CN101540397B - Graphite particles - Google Patents
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- CN101540397B CN101540397B CN2009101182203A CN200910118220A CN101540397B CN 101540397 B CN101540397 B CN 101540397B CN 2009101182203 A CN2009101182203 A CN 2009101182203A CN 200910118220 A CN200910118220 A CN 200910118220A CN 101540397 B CN101540397 B CN 101540397B
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- graphite granule
- graphite
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- 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 present invention provides a graphite particle for lithium secondary cell cathode, which is characterized in that when applying the mixture of the graphite particles and the organic binder, the graphite particles are uneasy to be oriented in the plane direction of current collector. The invention further provides a graphite particle for lithium secondary cell cathode, which is capable of releasing and absorbing ions in using process. Pores are provided in the graphite particles, which is capable of absorbing the expansion and contraction of the electrode due to ion absorbing and releasing. The invention further provides a graphite particle for lithium secondary cell cathode, which comprises parts that the planes of orientation were not parallel to one another.
Description
The application is for dividing an application, and the application number of its female case application is 200610095986.0, and the applying date is on August 7th, 1997, and denomination of invention is " graphite granule ".
The present invention relates to a kind of novel graphite particle, a kind of method of producing said novel graphite particle, a kind of graphite thickener that uses said graphite granule, a kind of negative pole that is used for lithium secondary battery that uses said graphite thickener, a kind of method of producing said negative pole, and a kind of lithium secondary battery.More specifically, the present invention relates to a kind of lithium secondary battery that is applicable to portable instrument, electric automobile, electrical power storage etc., it has the fast charging and discharging performance of excellence and excellent cycle performance etc., the invention still further relates to a kind of graphite granule as its negative pole, a kind of method of producing said graphite granule, a kind of graphite thickener that uses said graphite granule, a kind of negative pole that is used for lithium secondary battery that uses said graphite thickener, and a kind of method of producing said negative pole.
As the graphite granule of prior art, can be natural graphite particles, the Delanium particle of the Delanium particle by coke graphitization preparation, the graphitization preparation by organic polymer and pitch etc., by pulverizing graphite granule that these graphite obtain etc.By graphite granule and organic bond and organic solvent are mixed with a kind of graphite thickener, with said graphite thickener coating Copper Foil, evaporate said solvent then, can be the negative pole of these graphite granules as lithium secondary battery.For example, in JP-B 62-23433, plan by using graphite to eliminate as negative pole because the internal short-circuit problem that the skeleton of lithium causes and improve said cycle performance.
But, in the natural graphite particles of the good growth of graphite crystal therein and in the Delanium particle that the graphitization by coke prepares, interlayer adhesion on the c of crystal direction of principal axis is lower than the adhesion on crystal plane direction, so, destroyed the combination between the graphite linings when pulverizing, formation has the what is called " sheet-like particle " of wide aspect ratio.Form electrode on the current collector if the exfoliated graphite particles of wide aspect ratio mixed with adhesive and be coated to, said exfoliated graphite particles aligns in the face direction of current collector.As a result and since lithium enter graphite crystal repeat absorb and discharge, on the c direction of principal axis, produce strain, cause the internal sabotage of electrode.Therefore, said cycle period worsens, and said fast charging and discharging performance also is tending towards variation.
And the graphite granule that has the prior art of megacryst size in crystal plane direction needs the long time to carry out the absorption and the release of lithium.In addition, the exfoliated graphite particles of the prior art of wide aspect ratio has bigger specific area.Therefore, the lithium secondary battery that is obtained is having bigger irreversible capacity in the circulation for the first time, and such graphite granule is poor to the associativity of current collector, thereby needs a large amount of bonds.If the associativity to current collector is bad, then bad and discharge capacity, fast charging and discharging performance and cycle performance deterioration of electric current collection effect.Therefore, wish a kind of graphite granule of exploitation, when making lithium secondary battery, its fast charging and discharging performance and cycle performance excellence, perhaps the irreversible capacity in circulation for the first time is little and cycle performance is excellent, and perhaps the irreversible capacity in circulation for the first time is little and can improve fast charging and discharging performance and cycle performance.
The invention provides the graphite granule that addresses the above problem and be applicable to as the negative pole of lithium secondary battery with fast charging and discharging performance and cycle performance excellence.
The present invention also provides the negative pole that is applicable to and lithium secondary battery that cycle performance excellent little as the reversible capacity that circulates for the first time.
The present invention also provides a kind of production to be applicable to method as the graphite granule of the negative pole of lithium secondary battery, said secondary cell fast charging and discharging performance and cycle performance excellence, perhaps for the first time the irreversible capacity of circulation is little and cycle performance is excellent, perhaps irreversible capacity little and the fast charging and discharging performance and the cycle performance excellence of circulation for the first time.
The present invention also provides a kind of graphite thickener that is applicable to as the negative pole of lithium secondary battery, said lithium secondary battery fast charging and discharging performance and cycle performance excellence, perhaps for the first time the irreversible capacity of circulation is little and cycle performance is excellent, perhaps irreversible capacity little and the fast charging and discharging performance and the cycle performance excellence of circulation for the first time.
The present invention also provides a kind of negative pole of lithium secondary battery of high power capacity, said lithium secondary battery fast charging and discharging performance and cycle performance excellence, perhaps for the first time the irreversible capacity of circulation is little and cycle performance is excellent, perhaps irreversible capacity little and fast charging and discharging performance and the cycle performance excellence that circulates for the first time, and a kind of method of producing said negative pole.
The present invention also provides a kind of lithium secondary battery of high power capacity, said lithium secondary battery fast charging and discharging performance and cycle performance excellence, perhaps for the first time the irreversible capacity of circulation is little and cycle performance is excellent, perhaps irreversible capacity little and the fast charging and discharging performance and the cycle performance excellence of circulation for the first time.
Graphite granule of the present invention has following feature (1)～(6).
(1), makes the not parallel each other graphite granule that obtains of the crystal face that aligns of particle of each writing board shape the particle of a plurality of writing board shapes combination or combine.
(2) said graphite granule aspect ratio is 5 or littler graphite granule.
(3) its specific area is 8m
2/ g or littler graphite granule.
(4) crystalline size on the c of crystal direction of principal axis (thickness direction) is 500 dusts or bigger, is of a size of 1,000 dust or littler graphite granule on crystal plane direction, and these two sizes are measured by the wide angle of X ray diffraction.
(5) weight with graphite granule is benchmark, and size is 10
2～10
6The pore volume of dust is 0.4～2.0cc/g.
(6) weight with graphite granule is benchmark, and size is 1 * 10
2～2 * 10
4The pore volume of dust is 0.08～0.4cc/g.
The invention still further relates to a kind of method of producing above-mentioned graphite granule, be characterised in that can graphited aggregation (raw material), graphite, can graphited adhesive and the graphitization catalyst of 1～50wt% mix, calcine and pulverize said mixture then.
The invention still further relates to a kind of graphite thickener, by in above-mentioned graphite granule or the graphite granule produced by said method, adding a kind of organic bond and solvent, and the said mixture of homogenizing and obtaining.
The negative pole that is used for lithium secondary battery of the present invention passes through to use above-mentioned graphite thickener production, and has following feature (1)～(3).
(1) a kind of negative pole that is used for lithium secondary battery obtains by applying above-mentioned graphite thickener and form an integral body on a current collector.
(2) a kind of negative pole that is used for lithium secondary battery, by the mixture of a kind of graphite granule and organic solvent and current collector integration are obtained, wherein, suppress and the density of the mixture of the graphite of integration and organic bond is 1.5～1.9g/cm
3
(3) a kind of negative pole that is used for lithium secondary battery, by the mixture of a kind of graphite granule and organic bond and a kind of current collector integration are obtained, wherein, the content of said organic bond is that benchmark is 3～20wt% with said mixture.
The invention still further relates to a kind of production and be used for the method for negative pole of the lithium secondary battery of (2), be characterised in that to a kind of can graphited aggregation or graphite and a kind of graphitization catalyst that adds 1～50wt% in can graphited adhesive, the said mixture of homogenizing, calcine said mixture, broken back obtains graphite granule, in said graphite granule, add a kind of organic bond and a kind of organic solvent, said mixture is coated on a kind of current collector, evaporate said solvent, then compacting and integration.
In addition, the present invention relates to a kind of lithium secondary battery, comprise a shell, lid, at least one pair of positive and negative electrode, said shell, lid and electrode are installed by the isolation of dividing plate, near said shell, lid and electrode, provide electrolyte solution, wherein, said negative pole is with above-mentioned graphite granule manufacturing.
Figure 1A and 1B are the scanning electron microscopy pictures of graphite granule of the present invention, and wherein, Figure 1A is the image of the outer surface of said particle, and Figure 1B is the image in the cross section of said particle
Fig. 2 is the front view of the partial cross section of cylindrical lithium secondary battery.
Fig. 3 is the figure that concerns between expression discharge capacity and the charge and discharge cycles number of times.
Fig. 4 is illustrated in the figure that concerns between discharge capacity and the charging and discharging currents.
Fig. 5 is the profile diagram of one embodiment of the present of invention.It is the lithium secondary battery that is used to measure charge-discharge performance and irreversible capacity.
Graphite granule of the present invention can be divided into six kinds according to its feature.
First kind of particle of the present invention is a kind of a plurality of tabular particle combination or combines, thereby make each other uneven graphite granule of its crystal face that aligns.
In the present invention, term " tabular particle " refers to be shaped as the particle with a major axis and a minor axis, and namely its shape is not desirable sphere. For example, this particle comprises the part of flake shaped particle, laminar particle and blocky-shaped particle.
" crystal face that align mutually be not parallel to each other " of term in a plurality of tabular particles refers to that a plurality of groups of grains are combined the state that its crystal face that aligns is not arranged in one direction when the flat crystal face of each particle or near even curface during as a crystal face that aligns.
From component material, each tabular particle is preferably by forming or be made up of graphite by graphited raw material (aggregation).
In above-mentioned graphite granule, said tabular particle makes up or combines. It is a kind of state of instigating Particle Phase to combine by intermediate mediums such as adhesives between mutually that term " combines ", term " combination " refers to a kind of state that particle flocks together owing to factors such as its shapes, and each particle does not combine by intermediate mediums such as adhesives. From the viewpoint of mechanical strength, the particle that combines is preferred.
The size of single tabular particle is 1～100 μ m preferably, and more preferably 1～50 μ m represents with average particulate diameter. Preferably 2/3 of the single tabular particle of this size average particle size particle size that is graphite granule said combination or that combine or littler, make up or the quantity of the tabular particle that combines preferably 3 or more. In the present invention, said average particle size particle size can be used laser light scattering particle Size Distribution analysis-e/or determining.
If such graphite granule is as negative pole, said graphite crystal is not easy to align at current collector, and lithium absorbs easily in the negative pole that enters said graphite formation and therefrom discharges easily. Therefore, can improve charge-discharge performance and the cycle performance of the lithium secondary battery that obtains.
Figure 1A and 1B are the scanning electron microscopy pictures of graphite granule of the present invention, and wherein, Figure 1A is the scanning electron microscopy picture of the outer surface of graphite granule of the present invention, and Figure 1B is the scanning electron microscopy picture in the cross section of graphite granule of the present invention. In Figure 1A, can observe, many exfoliated graphite particles combine, and its crystal face that aligns is not parallel to each other mutually, form a kind of graphite granule.
Second graphite granule of the present invention is that a kind of aspect ratio is 5 or littler graphite granule, and when using this graphite granule, particle aligning on current collector is difficult to realize that so be similar to above-mentioned situation, lithium is absorbed easily and discharges.
Said aspect ratio is preferably in 1.2～5 scope. Less than 1.2 o'clock, the contact area between the particle reduced in said aspect ratio, so the electric conductivity reduction, and owing to above-mentioned same reason, the preferred scope of aspect ratio is 1.3 or bigger.
On the other hand, the upper limit of said aspect ratio is 5, preferably 3 or littler, when said aspect ratio greater than 5 the time, fast charging and discharging performance aggravates. Therefore, the most preferred numerical value of said aspect ratio is 1.3～3.
If graphite granule represents with A in the length of long axis direction, represent with B that in the length of short-axis direction then aspect ratio represents with A/B. In the present invention, by amplifying graphite granule at microscopically, select at random 100 particles, measure its A/B and calculate its mean value and determine aspect ratio.
Aspect ratio be 5 or littler graphite granule in, combination or bond material with graphite granule of reduced size are preferred.
The third graphite granule of the present invention is that a kind of specific area is 8m2/ g or littler graphite granule. Said specific area is 5m preferably2/ g or littler, more preferably 1.5～5m2/ g, further preferably 2～5m2/ g. By using such graphite granule as negative pole, can improve fast charging and discharging performance and the cycle performance of the lithium secondary battery of gained, and reduce the irreversible capacity in for the first time circulation. If said specific area is greater than 8m2/ g, the irreversible capacity height of the circulation first time of the lithium secondary battery of gained, energy density is low, and exists the preparation negative pole need to use the problem of a large amount of adhesives. On the other hand, if said specific area less than 1.5m2/ g, fast charging and discharging performance and the cycle performance of the lithium secondary battery of gained aggravate. Said specific area can be passed through the known method mensuration such as BET (nitrogen adsorption method).
The 4th kind of particle of the present invention is that a kind of crystalline size Lc of the c-axis at crystal (002) direction of measuring with the wide angle of X ray diffraction approach is 500 dusts or bigger, and the crystalline size La on crystal plane direction (110) is 1,000 dust or littler graphite granule. By using such graphite granule as negative pole, can improve fast charging and discharging performance and the cycle performance of the lithium secondary battery of gained. Crystalline size Lc on c-axis (002) direction of crystal is preferably 1,000～100, in the scope of 000 dust, suppose and surpass 3, the Lc of 000 dust can not use the wide angle of X ray diffraction Accurate Measurement, and the crystalline size on the crystal plane direction (110) of said crystal is preferably at 800～50 dusts.
If the crystalline size Lc (002) on the c-axis direction is less than 500 dusts, perhaps at the size La (110) of said crystal plane direction greater than 1,000 dust, charging capacity diminishes.
In the 4th kind of graphite granule, the interlamellar spacing d (002) of the crystal by the wide angle of the X ray of graphite granule diffraction is 3.38 dusts or littler preferably, more preferably at 3.37～3.35 dusts. If the interlamellar spacing d of crystal (002) surpasses 3.38 dusts, charging capacity is tending towards reducing.
The 5th kind of graphite granule of the present invention be characterised in that, take the weight of graphite granule as benchmark, pore size is 102～10
6Pore volume in the dust scope is 0.4～2.0cc/g. By using such graphite granule as negative pole, expansion and the contraction of electrode when discharging and recharging absorbed by the pore of graphite granule, therefore can suppress the internal sabotage of electrode, thereby improve the cycle performance of the lithium secondary battery that obtains. Pore size is 102～10
6Pore volume in the dust scope is more preferably in 0.4～1.5cc/g scope, further preferably in 0.6～1.2cc/g scope. If total pore volume is less than 0.4cc/g, cycle performance is bad. If total pore volume greater than 2.0cc/g, makes the integration of graphite granule and current collector need a large amount of adhesives, this has reduced the capacity of the lithium secondary battery of producing. Said pore volume can be determined by the hole diameter distribution measuring that mercury apertometer method is carried out. Pore size also can be by determining with the pore size distribution measuring of mercury apertometer method.
The 6th kind of graphite granule of the present invention is characterised in that weight take graphite granule as benchmark, and pore size is 1 * 102～2×10
4Pore volume in the dust scope is in 0.08～0.4cc/g scope. If use such graphite granule as negative pole, expansion and the contraction of electrode when discharging and recharging absorbed by the pore of graphite granule, therefore can suppress the internal sabotage of electrode, thereby improve the cycle performance of the lithium secondary battery that obtains. Pore size is 1 * 102～2×10
4Pore volume in the dust scope is more preferably in 0.1～0.3cc/g scope. If the pore volume of size in this scope is less than 0.08cc/g, cycle performance is bad. If the pore volume of size in this scope greater than 4cc/g, makes graphite granule and current collector integration need a large amount of adhesives, this has reduced the capacity of the lithium secondary battery of gained. The volume of the pore of size in this scope also can be by determining with the pore size distribution measuring of mercury apertometer method.
In six kinds of graphite granules of above-mentioned second to the of the present invention, preferably said graphite granule has the feature of first kind of graphite granule, and namely said graphite granule is the mutual uneven graphite granule of crystal face that a kind of wherein a plurality of tabular particles make up or combine it is aligned. If with such graphite granule as negative pole, can not easily realize said graphite crystal aligning on current collector, promote lithium to enter absorption and the release of lithium from negative pole graphite of negative pole graphite, can further improve fast charging and discharging performance and the cycle performance of said lithium secondary battery.
First kind of graphite granule equally preferably of the present invention and the third～the 6th kind of graphite granule has the feature of second kind of graphite granule of the present invention, the aspect ratio that is them is 5 or littler, because this makes that particle aligning on current collector is difficult to realize, similar to above-mentioned content, promoted the absorption and the release of lithium.The aspect ratio of said graphite granule preferably 3 or littler.The lower limit of said aspect ratio preferably 1.2 or bigger, more preferably 1.3 or bigger.
First kind and second kind of graphite granule equally preferably of the present invention and the 4th kind～the 6th kind graphite granule have the feature of the third graphite granule of the present invention, and promptly their specific area is 8m
2/ g or littler, more preferably 5m
2/ g, further preferably 2～5m
2/ g.Also have a kind of trend, if said specific area further increases, the irreversible capacity of prepared lithium secondary battery increases and energy density reduces.Also have a kind of trend, if said specific area increases, the irreversible capacity of not only prepared lithium secondary battery increases, and the amount of the needed adhesive of preparation negative pole also increases.
In addition; in first kind of the present invention～the third graphite granule and the 5th kind and the 6th kind of graphite granule; the interlamellar spacing d (002) of the crystal by the wide angle of the X ray of powdered graphite diffractometry preferably should be 3.38 dusts or littler; 3.37 dusts or littler more preferably are because littler interlamellar spacing d (002) has provided higher discharge capacity.On the other hand, the crystalline size Lc (002) on the c direction of principal axis preferably should be 500 dusts or bigger, and 1,000 dust or bigger more preferably is because bigger Lc (002) provides higher discharge capacity.
In addition, first kind preferably of the present invention～the 4th kind of graphite granule has the feature of the 5th kind and the 6th kind graphite granule of the present invention, be that they have pore volume corresponding to the pore of specific dimensions, because expansion and the contraction of electrode when discharging and recharging can be absorbed by the pore of graphite granule, therefore, the internal sabotage that can suppress electrode, so, the cycle performance of said lithium secondary battery can be improved.
In the present invention, the gravel size decision of first kind～the 6th kind of graphite granule be 1～100 μ m, more preferably 10～50 μ m represent with average particulate diameter.
Though making the method for the above-mentioned graphite granule that satisfies above-mentioned feature does not limit especially, such graphite granule can by to a kind of can graphited raw material or graphite with can the mixture of graphited adhesive in the graphitization catalyst that adds and mix 1～50wt%, calcine then and pulverize and obtain.By such process, in the space of having discharged said graphitization catalyst, form pore, thereby can give graphite granule of the present invention good performance.The amount of said graphitization catalyst is 3～20wt% preferably.
In addition, can be by the method for suitably selecting graphite or aggregation are mixed with adhesive, the amount of mixing ratio such as adhesive etc., and the pulverization conditions after calcining prepares every kind of above-mentioned graphite granule.
As can graphited raw material, can use the carbonization product of coke powder, resin etc., can unrestrictedly use any dusty material, as long as said dusty material can graphitization.In these dusty materials, can easily graphited coke powder, be preferred as needle coke etc.
As graphite, can use native graphite powder, Delanium powder etc.So long as pulverous, can use any graphite.Preferably can graphited raw material and the particle diameter of graphite less than the particle diameter of graphite granule produced according to the invention.
As graphite catalyst, can use metal and carbide and oxides such as iron, nickel, titanium, silicon, boron.In these graphitization catalyst, the carbide of silicon or boron and oxide are preferred.
The average particulate diameter of said graphitization catalyst is 150 μ m or littler preferably, more preferably 100 μ m or littler, further preferably 50 μ m or littler.When said average particulate diameter during greater than 150 μ m, the growth of crystal is tending towards inhomogeneous, and charge/discharge capacity is tending towards inhomogeneous.
Graphite granule with gained is a benchmark, and the addition of said graphitization catalyst is 1～50wt%, preferably 5～40wt%, more preferably 5～30wt%.If the amount of graphitization catalyst is less than 1wt%, the growth of graphite crystal can not be satisfactory, simultaneously, and the pore smaller volume in said graphite granule.On the other hand, if the amount of graphitization catalyst greater than 50wt%, machinability worsens, simultaneously, the pore volume in said graphite granule becomes too big.
As adhesive, organic materials such as tar, pitch, thermosetting resin, thermoplastic resin are preferred.With can graphited tabular raw material or graphite be benchmark, the amount of adhesive is 5～80wt% preferably, 10～80wt% more preferably, further preferably 15～80%.If the amount of said adhesive is too big or too little, the aspect ratio of said graphite granule and specific area have the trend that becomes too big.
A kind of can graphited aggregation or the graphite method of mixing with a kind of adhesive do not limit especially, and carry out said mixing with muller.Preferably, under the temperature of the softening point that is lower than said adhesive, carry out said mixing.Specifically, when said adhesive is pitch, tar etc., preferably carry out said mixing, when said adhesive is thermosetting resin, preferably carry out said mixing at 20～100 ℃ at 50～300 ℃.
Subsequently, the mixture that obtains above of calcining carries out graphitization processing.If necessary, before graphitization, can be shaped as desirable shape to said mixture.In addition, if necessary, can before graphitization processing, pulverize the mixture of formed thereby, particle diameter is adjusted to required value.Said calcining is preferably carried out under said mixture is difficult to the condition of oxidation.For example, said calcining is carried out in nitrogen, argon gas or vacuum.Preferably 2,000 ℃ or higher of said graphited temperature, more preferably 2,500 ℃ or higher, further preferably 2,800～3,200 ℃.
If said graphited temperature is too low, graphite crystal is grown unsatisfactorily, and said graphitization catalyst is tending towards being retained in the said graphite granule.If said graphitization catalyst is retained in the prepared graphite granule, then discharge capacity reduces.If graphited temperature is too high, the distillation of graphite may take place.
Preferably in step subsequently, pulverize the graphited product that is obtained.The breaking method of said graphitization product does not limit especially, but can use jet mill, vibration milling, rod mill, hammer mill etc.Average particulate diameter after the pulverizing is 1～100 μ m preferably, more preferably 10～50 μ m.If said average particulate diameter is too big, exists in electrode surface and form erose trend easily.
In the present invention, above-mentioned graphite granule 1～6 can obtain by above-mentioned step.
By being mixed with a kind of organic bond and a kind of organic solvent, above-mentioned graphite granule produces graphite thickener of the present invention.
As said organic bond, can use polyethylene, polypropylene, ethylene-propylene terpolymer, butadiene rubber, styrene butadiene rubbers, butyl, have the polymer of macroion conductivity etc.
As said polymer, can use polyvinylidene fluoride, polyethylene glycol oxide, Polyglycol 166-450, poly-phosphine piperazine, polyacrylonitrile etc. with macroion conductivity.
In these organic bonds, the polymer with macroion conductivity is preferred.Polyvinylidene fluoride is particularly preferred.
The graphite granule of the preferably per 100 parts of weight of mixing ratio between said graphite granule and the said organic bond is the organic bond of 3～10 parts of weight.
Said solvent does not limit especially.Can use organic solvents such as N-N-methyl-2-2-pyrrolidone N-, dimethyl formamide, isopropyl alcohol.
The amount of said solvent does not limit especially, as long as but can adjust to said graphite thickener the viscosity of requirement, can be content arbitrarily.Preferably, be benchmark with the graphite thickener, use the solvent of 30～70wt%.
The negative pole that is used for lithium secondary battery of the present invention is divided into three types roughly according to its feature.
First kind of negative pole that is used for lithium secondary battery of the present invention is characterised in that a kind of of the above-mentioned graphite granule of use.By being shaped as shapes such as thin slice, bead, said graphite thickener can obtain this negative pole that is used for lithium secondary battery.
Said graphite thickener is coated on a kind of current collector and with said current collector integration, form a kind of negative pole.
As said current collector, can use the paper tinsel or the net of nickel, copper etc.Can carry out said integration by the combination of using mould pressing method such as roll-in, compacting or these methods.
Second kind of negative pole that is used for lithium secondary battery of the present invention is characterised in that the mixture and a kind of current collector integration of a kind of graphite granule with organic bond, after said integration, the density of the mixture of said graphite granule and adhesive is 1.5～1.9g/cm
3, 1.55～1.85g/cm preferably
3, 1.6～1.85g/cm more preferably
3, 1.6～1.8g/cm further preferably
3The density of the graphite granule by increase constituting negative pole of the present invention and the mixture of adhesive, the lithium secondary battery that obtains from said negative pole can have the energy density of the unit volume of increase.If the density of the mixture of graphite granule and adhesive is greater than 1.9g/cm
3, said fast charging and discharging performance worsens.If said density is less than 1.5g/cm
3, the lithium secondary battery that is obtained has the energy density of reduction.
At the second kind of the present invention used graphite granule of negative pole that is used for lithium secondary battery can be any graphite, as long as can design its density in above-mentioned scope.Material beyond the above-mentioned graphite granule of the present invention also is operable as native graphite etc.Yet, in all these graphite granules, above-mentioned graphite granule of the present invention is particularly preferred, because when the density of the negative pole that increases prepared lithium secondary battery, use graphite of the present invention might improve discharge capacity, fast charging and discharging performance and cycle performance.
The mixing ratio of used organic bond, current collector and the solvent types of second kind of the present invention negative pole that is used for lithium secondary battery and these components can with used identical of first kind of the present invention negative pole that is used for lithium secondary battery.
For the density of the mixture that makes graphite granule and organic bond drops in the above-mentioned scope, preferably under the condition of exerting pressure, carry out the integration of the mixture of current collector and graphite and organic bond after integration.Said pressure can apply by roll or forcing press etc.
The negative pole that the third is used for lithium secondary battery of the present invention is characterised in that the weight with the mixture of graphite and organic bond is benchmark, and the amount of organic bond is 3～20wt%, preferably 11～20wt%.Make it in such scope by the amount of adjusting said organic bond, can make the discharge capacity of the negative pole that is used for lithium secondary battery of said mixture of Unit Weight higher.Mixture with graphite granule or organic bond is a benchmark, and the amount of said organic bond is 12～16wt% more preferably.If the amount of said organic bond is less than 3wt%, between the graphite granule and a little less than the adhesion between graphite granule and the current collector, therefore, resistance height on its interface, the conductivity of prepared lithium secondary battery is low, and the discharge capacity of the mixture of the discharge capacity of the graphite granule of Unit Weight and the graphite granule of Unit Weight and organic bond is low.In addition, said graphite granule expands when discharging and recharging and shrinks.Therefore, when repeating to discharge and recharge, destroying easily between the graphite granule and between graphite granule and current collector, therefore, cycle performance worsens.On the other hand, when the amount of said organic bond during greater than 20wt%, between the graphite granule and the organic bond that between graphite granule and current collector, has a large amount of low electric conductivities, therefore, the conductivity of negative pole reduces, the discharge capacity of the graphite granule of Unit Weight reduces, and the result reduces the discharge capacity of the mixture of Unit Weight graphite granule and organic bond.In addition, because said organic bond neither charges and does not also discharge, so, the addition of organic bond surpasses 20wt% makes the amount of the graphite granule in said mixture little of less than 80wt%, therefore, the discharge capacity of the mixture of Unit Weight graphite granule and organic bond diminishes.
Using above-mentioned graphite granule of the present invention is preferred as the graphite granule that the third is used for the negative pole of lithium secondary battery of the present invention, because when the negative pole that makes prepared lithium secondary battery has high density, thereby discharge capacity, fast charging and discharging performance and cycle performance have been improved.
Used organic bond, current collector and solvent types in the negative pole of the third lithium secondary battery of the present invention, the mold pressing parameter of the mixing ratio of these compositions and said current collector and said mixture can with used identical of first kind of the present invention negative pole that is used for lithium secondary battery.The same with second kind of negative pole that is used for lithium secondary battery, preferably select said mold pressing parameter to make that the density of mixture of integration of graphite granule and adhesive is 1.5～1.9g/cm
3
Every kind of negative pole of lithium secondary battery is installed, is made its intermediate medium that passes through a dividing plate relative, after this, pour a kind of electrolyte solution into a positive pole.By such process, can prepare a kind of lithium secondary battery, to compare with the lithium secondary battery of prior art, the capacity of said secondary cell is higher, charge-discharge performance and cycle performance are more superior, and irreversible capacity is littler.
The material that is used as the positive pole of lithium secondary battery of the present invention does not limit especially, can use LiNiO individually or with the form of mixture
2, LiCoO
2, LiMn
2O
4Deng.
As said electrolyte solution, can use by LiClO
4, LiPF
6, LiAsF
6, LiBF
4, LiSO
3CF
3Be dissolved in the so-called organic electrolyte solution for preparing in the nonaqueous solventss such as ethylene carbonate, diethyl carbonate, dimethoxy-ethane, dimethyl carbonate, oxolane, propylene carbonate Deng lithium salts.
As said dividing plate, for example, can use with nonwoven fabrics, cloth, microporous membrane and the combination thereof as main component such as polyethylene, polypropylene.
Fig. 2 represents the front view of partial cross section of an a kind of embodiment of cylindrical lithium secondary battery; Wherein, the 1st, anodal, the 2nd, negative pole, the 3rd, dividing plate, the 4th, positive terminal, the 5th, anode connector, the 6th, positive cover, the 7th, battery can, the 8th, sealing gasket.
Below with reference to embodiment and as required, accompanying drawing is explained the present invention.
(1) preparation of graphite granule
Is the average particulate diameter of 70 parts of weight that the iron oxide of the tar asphalt of the coke powder of 10 μ m, 20 parts of weight, 10 parts of weight and the coal tar of 20 parts of weight mix, and stirs 1 hour at 100 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 20 μ m.According to the scanning electron microscopy picture (SEM image) of the graphite granule that is obtained, the structure of said graphite granule makes its crystal face that aligns be not parallel to each other mutually for a plurality of tabular particles wherein combine.From the graphite granule that is obtained, select 100 particles at random, measure the mean value of its aspect ratio.The said mean value of result is 1.8.In the wide angle of the X ray diffraction of the graphite granule of gained, the interlamellar spacing d of said crystal (002) is 3.360 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.The specific area of measuring with the BET method is 3.5m
2/ g.
(2) preparation of lithium secondary battery
Prepare lithium secondary battery with shape shown in Figure 2 with following method.Use the LiCoO of 88wt%
2As positive electrode active materials.Using average particulate diameter is that the sheet native graphite of 1 μ m is as electric conducting material.The polyvinylidene fluoride (PVDF) that uses 5wt% is as adhesive.In these materials, add N-N-methyl-2-2-pyrrolidone N-(its amount is that benchmark is 50wt% with said thickener, down together), said mixture homogenization is obtained a kind of as the thickener that forms anodal mixture.With method same as described above, prepare a kind of negative active core-shell material as adhesive by in the powdered graphite that in (1), obtains of 90 parts of weight, adding 10% PVDF.To wherein adding N-N-methyl-2-2-pyrrolidone N-(its amount is that benchmark is 50wt% with said thickener, down together),, obtain a kind of thickener that is used to form the mixture of negative pole said mixture homogenization.
Subsequently, the both sides of the above-mentioned thickener that the is used to form anodal mixture aluminium foil that to be coated in a thickness be 25 μ m and in a vacuum 120 ℃ of dryings 1 hour.After drying, making its thickness by roll compaction is that 190 μ m come electrode of moulding, and the amount of the coating that is used to form anodal mixture on the unit are is 49mg/cm
2The size that it is cut into wide 40mm, long 285mm prepares positive pole 1, supposes that two end sections (length is every end 10mm) of anodal 1 are not used in the coating that forms anodal mixture, thereby the aluminium foil in these parts is come out.Aluminium foil end partly to being exposed contacts in conjunction with positive terminal 4 by the ultrasonic wave combined techniques.
On the other hand, on the thickener of the mixture that the is used to form negative pole Copper Foil that to be coated in a thickness be 10 μ m and 120 ℃ of vacuumizes 1 hour.After the drying,, and its thickness adjusted to 175 μ m by electrode of roll compaction moulding.The amount of the coating of the mixture that is used to form negative pole on the per unit area is 20mg/cm
2, the size that it is cut into wide 40mm, long 290mm prepares negative pole 2.Identical with anodal 1, two end sections of negative pole 2, each end sections length is 10mm, is not used in the coating of the mixture of negative pole, thereby exposes said Copper Foil.To of the Copper Foil that exposed part, by the ultrasonic wave contact in conjunction with an anode connector 5.
As dividing plate 3, used thickness is that 25 μ m, width are the microporous membrane that the polyethylene of 44mm is made.Then, as shown in Figure 2, pile positive pole 1, dividing plate 3, negative pole 2 and dividing plate 3 successively, the lamination that roll-in obtains like this prepares a kind of electrode group.Said electrode group is inserted in the cell sealing shell 7 that is of a size of the Single-3 size, and anode connector 5 is by the bottom of solder bond at said can, and a part that is used for the extruding of caulked positive cover 6 is provided.Then, in said cell sealing shell 7, pour the electrolyte solution for preparing by the lithium hexafluoro phosphate that dissolves 1 mol in 1: 1 the mixture of ethylene carbonate and dimethyl carbonate (not shown) into.By welding a positive terminal 4 is combined on the positive cover 6, then, caulked positive cover 6 obtains a kind of lithium secondary battery.
On the lithium secondary battery that obtains like this, repeat to discharge and recharge with the charging and discharging currents of 300mA, last charging voltage is 4.15V, last discharge voltage is 2.8V.In addition, when charging and discharging currents is in 300mA～900mA scope, carry out fast charging and discharging.The result is shown in Fig. 3 and Fig. 4.
Embodiment 2
Is the average particulate diameter of 70 parts of weight that the iron oxide of the tar asphalt of the coke powder of 10 μ m, 10 parts of weight, 2 parts of weight and the coal tar of 20 parts of weight mix, and stirs 1 hour at 100 ℃.Subsequently, said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 20 μ m.Under electron microscope, carry out the combination of a plurality of tabular particles of studies show that of the graphite granule that obtains or combine making its crystal face that aligns be not parallel to each other mutually to have formed a kind of graphite granule.Select 100 particles from the graphite granule that is obtained at random, the mean value of measuring its aspect ratio has obtained 4.8 result.The wide angle of the X ray of the graphite granule of gained diffraction shows that the interlamellar spacing d of said crystal (002) is 3.363 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.The specific area of measuring with the BET method is 4.3m
2/ g.
With with embodiment 1 in identical process, prepare a kind of lithium secondary battery from the graphite granule of such acquisition, and use the method identical to study its battery performance with embodiment 1.The result is shown in Fig. 3 and Fig. 4.
Be average particulate diameter that to obtain average particulate diameters 2,800 ℃ of calcinings under blanket of nitrogen be the graphite granule of 20 μ m for the coke powder of 20 μ m.The graphite granule of Huo Deing constitutes a kind of flake graphite like this, and its average aspect ratio is 6, specific area is 11m
2Interlamellar spacing d in/g, the crystal (002) is 3.365 dusts, and crystalline size Lc (002) is 800 dusts.
By with embodiment 1 in identical process, the flake graphite that obtains is like this prepared a kind of lithium secondary battery, and uses the method identical to study its battery performance with embodiment 1.The result is shown in Fig. 3 and Fig. 4.
The lithium secondary battery that obtains in embodiments of the invention 1,2 and 3 is comparing aspect the absorption of lithium and the release each other.The result is as described below.Fig. 3 be illustrated in lithium secondary battery repeat to discharge and recharge the discharge capacity in the test and the figure of the relation between the charge and discharge cycles number of times.In Fig. 3, curve 9 is illustrated in the discharge capacity of the lithium secondary battery that is obtained among the embodiment 1; The discharge capacity of the lithium secondary battery that is obtained among the curve 10 expression embodiment 2; Curve 11 is illustrated in the discharge capacity of the lithium secondary battery that is obtained among the embodiment 3.
In Fig. 3, it is 750mAh that the lithium secondary battery that is obtained in embodiment 1 shows high discharge capacity, is benchmark with the peak capacity, and the capacity changing down of the discharge capacity in 500 circulations is 8%.It is 720mAh that the lithium secondary battery that is obtained in embodiment 2 shows high discharge capacity, is benchmark with the peak capacity, and the capacity changing down of the discharge capacity in 500 circulations is 12%.It is 650mAh that the lithium secondary battery that is obtained in embodiment 3 shows high discharge capacity, is benchmark with the peak capacity, and the capacity changing down of the discharge capacity in 500 circulations is 31%.
Fig. 4 is illustrated in charging and discharging currents in the fast charging and discharging test and the relation between the discharge capacity.Curve 12 is illustrated in the discharge capacity of the lithium secondary battery that is obtained among the embodiment 1; Curve 13 is illustrated in the discharge capacity of the lithium secondary battery that is obtained among the embodiment 2; Curve 14 is illustrated in the discharge capacity of the lithium secondary battery that is obtained among the embodiment 3.Under the charging and discharging currents of 900mA, the lithium secondary battery that is obtained in embodiment 1 shows the discharge capacity of 630mAh, and the lithium secondary battery that is obtained in embodiment 2 shows the discharge capacity of 520mAh.On the other hand, the lithium secondary battery that is obtained in embodiment 3 shows the discharge capacity of 350mAh.Under the charging and discharging currents of 300mAh, be to be 16% in the lithium secondary battery that in embodiment 1, obtained of the capacity changing down of benchmark with the discharge capacity, being 28% in the lithium secondary battery that is obtained in embodiment 2, is 46% in the lithium secondary battery that is obtained in embodiment 3.
Based on the result of the test of embodiment 1,2 and 3, verified, use the capacitance of lithium secondary battery height of first kind of the present invention, second kind and the third graphite granule, the charge-discharge performance excellence, and have good fast charging and discharging performance.
Is the average particulate diameter of 50 parts of weight that the carborundum of the tar asphalt of the coke powder of 10 μ m, 20 parts of weight, 10 parts of weight and the coal tar of 20 parts of weight mix, and stirs 1 hour at 100 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 20 μ m.Therefrom select 100 particles at random, measuring its average aspect ratio is 1.5.Measure with the BET method, the specific area of the graphite granule of Huo Deing is 2.9m like this
2/ g.Measure with the wide angle of X ray diffraction, the interlamellar spacing d of said crystal (002) is 3.360 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.According to the scanning electron microscopy picture (SEM image) of the graphite granule that is obtained, the structure of the graphite granule that is obtained is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.
Subsequently, the polyvinylidene fluoride that is dissolved in the N-N-methyl-2-2-pyrrolidone N-of the graphite granule of such acquisition of 90wt% and 10wt% (weight of solid constituent) is mixed, obtain a kind of graphite thickener.Said graphite thickener is coated on the rolled copper foil that thickness is 10 μ m, dry and (0.5 ton/cm of 490MPa
2) the moulding of surface pressing dip mold, obtain a kind of specimen electrode.Adjust the thickness of its bed of graphite particles and its density respectively to 75 μ m and 1.5g/cm
3The specimen electrode that makes such preparation is estimated its performance as the negative pole of lithium secondary battery through the constant current charge-discharge test with 3 connections.Fig. 5 is the profile diagram of said lithium secondary battery.Estimate said specimen electrode by preparing a kind of electrolyte solution, said electrolyte solution 16 is by the LiPF in the mixture of 1: 1 (volume) being dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC)
4Form the LiPF in said solution
4Concentration be 1 mol, as shown in Figure 5, in a glass battery 15, introduce the solution of gained, laminated specimen electrode (negative pole) 17, dividing plate 18 and a counterelectrode (positive pole) 19, and hang a reference electrode 20 from top to bottom, prepare a kind of lithium secondary battery.With lithium metal as counterelectrode 19 and reference electrode 20; With microporous polyethylene film as dividing plate 18.Use the lithium secondary battery that obtains like this, at 0.3mA/cm
2(unit are specimen electrode) charges and reaches 5mV (V is to Li/Li+) until the voltage between specimen electrode 17 and counterelectrode 19, and discharging then reaches 1V (V is to Li/Li+) until said voltage, repeats this circulation and forms a test.Table 1 is illustrated in the circulation for the first time, the discharge capacity and the irreversible capacity of the charging capacity of the graphite granule of per unit weight, the graphite granule of per unit weight, and the discharge capacity of the graphite granule of the per unit weight in the 50th circulation.In addition, as the evaluation of fast charging and discharging performance, table 2 is illustrated in a kind of with 0.3mA/cm
2Constant current charge, then with 0.3,2.0,4.0 and 6.0mA/cm
2The experiment of discharging current discharge of variation in the variation of discharge capacity.
Is the average particulate diameter of 50 parts of weight that the carborundum of the tar asphalt of the coke powder of 10 μ m, 10 parts of weight, 5 parts of weight and the coal tar of 10 parts of weight mix, and stirs 1 hour at 100 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 20 μ m.Therefrom select 100 particles at random, calculating its average aspect ratio is 4.5.Measure with the BET method, the specific area of the graphite granule of Huo Deing is 4.9m like this
2/ g.Measure with the wide angle of X ray diffraction, the interlamellar spacing d of said graphite crystal (002) is 3.362 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.Here the structure of the graphite granule that is obtained is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.
Subsequently, the process that repeats embodiment 4 obtains a kind of lithium secondary battery, use then with embodiment 4 in identical method test.Table 1 is illustrated in the circulation for the first time, the discharge capacity and the irreversible capacity of the charging capacity of the graphite granule of per unit weight, the graphite granule of per unit weight, and the discharge capacity of the graphite granule of the per unit weight in the 50th circulation.In addition, as the evaluation of fast charging and discharging performance, table 2 is illustrated in a kind of with 0.3mA/cm
2Constant current charge, then with 0.3,2.0,4.0 and 6.0mA/cm
2The experiment of discharging current discharge of variation in the variation of discharge capacity.
Embodiment 6
Is the average particulate diameter of 50 parts of weight that the tar asphalt of the coke powder of 10 μ m, 5 parts of weight, the coal tar of 5 parts of weight mix, and stirs 1 hour at 100 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 20 μ m.Therefrom select 100 particles at random, measuring its average aspect ratio is 5.Measure with the BET method, the specific area of the graphite granule of Huo Deing is 6.3m like this
2/ g.Measure with the wide angle of X ray diffraction, the interlamellar spacing d of said graphite crystal (002) is 3.368 dusts, and crystalline size Lc (002) is 700 dusts.The structure of the graphite granule of Huo Deing is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually like this.
Subsequently, the process that repeats embodiment 4 prepares a kind of lithium secondary battery, use then with embodiment 4 in identical method test.Table 1 is illustrated in the circulation for the first time, the discharge capacity and the irreversible capacity of the charging capacity of the graphite granule of per unit weight, the graphite granule of per unit weight, and the discharge capacity of the graphite granule of the per unit weight in the 50th circulation.In addition, as the evaluation of fast charging and discharging performance, table 2 is illustrated in a kind of with 0.3mA/cm
2Constant current charge, then with 0.3,2.0,4.0 and 6.0mA/cm
2The experiment of discharging current discharge of variation in the variation of discharge capacity.
Be average particulate diameter the coke powder of 20 μ m under blanket of nitrogen 2,800 ℃ of calcinings, obtaining average particulate diameter is the graphite granule of 20 μ m.The graphite granule of Huo Deing constitutes a kind of sheet-like particle like this, and on average this is 7 in length and breadth for it, and the specific area of measuring with the BET method is 8.5m
2/ g.Measure with the wide angle of X ray diffraction, the interlamellar spacing d of said crystal (002) is 3.368 dusts, and crystalline size Lc (002) is 800 dusts.
The process that repeats embodiment 4 obtains a kind of lithium secondary battery, use then with embodiment 4 in identical method test battery performance.Table 1 is illustrated in the circulation for the first time, the discharge capacity and the irreversible capacity of the charging capacity of the graphite granule of per unit weight, the graphite granule of per unit weight, and the discharge capacity of the graphite granule of the per unit weight in the 50th circulation.In addition, as the evaluation of fast charging and discharging performance, table 2 is illustrated in a kind of with 0.3mA/cm
2Constant current charge, then with 0.3,2.0,4.0 and 6.0mA/cm
2The experiment of discharging current discharge of variation in the variation of discharge capacity.
Table 1
Table 2
Find out obviously that from table 1 and 2 use first kind of the present invention, second kind to compare with embodiment 7 with the lithium secondary battery of the third graphite granule, discharge capacity is higher, the irreversible capacity of circulation is littler for the first time, and cycle performance and fast charging and discharging performance are more excellent.
Among the embodiment 8～11 given below, studied and used the 4th kind of graphite granule of the present invention as graphite granule, with first kind of the present invention negative material that is used for the negative material of lithium secondary battery as lithium secondary battery.
(1) preparation of graphite granule
Is the average particulate diameter of 50 parts of weight that the average particulate diameter of the tar asphalt of the coke powder of 10 μ m, 20 parts of weight, 12 parts of weight is that the iron oxide of 65 μ m and the coal tar of 18 parts of weight mix, and stirs 1 hour at 200 ℃.Said mixture earlier 800 ℃ of calcinings, then under blanket of nitrogen 2,800 ℃ of calcinings, pulverizing then and obtaining average particulate diameter is the graphite granule of 20 μ m.According to the scanning electron microscopy picture (SEM image) of the graphite granule that is obtained, the structure of said graphite granule is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.Selecting at random on 100 particles, the mean value that calculates its aspect ratio is 1.7.In the wide angle of the X ray diffraction of the graphite granule of gained, the interlamellar spacing d of said crystal (002) is 3.360 dusts, is 720 dusts at the crystalline size La (110) of crystal plane direction, and the crystalline size Lc (002) on the c direction of principal axis is 1,800 dust.
(2) preparation of lithium secondary battery
Prepare lithium secondary battery shown in Figure 2 with following method.Use the LiCoO of 88wt%
2As positive electrode active materials, the average particulate diameter of 7wt% is that the sheet native graphite of 1 μ m is as electric conducting material, the polyvinylidene fluoride (PVDF) that uses 5wt% is as adhesive, prepare a kind of thickener that is used to form anodal mixture to wherein adding N-N-methyl-2-2-pyrrolidone N-(its amount is that benchmark is 50wt% with said thickener, down together) and the said mixture of homogenizing.Similarly, the powdered graphite that obtains in (1) by using 90 parts of weight is as negative active core-shell material, 10% PVDF is as adhesive, (its amount is that benchmark is 50wt% with said thickener to add the N-N-methyl-2-2-pyrrolidone N-, together following) and the said mixture of homogenizing, prepare a kind of thickener that is used to form the mixture of negative pole.
Subsequently, the both sides of the thickener that is used to form anodal mixture that obtains the above aluminium foil that to be coated in a thickness be 25 μ m and in a vacuum 120 ℃ of dryings 1 hour.After drying, make its thickness be adjusted into 190 μ m by roll compaction.The amount of the coating that is used to form anodal mixture on the unit are is 49mg/cm
2The size that is cut into 40mm (wide) * 285mm (length) obtains positive pole 1, but two end sections of anodal 1, and length is every end 10mm, is not used in the coating that forms anodal mixture, thereby the aluminium foil in these parts is come out.Aluminium foil end partly to being exposed contacts in conjunction with positive terminal 4 by the ultrasonic wave combined techniques.
On the other hand, the both sides of the thickener of the mixture that is used to form negative pole that obtains the above Copper Foil that to be coated in a thickness be 10 μ m and 120 ℃ of vacuumizes 1 hour.After the drying,, and its thickness adjusted to 175 μ m by electrode of roll compaction moulding.The amount of the coating of the mixture that is used to form negative pole on the per unit area is 20mg/cm
2, be cut into the size of 40mm (wide) * 290mm (length), obtain negative pole 2.Identical with anodal 1, two end sections of negative pole 2, each end sections length is 10mm, is not used in the coating of the mixture of negative pole, thereby exposes said Copper Foil.To of the Copper Foil that exposed part, by the ultrasonic method contact in conjunction with an anode connector 5.
As dividing plate 3, used thickness is that 25 μ m, width are the microporous membrane that the polyethylene of 44mm is made.Then, as shown in Figure 2, pile positive pole 1, dividing plate 3, negative pole 2 and dividing plate 3 successively, and roll-in forms a kind of electrode group.Said electrode group is inserted in the cell sealing shell 7 of a Single-3 specification, anode connector 5 is by the bottom of solder bond at said can, and a part that is used for the extruding of caulked positive cover 6 is provided.Then, in said cell sealing shell 7, pour the electrolyte solution for preparing by the lithium hexafluoro phosphate that in 1: 1 mixture of ethylene carbonate and dimethyl carbonate (not shown), dissolves 1 mol into.A positive terminal 4 is combined on the positive cover 6, and then, caulked positive cover 6 obtains a kind of lithium secondary battery.
With the lithium secondary battery that obtains above, repeat to discharge and recharge test with the charging and discharging currents of 300mA, last charging voltage is 4.15V, last discharge voltage is 2.8V.In addition, when in 300mA～600mA scope, changing charging and discharging currents, carry out the fast charging and discharging test.Measured the discharge capacitance of the graphite granule of the discharge capacity of graphite granule of the per unit weight in circulation for the first time and the per unit weight in the 100th circulation.The result is shown in table 3.
Embodiment 9
Is the average particulate diameter of 55 parts of weight that the average particulate diameter of the tar asphalt of the coke powder of 10 μ m, 22 parts of weight, 8 parts of weight is that the boron nitride of 25 μ m and the coal tar of 15 parts of weight mix, and stirs 1 hour at 200 ℃.Said mixture earlier 800 ℃ of calcinings, then under blanket of nitrogen 2,800 ℃ of calcinings, pulverizing then and obtaining average particulate diameter is the graphite granule of 20 μ m.According to the scanning electron microscopy picture (SEM image) of the graphite granule that is obtained, the structure of said graphite granule is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.Selecting at random on 100 particles, the mean value that calculates its aspect ratio is 1.5.In the wide angle of the X ray diffraction according to the graphite granule of gained, the interlamellar spacing d of said crystal (002) is 3.363 dusts, is 560 dusts at the crystalline size La (110) of crystal plane direction, and the crystalline size Lc (002) on the c direction of principal axis is 1,760 dust.
By the process identical, prepare a kind of lithium secondary battery with the graphite granule that obtains like this, and use the method identical to study its battery performance with embodiment 8 with embodiment 8.The result is shown in table 3.
Embodiment 10
Is the average particulate diameter of 57 parts of weight that the tar asphalt of the coke powder of 15 μ m, 23 parts of weight, the coal tar of 20 parts of weight mix, and stirs 1 hour at 200 ℃.Said mixture is calcined in blanket of nitrogen at 800 ℃ earlier, then under blanket of nitrogen 2,600 ℃ of calcinings, pulverizing then and obtaining average particulate diameter is the graphite granule of 20 μ m.According to scanning electron microscopy picture (SEM image), the structure of said graphite granule is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.Selecting at random on 100 particles, the mean value of measuring its aspect ratio is 2.0.In the wide angle of the X ray diffraction according to the graphite granule of gained, the interlamellar spacing d of said crystal (002) is 3.390 dusts, is 460 dusts at the crystalline size La (110) of crystal plane direction, and the crystalline size Lc (002) on the c direction of principal axis is 300 dusts.
By the process identical, prepare a kind of lithium secondary battery with the graphite granule that obtains like this, and use the method identical to study its battery performance with embodiment 8 with embodiment 8.The result is shown in table 3.
Embodiment 11
The process that repeats embodiment 10 prepares the graphite granule that average particulate diameter is 20 μ m, but said calcining is carried out at 3,000 ℃.According to scanning electron microscopy picture (SEM image), the structure of graphite granule for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.Selecting at random on 100 particles, the mean value of measuring its aspect ratio is 2.2.In the wide angle of the X ray diffraction according to the graphite granule of gained, the interlamellar spacing d of said crystal (002) is 3.357 dusts, is 1,730 dust at the crystalline size La (110) of crystal plane direction, and the crystalline size Lc (002) on the c direction of principal axis is 2,050 dusts.
By the process identical, prepare a kind of lithium secondary battery with the graphite granule that obtains like this, and use the method identical to study its battery performance with embodiment 1 with embodiment 8.The result is shown in table 3.
Table 3
From table 3, can obviously find out, even use the 4th kind of graphite granule of the present invention to show under high discharge capacity under the charging and discharging currents of 300mA and strong charging and discharging currents, to keep at 600mA high discharge capacity 70% or more, show excellent fast charging and discharging performance.
In embodiment 12～15, studied and used the 5th kind and the 6th kind of graphite granule of the present invention as graphite granule, with first kind of the present invention negative material that is used for the negative material of lithium secondary battery as lithium secondary battery.
Is the average particulate diameter of 40 parts of weight that the average particulate diameter of the tar asphalt of the coke powder of 5 μ m, 25 parts of weight, 5 parts of weight is that the carborundum of 48 μ m and the coal tar of 20 parts of weight mix, and stirs 1 hour at 200 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 30 μ m.Use Shimadzu Poresizer 9320, the pore size of measuring the graphite granule that is obtained by mercury apertometer method distributes, and finds that pore size is 10
2～10
6In the dust scope, total pore volume of the graphite granule of Unit Weight is 0.6cc/g.In addition, pore size is 1 * 10
2～2 * 10
4The volume of the pore of dust is the graphite granule 0.20cc/g of Unit Weight.Select 100 particles at random, the mean value that records its aspect ratio is 1.5.Measure with the BET method, the specific area of graphite granule is 1.5m
2/ g.In the diffraction of the wide angle of the X ray of said graphite granule, the interlamellar spacing d of said crystal (002) is 3.362 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.In addition, according to scanning electron microscopy picture (SEM image), the structure of said graphite granule is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.
Subsequently, the polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule of such acquisition of 90wt% with 10wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Said graphite thickener is coated on the rolled copper foil that thickness is 10 μ m, dry and (0.5 ton/cm of 490MPa
2) the moulding of surface pressing dip mold, obtain a kind of specimen electrode.Adjust the thickness of its bed of graphite particles and its density respectively to 90 μ m and 1.6g/cm
3
The specimen electrode that makes such preparation is estimated its performance as the negative pole of lithium secondary battery through the constant current charge-discharge test with 3 connections.Fig. 5 is the profile diagram of said lithium secondary battery.As shown in Figure 5, the LiPF in the mixture of 1: 1 (volume) being dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC) by in aquarium 1, introducing 1 mol
4As electrolyte solution 2, the lamination of specimen electrode 3, dividing plate 4 and counterelectrode 5 is installed, and is hung a reference electrode 6 from top to bottom, form a lithium secondary battery and carry out the evaluation of said specimen electrode.With lithium metal as counterelectrode 5 and reference electrode 6; With microporous polyethylene film as dividing plate 4.Use the lithium secondary battery that obtains like this, at 0.5mA/cm
2(unit are specimen electrode) charges and reaches 5mV (V is to Li/Li+) until the voltage between specimen electrode 3 and counterelectrode 5, and discharging then reaches 1V (V is to Li/Li+) until said voltage, repeats this circulation and forms a test.Table 4 is illustrated in the circulation for the first time, the charging capacity of the graphite granule of per unit weight, and the discharge capacity of the graphite granule of the per unit weight in the 30th circulation.
Is the average particulate diameter of 50 parts of weight that the average particulate diameter of the pitch of the coke powder of 20 μ m, 20 parts of weight, 7 parts of weight is that the carborundum of 48 μ m and the coal tar of 10 parts of weight mix, and stirs 1 hour at 200 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 30 μ m.The pore size distribution measuring that is undertaken by the mercury apertometer method of using Shimadzu Poresizer 9320 shows that the pore of the graphite granule that is obtained is 10
2～10
6In the dust scope, total pore volume of Unit Weight graphite granule is 1.5cc/g.Size is 1 * 10
2～2 * 10
4The volume of the pore in the dust scope is 0.13cc/g for the Unit Weight graphite granule.Select 100 particles at random, the mean value of measuring its aspect ratio is 2.3.Measure with the BET method, the specific area of said graphite granule is 3.6m
2/ g.By the wide angle of the X ray of said graphite granule diffraction, the interlamellar spacing d of said crystal (002) is 3.361 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.The structure of the graphite granule that is obtained is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 12 by the process identical with embodiment 12.Table 4 is illustrated in the charging capacity and the discharge capacity of the graphite granule of the per unit weight in the circulation for the first time, and the discharge capacity of the graphite granule of the per unit weight in the 30th circulation.
Obtaining average particulate diameter at 2,800 ℃ of calcining Meso Carbon Microbeads (made by Kawasaki Steel Corporation, commodity are called KMFC) under blanket of nitrogen is the graphite granule of 25 μ m.Use Sbimadzu Poresizer 9320, the pore size of measuring the graphite granule that is obtained by mercury apertometer method distributes.As a result, the pore of said graphite is 10
2～10
6In the dust scope, total pore volume of the graphite granule of Unit Weight is 0.35cc/g.Size is 1 * 10
2～2 * 10
4The volume of the pore in the dust scope is the 0.06cc/g of Unit Weight graphite granule.Therefrom select 100 particles at random, the mean value of measuring its aspect ratio is 1.Measure with the BET method, the specific area of said graphite granule is 1.4m
2/ g.With the wide angle of the X ray of said graphite granule diffractometry, the interlamellar spacing d of said crystal (002) is 3.378 dusts, and crystalline size Lc (002) is 500 dusts.
Prepare a kind of lithium secondary battery by repeating embodiment 12 identical processes, and use the method test identical with embodiment 12.Table 4 is illustrated in the charging capacity and the discharge capacity of the graphite granule of the per unit weight in the circulation for the first time, and the discharge capacity of the graphite granule of the per unit weight in the 30th circulation.
Is the average particulate diameter of 50 parts of weight that the average particulate diameter of the pitch of the coke powder of 5 μ m, 10 parts of weight, 30 parts of weight is that the iron oxide of 65 μ m and the coal tar of 20 parts of weight mix, and stirs 1 hour at 200 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 15 μ m.Use Shimadzu Poresizer 9320, the pore size of measuring the graphite granule that is obtained by mercury apertometer method shows that the pore of said graphite granule is 10
2～10
6In the dust scope, total pore volume of Unit Weight graphite granule is 2.1cc/g.Size is 1 * 10
2～2 * 10
4The volume of the pore in the dust scope is Unit Weight graphite granule 0.42cc/g.Select 100 particles at random, the mean value of measuring its aspect ratio is 2.8.Measure with the BET method, the specific area of said graphite granule is 8.3m
2/ g.By the wide angle of the X ray of said graphite granule diffractometry, the interlamellar spacing d of said crystal (002) is 3.365 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 12 by the process identical with embodiment 12.Table 4 is illustrated in the charging capacity and the discharge capacity of the graphite granule of the per unit weight in the circulation for the first time, and the discharge capacity of the graphite granule of the per unit weight in the 30th circulation.
Table 4
| |
|
|
|
|
| The charging capacity (mAh/g) of the circulation first time | 392 | 380 | 321 | 384 |
| The discharge capacity (mAh/g) of the circulation first time | 353 | 345 | 288 | 338 |
| The discharge capacity (mAh/g) of the 30th circulation | 346 | 338 | 159 | 286 |
From table 4, can obviously find out, use the lithium secondary battery of the 5th kind and the 6th kind graphite granule of the present invention to have high capacity and cycle performance excellence.
In embodiment 16～21, studied and used second kind of negative material that is used for the negative material of lithium secondary battery as lithium secondary battery of the present invention.
Is the average particulate diameter of 50 parts of weight that the carborundum of the tar asphalt of the coke powder of 8 μ m, 20 parts of weight, 5 parts of weight and the coal tar of 15 parts of weight mix, and stirs 1 hour at 100 ℃.Said mixture under blanket of nitrogen 2,800 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 25 μ m.Select 100 particles at random, the mean value that records its aspect ratio is 1.5.Measure with the BET method, the specific area of said graphite granule is 2.1m
2/ g.By the wide angle of the X ray of said graphite granule diffractometry, the interlamellar spacing d of said crystal (002) is 3.365 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.The structure of the graphite granule that is obtained is for a plurality of tabular particles combination wherein or combine and make its crystal face that aligns be not parallel to each other mutually.
Subsequently, the polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains above of 90wt% with 10wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Said graphite thickener is coated on the rolled copper foil that thickness is 10 μ m, and drying is suppressed under the pressure of 30MPa to remove said N-N-methyl-2-2-pyrrolidone N-, obtains a kind of specimen electrode.Adjust the thickness of its graphite granule-PVDF layer and density respectively to 80 μ m and 1.55g/cm
3Make the constant current charge-discharge test of specimen electrode through carrying out of such preparation, estimate its performance as the negative pole of lithium secondary battery with 3 connections.Fig. 5 is the profile diagram of said lithium secondary battery.As shown in Figure 5, the LiPF in the mixture of 1: 1 (volume) being dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC) by in aquarium 1, introducing 1 mol
4As electrolyte solution 2, the lamination of specimen electrode 3, dividing plate 4 and counterelectrode 5 is installed, and is hung a reference electrode 6 from top to bottom, form a lithium secondary battery and carry out the evaluation of said specimen electrode.With lithium metal as counterelectrode 5 and reference electrode 6; With microporous polyethylene film as dividing plate 4.Use the lithium secondary battery that obtains like this, at 0.2mA/cm
2(graphite granule of the unit are in the specimen electrode-PVDF mixture) charges and reaches 5mV (V is to Li/Li+) until the voltage between specimen electrode 3 and counterelectrode 5, discharge then and reach 1V (V is to Li/Li+) until said voltage, form a test 50 times though repeat this circulation, do not find the reduction of discharge capacity.In addition, as the evaluation of fast charging and discharging performance, at 0.3mA/cm
2Constant current under charge, then 0.5,2.0,4.0 and 6.0mA/cm
2The discharging current of variation under discharge.Relation table between discharge capacity and graphite granule-PVDF mixture is shown in table 5.
Prepare a kind of specimen electrode by the process that repeats embodiment 16, the pressure change during still compacting is 40MPa.Obtaining in the specimen electrode like this, the thickness of said graphite granule-PVDF mixture is 80 μ m, and its density is 1.63g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method identical to test with embodiment 16 by repeating the process identical with embodiment 16.As a result, do not find the reduction of discharge capacity.In addition, as the evaluation of fast charging and discharging performance, at 0.3mA/cm
2Constant current under charge, then 0.5,2.0,4.0 and 6.0mA/cm
2The discharging current of variation under discharge.Said discharge capacity is shown in table 5.
Prepare a kind of specimen electrode by the process identical, but the pressure change during compacting is 80MPa with embodiment 16.Obtaining in the specimen electrode like this, the thickness of the mixture of said graphite granule and PVDF is 80 μ m, and its density is 1.75g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 16 by the process identical with embodiment 16.As a result, do not find the reduction of discharge capacity.For estimating fast charging and discharging performance, at 0.3mA/cm
2Constant current under charge, then 0.5,2.0,4.0 and 6.0mA/cm
2The discharging current of variation under discharge.Said discharge capacity is shown in table 5.
Prepare a kind of specimen electrode by the process that repeats embodiment 16, the pressure change during still compacting is 100MPa.Obtaining in the specimen electrode like this, the thickness of the mixture of said graphite granule and PVDF is 80 μ m, and its density is 1.85g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 16 by the process identical with embodiment 16.As a result, do not find the reduction of discharge capacity.For estimating fast charging and discharging performance, at 0.3mA/cm
2Constant current under charge, then 0.5,2.0,4.0 and 6.0mA/cm
2The discharging current of variation under discharge.Said discharge capacity is shown in table 5.
Prepare a kind of specimen electrode by the process with embodiment 16, the pressure change during still compacting is 20MPa.Obtaining in the specimen electrode like this, the thickness of the mixture of said graphite granule and PVDF is 80 μ m, and its density is 1.45g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 16 by the process identical with embodiment 16.As a result, do not find the reduction of discharge capacity.For estimating fast charging and discharging performance, at 0.3mA/cm
2Constant current under charge, then 0.5,2.0,4.0 and 6.0mA/cm
2The discharging current of variation under discharge.Said discharge capacity is shown in table 5.
Embodiment 21
Prepare a kind of specimen electrode by the process with embodiment 16, the pressure change during still compacting is 140MPa.Obtaining in the specimen electrode like this, the thickness of the mixture of said graphite granule and PVDF is 80 μ m, and its density is 1.93g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 16 by the process identical with embodiment 16.As a result, observe the reduction of 15.7% discharge capacity.For estimating fast charging and discharging performance, at 0.3mA/cm
2Constant current under charge, then 0.5,2.0,4.0 and 6.0mA/cm
2The discharging current of variation under discharge.Said discharge capacity is shown in Fig. 5.
Table 5
As shown in table 5, can obviously find out, use the discharge capacity height of the lithium secondary battery of second kind of negative pole that is used for lithium secondary battery of the present invention, the fast charging and discharging performance excellence.
In embodiment 22～29, studied and used of the present invention the third to be used for the negative material of the negative pole of lithium secondary battery as lithium secondary battery.
Embodiment 22
Is the average particulate diameter of 50 parts of weight that the carborundum of the tar asphalt of the coke powder of 10 μ m, 20 parts of weight, 5 parts of weight and the coal tar of 15 parts of weight mix, and stirs 1 hour at 100 ℃.Said mixture under blanket of nitrogen 3,000 ℃ of calcinings, pulverize obtaining average particulate diameter then is the graphite granule of 25 μ m.Select 100 particles at random, the mean value that records its aspect ratio is 1.3.Measure with the BET method, the specific area of said graphite granule is 1.9m
2/ g.By the wide angle of the X ray of said graphite granule diffractometry, the interlamellar spacing d of said crystal (002) is 3.36 dusts, and crystalline size Lc (002) is 1,000 dust or bigger.In addition, according to the scanning electron microscopy picture (SEM image) of the graphite granule of such acquisition, the structure of said graphite granule is for a plurality of tabular particles combinations wherein or combine and make its crystal face that aligns be not parallel to each other mutually.
Subsequently, the polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule of such acquisition of 89wt% with 11wt% (weight with solid constituent is represented) mixed, obtain a kind of graphite thickener.Said graphite thickener is coated on the rolled copper foil that thickness is 10 μ m, and drying obtains a kind of specimen electrode with roll compaction, and wherein, the thickness of graphite granule-PVDF layer is 80 μ m, and its density is 1.5g/cm
3
Make the constant current charge-discharge test of specimen electrode through carrying out of such preparation, estimate its performance as the negative pole of lithium secondary battery with 3 connections.Fig. 5 is the profile diagram of said lithium secondary battery.As shown in Figure 5, a kind of by preparing by the LiPF in the mixture of 1: 1 (volume) being dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC)
4The electrolyte solution of forming 2, make that the concentration of said solution is 1 mol, in an aquarium 1, introduce the solution of gained, as shown in Figure 5, the lamination of laminated specimen electrode 3, dividing plate 4 and counterelectrode 5, and hang a reference electrode 6 from top to bottom, prepare a lithium secondary battery and estimate said specimen electrode.With lithium metal as counterelectrode 5 and reference electrode 6; With microporous polyethylene film as dividing plate 4.Use the lithium secondary battery that obtains like this, at 0.3mA/cm
2(graphite granule of the unit are in the specimen electrode-PVDF mixture) charges and reaches 5mV (V is to Li/Li+) until the voltage between specimen electrode 3 and counterelectrode 5, then at 0.3mA/cm
2Constant current under discharge and reach 1V (V is to Li/Li+) until said voltage, repeat this circulation and form a test.The discharge capacity of the discharge capacity of the graphite granule of table 6 expression per unit weight, the discharge capacity of per unit weight graphite granule-PVDF mixture and the per unit weight graphite granule-PVDF mixture in the 50th circulation.In addition, as the evaluation of fast charging and discharging performance, table 6 has also been represented a kind of at 0.3mA/cm
2Constant current under charge the discharge capacity in the experiment of under 0.3 electric current, discharging then.
Embodiment 23
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 87wt% with 13wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Embodiment 24
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 85wt% with 15wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Embodiment 25
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 82wt% with 18wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Embodiment 26
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 80wt% with 20wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Embodiment 27
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 92wt% with 8wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Embodiment 28
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 97.5wt% with 2.5wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Embodiment 29
The polyvinylidene fluoride (PVDF) that be dissolved in N-N-methyl-2-2-pyrrolidone N-of the graphite granule that obtains in embodiment 22 of 78wt% with 22wt% (weight with solid constituent is represented) mixed, prepare a kind of graphite thickener.Then, the process that repeats embodiment 22 obtains a kind of specimen electrode, and wherein, the thickness of said graphite granule-PVDF mixture layer is 80 μ m, and its density is 1.5g/cm
3
Then, prepare a kind of lithium secondary battery, and use the method test identical with embodiment 22 by the process identical with embodiment 22.The result is shown in table 6.
Table 6
| Embodiment 22 | Embodiment 23 | Embodiment 24 | Embodiment 25 | Embodiment 26 | Embodiment 27 | Embodiment 28 | Embodiment 29 | |
| With graphite granule/PVDF (organic binder bond) mixture is the PVDF content (%) of benchmark | 10 | 13 | 15 | 18 | 20 | 8 | 2.5 | 22 |
| (discharging current is 0.3mA/cm to the discharge capacity of Unit Weight graphite granule (mAh/g) 2) | 325 | 338 | 355 | 259 | 363 | 320 | 275 | 335 |
| (discharging current is 0.3mA/cm to the discharge capacity (mAh/g) of Unit Weight graphite granule/PVDF mixture 2) | 293 | 294 | 302 | 294 | 290 | 294 | 267 | 261 |
| (discharging current is 0.3mA/cm to the discharge capacity (mAh/g) of the graphite granule/PVDF mixture of Unit Weight in the 50th circulation 2) | 287 | 290 | 295 | 292 | 286 | 265 | 134 | 252 |
| (discharging current is 3.0mA/cm to the discharge capacity (mAh/g) of Unit Weight graphite granule/PVDF mixture 2) | 267 | 282 | 280 | 278 | 271 | 250 | 160 | 232 |
As shown in table 6, clearly, the third capacitance of lithium secondary battery height, fast charging and discharging performance and cycle performance excellence of the present invention.
Graphite granule of the present invention is applicable to the lithium secondary battery of fast charging and discharging performance and cycle performance excellence.
In addition, graphite granule of the present invention is applicable to the lithium secondary battery that irreversible capacity is little and cycle performance is excellent in circulation for the first time.
In addition, according to the method for production graphite granule of the present invention, can obtain to be applicable to the lithium secondary battery of the irreversible capacity of the lithium secondary battery that irreversible capacity is little and cycle performance is excellent of the lithium secondary battery of fast charging and discharging performance and cycle performance excellence or circulation for the first time or circulation for the first time little and fast charging and discharging performance and cycle performance excellence.
In addition, graphite thickener of the present invention is applicable to the lithium secondary battery of fast charging and discharging performance and cycle performance excellence, or the lithium secondary battery that irreversible capacity is little and cycle performance is excellent of circulation for the first time, the perhaps lithium secondary battery of little and fast charging and discharging performance and cycle performance excellence of the irreversible capacity of circulation for the first time.
In addition, the negative material of lithium secondary battery and the lithium secondary battery that production method is applicable to capacity height and Rapid Cycle performance and cycle performance excellence of being used for of the present invention, the perhaps lithium secondary battery that irreversible capacity is little and cycle performance is excellent of circulation for the first time, the perhaps lithium secondary battery of little and fast charging and discharging performance and cycle performance excellence of the irreversible capacity of circulation for the first time.
In addition, capacitance of lithium secondary battery height of the present invention and fast charging and discharging performance and cycle performance excellence, perhaps for the first time the irreversible capacity of circulation is little and cycle performance is excellent, perhaps irreversible capacity little and the fast charging and discharging performance and the cycle performance excellence of circulation for the first time.
Claims (15)
1. graphite granule, it is the graphite granule that is used for lithium secondary battery anode, the specific area of described graphite granule is 8m
2Below/the g, aspect ratio is below 5, and described graphite granule is made of a plurality of tabular particles, and the tabular particle makes up or the feasible crystal face that aligns that combines is not parallel to each other mutually.
2. graphite granule according to claim 1, the aspect ratio of wherein said graphite granule are 1.2～5.
3. graphite granule according to claim 1, the specific area of wherein said graphite granule are 2～5m
2/ g.
4. graphite granule according to claim 1 is that crystalline size on the thickness direction is 500 dusts or bigger at the c of crystal direction of principal axis wherein, and the crystalline size on crystal plane direction is 1000 dusts or littler, and these two sizes are measured by the wide angle of X ray diffraction.
5. graphite granule according to claim 4, wherein the interlamellar spacing of the crystal of measuring by the wide angle of the X ray of graphite granule diffraction is 3.38 dusts or littler.
6. graphite granule according to claim 1, wherein the weight with graphite granule is benchmark, pore size is 10
2～10
6Pore volume in the dust scope is at 0.4～2.0cc/g.
7. graphite granule according to claim 1, wherein the weight with graphite granule is benchmark, pore size is 1 * 10
2～2 * 10
4Pore volume in the dust scope is at 0.08～0.4cc/g.
8. method of making claim 1,4,6 or 7 described graphite granules, comprise: the graphitization catalyst that adds 1～50wt% in raw material forms mixture, this mixture of homogenizing, and calcine this mixture, pulverize afterwards, described raw material comprises (a) graphite or can graphited material and (b) can graphited adhesive.
9. the manufacture method of graphite granule according to claim 8, the average particulate diameter of wherein said graphitization catalyst are 150 μ m or still less.
10. a graphite thickener comprises claim 1,4,6 or 7 described graphite granules, organic bond and solvent.
11. a negative pole that is used for lithium secondary battery, it is by being coated in the described graphite thickener of claim 10 on the current collector and carrying out integration and make.
12. negative pole that is used for lithium secondary battery, it is by making the mixture of claim 1,4,6 or 7 described graphite granules and organic bond and the integration of current collector, wherein, the density of the mixture of graphite granule of measuring after the pressurization integration and organic bond is 1.5～1.9g/cm
3
13. negative pole that is used for lithium secondary battery, it is by making the mixture of claim 1,4,6 or 7 described graphite granules and organic bond and the integration of current collector, wherein, weight with the mixture of graphite granule and organic bond is benchmark, and the amount of described organic bond is 3～20wt%.
14. the negative pole that is used for lithium secondary battery according to claim 13, wherein the weight with the mixture of graphite granule and organic bond is benchmark, and the amount of described organic bond is 11～20wt%.
15. lithium secondary battery, comprise shell, lid and at least one pair of positive pole and negative pole, described shell, lid and electrode dispose across the intermediate medium of dividing plate, and electrolyte solution is distributed in around it, and described negative pole is claim 11,12,13 or 14 described negative poles.
Applications Claiming Priority (18)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1996-209713 | 1996-08-08 | ||
| JP1996209713 | 1996-08-08 | ||
| JP20971396 | 1996-08-08 | ||
| JP1996-264265 | 1996-10-04 | ||
| JP26426596 | 1996-10-04 | ||
| JP1996264265 | 1996-10-04 | ||
| JP1996-288109 | 1996-10-30 | ||
| JP28810996 | 1996-10-30 | ||
| JP1996288109 | 1996-10-30 | ||
| JP1996-323921 | 1996-12-04 | ||
| JP32392196 | 1996-12-04 | ||
| JP1996323921 | 1996-12-04 | ||
| JP34840696 | 1996-12-26 | ||
| JP1996-348406 | 1996-12-26 | ||
| JP34840596 | 1996-12-26 | ||
| JP1996348405 | 1996-12-26 | ||
| JP1996348406 | 1996-12-26 | ||
| JP1996-348405 | 1996-12-26 |
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| CN97197784A Division CN1076711C (en) | 1996-08-08 | 1997-08-07 | Graphite particles and lithium secondary cell using them as cathode material |
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| JP5996473B2 (en) | 2013-03-29 | 2016-09-21 | Ｊｘエネルギー株式会社 | Method for producing graphite and particles for producing graphite |
| CN106099105A (en) * | 2015-08-31 | 2016-11-09 | 三峡大学 | A kind of spherical porous artificial plumbago negative pole material |
| CN106252662A (en) * | 2016-08-26 | 2016-12-21 | 上海杉杉科技有限公司 | A kind of preparation method of low bulk graphite |
| CN106395811B (en) * | 2016-08-26 | 2022-12-13 | 宁波杉杉新材料科技有限公司 | Preparation method of low-expansion long-cycle natural graphite |
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| CN101630741B (en) | 2011-02-02 |
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