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Carbonaceous lithium ion battery negative electrode material with nuclear shell structure and producing method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in electrode manufacturing, battery electrodes, structural parts, etc., can solve the problems of poor cycle performance, high initial irreversible amount, and reduce the first irreversible amount, and achieve long cycle life and low initial irreversible Capacity, the effect of high capacity

Active Publication Date: 2008-08-20
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The present invention aims at the problem that the first irreversible amount of the graphite negative electrode material is high due to the unsaturated bonds of the surface carbon atoms, and the expansion and contraction effect caused by charging and discharging destroys the structure of the negative electrode film and makes the cycle performance poor. Carbon-coated graphite surface to reduce the first irreversible amount; slowly deintercalate graphite intercalation compound to form nano-micron gaps in graphite particles, reserve space for expansion and contraction, and improve cycle performance

Method used

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  • Carbonaceous lithium ion battery negative electrode material with nuclear shell structure and producing method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] a) Ordinary H prepared by chemical method 2 SO 4 -H 2 o 2 The system expandable graphite is pulverized to a particle size of 5-50 μm.

[0033] b) Heating the obtained graphite intercalation compound at 250° C. for 48 hours to slowly deintercalate.

[0034] c) Prepare a phenolic resin ethanol solution with a mass fraction of 3 wt%, immerse the deintercalated graphite in the solution, stir for 6 hours, let stand for 4 hours, filter, and dry the filtered graphite powder at 300°C.

[0035] d) heating the graphite powder obtained in the previous step to 1000° C. at a rate of 300° C. / h under nitrogen protection, keeping the temperature for 4 hours, and cooling with the furnace to obtain graphite powder coated with amorphous carbon on the surface.

[0036] The first cycle efficiency of the graphite powder coated with amorphous carbon on the surface obtained by this method is greater than 90%, and the test results of 38 cycles of discharge capacity change are as follows:

Embodiment 2

[0038] a) FeCl prepared by electrochemical method 3 The intercalated expandable graphite is pulverized to a particle size of 5-50 μm.

[0039] b) Heating the obtained graphite intercalation compound at 350° C. for 72 h to slowly deintercalate.

[0040] c) Prepare a 20 wt% sucrose aqueous solution, immerse the deintercalated graphite into the solution, stir for 0.5 hours, let stand for 6 hours, filter, and dry the filtered graphite powder at 100°C.

[0041] d) Under the protection of nitrogen, the graphite powder obtained in the previous step is heated to 700°C at a rate of 500°C / h, kept at a temperature of 0.5 hours, and cooled with the furnace to obtain graphite powder coated with amorphous carbon on the surface.

Embodiment 3

[0043] a) flake graphite powder with a particle size of 5-50 μm is prepared by chemical method 2 SO 4 Intercalated graphite intercalation compound.

[0044] b) Heat the obtained graphite intercalation compound at 205° C. for 12 hours, and slowly deintercalate it.

[0045] c) Prepare a 5% mass fraction phenolic resin ethanol solution, immerse the deintercalated graphite in the solution, stir for 2 hours, let stand for 6 hours, filter, and dry the filtered graphite powder at 200°C.

[0046] d) heating the graphite powder obtained in the previous step to 1000° C. at a rate of 250° C. / h under nitrogen protection, keeping the temperature for 3 hours, and cooling with the furnace to obtain graphite powder coated with amorphous carbon on the surface.

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Abstract

The present invention relates to a carbonaceous lithium ion cell negative electrode material with core-shell structure and its preparation method, belonging to the field of carbon material and chemical power supply technology. The described negative electrode material is formed from core portion and shell portion. The core portion is graphite obtained after the graphite intercalation compound is disintercalated, the shell portion is amorphous carbon obtained by pyrolysis of organics. Said invention also provides the concrete steps of its preparation method.

Description

technical field [0001] The invention relates to a carbonaceous lithium ion battery negative electrode material with a core-shell structure and a preparation method thereof, belonging to the technical field of carbon materials and chemical power sources. Background technique [0002] Lithium-ion batteries have shown broad application prospects and potential huge economic benefits with the advantages of high energy density, long cycle life, and environmental protection. In the development of lithium-ion batteries, the research and development of negative electrode materials has always occupied an important position. . Carbon materials (including graphite, mesocarbon microspheres, organic carbides, petroleum coke, etc.) have become the most widely used and researched negative electrode materials due to their high specific capacity, low electrode potential, high cycle efficiency and long cycle life. [0003] Graphite includes natural microcrystalline graphite, natural flake gra...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/04C01B31/00C01B31/02H01M4/38H01M4/62
CPCY02E60/12Y02E60/10
Inventor 郑永平张静邹麟沈万慈康飞宇
Owner TSINGHUA UNIV
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