CN1558458A - Graphite powder for negative electrode of lithium ion secondary cell and manufacturing method thereof - Google Patents
Graphite powder for negative electrode of lithium ion secondary cell and manufacturing method thereof Download PDFInfo
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- CN1558458A CN1558458A CNA2004100152693A CN200410015269A CN1558458A CN 1558458 A CN1558458 A CN 1558458A CN A2004100152693 A CNA2004100152693 A CN A2004100152693A CN 200410015269 A CN200410015269 A CN 200410015269A CN 1558458 A CN1558458 A CN 1558458A
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- lithium ion
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- ion secondary
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 256
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 47
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 238000004519 manufacturing process Methods 0.000 title description 5
- 239000010439 graphite Substances 0.000 claims abstract description 70
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 66
- 238000006253 efflorescence Methods 0.000 claims abstract description 61
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- 238000002360 preparation method Methods 0.000 claims abstract description 14
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- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims description 3
- 239000011574 phosphorus Substances 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 claims description 3
- 240000007594 Oryza sativa Species 0.000 claims description 2
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- 238000000034 method Methods 0.000 abstract description 41
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 34
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- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
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- LENZDBCJOHFCAS-UHFFFAOYSA-N tris Chemical compound OCC(N)(CO)CO LENZDBCJOHFCAS-UHFFFAOYSA-N 0.000 description 2
- 229910014451 C6Li Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
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- 229910052783 alkali metal Inorganic materials 0.000 description 1
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- 125000002837 carbocyclic group Chemical group 0.000 description 1
- 150000001721 carbon Chemical group 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
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- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
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- LVTJOONKWUXEFR-FZRMHRINSA-N protoneodioscin Natural products O(C[C@@H](CC[C@]1(O)[C@H](C)[C@@H]2[C@]3(C)[C@H]([C@H]4[C@@H]([C@]5(C)C(=CC4)C[C@@H](O[C@@H]4[C@H](O[C@H]6[C@@H](O)[C@@H](O)[C@@H](O)[C@H](C)O6)[C@@H](O)[C@H](O[C@H]6[C@@H](O)[C@@H](O)[C@@H](O)[C@H](C)O6)[C@H](CO)O4)CC5)CC3)C[C@@H]2O1)C)[C@H]1[C@H](O)[C@H](O)[C@H](O)[C@@H](CO)O1 LVTJOONKWUXEFR-FZRMHRINSA-N 0.000 description 1
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Classifications
-
- 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
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- Battery Electrode And Active Subsutance (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
The invention discloses graphite powder for negative electrodes of lithium ion secondary cells and method for its preparation, wherein the graphite powder is in spherical shape and has an end portion construction with closed surfaces, wherein the method comprises the steps of, (1) charging natural crystaline flake graphite into high speed disintegrator, performing efflorescence 10 to 80 minutes under the condition of 3000 to 6000 rotations per minute, (2) charging into slow run impulse type globurizing crushing machine, performing globurizing and dressing treatment for 40 to 180 minutes under the condition of 600-3000 rotations per minute.
Description
Technical field
The present invention relates to a kind of graphite powder and preparation method, graphite powder and preparation method that particularly a kind of lithium ion secondary battery negative pole uses.
Background technology
Lithium secondary battery or storage battery are such class non-aqueous secondary batteries, this battery active material of lithium as negative pole, oxide or chalkogenide with transition metal, for example, sulfide and selenides promptly use the inorganic or organic lithium salt solution that is dissolved in the inert organic solvents as electrolyte as the active material of positive pole.Because lithium is a kind of very alkali metal of electronegative potential that has, so provide the ability that is easy to be obtained by it high potential with lithium for battery as the negative pole in the battery.For this reason, as having the secondary cell that higher electromotive force and higher energy density are wished, lithium secondary battery attracts increasing attention, and they are expected in the various fields and find various uses as distribution battery or portability battery, and these fields comprise electronic equipment, electric equipment, motor vehicle and electrical power storage.Lithium secondary battery has entered practical application as the battery of compactness.At first, the lithium metal of paper tinsel form is used for forming negative pole by itself in the lithium secondary accumulator battery.In this case, the dissolving from lithium is reacted in discharge and charging, ionization and precipitation beginning, the Li during charging cycle then
+In-Li the reaction, lithium metal has as acicular crystal and is deposited on trend on the negative pole, and the discharge and the charging cycle that repeat cause the lithium skeleton, and the arborizations crystal is formed on this electrode.Along with the growth of lithium skeleton, can penetrate the spacer of battery, cause internal break by skeleton with direct contact of positive pole.Therefore, these batteries have the fatal shortcoming of very short cycle life in discharge that repeats and charging cycle.In order in lithium secondary battery, to eliminate this problem with lithium metal negative pole, the material with carbon element of lithium ion can be reversibly accepted and be discharged in use, for example, naturally the graphite of Cun Zaiing, Delanium, petroleum coke, carbide resin, carbon fiber RESEARCH OF PYROCARBON, carbon black etc., to form the negative pole of these batteries, the for example disclosed Japanese patent application No.57-208079 (1982) that do not examine, in such battery, the material that is used for negative pole can all be made up of material with carbon element basically.A kind of like this negative pole can be made like this, usually by means of a kind of appropriate adhesive, material with carbon element with form of powder attached to as on the metal substrate of current-collector.Electrode reaction ring with lithium secondary battery of the negative pole that material with carbon element makes is not illustrated fully, but can be by following understanding, in battery charge, electron transport is given the material with carbon element of negative pole, make the negative charging of material with carbon element thus, electrolyte comprises lithium ion, and these lithium ions are attracted to the carbon material used as anode of charging, and by electrochemistry be mingled with the reaction be received in wherein.On the contrary, during discharge cycles, remove the lithium ion that comprises the material with carbon element from negative pole, so that they are discharged in the electrolyte solution, thereby, realize charging and discharge by lithium ion being received in the negative material and they being discharged from material.In view of this mechanism, this class battery generally is called lithium " ion " secondary cell.Lithium rechargeable battery is not relating to the deposition of lithium metal on negative pole during the electrode reaction, avoided the deposition problems of the lithium skeleton of remarkable damage negative pole thus.The lithium secondary battery majority that current industrial is used is such, promptly has the carbon material negative pole type.The theoretical capacity of lithium secondary battery with lithium metal negative pole is very high, promptly on the capacity level of 3800mAh/g, have at lithium rechargeable battery under the situation of the carbon material negative pole of wherein accepting lithium ion, its theoretical capacity is restricted to 372mAh/g, has lithium-graphite to be mingled with Compound C even work as negative pole
6It also is that so this compound is a kind of like this graphite that Li forms, and makes in the space between the fine and close and regular layer crystal lattice that are mixed in graphite of lithium ion.In practice, the material with carbon element that is used as negative pole has interference lithium ion surface activity zone that enters and the dead band that can not receive lithium ion, therefore, even high kish is used for forming the negative pole of lithium rechargeable battery, the also extremely difficult capacity that reaches 372mAg/g, i.e. C
6The theoretical capacity of Li.In addition, when high crystalline carbon material or graphite are used for forming negative pole, the surface of electrode has than its inner high activity, because crystal structure interrupts on the surface, and along with electrolyte ingredient decomposes a little by the effect of high charge voltage, one deck passivating film has the active higher lip-deep trend that is deposited on.The electric weight that consumes for decomposition loses wastefully, reduce the charge/discharge coulombic efficiency of electrode thus, it is ampere-hour efficiency, promptly discharge to the ratio of charge capacity, the charge/discharge coulombic efficiency is the expression of secondary cell performance, calculate by formula [(discharge capacity)/(charging capacity) * 100%], a kind of like this instructions for use of material uses excessive material to design battery to positive pole, to allow the reduction of charge/discharge coulombic efficiency.This purposes for compact battery with the given shape that is limited by standard and so on is disadvantageous.
In order the discharge capacity that is used for the carbon negative pole of lithium rechargeable battery to be increased to as much as possible, the whole bag of tricks has been proposed for the production of the material with carbon element that is used for negative pole near the above-mentioned theory capacity.For example, disclosedly do not examine the use that discloses the middle carbonated product of microscopic beads mutually among Japanese patent application No.4-115458 (1992), No.5-234584 (1993) and the No.5-307958 (1993), middle phase microscopic beads forms in the Carbonization of Pitch process.Middle phase tiny balls is to show optically anisotropic liquid crystal spheric granules, and by making pitch under about 2000-3000 degree, stand several hrs or heat treatment for more time forms.When heat treatment further continued, microscopic beads was grown up and the formation one that finally is joined to one another, and was called the middle phase of body, showed optical anisotropy as a whole.Can be used as the material of carbonization in the middle of the body mutually, yet when as negative pole, the carbonated product of these materials do not have sufficiently high discharge capacity, the highest 290-320mAh/g.Disclosed unexamined Japanese patent application No.7-282812 (1995) has carried out such description, and the capacity with lithium rechargeable battery of the negative pole that graphitized carbon fibre makes can increase by the systematicness that improves graphite lattice arrangement layer structure in the negative pole.Point out that wherein the powdered of carbon fiber is introduced undesirable fault of construction, these defectives are disturbed the systematicness of the alignment layer structure of graphitized carbon fibre.The systematicness of graphite lattice arrangement layer structure rises to negative pole provides the highest 316mAh/g discharge capacity, is used to have enough high power capacity but can not produce, and for example surpasses the material with carbon element of the negative pole of 320mAh/g capacity.The disclosed Japanese patent application No.187972 (1994) that do not examine discloses a kind of like this material with carbon element, produce by at high temperature calcining with a kind of special resin of carbonization, this special resin is by making aromatic reactant thing crosslinking agent react to form having under the sour situation.The material with carbon element that generates has the microstructure of the crystal phase of the crystallization formation that includes the aromatic reactant thing, and crystal mixes with the amorphous phase that has crosslinking agent to derive.These two kinds have different thermal expansions and constriction coefficient mutually, and this makes material with carbon element have a plurality of internal structure defectives of space form.Carried out such description in this application, material with carbon element provides higher capacity when being used for forming the negative pole of lithium rechargeable battery, because except that because above-mentioned being mingled with causes interlayer to absorb the lithium ion (formation of C6Li), also take place to absorb the lithium metal by the space.This material with carbon element is imperfect with the viewpoint of cost, because owing to use resin dedicated its material cost that causes higher to carbonization, and, can not provide improved charge/discharge coulombic efficiency for negative pole.
Summary of the invention
The graphite powder and the preparation method that the object of the present invention is to provide a kind of lithium ion secondary battery negative pole to use, the technical problem that solves is to use can be by the cheap raw material native graphite of routine rather than by the resin dedicated material with carbon element that produces, and makes a kind ofly to have high discharge capacity and preferably have the negative material raw material that the lithium rechargeable battery that improves the charge/discharge coulombic efficiency is used.
The present invention is by the following technical solutions: the graphite powder that a kind of lithium ion secondary battery negative pole uses, described graphite powder be shaped as sphere, have the closed end construction in surface.
Graphite C plane layer of the present invention has closed end on the graphite powder surface that forms by the paired end that connects the C plane layer, the space of opening is arranged on graphite surface simultaneously.
The quantity that graphite C direction of principal axis of the present invention records clearance gap is 100 to 1500 for every micron.
It is 5 to 75um that graphite powder of the present invention has particle size distribution, and tap density is 0.95 to 1.05 grams per milliliter, the specific surface area of 4 to 7.5 meters squared per gram.
The preparation method of the graphite powder that a kind of lithium ion secondary battery negative pole uses, adopt following steps: (1) is 32 to 325 orders with granularity, phosphorus content is the natural flake graphite of 90-99.99%, join in the high speed disintegrator by automatic feeding system, efflorescence is 10 to 80 minutes under 3000 to 6000 rev/mins of conditions; (2) graphite powder that makes is joined in the low velocity impact formula nodularization pulverizer, the nodularization shaping was handled 40 to 180 minutes under 600 to 3000 rev/mins of conditions, obtained spherical graphite.
Spherical graphite of the present invention will wherein be removed less than the subparticle of 5um with greater than the gradation of 75um by grader again, obtain particle size distribution and be 5 to 75um, tap density is 0.95 to 1.05 grams per milliliter, and specific area is the spherical graphite of 4 to 7.5 meters squared per gram.
High speed disintegrator of the present invention is airslide disintegrating mill, high pressure flour mill or bar type mechanical crusher, low speed nodularization pulverizer is low velocity impact formula nodularization pulverizing, air-flow vortex pulverizing mill, micronizer, ultra micro ball mill, internal classification impact type micro mist pulverizer, pendulum type ring roll pulverizer, grader are gas flow sizing machine, jetting type grader, sub-micron grader or ultra micro rice gas flow sizing machine.
The present invention compared with prior art, graphite powder be shaped as sphere, can receive the natural graphite powder of a large amount of lithium ions, when this graphite powder is used as the material of lithium ion secondary battery negative pole, can reach at least at the 340mAh/g order of magnitude with stationary mode, preferably be at least the 350mAh/g order of magnitude, better be at least the 355mAh/g order of magnitude, and be the high discharge capacity of the 360mAh/g or the bigger order of magnitude under certain conditions; Since the cheap price of native graphite, and then can reduce the price that has negative material now, and its price only is 30 to 50% of MCMB; Improve the security performance of ion secondary battery.
Description of drawings
Fig. 1 is the photo of the present invention's graphite powder particle shape of taking under high resolution electron microscope (HREM).
Embodiment
Below in conjunction with drawings and Examples the present invention is described in further detail.As shown in Figure 1, be the high-resolution electron micrograph of the graphite powder of lithium ion secondary battery negative pole use of the present invention, the shape approximation sphere of expression graphite powder.Natural graphite powder is through carrying out sorting through certain pulverization conditions nodularization and through special screening installation, and then obtain the graphite powder of high-tap density and shape approximation sphere, its shape becomes almost spherical by the laminated structure of graphite itself, this kind graphite powder particle size distribution interval is narrow, specific area is little, spherical specific area minimum, the surface has the closed ends structure that forms at the C plane layer of its closed end pairing graphite linings lattice, has the layering form of the C plane layer being formed by several in the lip-deep closed ends structure of graphite powder, the C plane layer is closed at its place, end around adjoining course, between two adjacent layering closed ends structures, maintain in the open-ended space of C plane layer.The tap density appreciable impact of graphite powder has the discharge capacity of the lithium rechargeable battery of the negative pole that graphite powder forms.That is, can improve discharge capacity, make it possible to reach the desired value of above-mentioned discharge capacity thus by increasing tap density.In addition, can change its shape and increase tap density by efflorescence state native graphite.Spherical natural graphite powder of the present invention, has the closed end construction in surface, wherein the graphite C plane layer has closed end on the graphite powder surface that forms by the paired end that connects the C plane layer, stay space simultaneously in the graphite surface upper shed, every micron of the quantity that records clearance gap at the graphite C direction of principal axis is at least 100 and be at most 1500, best, graphite powder has 7.0m
2/ g or littler specific surface area.
Natural spherical plumbago powder of the present invention has the closed ends structure of the C plane layer of graphite linings lattice on the graphite powder surface, be called surperficial closed ends structure.By each C plane layer of graphite linings lattice, the end that it is desirable to carbon six side's network layers of being made up of six molten mutually each other in plane joint carbocyclic rings is connected to the end of another adjacent C plane layer, on the graphite powder surface, make one and form the right of a closed ends, form surperficial closed ends structure.The formation of this closed ends structure is considered to and can occurs on the graphite powder surface, be because the right closed ends structure of the C plane layer of closed graphite linings lattice wherein, on the graphite powder surface, have free than each C plane layer wherein aspect the energy level and to interrupt the hatch frame of end more stable by linking its end.
Lithium ion enters the easy degree as the material with carbon element of negative pole, along with lithium ion in the material with carbon element enter ground number of spots increase and increase.Thereby along with graphite linings lattice C plane layer end place clearance gap, its quantity of density per unit length that enters the effect in place increases, and the easier negative pole that enters of lithium ion increases the amount of lithium ions that is received by electrode thus, and therefore improves discharge capacity.Graphite powder according to the present invention has sufficiently high clearance gap density and desired shapes comparatively in graphite C plane layer end construction, realizing the remarkable improvement of discharge capacity, and the remarkable enhancing of security performance.General, graphite powder comprises having the axial a plurality of zones of different C, these zones are corresponding to the crystal grain of polycrystal powder.Each this zone has the axial zone of identical C and is called crystallite.In graphite powder according to the present invention, there is no need all crystallites that constitute powder and have the surperficial closed ends structure of above-mentioned C plane layer, but preferably basically all crystallites have this surperficial closed ends structure.
Graphite powder of the present invention has the surperficial closed ends structure of graphite C plane layer, and wherein the quantity of clearance gap is that density is in 100 to 1500 every micron scope.If this quantity is less than 100 every micron, owing to the quantity that enters the clearance gap in place as lithium ion reduces, the amount of lithium ions that is received by graphite also will reduce so.As a result, can not reach high discharge capacity on the 340mAh/g or the higher order of magnitude.The highest quantity, promptly every micron 1500 clearance gap form the quantity that obtains under the situation of each unit closed ends structure corresponding to the list that is formed an individual layer end by closure to the adjacent C plane layer.
If the end of graphite C plane layer in its surface be opening promptly form the closed ends structure freely and not, then not only lithium ion but also electrolyte solution may enter graphite.Because these open ends are chemically unstable, so because decomposition of solution certain ingredients but electrolyte solution may be emitted gas, cause that thus graphite separates from the current-collector that supports graphite thereon, thereby the cycle life that the surperficial closed ends structure of graphite powder causes standing the lithium rechargeable battery of recharge and discharge cycles improves.And it is bonded to each other that the surperficial closed ends structure of C plane layer allows to be present in all carbon six-membered rings of each C plane layer end, and thereby do not have an empty sp of carbon atom
2The mixed electronic track.This state than the state of each C plane layer opening wherein than torpescence.In view of the charge/discharge coulombic efficiency of lithium rechargeable battery is subjected to this fact of adverse effect of any reaction of graphite powder and electrolyte solution in the negative pole, shape and closed ends structure are useful to the improvement of charge/discharge coulombic efficiency.Even China ink has this closed ends structure, also may exist some carbon atoms to keep not bonding, and produce the end construction of opening, the end construction of opening is more active, and owing to may reduce the charge/discharge coulombic efficiency with the electrolyte solution reaction.In order further to improve the charge/discharge coulombic efficiency, advantageously change the shape of graphite powder and then reduce the specific area of graphite powder, with the reactivity of further reduction itself and electrolyte solution.For this reason, preferably approximate spherical according to graphite powder of the present invention so that specific area is minimum.By conventional N such as use BET absorptions
2Absorption process can be determined surface area.If graphite powder has the 7.0m of ratio
2The specific surface area that/g is big, then it has rising and reactivity electrolyte solution, and this may make charge/discharge coulombic efficiency and cycle life reduce.The minimum specific surface area is not conclusive, but its 5.5m2/g normally, and being more preferably is specific surface area surplus in the of 4.0 between the 7.5m2/g.Be more preferably, specific surface area is between 4.0 to 6.5m2/g.The specific surface area of graphite mainly becomes with the duration of the condition that is used for efflorescence, particularly efflorescence.
Graphite powder of the present invention preferably also has following performance: (1) natural spherical plumbago powder tap density after treatment is greater than 0.95g/ml, records with the FZ4-4 tap density instrument of Iron and Steel Research Geueral Inst production; (2) in C direction of principal axis graphite microcrystal size in the scope of 100 to 2000 dusts; (3) volume accumulative total average particulate diameter is in 5 to 35um scope, as by laser diffraction/scattering method, Britain MS2000 determine like that; (4) pattern is analyzed with scanning electron microscope observation, if the graphite microcrystal size be the length crystallite size that records at the C direction of principal axis less than 100 dusts then crystallite is so little, introduce tangible destruction in the lattice always and do not allow lithium ion to enter through the space of opening to receive efficiently therein.Crystallite size is better in the scope of 500 to 1500 dusts.
The average particulate diameter of graphite powder is the value at 50% accumulative total place of the volume cumulative distribution curve by the particle diameter that laser diffraction/the scattering method records within the scope of the present invention.If average particulate diameter is less than 5um, then graphite powder is so thin, to such an extent as to its specific area is very big, the charge/discharge coulombic efficiency is reduced.Greater than 35um, the lithium ion that has infiltrated dearly in the graphite powder may need the long period to the powder surface diffusion, disturbs discharge performance thus for average particulate diameter, particularly under the situation of big electric current or low temperature discharge.Average particulate diameter according to graphite powder of the present invention is better from 10 to 30um.And graphite powder preferably is substantially devoid of any coarse granule greater than 75um that discharge performance is had adverse effect under the situation of big electric current or low temperature discharge, also do not contain the fine particle less than 1um of any interference initial charge/discharge performance.In addition, when being applied to strip electrode plate as supporter comprising above coarse grained graphite powder, and this plate reels when forming convoluted electric-shocking plate and inserting in the appropriate battery container with a large amount of number of turns, and concentrated stress is applied on the coarse granule.The result, may produce these particles and see through the problem that generally has the adjacent thin barrier film of about 20um thickness, produce internal break thus between both positive and negative polarity, have the erose graphite powder of obvious different size for its length diameter, this problem more may take place.It is difficult removing these erose particles by screening.If, comprising the possibility of irregularly shaped particles so greater than 35um, the average particulate diameter of graphite powder can increase.
Natural graphite powder of the present invention can prepare by efflorescence, low speed nodularization and sorting.The efflorescence process can be produced separately and be satisfied the spherical graphite powder that requires according to the present invention, and promptly as long as the clearance gap quantity of closed ends C plane layer is at least 100 every micron to carry out efflorescence at a high speed at the C direction of principal axis.This preparation process is in following first process that is called.By first process, if used disintegrating apparatus, it is conventional equipment that shearing or impact or air-flow spiral pulverizer are preparation spherical graphite preferred equipment, then the quantity of clearance gap is that density is usually slightly larger than 100 every micron, for example, from 100 to 120 every micron, and can not reach the quantity of very high every micron clearance gap usually, for example, above 200.In second process, the natural graphite powder that makes above-mentioned like that efflorescence is in the low speed spheroidising, and is optimized under 100 to 1000 rev/mins condition and carries out spheroidising.This process can realize the space and the desired shapes of very large amount, for example, more than every micron 500 to 1500 order of magnitude, the shape approximation sphere.
The process of the natural spherical plumbago powder of the present invention's preparation is not limited to the first and second above-mentioned processes.Can adopt any process to produce graphite powder of the present invention, as long as finally can cause forming the graphite powder with C plane layer surface closed ends structure and high-tap density almost spherical, wherein the quantity that records clearance gap at the C direction of principal axis is 100 every micron at least.
The former natural graphite material that is used for nodularization is not conclusive, and can be the conventional any natural flake graphite powder of different manufacturers zones of different that uses.If carry out efflorescence later on, then may in the C of the graphite powder that forms by graphitization plane layer, cause forming of defective, and damage the surperficial closed ends structure of introducing by graphitization in the nodularization step.Therefore, in first process, as long as do not wish that graphite products is carried out any nodularization can diminish its particle.Thereby, in first process, before being used for spheroidising, should carry out efflorescence so that obtain the desired particle size of final graphite products, preferably as described above average particulate diameter between 10um to 50um.Yet, can after nodularization, supply to disperse the low power of usefulness to pulverize, or classification or sieve to remove particulate or to adjust average particulate diameter.Efflorescence comprises that any crushing process also has appreciable impact to the specific area of the graphite powder of final production.Along with the speed increase and the growth of efflorescence duration of used flour mill, specific surface area is tending towards increasing.The type of disintegrating apparatus influences the crystallite size of graphite products.Thereby, should select the type and the condition that is used for efflorescence of flour mill by considering the influence of its contrast surface area and graphite microcrystal size.Efflorescence can be undertaken by using conventional pulverizer flour mill, grinder to wait, and for example comprises hammer-mill, impact grinding, air-flow spiral pulverizer, Cyclonic pulverizer, atomizer mill, grinder and ball mill.Best, pulverizer is the impact grinding type, and an example is an impact grinder.As mentioned above, the condition influence that the microstructure of graphite crystal is used for efflorescence is bigger, particularly in first process, and should be carrying out efflorescence at a high speed, so that produce the graphite powder that in the closed ends structure, has 100 every micron or more clearance gap by this process.Be used for efflorescence to realize the actual conditions of this end, for example, the efflorescence speed of representing with revolution under the situation of rotary-type flour mill, become with the kind of pulverizer and the raw-material granular size of use with the efflorescence duration, and can be determined by experiment, thereby the graphite powder that generates has average particulate diameter, the shape of 100 every micron or more clearance gap and hope in the closed ends structure.
For example, pulverizer is enough to produce the graphite powder that has 100 every micron or more clearance gap in the closed ends structure by first process under 5000rpm or higher velocity of rotation.Quantity with lower velocity of rotation clearance gap can not often reach 100 every micron.In fact the highest velocity of rotation that can reach is generally 15000rpm.In the process of routine, efflorescence can continue the long period section on 30 the number of minutes magnitudes.Have less specific surface area in order to produce, the better graphite powder of shape, advantageously velocity of rotation does not increase De Taigao, and the efflorescence duration should be longer relatively.Coming the optimum condition of efflorescence with impact grinder is that speed with 3000-6000rpm reaches 30 to 60 minutes.
In second process, also high-speed like this efflorescence can be adopted, the graphite powder that in the closed ends structure, has the very high-density clearance gap might be produced thus, for example, on the order of magnitude of 500 every micron or more clearance gap.Yet, in second process,, needn't also be unfavorable for spheroidising simultaneously to carry out efflorescence at a high speed owing to can increase the density of clearance gap greatly by the efflorescence of first process.Thereby, for example can carry out efflorescence with the velocity of rotation of 100-2000rpm.Alternatively, can use shearing-type, extrusion pressing type pulverizer such as mechanical nodularization mill, carry out the efflorescence process with low per minute tens to the velocity of rotation that hundreds of changes that reaches, in second process, the selection degree of freedom of flour mill and efflorescence speed is bigger, and thereby easily be used for the condition of efflorescence with control, one can produce and has 7.0m
2The graphite powder of/g or littler specific surface area.
A kind of efflorescence that can adopt can the selection technology be that the mechanical type impact grinding is used in combination or the mechanical nodularization impact grinding of independent use in second process with high speed disintegrator in first process.In this case, the high speed disintegrator that uses in first process should be as described above with at a high speed promptly, 3000rpm or higher operation.Machinery nodularization impact grinding machine is finished it and is pulverized function, mainly by utilization the irregular part of grain edges is applied shearing and modifies shaping.Therefore, in order to make such crushing process easier, be preferably in to pulverize at a high speed and finish afterwards the mechanical shock mill to be used for material with carbon element.Use the advantage of mechanical nodularization impact grinding to be, be easy to control crystallite size, special in bigger size, also have than the homogeneous granules size at powder with efflorescence.
By using the technology of just having mentioned, might in addition by first process, promptly in the closed ends structure, have 1000 every micron or more clearance gap, promptly have the graphite powder of utmost point low tone distance or high tap density by promptly using high speed disintegrator to use mechanical nodularization impact grinding to produce again.
Natural spherical plumbago powder by high speed efflorescence and low speed nodularization sorting has the clearance gap of being a bit larger tham 100 every micron in the closed ends structure, except high speed disintegrator and the combination of mechanical shock mill are used for the situation of efflorescence, cause the quantity of clearance gap to enlarge markedly.Here it is by the graphite powder according to first process according to the present invention preparation.Although the quantity of clearance gap is a bit larger tham 100 every micron, to compare in the graphite powder that has less than every micron 100 clearance gap, this graphite powder has significantly improved discharge capacity.Can or sieve the graphite powder classification for preparing by first or second process to adjust average particle size particle size.The time that can carry out classification is not limited to the end of process.Any stage after efflorescence can carry out, and can repeat one or many.
Spherical graphite powder of the present invention can be used for the same use with conventional graphite powder.Because it has the clearance gap of increase quantity, it is the closed ends structure of the graphite linings lattice C plane layer of every micron 100 to 150 clearance gap, clearance gap mainly enters the place as lithium ion, so graphite powder can show the improved function that is mingled with, and receive the lithium ion of increase therein.Graphite powder of the present invention is suitable for use as the material of lithium ion secondary battery negative pole, and because graphite powder receives the ability of the lithium ion of increase, it can provide improves the assembling lithium rechargeable battery that discharge capacity surpasses conventional batteries.The closed ends structure of graphite powder C plane layer makes electrolyte solution be not easy to infiltrate graphite powder, the cycle life when having prolonged battery recharge and discharge cycles thus.Have in the most preferred embodiment of low specific surface area at graphite, also improved the charge/discharge enclosed pasture efficient of battery.
Embodiment one, prepares the graphite powder with surperficial closed ends structure of the present invention by first process.Get native graphite 32 order 200kg, use high speed disintegrator, a kind of high-speed rotary pulverizer with 16 or 24 hammers, efflorescence is 10 minutes under the 6000rpm velocity of rotation, the graphite powder that generates was handled 40 minutes under the 3000rpm velocity of rotation with low velocity impact formula nodularization pulverizer again, and the graphite powder of generation is by grader sorting extremely positive 5um and negative 75um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 25um of average particulate diameter of graphite powder in each batch.Be used for producing as follows electrode at the graphite powder of each batch preparation, in being used as the N-N-methyl 2-pyrrolidone N-alkane of solvent, mix the graphite powder of 90 parts of weight and the vinylidene of 10 parts of weight, to produce the mucilage material useful to the production of lithium ion secondary battery negative pole.The mucilage material is coated on the copper foil plate with 20um thickness as current-collector with homogeneous thickness with scalpel.After drying, overlay is with 1ton/cm
2Pressure cold pressing, and down further dry at 120 ℃ in a vacuum.The synthetic material that generates is cut into the sheet of a centimeter square, and these sheets are as the negative pole of test.In the primary cell of the negative pole that has test, carry out the estimation of negative pole, and measurement electrode and reference electrode there are all lithium to make by constant current charge and discharge test.The non-aqueous electrolytic solution of using in primary cell is the 1MLiCLO4 solution (1: 1 volume ratio) that is dissolved in the mixed solvent of ethylene carbonate and dimethyl carbonate.By with 0.3mA/cm
2Current density the primary cell initial charge to receiving lithium ion to allow negative pole with respect to Li reference electrode 0.0V voltage, by it being discharged into voltage with respect to lithium reference electrode 1.5V so that lithium ion is discharged in the solution, test primary cell subsequently with identical current density.Recharge and discharge cycles ten times are measured discharge capacity in each discharge cycles.Mean value from the second time to the tenth discharge capacity that discharge cycles records is illustrated in the table 1.The percentage of charging/hall, the room enclosed pasture efficient of the expression electric weight that to be the electric weight of emitting in first discharge cycles need with respect to charging in first charging cycle in table 1.Be sorted into positive 5um after the negative 75um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 550 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment two, prepare the graphite powder with surperficial closed ends structure of the present invention by first process.By getting native graphite 200 order 200kg with a kind of high-speed rotary pulverizer with 16 or 24 hammers of high speed disintegrator, efflorescence is 20 minutes under the 5500rpm velocity of rotation.The graphite powder that generates was handled 60 minutes under the 2500rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 5um and negative 63um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 23um of average particulate diameter of graphite powder in each batch.Be sorted into positive 5um after the negative 63um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 660 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment three, prepare the graphite powder that has according to surperficial closed ends structure of the present invention by first process.By getting native graphite 325 order 200kg high speed disintegrators, a kind of high-speed rotary pulverizer with 16 or 24 hammers, efflorescence is 30 minutes under the 5000rpm velocity of rotation.The graphite powder that generates was handled 80 minutes under the 2000rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 6um and negative 60um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure, the about 21um of average particulate diameter of graphite powder in each batch.Be sorted into positive 6um after the negative 60um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 750 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment four, prepare the graphite powder that has according to surperficial closed ends structure of the present invention by first process.By getting native graphite 325 order 200kg high speed disintegrators, a kind of high-speed rotary pulverizer with 16 or 24 hammers, efflorescence is 40 minutes under the 4500rpm velocity of rotation, and the graphite powder of generation was handled 100 minutes under the 1800rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 6um and negative 56um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 20um of average particulate diameter of graphite powder in each batch.Be sorted into positive 6um after the negative 56um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 790 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment five, prepare the graphite powder that has according to surperficial closed ends structure of the present invention by first process.By getting native graphite 200 order 200kg, use high speed disintegrator, a kind of high-speed rotary pulverizer with 16 or 24 hammers, efflorescence is 50 minutes under the 4000rpm velocity of rotation.The graphite powder that generates was handled 120 minutes under the 1500rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 6um and negative 55um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 19um of average particulate diameter of graphite powder in each batch is sorted into positive 6um after the negative 55um at the graphite powder that efflorescence is handled, and is used for making the electrode that is used for testing with the same way as of description in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 810 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment six, prepare the graphite powder that has according to surperficial closed ends structure of the present invention by first process.By getting native graphite 325 order 200kg high speed disintegrators, a kind of high-speed rotary pulverizer with 16 or 24 hammers, efflorescence is 60 minutes under the 3600rpm velocity of rotation.The graphite powder that generates was handled 140 minutes under the 1200rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 6um and negative 53um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 18um of average particulate diameter of graphite powder in each batch.Be sorted into positive 6um after the negative 53um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 830 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment seven, prepare the graphite powder that has according to surperficial closed ends structure of the present invention by first process.By getting native graphite 200 order 200kg high speed disintegrators, a kind of high-speed rotary pulverizer with 16 or 24 hammers, efflorescence is 70 minutes under the 3300rpm velocity of rotation.The graphite powder that generates was handled 160 minutes under the 900rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 6um and negative 50um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 17um of average particulate diameter of graphite powder in each batch.Be sorted into positive 6um after the negative 50um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 890 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Embodiment eight, prepare the graphite powder that has according to surperficial closed ends structure of the present invention by first process.By getting native graphite 200 order 200kg, use high speed disintegrator, the efflorescence 80 minutes under the 3000rpm velocity of rotation of a kind of high-speed rotary pulverizer with 16 or 24 hammers.The graphite powder that generates was handled 180 minutes under the 600rpm velocity of rotation with low velocity impact formula nodularization pulverizer again.The graphite powder that generates is by grader sorting extremely positive 7um and negative 44um and be used for making electrode.The distribution of sizes of graphite powder of sieving uses laser diffraction/scattering distribution of sizes analyzer to measure.The about 15um of average particulate diameter of graphite powder in each batch.Be sorted into positive 7um after the negative 44um at the graphite powder that efflorescence is handled, be used for making the electrode that is used for testing with the same way as of describing in the example 1.For discharge capacity and charge/discharge coulombic efficiency that graphite powder obtains, the related data that reaches about powder is illustrated in the table 1.The graphite powder that obtains in this example has every micron 990 clearance gap in the closed ends structure, can increase the quantity of clearance gap by adopting the low speed efflorescence, makes two C planes away from each other be carried out to the possibility that connects less thus.
Table 1
| Instance number | Pulverizing speed rpm | Efflorescence time minute | Nodularization speed rpm | Nodularization time minute | Specific area m 2/ ??g | Tap density g/m l | Pattern is described | Particle size distribution um | Average grain diameter um | Discharge capacity mAh/g | Charge/discharge coulombic efficiency (%) |
| Example 1 | ?600 ?0 | ??10 | ??300 ??0 | ??40 | ??4.6 ??3 | ??0.9 ??5 | The pattern almost spherical has irregularly shaped | ??5-7 ??5 | ????25. ????29 | ????342 | ????85 |
| Example 2 | ?550 ?0 | ??20 | ??250 ??0 | ??60 | ??5.1 | ??0.9 ??6 | ??5-6 ??3 | ????23. ????3 | ????348 | ????85.3 | |
| Example 3 | ?500 ?0 | ??30 | ??200 ??0 | ??80 | ??5.3 | ??0.9 ??6 | ??6-6 ??0 | ????21. ????6 | ????347 | ????86.1 | |
| Example 4 | ?450 ?0 | ??40 | ??180 ??0 | ??100 | ??5.5 ??3 | ??0.9 ??5 | ??6-5 ??6 | ????20. ????03 | ????352 | ????87.8 | |
| Example 5 | ?400 ?0 | ??50 | ??150 ??0 | ??120 | ??5.9 ??2 | ??0.9 ??7 | ??6-5 ??5 | ????19. ????63 | ????347 | ????88.1 |
| Example 6 | ?360 ?0 | ??60 | ??120 ??0 | ??140 | ??6.3 ??1 | ???0.9 ???8 | Shape is better, uniform particles | ???6-5 ???3 | ??18. ??32 | ??350 | ????89 |
| Example 7 | ?330 ?0 | ??70 | ??900 | ??160 | ??6.5 ??6 | ???1.0 ???1 | ???6-5 ???0 | ??17. ??16 | ??360 | ????90.3 | |
| Example 8 | ?300 ?0 | ??80 | ??600 | ??180 | ??6.9 ??3 | ???1.0 ???5 | ???7-4 ???4 | ??16. ??09 | ??352 | ????89.6 |
Native graphite of the present invention is the natural flake graphite that phosphorus content is 90-99.99%.As seeing by table 1, have 100 every micron or more a plurality of clearance gap in the surperficial closed ends structure of graphite linings lattice of the present invention, be used from those graphite powders of effect that lithium ion enters the place, narrow distributed area, high tap density, when being used for lithium rechargeable battery, can produce the high discharge capacity that surpasses 340mAh/g.
How closely knit the tap density of powder be can be filled into index to powder in given volume, and it influences the energy density of electrode per unit volume.For this reason, measure the packing density of each part of graphite powder according to the bulk density method of measurement of JIS Z500 regulation.
Reducing of graphite powder average particulate diameter during particularly less than 5um, causes the reduction of charge/discharge coulombic efficiency and the packing density of electrode to reduce.When the average particulate diameter of graphite during greater than 35um, the stability on the pole plate reduces.
Because well the tamping of high discharge capacity and charge/discharge coulombic efficiency and graphite powder (high-tap density), be equipped with by according to the present invention, the lithium rechargeable battery of the negative pole that the graphite powder of 100 or more a plurality of clearance gap forms is arranged in the closed ends structure of surface, show high battery capacity.In addition, owing to there is not the closed ends structure of C plane layer of the graphite powder of open end, this closed ends structure battery has excellent cycle performance.Thereby, confirmed wherein to use all batteries in the example of graphite powder according to the present invention, in the last circulation of 200 cycle chargings that repeat and discharge test, can keep at least 80% peak capacity.
On the contrary, wherein use in the comparative example that has in the closed ends structure less than the graphite powder of 100 clearance gap, battery capacity and cycle performance all reduce significantly.
According to the present invention, can prepare the graphite powder of surperficial closed ends structure with graphite C plane layer, wherein the closed ends structure has the clearance gap that increases quantity, mainly enters the place as lithium ion.Make the material of lithium ion secondary battery negative pole with graphite powder, make a kind of lithium rechargeable battery that has the good circulation life-span and surpass 320 high discharge capacity of assembling have high charge/discharge coulombic efficiency.Therefore, the present invention will help to improve the performance of lithium rechargeable battery, it is a kind of high capacity lithium ion cells cathode preferred raw materials, this kind material is through obtaining the negative material of a kind of high power capacity, high efficiency, good cycle after the surface modification treatment, this kind material is because the capacity height, cheap, be a kind of desirable negative material.Along with, the fast development of lithium battery, this material will substitute MCMB and other Delanium.
Claims (7)
1. the graphite powder that uses of a lithium ion secondary battery negative pole is characterized in that: described graphite powder be shaped as sphere, have the closed end construction in surface.
2. the graphite powder that lithium ion secondary battery negative pole according to claim 1 uses, it is characterized in that: described graphite C plane layer has closed end on the graphite powder surface that forms by the paired end that connects the C plane layer, the space of opening is arranged on graphite surface simultaneously.
3. the graphite powder that lithium ion secondary battery negative pole according to claim 2 uses, it is characterized in that: the quantity that described graphite C direction of principal axis records clearance gap is 100 to 1500 for every micron.
4. the graphite powder that lithium ion secondary battery negative pole according to claim 3 uses is characterized in that: it is 5 to 75um that described graphite powder has particle size distribution, and tap density is 0.95 to 1.05 grams per milliliter, the specific surface area of 4 to 7.5 meters squared per gram.
5. the preparation method of the graphite powder that uses of a lithium ion secondary battery negative pole, adopt following steps: (1) is 32 to 325 orders with granularity, phosphorus content is the natural flake graphite of 90-99.99%, join in the high speed disintegrator by automatic feeding system, efflorescence is 10 to 80 minutes under 3000 to 6000 rev/mins of conditions; (2) graphite powder that makes is joined in the low velocity impact formula nodularization pulverizer, the nodularization shaping was handled 40 to 180 minutes under 600 to 3000 rev/mins of conditions, obtained spherical graphite.
6. the preparation method of the graphite powder that lithium ion secondary battery negative pole according to claim 5 uses, it is characterized in that: described spherical graphite will wherein be removed less than the subparticle of 5um with greater than the gradation of 75um by grader again, obtain particle size distribution and be 5 to 75um, tap density is 0.95 to 1.05 grams per milliliter, and specific area is the spherical graphite of 4 to 7.5 meters squared per gram.
7. the preparation method of the graphite powder that lithium ion secondary battery negative pole according to claim 6 uses, it is characterized in that: described high speed disintegrator is airslide disintegrating mill, high pressure flour mill or bar type mechanical crusher, low speed nodularization pulverizer is low velocity impact formula nodularization pulverizing, air-flow vortex pulverizing mill, micronizer, ultra micro ball mill, internal classification impact type micro mist pulverizer, pendulum type ring roll pulverizer, grader are gas flow sizing machine, jetting type grader, sub-micron grader or ultra micro rice gas flow sizing machine.
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| WO2006125358A1 (en) * | 2005-05-27 | 2006-11-30 | Btr Energy Materials Co., Ltd. | A composite carbon material of negative electrode in lithium ion battery and its preparation method |
| CN101392105A (en) * | 2007-09-18 | 2009-03-25 | 青岛泰达天润碳材料有限公司 | Spherical graphite processing method and equipment system thereof |
| CN102224623A (en) * | 2009-08-05 | 2011-10-19 | 松下电器产业株式会社 | Non-aqueous electrolyte secondary cell |
| CN102347481A (en) * | 2011-10-14 | 2012-02-08 | 黑龙江省牡丹江农垦奥宇石墨深加工有限公司 | Superfine spherical graphite as well as preparation method and application thereof |
| CN102800854A (en) * | 2012-09-03 | 2012-11-28 | 湛江市聚鑫新能源有限公司 | Modification method of natural crystalline flake graphite for lithium-ion battery |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2163899C (en) * | 1994-04-08 | 2007-09-18 | Atsuo Omaru | Non-aqueous electrolyte secondary battery |
| JPH08315817A (en) * | 1995-05-17 | 1996-11-29 | Sony Corp | Manufacture of carbon negative electrode material and nonaqueous electrolyte secondary battery |
| JP3698181B2 (en) * | 1996-12-04 | 2005-09-21 | 住友金属工業株式会社 | Negative electrode material for lithium ion secondary battery |
| TW399029B (en) * | 1996-12-25 | 2000-07-21 | Sony Corp | Graphite powder suitable for negative electrode material of lithium ion secondary batteries |
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2004
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| CN114229840B (en) * | 2022-01-07 | 2023-10-20 | 五星新材科技有限公司 | Fine particle natural graphite synthesizer |
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