE TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The technical problem to be solved in the present invention is to provide a kind of microcrystalline graphite for negative electrode materials of lithium batteries in view of the poor electrical properties of natural microcrystalline graphite in the prior art, which is treated by chemical purification to improve its charge and discharge performance.

Method used

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  • Microcrystal graphite used for negative electrode material of lithium battery, and preparation method of microcrystal graphite
  • Microcrystal graphite used for negative electrode material of lithium battery, and preparation method of microcrystal graphite
  • Microcrystal graphite used for negative electrode material of lithium battery, and preparation method of microcrystal graphite

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Embodiment 1

[0054] This embodiment provides a method for preparing microcrystalline graphite for negative electrode materials of lithium batteries, comprising the following steps:

[0055] S1. Raw ore treatment: crush Lutang aphanitic graphite, and then conduct deep grinding on the microcrystalline graphite raw ore, and obtain materials with a fineness of -0.074mm through grinding, and increase the content of materials with a fineness of -0.074mm 90% of the raw ore samples are subjected to flotation, specifically as figure 1 As shown, a roughing process is adopted for four times of selection and one sweeping process, followed by drying and magnetic separation to obtain microcrystalline graphite with a fixed carbon content of 90%;

[0056] Wherein, the properties of Lutang aphanitic graphite described in step S1 are as follows: moisture 2.4%, volatile matter 2.99%, ash content 18.37%, carbon content 78.64%, specific surface area 12.8㎡ / g.

[0057] S2. acid leaching purification: the microc...

Embodiment 2

[0061] The implementation is basically the same as in Example 1, except that the process conditions are different in step S2, as follows:

[0062] S2. acid leaching purification: the microcrystalline graphite obtained in step S1 is mixed with a mixed acid, the mixed acid is a mixed acid of HF and HCL, the liquid-solid ratio of the mixed acid to graphite is 2ml / g, the volume content of HF is 30%, and that of HCL The volume content is 10%, and then carry out acid leaching under normal pressure under the conditions of temperature 60°C and reaction time 1h. The leaching residue is washed with distilled water or deionized water until the graphite precipitates when the washing solution is neutral, and then filtered. Dry at ~150°C for 2-3 hours to obtain purified microcrystalline graphite with a fixed carbon content of 99.12%.

Embodiment 3

[0064] The implementation is basically the same as in Example 1, except that the process conditions are different in step S2, as follows:

[0065] S2. acid leaching purification: the microcrystalline graphite obtained in step S1 is mixed with a mixed acid, the mixed acid is a mixed acid of HF and HCL, the liquid-solid ratio of the mixed acid to graphite is 3.5ml / g, the volume content of HF is 60%, and the HCL The volume content is 20%, and then carry out normal pressure acid leaching at a temperature of 80°C and a reaction time of 4 hours. The leaching residue is washed with distilled water or deionized water until the graphite precipitates when the washing solution is neutral, and then filtered, and heated at a temperature of Dry at 80-150° C. for 2-3 hours to obtain purified microcrystalline graphite with a fixed carbon content of 99.56%.

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Abstract

The invention relates to the technical field of a negative electrode material of a lithium battery, and discloses microcrystal graphite used for a negative electrode material of a lithium battery, anda preparation method of the microcrystal graphite. The cyclic specific capacity of the microcrystal graphite material at the current density of 100 mA / g can reach 224 mAh / g; the initial efficiency isrelatively high and can reach greater than 90%, and high stability is achieved; in a high rate condition, the cyclic specific capacity of the material is relatively low, and the reversible specific capacity is about 50 mAh / g; however, the material is excellent in high-rate cycle performance, particularly, in different charging-discharging rate conversion conditions, relatively high cycle stability still can be kept; and therefore, the microcrystal graphite negative electrode material disclosed in the invention can be applied to the field of a supercapacitor which has not high requirement on the cycle capacity and has extremely high requirement on the high-rate cycle stability.

Description

technical field [0001] The present invention relates to the technical field of lithium battery negative electrode materials, and more specifically, to a microcrystalline graphite used for lithium battery negative electrode materials and a preparation method thereof. Background technique [0002] Graphite is one of the most studied carbon anode materials for lithium-ion batteries. Graphite materials have good conductivity, high crystallinity, and a good layered structure. The layers are hexagonal like benzene rings composed of carbon atoms in the sp2 state huge plane. The carbon atoms in the layer are connected by δ covalent bonds, the bond length is 0.1421nm, and the three δ bonds form an angle of 120° with each other. In addition, there is a large π bond connecting all the carbon atoms in the plane. The layers are connected by weak van der Waals force, and the interlayer spacing of ideal graphite is 0.3354nm. At a lower potential, lithium ions can reversibly intercalate a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583H01M10/0525H01G11/32
CPCH01G11/32H01M4/583H01M10/0525Y02E60/10Y02E60/13
Inventor 林前锋李丽萍
Owner HUNAN GUOSHENG GRAPHITE TECH CO LTD
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