CN104617291A - Uniform carbon coated lithium ion battery anode/cathode material and preparation method thereof - Google Patents

Uniform carbon coated lithium ion battery anode/cathode material and preparation method thereof Download PDF

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Publication number
CN104617291A
CN104617291A CN201510035167.6A CN201510035167A CN104617291A CN 104617291 A CN104617291 A CN 104617291A CN 201510035167 A CN201510035167 A CN 201510035167A CN 104617291 A CN104617291 A CN 104617291A
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China
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cathode material
lithium ion
preparation
ion battery
positive
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CN201510035167.6A
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Inventor
焦玉聪
董安钢
张先峰
丁艺
杨柳
于慧娟
郭冠南
李瀚文
杨东
胡建华
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Fudan University
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Fudan University
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/523—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron for non-aqueous cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention belongs to the technical field of inorganic materials, and in particular discloses a uniform carbon coated lithium ion battery anode/cathode material and a preparation method thereof. The preparation method comprises the following steps: acidifying a specific nitrogen-containing compound (such as 3-cyanopyridine or aminoacetonitrile disulfate) by using sulfuric acid, so as to obtain an ionic liquid; sufficiently mixing the ionic liquid with a requested anode/cathode material, calcining to carbonize the anode/cathode material at certain temperature, and applying the anode/cathode material to the positive/negative electrode of a lithium battery, so as to obtain the carbon coated lithium ion battery anode/cathode material with high conductivity and capacity. According to the uniform carbon coated lithium ion battery anode/cathode material, a specific cyano structure is adopted to achieve nitrogen doping, so that the conductivity of the material is improved. As a carbon coated material of the positive/negative electrode of the lithium battery, the uniform carbon coated lithium ion battery anode/cathode material can be compounded with multiple cathode materials such as silicon, ferroferric oxide, lithium iron phosphate and graphite, and excellent battery circulation property can be achieved.

Description

Lithium ion battery plus-negative plate material that a kind of uniform carbon is coated and preparation method thereof
Technical field
The invention belongs to technical field of inorganic material, be specifically related to coated positive and negative pole material of a kind of carbon in lithium ion battery and preparation method thereof.
Technical background
Conventional lithium ion battery negative material is graphite material, and positive electrode has the materials such as cobalt acid lithium, LiMn2O4, LiFePO4.Wherein the embedding lithium capacity of negative pole graphite material is 372mAh/g, is widely used in the industry-by-industry of daily life.But because its capacity is on the low side, its flying power more and more can not meet people's requirement, therefore people start to attempt the new negative material of research to improve its flying power of lithium ion.Wherein, silicon, tin, metal oxide etc. all become the alternative of new negative material due to the theoretical capacity of its superelevation.But these materials, when embedding lithium takes off lithium, all exist the situation that volume significantly expands, this makes it as negative material cycle performance extreme difference, therefore needs to carry out the process of bag carbon to improve its cycle performance.And for positive electrode, its main Problems existing is that its conductivity and ionic diffusion coefficient are very low.Therefore the nitrogenous material with carbon element of excellent electric conductivity is introduced, also very crucial to positive electrode.
The present invention's carbon source material used, preparation is simple, and productive rate is high.Further, because its surface group has certain interaction with metal oxide as tri-iron tetroxide is surperficial, make at a certain temperature, both can well be attached together, and can obtain the coated material of better carbon by calcining; Meanwhile, because it contains nitrogen element, after carbonization, residual nitrogen element can improve the electric conductivity of material, and this as materials such as silicon, lithium ferric manganese phosphate, LiMn2O4s, has extraordinary performance improvement effect to the positive and negative pole material of poor electric conductivity.Therefore in the present invention, carbon source material used has boundless application prospect in the coated field of lithium ion positive and negative pole material.
Summary of the invention
Positive and negative pole material that the object of the present invention is to provide a kind of conductivity is high, covered effect is good carbon in lithium ion battery coated and preparation method thereof.
In order to achieve the above object, the technical scheme that the present invention takes is:
By the specific nitrogen-containing compound of sulfuric acid acidation, obtain ionic liquid, ionic liquid is fully mixed with required positive and negative pole material, calcines carbonization at a certain temperature, be applied to lithium battery both positive and negative polarity, the lithium ion battery plus-negative plate material with high conductivity and capacity can be obtained.Concrete steps are:
(1) sulfuric acid and the nitrogen-containing compound as carbon source are reacted (0 ~ 10 DEG C) at low temperatures, obtain ionic liquid; Gained ionic liquid comes modulation its carbonization productive rate, nitrogen content and specific area by the kind changing nitrogen-containing compound;
(2) gained ionic liquid and the lithium battery positive and negative pole material that can be wrapped by are scattered in good solvent (as water or DMF), mix under 35-45 DEG C (preferably 40 DEG C), remove solvent, the carbon source fully mixed and active cell material;
(3) gained battery material is placed in argon gas or nitrogen carbonization calcining under high temperature, calcining heat is 400 ~ 600 DEG C, namely obtains and has high electrical conductivity and the coated positive and negative pole material of uniform carbon.
Resulting materials is carried out lithium battery test, higher capacity and cycle performance can be obtained.
Nitrogen-containing compound described in step (1) is nicotinonitrile, 1,10-phenanthroline, 2,2-bipyridine, the nitrogen-containing compounds such as 1-vinyl imidazole, 1-cyanoethyl-2-phenylimidazole, diethylamine or amino acetonitrile bisulfate; Sulfuric acid is the concentrated sulfuric acid (as 95%).
The lithium battery positive and negative pole material be wrapped by described in step (2), comprising: commercial graphite material, positive pole material phosphoric acid salt is as LiFePO4, iron manganese phosphate for lithium etc., and negative material is as Fe 3o 4, silicon materials etc.
TEM (transmission electron microscope) analysis
Fig. 1 is the coated Fe of ionic liquid 3o 4nano particle is transmission electron microscope picture after 500 DEG C of calcinings.As can be seen from the figure, Fe 3o 4nanoparticle surface is uniformly coated with one deck material with carbon element.
Thermogravimetic analysis (TGA)
Fig. 2 is the coated Fe of ionic liquid 3o 4after nano particle carbonization under air TGA figure.As can be seen from the figure, the carbon covering amount of nano particle is about 20%.
Circulating battery capacity analysis
Fig. 3 is the coated Fe of ionic liquid 3o 4as the circulating battery Capacity Plan of lithium cell cathode material after nano particle carbonization, and the Fe not using carbon coated 3o 4the contrast of the circulation volume figure after nano particle carbonization.Both all carry out loop test under the current density of 350mA/g.
Circulating battery volt-ampere characterizes
Fig. 4 is the coated Fe of ionic liquid 3o 4as the cyclic curve of first three time of the circulating battery volt-ampere of lithium cell cathode material after nano particle carbonization.Test condition is 0.1mV/s.
In sum, hinge structure of the present invention has following characteristics:
The present invention utilizes the multiple nitrogen-containing compound of sulfuric acid acidation, obtains ionic liquid.Calcine after gained ionic liquid is mixed with both positive and negative polarity uniform liquid carbonization needed for lithium battery active material.The present invention has the following advantages, the carbonization productive rate on the one hand after the carbonization of gained ionic liquid, nitrogen content, and specific area is all by using different nitrogen-containing compounds to regulate; On the other hand, gained material with carbon element is owing to making material conductivity significantly improve containing nitrogen element, and the material of a lot of poorly conductive all can use this material to improve conductivity thus to improve its application efficiency in lithium battery.
The inventive method is simple, and raw material is easy to get, and preparation amount is large, and cost is low, and material conductivity is high, obvious to positive and negative pole material covered effect, effectively can improve the conductivity of positive and negative pole material and significantly improve its circulation volume.
Accompanying drawing explanation
Fig. 1 is the coated Fe of ionic liquid 3o 4nano particle is transmission electron microscope picture after 500 DEG C of calcinings.
Fig. 2 is the coated Fe of ionic liquid 3o 4after nano particle carbonization under air TGA figure.
Fig. 3 is the coated Fe of ionic liquid 3o 4as the circulating battery capacity comparison figure of lithium cell cathode material after nano particle carbonization.
Fig. 4 is the coated Fe of ionic liquid 3o 4as the circulating battery voltammogram of lithium cell cathode material after nano particle carbonization.
Embodiment
Embodiment 1: nicotinonitrile is obtained ionic liquid [CNPy] [HSO with sulfuric acid mixing acidifying 4].Get 0.8g ionic liquid, be dispersed in dimethyl formamide (DMF) solution containing 0.4g ferriferrous oxide nano-particle of having an appointment, shake ultrasonic mixing, at 120 DEG C, heat 30min, remove remaining DMF.Put into tube furnace, the lower 500 DEG C of heating of nitrogen 2 hours, obtain the ferriferrous oxide nano-particle that carbon is coated.
Embodiment 2: nicotinonitrile is obtained ionic liquid [CNPy] [HSO with sulfuric acid mixing acidifying 4].Get 0.6g ionic liquid, being dispersed to containing having an appointment in the DMF solution of 0.2g water-soluble ferroferric oxide cluster, shaking ultrasonic mixing, at 120 DEG C, heat 30min, remove remaining DMF.Put into tube furnace, the lower 500 DEG C of heating of nitrogen 2 hours, obtain the tri-iron tetroxide cluster that carbon is coated.
Embodiment 3: nicotinonitrile is obtained ionic liquid [CNPy] [HSO with sulfuric acid mixing acidifying 4].Get 1.5g ionic liquid, be dispersed in 5ml water; Get 0.12g silicon, ultrasonic disperse is in 5ml ethanol; Both are blended, and ultrasonic 15 minutes, remove solvent, put into tube furnace, the lower 1000 DEG C of calcinings of nitrogen 2 hours, obtain the silicon nano material that carbon is coated.

Claims (5)

1. a preparation method for the carbon in lithium ion battery positive and negative pole material that uniform carbon is coated, is characterized in that concrete steps are:
(1) sulfuric acid and the nitrogen-containing compound as carbon source are reacted under 0 ~ 10 DEG C of low temperature, obtain ionic liquid;
(2) gained ionic liquid and the lithium battery positive and negative pole material that can be wrapped by are scattered in good solvent, mix at 35-45 DEG C, remove solvent, the carbon source fully mixed and active cell material;
(3) gained battery material is placed in argon gas or nitrogen carbonization calcining under high temperature, calcining heat is 400 ~ 600 DEG C, namely obtains and has high electrical conductivity and the coated positive and negative pole material of uniform carbon.
2. preparation method as claimed in claim 1, it is characterized in that step (1) described nitrogen-containing compound is nicotinonitrile, 1,10-phenanthroline, 2,2-bipyridines, 1-vinyl imidazole, 1-cyanoethyl-2-phenylimidazole, diethylamine or amino acetonitrile bisulfate.
3. described preparation method as claimed in claim 1, is characterized in that the positive and negative pole material be wrapped by described in step (2), comprises commercial graphite material, phosphate, Fe 3o 4, silicon materials.
4. described preparation method as claimed in claim 1, is characterized in that described in step (2), good solvent is water or DMF.
5. the carbon in lithium ion battery positive and negative pole material that the uniform carbon prepared by the described preparation method of one of claim 1-4 is coated.
CN201510035167.6A 2015-01-24 2015-01-24 Uniform carbon coated lithium ion battery anode/cathode material and preparation method thereof Pending CN104617291A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106684360A (en) * 2017-01-20 2017-05-17 江西紫宸科技有限公司 Carbon coating method of artificial graphite negative material, negative material and lithium ion battery
CN110642237A (en) * 2019-09-30 2020-01-03 广东凯金新能源科技股份有限公司 Preparation method of carbon-coated graphite negative electrode material
CN113224319A (en) * 2021-03-31 2021-08-06 广西大学 Preparation method of nitrogen-sulfur co-doped carbon-coated transition metal nano sulfide electrochemical oxygen catalyst
CN113655392A (en) * 2021-08-02 2021-11-16 合肥国轩高科动力能源有限公司 Method for judging surface coating uniformity of electrode material

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102315440A (en) * 2010-07-09 2012-01-11 中国科学院物理研究所 Spinel composite material, preparation method and application thereof
CN102763251A (en) * 2009-12-22 2012-10-31 徐光锡 Electrochemical device
CN103647072A (en) * 2013-12-25 2014-03-19 南京师范大学 Preparation method of nitrogen-doped carbon wrapping layer with adjustable carbon/nitrogen content ratio on surface of nickel oxide
CN104282896A (en) * 2014-09-18 2015-01-14 东莞市翔丰华电池材料有限公司 Nitrogen-doped carbon-coated graphite negative electrode material and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102763251A (en) * 2009-12-22 2012-10-31 徐光锡 Electrochemical device
CN102315440A (en) * 2010-07-09 2012-01-11 中国科学院物理研究所 Spinel composite material, preparation method and application thereof
CN103647072A (en) * 2013-12-25 2014-03-19 南京师范大学 Preparation method of nitrogen-doped carbon wrapping layer with adjustable carbon/nitrogen content ratio on surface of nickel oxide
CN104282896A (en) * 2014-09-18 2015-01-14 东莞市翔丰华电池材料有限公司 Nitrogen-doped carbon-coated graphite negative electrode material and preparation method thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106684360A (en) * 2017-01-20 2017-05-17 江西紫宸科技有限公司 Carbon coating method of artificial graphite negative material, negative material and lithium ion battery
CN106684360B (en) * 2017-01-20 2019-04-12 江西紫宸科技有限公司 Carbon coating method, negative electrode material and the lithium ion battery of artificial plumbago negative pole material
CN110642237A (en) * 2019-09-30 2020-01-03 广东凯金新能源科技股份有限公司 Preparation method of carbon-coated graphite negative electrode material
CN113224319A (en) * 2021-03-31 2021-08-06 广西大学 Preparation method of nitrogen-sulfur co-doped carbon-coated transition metal nano sulfide electrochemical oxygen catalyst
CN113655392A (en) * 2021-08-02 2021-11-16 合肥国轩高科动力能源有限公司 Method for judging surface coating uniformity of electrode material

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