CN100373670C - Positive electrode active material, production method thereof and non-aqueous electrolyte secondary battery - Google Patents

Positive electrode active material, production method thereof and non-aqueous electrolyte secondary battery Download PDF

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Publication number
CN100373670C
CN100373670C CNB03805003XA CN03805003A CN100373670C CN 100373670 C CN100373670 C CN 100373670C CN B03805003X A CNB03805003X A CN B03805003XA CN 03805003 A CN03805003 A CN 03805003A CN 100373670 C CN100373670 C CN 100373670C
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active material
positive active
mentioned
battery
roasting
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CN1692511A (en
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小槻勉
芳泽浩司
永山雅敏
越名秀
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Osaka City University
Panasonic Holdings Corp
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Osaka University NUC
Matsushita Electric Industrial Co Ltd
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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

A non-aqueous electrolyte secondary battery of 3V class having an excellent voltage flatness and high-rate cycle service life at a low cost. The battery uses an anode active material expressed by Li2+/-agr;[Me]4O8-x (wherein 0 <= agr<0.4, 0 <= x < 2, Me is a transition metal element containing Mn and at least one selected from a group consisting of Ni, Cr, Fe, Co, and Cu and exhibiting a two-phase reaction in a charge-discharge region.

Description

Positive active material and manufacture method thereof and rechargeable nonaqueous electrolytic battery
Technical field
The rechargeable nonaqueous electrolytic battery that the present invention relates to positive active material and adopt this material.
Background technology
In recent years, the rechargeable nonaqueous electrolytic battery as the main power source of mobile communication equipment and portable electric appts etc. is characterised in that to have high electromotive force and high energy density.As used positive active material, available cobalt acid lithium (LiCoO for example 2), lithium nickelate (LiNiO 2) and galaxite (LiMn 2O 4) etc.These active materials to the voltage of lithium more than 4V.On the other hand, use material with carbon element usually, by itself and above-mentioned positive active material are made up the lithium ion battery that just constitutes the 4V level as negative pole.
For battery, require it to have high-energy-density certainly, also require simultaneously its high speed characteristics (highrate) and pulse characteristic are improved.Because of discharging and recharging at a high speed and can increasing load to active material, the result uses technology in the past to be difficult to keep cycle life.
For device therefor,, also require it to have the flatness of the cell voltage of charging and discharging curve even when carrying out above-mentioned high rate discharge.But the cobalt acid lithium (LiCoO that has the positive active material of layer structure in use 2) and lithium nickelate (LiNiO 2) when waiting, though comparatively smooth in the past, obtain the charging and discharging curve of S shape, when high speed operation, also be difficult to keep smooth charging/discharging voltage.When above-mentioned positive active material discharged and recharged at every turn, bigger expansion and the contraction of layer direction can appear repeatedly.The stress of Chan Shenging makes the cycle life that discharges and recharges at a high speed shorten especially for this reason.
On the other hand, angle from the detection of remaining capacity, the charging and discharging curve that has adopted above-mentioned positive active material and got is because of being considered to also have comparatively smooth shape, must correctly measure narrow potential range, so above-mentioned positive active material is not suitable for detecting its remaining capacity, particularly when the charging lithium is inserted into negative pole, the current potential of negative pole can be reduced to suddenly near the 0.1V, with almost constant current potential lithium is inhaled storage then.For positive active material, special because have the LiMn of spinel structure 2O 4Can draw more smooth charging and discharging curve, so and cobalt acid lithium (LiCoO with layer structure 2) and lithium nickelate (LiNiO 2) compare, be not suitable for carrying out the detection of remaining capacity.
Usually, want the remaining capacity of cognitive rechargeable nonaqueous electrolytic battery, as the open method of being put down in writing for the flat 11-072544 of communique number of Japan special permission etc., beyond detection voltage, also detect electric current and time, and perform calculations in integrated circuit according to these information, just can be familiar with the remaining capacity of battery.
For monitoring finishing of charging, speciallyying permit in open communique 2000-348725 number in Japan has the people to propose to use LiMn 2O 4As positive active material, use Li 4Ti 5O 12With the scheme of native graphite as negative electrode active material.This technology has disclosed one section end of monitoring charging that can be provided with potential difference by the anticathode current potential, and the Li that current potential is passed with 1.5V 4Ti 5O 12The negative pole that combines with the native graphite of current potential being passed with 0.1V.
Below just use the positive pole that contains the original positive active material that has spinel structure that in the past proposed, and the battery system that contains the negative pole of the titanyl compound that contains lithium that has the spinelle skeleton in the negative pole describes.
In open the flat 11-321951 of communique number of Japan special permission, proposed: synthetic composition formula Li (1+x)Mn (2-x-y)M yO z(0≤x in the formula≤0.2,0.2≤y≤0.6,3.94≤z≤4.06, M is a nickel, perhaps in must composition nickel, add aluminium and be selected from least a element in the transition elements) shown in positive active material, do not contain the synthetic method of the positive active material of impurity NiO.Specifically put down in writing mixture that manganese compound and compounds of metal M are mixed after carrying out roasting under 900 ℃-1100 ℃, the method that makes the compound of said mixture and lithium carry out roasting together once more.
But, utilize this method, because of the reaction of manganese and metal M is the reaction of solid and solid, so that both equably solid solution be difficult.In addition, carry out roasting,, be difficult to make the positive active material of target so can reduce thereafter and reactivity lithium at the high temperature more than 900 ℃.
Open the flat 9-147867 of communique number following material is disclosed in Japan's special permission: with general formula Li X+yM zMn 2-y-zO 4Shown in, have spinel structure, M represents the positive active material that the insertion compound of transition metal, 0≤x≤1,0≤y＜0.33,0＜z＜1 discharges and recharges the current potential of Li/Li+ more than 4.5V.
Japan's special permission openly discloses to possess for the flat 7-320784 of communique number and has contained with Li 2MnO 3Or LiMnO 2As the positive pole of active material, contain to inhale the Li of storage lithium 4/3Ti 5/3O 4Or LiTi 2O 4Battery as the negative pole of active material.Japan's special permission openly discloses for the flat 7-335261 of communique number possesses the cobalt of containing acid lithium (LiCoO 2) positive pole, contain lithium titanate (Li 4/3Ti 5/3O 4) the battery of negative pole.In addition, Japan's special permission discloses following battery open the flat 10-27609 of communique number: possess and contain with lithium or lithium alloy, perhaps have the negative pole of the lithium-titanyl compound of spinel structure as active material; Contain oxide Li with lithium one manganese with spinel structure 4/3Mn 5/3O 4Positive pole as active material; Contain electrolyte LiN (CF 3SO 2) 2Electrolyte with mixed solvent more than the 2 composition systems that comprise ethylene carbonate.
Adopt the transition metal oxide (LiA that contains lithium open disclose for the flat 10-27626 of communique number of Japan special permission xB 1-xO 2) as positive active material, adopt lithium titanyl compound (Li 4/3Ti 5/3O 4) as negative electrode active material, the actual capacity of negative electrode active material to the ratio of the actual capacity of the active material of positive pole below 0.5.Japan's special permission discloses employing lithium manganese oxide (Li open the flat 10-27627 of communique number 4/3Mn 5/3O 4) as positive active material, adopt Li-Ti oxide (Li 4/3Ti 5/3O 4) and lithium as negative pole, Li-Ti oxide to the mol ratio of lithium manganese oxide below 1.0, lithium to the mol ratio of Li-Ti oxide below 1.5.
Japan's special permission openly discloses positive pole communique 2001-243952 number and has contained composition formula Li 1-xA xNi 1-yM yO 2(A is the metal more than a kind in the alkalies and alkaline earth of being selected from except that Li, M be selected among Co, Mn, Al, Cr, Fe, V, Ti and the Ga more than a kind, 0≤x≤0.2,0.05≤y≤0.5) positive active material that 2 particles that 1 particles aggregate of the average grain diameter shown in more than 0.5 μ m forms constitute; Negative pole contains the composition formula LiaTibO as negative electrode active material 4Lithium-titanium composite oxide shown in (0.5≤a≤3,1≤b≤2.5).
In addition, Japan's special permission discloses the battery that possesses following positive pole and negative pole open communique 2001-210324 number: above-mentioned positive pole comprises the composition formula Li as positive active material 1+xM yMn 2-x-yO 4-z(M be selected among Ti, V, Cr, Fe, Co, Ni, Zn, Cu, W, Mg and the Al more than a kind, 0≤x≤0.2,0≤y≤0.5,0≤z＜0.2) shown in, by adopting Cu κ αThe half value of (400) diffraction maximum that the powder X-ray diffractometry of ray records is wide (θ is the angle of diffraction) more than 0.02 θ, below 0.1 θ, is formed by 1 particle and is shaped as octahedral complex Li-Mn-oxide; And negative pole comprises the composition formula Li as negative electrode active material aTi bO 4Lithium-titanium composite oxide shown in (0.5≤a≤3,1≤b≤2.5).
But utilization technology in the past can not fully solve the problem with aforesaid high speed characteristics and pulse characteristic raising.This is because if discharge and recharge at a high speed, can cause big load to active material, causes structural deterioration, so be difficult to keep cycle life.In addition, have the cobalt acid lithium of layer structure and graphite material etc. when discharging and recharging, on layer direction, occur bigger expansion and contraction repeatedly,, particularly when discharging and recharging at a high speed, cycle life is shortened so cause the stress of active material and electrolyte to ooze out between electrode.Therefore, in order to prolong the life-span of aforesaid battery, suppressing the expansion of active material and shrinking just becomes important topic.
For the battery of the power supply that is used as electronic equipment, people need its discharge curve with even shape, even carry out high rate discharge as mentioned above, also can keep the flatness of voltage.Yet the discharge curve of the actual battery that uses existence all the time has S shape and voltage slowly reduces, and, is discharging latter stage the situation that cell voltage can descend suddenly though perhaps curve is smooth.Under the former situation,, exist voltage to be preferably smooth problem though not too difficulty is carried out the monitoring of remaining capacity.On the other hand, under the latter's the situation, till discharge was finished, change in voltage was very little, and consequently very difficulty is monitored the remaining capacity of battery.Therefore, make the battery that suitably to monitor remaining capacity and become another problem.
The objective of the invention is and to address the above problem.Be the present invention the following is purpose: design battery by the Capacity Ratio of current collector material, interlayer and the both positive and negative polarity active material of selected, electrolyte, positive pole and the negative pole of composition, crystal structure and the synthetic method of positive active material, battery system etc. is carried out optimization, provide a kind of speed characteristic, cycle life, fail safe and keeping quality all improved rechargeable nonaqueous electrolytic battery.The present invention also provides a kind of rechargeable nonaqueous electrolytic battery that adopts following positive active material: this active material has smooth charging and discharging curve, and latter stage voltage drop (drop) is set consciously in discharge, easily remaining capacity is monitored.
Summary of the invention
1. positive active material
The present invention relates to have the positive active material of following feature: by formula Li 2 ± α(Me) 4O 8-xShown in, the reaction of its charge-discharge region is 2 phase reactions, 0≤α in the formula＜0.4,0≤x＜2, and Me contains Mn and at least a transition metal that is selected among Ni, Cr, Fe, Co and the Cu.
Above-mentioned positive active material more fortunately transition metal mutually in have 2 * 2 superlattice.
In above-mentioned positive active material, the ratio of Mn and other transition metal better is essentially 3: 1.
Above-mentioned positive active material better has spinels crystallization (spinel-framework-structure), and has Li and/or Me on 16 (c) position of Fd3m space group.
The charging potential of above-mentioned positive active material and the difference of discharge potential are preferably 0.2-0.8V.
In addition, belong to the lattice constant of cubic system more fortunately below 8.3 .
Above-mentioned positive active material does not preferably have 8 bodies.That is, the form of the particle of above-mentioned positive active material is preferably any following form: 24 bodies of rhomboid (icositetraedraon), oblique side's 12 bodies (rhombic dodecahedron) and have 8 hexagons and 14 bodies (tetradecahedron) of 6 dimetric.
Above-mentioned positive active material is made of the crystal grain of the particle diameter with 0.1-8 μ m and the mixture of the offspring of the above-mentioned crystal grain of the particle diameter with 2-30 μ m.
2. the manufacture method of positive active material
The present invention relates to have the manufacture method of the positive active material of following feature: contain following 3 operations: (1) will be contained Mn and be selected from the operation that compound at least a among Ni, Cr, Fe, Co and the Cu makes raw mix, the perhaps synthetic operation that contains the Mn compound and be selected from least a cocrystalization compound among Ni, Cr, Fe, Co and the Cu; (2) operation that above-mentioned raw materials mixture or cocrystalization compound and lithium compound are mixed; (3) more than 600 ℃ the 1st roasting being carried out in the mixture heating of above-mentioned operation (2) gained, make formula: Li 2 ± α(Me) 4O 8-xShown in, the reaction of charge-discharge region is the operation of the positive active material of 2 phase reactions, O≤α in the formula＜0.4,0≤x＜2, Me contains Mn and is selected from least a transition metal among Ni, Cr, Fe, Co and the Cu.
The temperature of above-mentioned the 1st roasting is more fortunately more than 900 ℃.
Above-mentioned manufacture method contains the operation of carrying out the 2nd roasting under than the low temperature of above-mentioned the 1st sintering temperature after above-mentioned the 1st roasting.
Above-mentioned the 2nd sintering temperature of this moment is preferably 350 ℃-950 ℃.In addition, above-mentioned the 2nd sintering temperature is more preferably 650 ℃-850 ℃.
After more above-mentioned the 1st roasting of above-mentioned manufacture method and/or after the 2nd roasting, also contain operation with above-mentioned positive active material quenching.
Above-mentioned quenching carries out with the cooling rate more than 4.5 ℃/minute, better carries out with the cooling rate more than 10 ℃/minute.
Above-mentioned quenching better proceeds to till the room temperature.
3. rechargeable nonaqueous electrolytic battery
The invention still further relates to rechargeable nonaqueous electrolytic battery: have the positive pole that contains above-mentioned positive active material, the negative pole that contains titanyl compound, nonaqueous electrolyte and interlayer, have the practical charge-discharge region of 2.5V-3.5V and the practical average voltage of 3V with following feature.
Above-mentioned titanyl compound better has spinel structure.
Above-mentioned titanyl compound better is Li 4Ti 5O 12
Above-mentioned rechargeable nonaqueous electrolytic battery better is the drop that has on the work discharge voltage O.2V-0.8V.
Above-mentioned positive pole and negative pole better have the collector body that is made of aluminum or aluminum alloy.
Above-mentioned nonaqueous electrolyte better contains and is selected from least a in propylene carbonate, gamma-butyrolacton, gamma-valerolactone, methyl diethylene glycol dimethyl ether, sulfolane, trimethyl phosphate, triethyl phosphate and the carbonic acid methoxy ethyl ester.
Above-mentioned interlayer better is made of nonwoven fabrics.
Above-mentioned nonwoven fabrics better is made of at least a in polyethylene, polypropylene and the polybutylene terephthalate (PBT).
Above-mentioned negative electrode active material verify above-mentioned positive active material weight ratio more fortunately more than 0.5, less than 1.2.
Description of drawings
Fig. 1 is the electrochemical properties figure of positive active material of the present invention, and this positive active material is to carry out roasting in 12 hours (the 1st roasting) by the mixture with cocrystalization compound and lithium compound under 1000 ℃ (a), 900 ℃ (b), 800 ℃ (c), 700 ℃ (d) and 600 ℃ (e) in air to form.
Fig. 2 is the figure of the TG curve (thermogravimetry) of the positive active material after demonstration the 1st roasting.
Fig. 3 is the charging and discharging curve figure that shows positive active material of the present invention, and this positive active material is by after carrying out 12 hours the 1st roasting under 1000 ℃, carries out 48 hours the 2nd roasting under 700 ℃ and makes.
Fig. 4 is the SEM photo that shows the cross section of positive active material of the present invention (a) and positive active material in the past (b).
Fig. 5 is the SEM photo of the positive active material particle that makes of the condition by situation 1.
Fig. 6 is the SEM photo of the positive active material particle that makes of the condition by situation 2.
Fig. 7 is the SEM photo of the positive active material particle that makes of the condition by situation 3.
Fig. 8 is the SEM photo of the positive active material particle that makes of the condition by situation 4.
Fig. 9 is the X-ray diffractogram of the positive active material of the present invention that makes under various the 1st sintering temperatures.
Figure 10 is the figure of measurement result that is presented at the FT-IR of the positive active material of the present invention that makes under various the 1st sintering temperatures.
Figure 11 is the X-ray diffractogram of the positive active material of the present invention that makes under various conditions.
Figure 12 is the figure of measurement result that shows the FT-IR of the positive active material of the present invention that makes under various conditions.
Figure 13 is the figure that shows the situation of each atom site in the crystal structure of positive active material of the present invention.
Figure 14 is the figure of variation that shows the elementary cell constant of the positive active material that makes through quenching.
Figure 15 is the figure that shows the X-ray diffraction graphic change when positive active material of the present invention discharges and recharges.
Figure 16 is the figure that shows the variation of the lattice constant when positive active material of the present invention discharges and recharges.
Figure 17 is the figure that shows the behavior that discharges and recharges of battery system of the present invention.
Figure 18 is the figure that shows the cycle life when battery system of the present invention is recycled to 200 times.
Figure 19 is the figure that shows the part throttle characteristics of battery system of the present invention.
Figure 20 is the figure that shows the high-rate discharge characteristic (no drop) of battery system of the present invention.
Figure 21 is the figure that show to measure the measurement result that is accompanied by the dilatometer that discharges and recharges the expansion that produced and contraction.
Figure 22 is the figure that shows the electrochemical behavior of the positive active material of the present invention that makes through quenching.
Figure 23 is the figure that shows the discharge behavior of battery system of the present invention.
Figure 24 is the figure that shows the high speed characteristics of battery system of the present invention.
Figure 25 is the figure that shows the pulse discharge characteristic of battery system of the present invention.
Figure 26 is a part of sectional front view of the cylindrical battery that makes of embodiments of the invention.
Embodiment
The present invention is by with the design object optimization of the novel composition of positive active material and the capacity ratio of synthetic method and other battery constituent material and positive active material and negative electrode active material etc., provide have smooth charging/discharging voltage, good high speed characteristics and the rechargeable nonaqueous electrolytic battery of long cycle life.
Adopt positive active material of the present invention to design suitable battery system, can near the latter stage of discharging, be freely formed the drop of current potential.Like this, rechargeable nonaqueous electrolytic battery of the present invention can increase the alarm function of correct grasp remaining capacity and correct display power supply capacity consumption.
Utilize positive active material of the present invention because of drawing the discharge curve of even shape, so can be by using for example Li of the discharge curve that can draw even shape 4Ti 5O 12Be used as negative pole, just can make the battery that to draw for the discharge curve of the best even shape of electronic equipment.
In addition, because the battery of the invention described above has obtained the voltage of 3V level, can replace in the past lithium 1 primary cell and the battery pack of dry cell 2 joint, use and can obtain remarkable result in the electronic equipment of for example camera, digital camera, game machine, portable MD cassette player and earphone stereo ceiver etc.
1. positive active material of the present invention is synthetic
The present invention relates to have the positive active material of following feature: by composition formula Li 2 ± α(Me) 4O 8-xShown in, the reaction of charge-discharge region is 2 phase reactions, 0≤α＜0.4,0≤x＜2 wherein, and Me contains Mn and is selected from least a transition metal among Ni, Cr, Fe, Co and the Cu.Above-mentioned composition formula better satisfies 0≤x＜1.3.
Below just with Li[Ni 1/2Mn 3/2] O 4For the positive active material of representing of the present invention describes.These explanations also describe at the positive active material with other compositions in the above-mentioned composition formula scope.
Li[Ni 1/2Mn 3/2] O 4Can form according to the rules by the raw material that will contain oxide, hydroxide and/or the carbonate etc. that constitute element and mix, and the mixture of gained carried out roasting (the 1st roasting) and synthesize.But, must be with the particle diameter of each raw material unified and fully mix for homogeneous reaction, so need the powder technology of height this moment when synthetic.
On the other hand, Li[Ni 1/2Mn 3/2] O 4Also can in the aqueous solution, synthesize by making nickel and manganese as hydroxide or carbonate co-precipitation.At this moment, be evenly dispersed in the particle because of making the nickel and the manganese that are difficult to disperse in advance, so can be easier to synthesize.
Thus, following about synthetic example in, adopted the cocrystalization compound of the hydroxide that makes and as the lithium hydroxide of lithium compound.After above-mentioned substance fully mixed, the mixture of gained is carried out roasting (the 1st roasting).The mixture of the hydroxide of eutectic and lithium hydroxide can be configured as graininess to react more effectively.
Here, Fig. 1 is the electrochemical properties figure of positive active material, and this positive active material is to carry out roasting in 12 hours (the 1st roasting) by the mixture with cocrystalization compound and lithium compound under 1000 ℃ (a), 900 ℃ (b), 800 ℃ (c), 700 ℃ (d) and 600 ℃ (e) in air to make.Specifically, (the Ni that fully mixes the eutectic gained 1/4Mn 3/4) (OH) 2And LiOHH 2O and make mixture thereafter, is configured as graininess with this mixture, the formed body that roasting makes and make Li[Ni 1/2Mn 3/2] O 4
For electrochemical properties, the testing battery of making as described below is measured.
At first, with the Li[Ni of 80 weight portions 1/2Mn 3/2] O 4, the conductive agent acetylene black of 10 weight portions and 10 weight portions the poly-inclined to one side vinylidene fluoride (PVdF) of adhesive mix, (NMP) makes paste with the mixture diluted that makes with the N-N-methyl-2-2-pyrrolidone N-.This paste is coated on the collector body that is made of aluminium foil.The collector body that this is coated in a vacuum, carry out 30 minutes drying under 60 ℃ after, be cut into 15mm * 20mm size., more in a vacuum, 150 ℃ under collector body cut off after carried out 14 hour drying, make the electrode of test usefulness thereafter.
As to electrode, adopt the electrode of on stainless steel, pressing attached lithium sheet metal to form.As interlayer, adopt the porous film of polyethylene system; As electrolyte, use the LiPF that in the mixed solvent that ethylene carbonate (EC) and dimethyl carbonate (DMC) is mixed with 3: 7 (volume ratio), dissolves 1.0M 6The solution that forms.
Order will test and carry out superimposedly with electrode, interlayer and lithium metal, behind the injection electrolyte, clamp from the outside with suitable intensity with the anchor clamps of stainless steel, make testing battery.With 0.17mA/cm 2Current density between 3.0V-5.0V, repeatedly the testing battery that makes is discharged and recharged.
Fig. 1 has shown the positive active material that adopts each roasting temperature to form, and for the lithium metal, discharge voltage may be up to 4.6V-4.8V, and charge/discharge capacity is about 125mAh/g.Therefrom as can be known: sintering temperature is high more, and polarization characteristic is excellent more.
Also as can be known: along with increase in temperature, near the drop of the voltage the 4V is regular to be increased.Utilize the present invention can utilize above-mentioned phenomenon to provide and be fit to the battery that electronic equipment detects remaining capacity.That is, control the opportunity that the required remaining capacity of battery is detected by sintering temperature being carried out various changes.Because of this voltage drop appears near the 4V, its fabric width is 0.2V-0.8V, counts V bigger variation like this, so will have the battery of this drop when being used for electronic equipment, the trouble of the power interruptions of this electronic equipment also can not occur.
As from the foregoing: positive active material of the present invention can mix by the compound with raw mix or cocrystalization compound and lithium, carries out the 1st roasting, thereafter, slowly atmosphere temperature is reduced (slowly cooling) and makes.The condition of the gentle slow cool down of the 1st roasting is as described below:
The 1st roasting: lower limit: 600 ℃, be preferably 900 ℃
The upper limit: 1000 ℃
Time: 2-72 hour
Slow cooling rate: lower limit: 4.5 ℃/minute
The upper limit: 10 ℃/minute
2. the raising of control of the voltage drop in discharge latter stage of positive active material and polarization characteristic
As mentioned above, sintering temperature is high more, and polarization becomes more little, but the regional wide change of the 4V section of this moment is big.Yet people wish to suppress polarization certainly lessly, and can freely control the regional wide of 4V.For this reason, the present inventor furthers investigate synthetic method.
Fig. 2 has shown the TG curve (thermogravimetry) of the positive active material after the 1st roasting.Here used positive active material is the Li[Ni that forms by roasting under 500 ℃ of low temperature 1/2Mn 3/2] O 4Heat up with per 50 ℃ temperature, this positive active material is heated between 700 ℃-850 ℃, when each temperature, keep positive active material, allow temperature carry out stepped intensification.When the decline temperature, too temperature is controlled.Programming rate is 10 ℃/minute, and atmosphere is atmosphere.
In Fig. 2, a is that temperature, b show the weight that changes when heating up, the weight that changes when c is cooling.Can observe from Fig. 2: till 400 ℃, be considered to the irregular loss in weight relevant with moisture.Be warming up to 1000 ℃ process from 400 ℃, in 700 ℃-1000 ℃ scope, weight just reduces; On the other hand, during the weight change of observation in the temperature-fall period as can be known: reduce to 800 ℃ the process from 1000 ℃, the weight of minimizing was the same when weight increased (recoverys) and intensification, became with the speed of this test.When reducing to 700 ℃, speed is slack-off, and weight is almost completely recovered.The increase of this weight be considered to because the oxygen that discharges during high temperature by roasting again (the 2nd roasting), promptly reoxidizing of positive active material makes oxygen turn back to cause in this positive active material.Therefore, when recovering the operation of weight, present inventor's suggestion is preferably lowered the temperature with the speed below 10 ℃/minute to the temperature of the positive active material of gained after the 1st roasting.
Next, carry out 12 hours the 1st roasting under Fig. 3 has shown 1000 ℃ after, under 700 ℃, carry out again 48 hours the 2nd roasting and the charging and discharging curve figure of positive active material.From this result as can be known: this positive active material has the charge/discharge capacity that is about 135mAh/g, has one section that is about 15mAh/g near 4V, the polarization characteristic excellence.
From the above: the positive active material that forms for roasting under 1000 ℃ of high temperature (the 1st roasting) once, be lower than under 1000 ℃ the temperature, for example the drop of the positive active material when 700 ℃ are carried out roasting again (the 2nd roasting) and near the drop the 4V can be controlled at as shown in Figure 1 700 ℃.
In addition, the positive active material that has passed through the 1st roasting and the 2nd roasting had been because of once having carried out roasting under 1000 ℃, do not have pore but had the crystal grain of having grown, so have high packed density.And the polarization characteristic of this positive active material is good.
From the above, from the angle of the voltage section of falling and polarization characteristic, positive active material of the present invention better by the compound with raw mix or cocrystalization compound and lithium, carries out the 1st roasting, carries out the 2nd roasting then and makes.The optimum condition of the 1st roasting and the 2nd roasting is as described below:
The 1st roasting
Lower limit: 600 ℃, be preferably 900 ℃
Lower limit: 1000 ℃
Time: 2-72 hour
The 2nd roasting
Lower limit: 350 ℃, be preferably 650 ℃
The upper limit: 950 ℃, be preferably 850 ℃
Time: 2-72 hour
From result shown in Figure 2 and electrochemical properties evaluation as can be known: more than 600-1000 ℃, more fortunately 900-1000 ℃ carry out the 1st roasting after, quenching to 350 ℃～950 ℃, again 350-950 ℃, more fortunately 650-850 ℃ carry out the 2nd roasting.
By utilizing aforesaid condition, the polarization characteristic of the positive active material of gained is improved, can suitably control near charging and discharging curve figure shown drop 4V simultaneously.In above test, the programming rate during roasting is 7.5 ℃/minute, and cooling rate is 4.5 ℃/minute.
(3) control of the particle shape of active material
When being applied in positive active material in the battery, the particle shape of positive active material is important factor, and the capacity of the lithium ion battery of selling on the market and the enhancing of performance are to exaggerate not at all by the saying that the form of control particle is carried out.The present inventor is conceived to this point, the further investigation discovery has been carried out in particle shape preferably and control thereof to positive active material of the present invention: as mentioned above, in the manufacture method of positive active material of the present invention, after carrying out the 1st roasting under the high temperature (more than 900 ℃), better carrying out to reoxidize is the 2nd roasting of purpose.
At this moment, utilize SEM under with 1000 ℃, 12 hours condition, carrying out the 1st roasting, under the condition of 700 ℃ and 48 hours, carry out the 2nd roasting and the cross sectional shape of particle of positive active material of the present invention take.The SEM photo of gained is presented among Fig. 4 (a) (magnification ratio is 300000 times).Fig. 4 (b) be do not carry out the 2nd roasting and all the other all with the SEM photo of the same positive active material that makes of positive active material of Fig. 4 (a).
As can be seen from Figure 4: because once under 1000 ℃, carried out roasting, so the crystal grain prosperity of positive active material.This particle is 1 particle of 2-3 μ m, and this particle is the particle that its inner impunctate fully exists filling to form.
Coating density and packed density when the form of the particle of positive active material (the particularly shape of profile) makes pole plate to adopting positive active material have considerable influence.Japan speciallys permit the motion that openly discloses for particle shape for communique 2001-210324 number, has put down in writing the octahedron that is shaped as of 1 particle particularly.
Positive active material of the present invention preferably has and is different from octahedral shape fully, at that point, obviously is different from technology in the past, and it the reasons are as follows described.
At first, about the method for control particle shape, to make Li[Ni 1/2Mn 3/2] O 4Positive active material be that example describes.For positive active material, has same trend within the scope of the invention with other compositions.
(1) situation 1 (Fig. 5)
By in about 3 hours, temperature being warming up to 1000 ℃ from room temperature, keep carrying out in 12 hours the 1st roasting down at 1000 ℃.
After the 1st roasting, in 2 hours, temperature is cooled to room temperature (slowly cooling rate is 8 ℃/minute) from 1000 ℃.
(2) situation 2 (Fig. 6)
By in about 3 hours, temperature being warming up to 1000 ℃ from room temperature, keep carrying out in 12 hours the 1st roasting down at 1000 ℃.
After the 1st roasting, spend 30 minutes with temperature and be cooled to 700 ℃ from 1000 ℃, keep carrying out in 48 hours the 2nd roasting down at 700 ℃.
After the 2nd roasting, spend 1.5 hours with temperature and be cooled to room temperature (slowly cooling rate is 7.5 ℃/minute) from 700 ℃.
(3) situation 3 (Fig. 7)
By in about 3 hours, temperature being warming up to 1000 ℃ from room temperature, keep carrying out in 12 hours the 1st roasting down at 1000 ℃.
After the 1st roasting, from 1000 ℃ of quenchings to room temperature.
In about 1 hour, temperature is warming up to 700 ℃, keeps carrying out in 48 hours the 2nd roasting down at 700 ℃.
After the 2nd roasting, spend 1.5 hours with temperature and be cooled to room temperature from 700 ℃.
(4) situation 4 (Fig. 8)
By in about 3 hours, temperature being warming up to 1000 ℃ from room temperature, keep carrying out in 12 hours the 1st roasting down at 1000 ℃.
After the 1st roasting, from 1000 ℃ of quenchings to room temperature.
Roughly distinguish, in situation 3 and 4, adopted the quenching operation, in situation 2 and 3, adopted 700 ℃ reoxidize (the 2nd roasting) operation.
The SEM photo that in Fig. 5-8, has shown the positive active material particle that the condition according to situation 1-4 makes.From these SEM photos as can be known: the particle shape of positive active material of the present invention is not octahedra.Such form is difficult to be described, and above-mentioned positive active material can be described as the positive active material that contains 24 bodies of rhomboid (icositetrahedraon) or tiltedly square 12 bodies (rhombic dodecahedron).Say in further detail: above-mentioned positive active material is the positive active material that contains 14 bodies (tetradecahedron) that have 8 hexagons and 6 dimetric.In Fig. 7 and 8, (a) adopted 1000 times, (b) adopted 30000 times multiplying power.
The control of particle shape is subjected to the considerable influence of quenching operation as can be known.The seamed edge of the particle of the positive active material of situation 1 and 2 gained is outstanding, and the seamed edge of the particle of the positive active material that situation 3 and 4 makes is round.That is, hence one can see that: can obtain having positive active material than round arris edge by taking the quenching operation.
When the positive active material with situation 1-4 gained is coated on the pole plate that battery uses, if use the positive active material of seamed edge circle just can improve the flowability of powder or coating paste, so but high density fill.
By on can think: positive active material of the present invention is the octahedra particle that complete technology different from the past proposes, and contain 24 bodies of rhomboid (icositetrahedraon), oblique side's 12 bodies (rhombicdodecahedron), say in further detail, contain 14 bodies (tetradecahedron) that have 8 hexagons and 6 dimetric, and brought into play through the form of this particle and positive active material that battery behavior is improved.In addition, whole powders of positive active material of the present invention preferably constitute by having crystal grain that is about 0.1-8 μ m particle diameter and the offspring with crystal grain of 2-30 μ m particle diameter.
As from the foregoing, positive active material of the present invention from the angle of the control of particle shape, better by the compound with raw mix or cocrystalization compound and lithium, carries out the 1st roasting, carries out quenching and makes.In addition, also can behind quenching, carry out the 2nd roasting.The condition of the 1st roasting, quenching and the 2nd roasting is as described below:
The 1st roasting
Lower limit: 600 ℃, be preferably 900 ℃
Lower limit: 1000 ℃
Time: 2-72 hour
Quench rate is more than 10 ℃/minute, more fortunately more than 20 ℃/minute, more preferably more than 50 ℃/minute
The 2nd roasting
Lower limit: 350 ℃, be preferably 650 ℃
The upper limit: 950 ℃, be preferably 850 ℃
Time: 2-72 hour
(4) crystal structure of positive active material, X-ray diffraction figure and FT-IR signal
For crystal structure, positive active material of the present invention has spinels crystalline texture (spinel-frameworkstructure).Fig. 9 has shown the X-ray diffraction figure of the positive active material of the present invention that makes under the 1st various sintering temperatures.
(a)-(e) be respectively under 600 ℃, 700 ℃, 800 ℃, 900 ℃ and 1000 ℃, to carry out the 1st roasting and the X-ray diffraction figure of the positive active material that makes.The composition of positive active material is Li[Ni 1/2Mn 3/2] O 4
Suppose to be cubic crystal in the X-ray diffraction figure of gained, belong to its Miller index, as shown in Figure 9, can belong to all peaks.As can be seen from Figure 9: carry out under the situation of the 1st roasting under the high temperature, the peak is steeper, and crystallographic strengthens.
The measurement result of the FT-IR of the positive active material shown in Fig. 9 (a)-(e) is illustrated respectively among (a)-(e) of Figure 10.From figure as can be known: under 700 ℃ positive active material (b) situation 8 steeper peaks are arranged, be higher than 700 ℃ or all be the peak of broad less than the peak of 700 ℃ positive active material.Hence one can see that, and the 1st roasting of carrying out under 700 ℃ is comparatively desirable for the arrangement of crystal.
No matter have or not quenching, can obtain X-ray diffraction figure about the same by the 2nd roasting.In order to study crystal structure more in great detail, the X-ray diffraction figure of the positive active material of said circumstances 3 and 4 gained is compared.
Figure 11 has represented the X-ray diffraction figure of the positive active material (b) of the positive active material (a) of said circumstances 3 gained and said circumstances 4 gained, and Figure 12 has shown the measurement result of the FT-IR of these positive active materials.The difference of these samples is whether passed through the process that reoxidizes.Consider these situations, to the X-ray diffraction figure of quenching sample carry out the result of structural analysis clear and definite following mechanism of the present invention, these mechanism become the factor of performance effect of the present invention.
Positive active material of the present invention we can say to have composition formula Li 2 ± α(Me) 4O 8-x(in the formula, 0≤α＜0.4,0≤x＜2 are preferably 0≤x＜1.3, and Me contains Mn and at least a transition metal that is selected among Ni, Cr, Fe, Co and the Cu).Below for easy understanding, describe with regard to the concrete example of α=0.
Belonging to LiMn 2O 4In the atomic arrangement of the spinel structure of the space group Fd3m that has, elemental lithium has occupied the 8a position, and the Me of transition metal (Mn) has occupied the 16d position, and oxygen has occupied the 32e position.But the 16c position is normally empty.Positive active material of the present invention has the feature of the element arrangements of allowing in this 16c position.
That is, this is because in positive active material of the present invention, and the amount of element that enters the 16c position by control is with regard to the drop of the voltage of the above-mentioned discharge curve of may command.
Carry out the 1st roasting and quenching and the sample of the positive active material that makes (does not have the 2nd roasting in parsing, promptly do not have and reoxidize) the X-ray diffraction figure time as can be known: if hypothesis Me is about 1/5,16c position with the 8a position is that 2/5,16d position are that 7/4 ratio exists, can fine and X-ray diffraction figure coupling.Can think thus by temperature being warming up to 1000 ℃ oxygen to be broken away from from spinel structure, transition metal is reduced, and the elemental lithium of a great deal of of the near surface of positive active material and transition metal move to the cause of 8a position and 16c position respectively.Because this phenomenon, the part in the spinel structure of positive active material of the present invention forms the rock salt structure.
Through the 1st roasting and quenching and above-mentioned sample, because of less than through importing the operation that reoxidizes of oxygen again, so from the judgements such as result of above-mentioned TG curve, by Li 1.2Me 2.4O 4Expression, the ratio with 1: 3 among the Me contains Ni and Mn.
From X-ray diffraction figure shown in Figure 11 as can be known: after carrying out the 1st roasting and quenching, through carry out under 700 ℃ reoxidize (the 2nd roasting) and positive active material (a) and the 1st roasting (1000 ℃) after temperature is reduced, continue at again in 700 ℃ of positive active materials (c) that get through reoxidizing (the 2nd roasting) down, by reoxidizing (the 2nd roasting), these rock salt structures reversibly revert to spinel structure.The flexibility of the crystal structure of such positive active material when causing positive active material to be subjected to stress because of high speed charge and discharge cycles etc., can realize the stabilisation of crystal structure, as a result of, can realize the long-life.
Can know from the measurement result of FT-IR shown in Figure 12 and to observe: through reoxidizing (the 2nd roasting) operation and positive active material (a) and (c) have 8 peaks.
To this, just carry out the 1st roasting, when the decline temperature, reoxidize and the X-ray diffraction figure of positive active material and the measurement result of FT-IR be presented at respectively the positive active material (b) of Figure 11 and Figure 12 and (d) in.Can find from the X-ray diffraction figure of these positive active materials: reoxidize (the 2nd roasting) and positive active material have much at one spinels crystalline texture.But the FT-IR measurement result is obviously different, does not clearly observe 8 peaks.These 8 peaks, because the local symmetry of the Fd3m of spinel structure (local symmetry), so can not predict in theory.Thus, also can differentiate positive active material of the present invention by the measurement result of FT-IR, this method is effective when having disappeared the positive active material of drop of voltage in fact in differentiating charging and discharging curve figure.
Then, to composition formula Li 2 ± α(Me) 4O 8-xα in (in the formula, 0≤α＜0.4,0≤x＜2 are preferably 0≤x＜1.3, and Me contains Mn and at least a transition metal that is selected among Ni, Cr, Fe, Co and the Cu) and the value of x describe.
The α value is the key element that changes for the control particle growth.If make the composition 2 of α value less than Chemical Measurement, can when synthetic, suppress particle and grow up, surface area is tending towards increasing.On the contrary, the α value increases, and can promote particle growth.Thus, design particle according to the battery desirable characteristics, just can suppress particle growth by the ratio of components that changes lithium this moment.In fact the scope of α value be about ± and 0.4, if depart from above-mentioned scope (amplitude of fluctuation), may exert an influence to the original function of positive active material.
On the other hand, for the value of x, because of the positive active material that makes through 1000 ℃ the 1st roasting and quenching as mentioned above with Li 1.2Me 2.4O 4Expression is so the x value is scaled 1.33.Can return to stoichiometric composition by reoxidizing (the 2nd roasting) oxygen amount, it is 2 that x is considered to, but in fact x on be limited to 1.3.Therefore, the present inventor considers returning of after reoxidizing oxygen, and the scope of setting x is 0≤x＜1.3.
The situation that in Figure 13, has shown each atom site in the positive active material crystal structure of the present invention.Figure 13 shows with respect to the x value, occupies the schematic diagram of situation of the element of each position.As shown in figure 13,, effectively utilize the position of original sky, can freely control the drop of the voltage shown in the discharge curve etc. by on each position, introducing various elements.
In addition, if consider in conjunction with the measurement result of XAFS etc., aspect drop, the zone of 4V is by with respect to Mn 3+→ Mn 4+Electrochemical reaction cause that and the zone of 5V (4.7V) is by Ni 2+→ Ni 4+Electrochemical reaction cause.Hence one can see that through the sample of 2 positive active materials of aforesaid quenching gained, by reoxidizing repeatedly etc., also can freely control above-mentioned drop behind quenching.
If positive active material of the present invention is differentiated, can be listed below some from above-mentioned explanation by X-ray diffraction figure or elementary cell.Suppose to make the positive active material of drop little (in fact almost can not find), preferably consider following some.
Figure 14 has shown the variation of the elementary cell constant of the positive active material that makes through quenching.Like this, lattice constant is below 8.33 , more fortunately below 8.25 , better below 8.2 .
For the ratio of Mn and other transition metal, from the shape of capacity and discharge curve is judged, in fact 3: 1 situation is best.Reason to this is not exclusively clear and definite, but under 3: 1 the situation, the transition metal layer in the skeleton of spinel structure can form the superlattice of (2 * 2), and its effect exerts an influence.In addition, measure the superlattice point (spot) that can be observed toward (2 * 2) direction, so can confirm to form the superlattice of (2 * 2) by electronics line diffraction.
Though in the open flat 9-147867 of communique of Japan's special permission, high-tension positive active material is narrated, only composition and simple structure are disclosed, not open at all to the manufacture method and the temperature province of the best.Specifically, only put down in writing, only put down in writing wider sintering temperature simply roasting being carried out in the raw material mixing.To this, the positive active material more excellent effect of positive active material of the present invention because of having brought into play more aforesaid prior art and having made, think that novel material, this material are that prior art does not have.Utilize Japanese the special permission in open the flat 9-147867 of communique number that be documented in of the condition free control particle shape of manufacture method of the present invention also not exist.
If be conceived to crystal structure especially, in open the flat 9-147867 of communique number of Japan's special permission the LiMn that has desirable spinel structure with transition metal or Li displacement is disclosed 2O 4Mn.It is to be the record of focus with the 16d position only, with LiNiVO 4Set forth in this article etc. visibly different situation.That is, be equal to non-atomic situation on the position of 8a position and original empty 16d in the open flat 9-147867 of the communique number record of Japan special permission.
To this, in the present invention, utilize these positions by the condition of suitable control manufacture method, with the part formation rock salt structure of positive active material, control the structure of positive active material consciously by reoxidizing (the 2nd roasting).That is, in same crystal, allow rock salt structure and spinels structure coexist, can freely control above-mentioned ratio.only have unlimited spinels structure, in fact do not show the situation of the positive active material of the voltage drop in the discharge curve, utilize the mensuration of FT-IR clearly to observe and have or not 8 peaks to become the signal of identification.
(5) 2 phase reactions
The battery that shows smooth discharge curve is favourable for device therefor.Usually, positive active material discharge and recharge the reaction be 1 phase reaction, at this moment, the shape of discharge curve is a S shape according to Nernst's equation.Though part is carried out 2 phase reactions in the layer structural material of cobalt acid lithium and lithium nickelate etc., major part all is to carry out with 1 phase reaction.For this reason, the discharge curve that still shows S shape in essence.Therefore, special in the latter stage of high rate discharge, cause that with the polarization combination bigger voltage reduces, and is difficult to obtain smooth discharge curve.
On the other hand, when discharging and recharging with 2 phase reactions, discharge curve is essentially smooth.The positive active material that carries out 2 phase reactions in the whole zone that preferably discharges and recharges in this sense.The X-ray diffraction figure that discharges and recharges that in Figure 15, has shown positive active material of the present invention.(a)-(m) of Figure 15 shown the situation of the discharge capacity of 15mAh/g, 30mAh/g, 50mAh/g, 60mAh/g, 70mAh/g, 75mAh/g, 80mAh/g, 90mAh/g, 100mAh/g, 105mAh/g, 110mAh/g, 120mAh/g and 136.3mAh/g respectively.Watch the variation at peak of (111), (311) and (400) of Figure 15 can confirm to have the shape of division (split), can know and carry out 2 phase reactions.
For easier to understand, be assumed to be cubic crystal by Figure 15 the variation of lattice constant be presented among Figure 16.If from the part that has 2 lattice constants have 2 mutually the coexistence consider, can calculate lattice constant.
As can be seen from Figure 16: half-sum was later half before the discharge of positive active material of the present invention can be divided into has carried out 2 phase reactions respectively.At LiMn with spinel structure in the past 2O 4In, carried out 2 phase reactions in the zone of half, in remaining zone, carry out 1 phase reaction, not to carry out 2 phase reactions in the whole zone.That is, the positive active material of the present invention that carries out 2 phase reactions in the whole zone is different from positive active material in the past, and flatness is fabulous, shows good discharge curve.
(6) adopt the 3V level rechargeable nonaqueous electrolytic battery of oxide cathode and the detection of remaining capacity
For having adopted positive active material of the present invention as positive pole, adopted the advantage of titanium oxide during to describe as negative pole with spinel structure.Positive active material of the present invention is compared with the spinel-type positive active material of in the past 4.5V level, has bigger reversible capacity and good polarization characteristic.
Use Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) during as negative pole, can constitute the battery of 3V level.
In open communique 2001-210324 number of Japan special permission, proposed to adopt the scheme of the oxide of titanium class as negative pole.But in the text of this communique, only put down in writing the positive active material that shows positive electrode capacity in the potential range zone of 4.3V to 3.5V.They are LiMn in the past 2O 4Perhaps, add the positive active material of the interpolation element of trace therein, be different from the positive active material of the charge-discharge region of the 4.7V of having of the present invention in order to improve cycle life etc.Therefore, Japan speciallys permit the battery system that the battery of openly being put down in writing for communique 2001-210324 number is the 2.5V level.
On the other hand, battery cording of the present invention has the actual scope that discharges and recharges of 2.5V-3.5V, and the lithium primary battery of the 3V level in this and the use of selling on the market has same zone.In addition, only use the angle of 1 batteries from using 2 equipment that save dry cells, battery cording of the present invention has versatility, is favourable.
Promptly, the difference of the cell voltage of the 0.5V of battery system, show bigger advantage or defective (handicap) in the practicality of market, to this, the battery system of the 2.5V level that Japan's special permission is openly put down in writing for communique 2001-210324 number is considered in fact do not have bigger value.In addition, Japan's special permission has proposed to have the above positive active material that discharges and recharges current potential of 4.5V open the flat 9-147867 of communique number, also discloses to adopt the battery system of charcoal as negative pole.The purpose of this technology is to realize having the high-tension lithium ion battery of 4.5V level, and these are different with the purpose that battery of the present invention is.
Positive active material of the present invention can be freely controlled the drop of the voltage in discharge latter stage of discharge curve, if suitably select battery system, also can detect remaining capacity like this.As mentioned above, the battery with discharge curve (discharge voltage) of even shape is favourable for electronic equipment, but from detecting the angle of remaining capacity, is disadvantageous.To this, the positive active material of the drop of the voltage in the discharge latter stage that can design discharge curve and can freely control discharge curve by the present invention with even shape.
Thus, have the angle of the discharge curve of even shape from hope, negative pole uses Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) be favourable as negative electrode active material.
This Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) and positive active material of the present invention have much at one capacity density.Thus, if use such negative electrode active material and positive active material, when making battery, the thickness of positive plate and negative plate can be consistent, from the angle of battery behavior, also is favourable.Adopting LiCoO 2/ graphite or LiMn 2O 4In the battery system that sell the market of/graphite, because of the capacity density height of negative pole, so on the thickness of positive plate and negative plate, can produce than big difference.Because this difference, electrolyte produce diffusion when electrode interior spreads poor.Consequently on the speed of anodal and negative pole, produce imbalance, exist on the one pole plate and bear load, the problem that deterioration shifts to an earlier date occurs.From this viewpoint also as can be known: with positive active material of the present invention and Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) the battery system that combines is comparatively desirable.
Above-mentioned negative electrode active material has shown the smooth charging and discharging curve of the 1.55V that is as the criterion with lithium metal.Shown use Li[Ni among Figure 17 1/2Mn 3/2] O 4As positive pole, use Li[Li 1/3Ti 5/3] O 4Charge status as the battery of negative pole system.Figure 18 has shown that above-mentioned battery is to be circulated to 200 times cycle life.Transverse axis among Figure 17 has shown the discharge capacity of the positive active material of per unit weight.The condition of discharging and recharging is 0.17mA/cm 2Current density and the constant current charge-discharge between the 0V-3.5V.
As shown in figure 17, battery of the present invention is the smooth charging/discharging voltage that has shown the average voltage of 3.2V, demonstrates the drop of voltage simultaneously latter stage in discharge.Can bring into play the Presentation Function of correct demonstration remaining capacity or the alarm function of power interruptions by utilizing this drop.The practicality scope of discharging and recharging of this battery system is that the lithium primary battery of the 3V level in the 2.5V-3.5V and the use of selling on the market has same zone.
Figure 19 has shown the part throttle characteristics of this battery system.(a) of Figure 19-(f) shown with 0.1mA/cm respectively 2, 0.17mA/cm 2, 0.33mA/cm 2, 0.67mA/cm 2, 1.0mA/cm 2And 1.67mA/cm 2The current density situation of discharging.Even can confirm also that from Figure 19 load has bigger variation, the drop of discharge voltage is also clear to be showed.
On the other hand, also this drop may not appear.Figure 20 has shown an example of this situation.Even improve load, tangible drop also do not occur.As the positive active material of this moment, use through 1000 ℃ the 1st roasting and 700 ℃ down the 2nd roasting (reoxidizing) and must positive active material.Figure 20 (a)～(b) has shown respectively with O.17mA/cm 2, 0.33mA/cm 2, 1.0mA/cm 2, 1.67mA/cm 2And 3.33mA/cm 2The current density situation of discharging.
Have bigger expansion and contraction when discharging and recharging for graphite, above-mentioned negative electrode active material is the material that does not have the nothing distortion of expanding and shrinking when discharging and recharging.Positive active material of the present invention also is not have the material that expands and shrink when discharging and recharging, thus can be by this negative pole and positive electrode material be used in combination, and can design does not in fact almost have the battery that expands and shrink and is.That is, can greatly improve the low of cycle life, speed characteristic and temperature characterisitic, above-mentioned lowly is causes toward outer the oozing out of battery system because of the deterioration, the electrolyte that expand and shrink the active material that causes.
In Figure 21, shown and utilized expansion and the contraction result that measure of dilatometer when discharging and recharging.The variation that the thickness of every group of positive plate and negative plate is respectively the thickness of the combination (lstack) that 60 μ m and 110 μ m, 1 positive plate and 1 negative plate form is measured.
As can be seen from Figure 21: expand and shrink representing, but high accuracy is measured corresponding to the form that discharges and recharges.Amounts of thickness variation is about 1 μ m, and every batteries only is 0.6%.Because people know the Li[Li as negative pole 1/3Ti 5/3] O 4For there not being the no deformable material that expands and shrink fully, so even this part is removed, the thickness of positive plate also has only 2% variation.With respect to LiCoO in the past 2When/graphite-like battery charged, positive pole was about 5%, negative pole is about 20% expansion, and the expansion of battery of the present invention and the degree of contraction and above-mentioned deformation extent great disparity are extremely low.Minimum expansion during discharging and recharging like this and contraction are the reasons that cycle life prolongs.By the present invention, particularly when discharging and recharging at a high speed, compare with in the past battery system, can greatly improve the cycle life of this moment.
(7) battery capacity design
When the volume load to battery designs, set the capacity of negative or positive electrode.This will design consciously according to the purposes of used equipment and properties of materials etc.In the battery system of 3V level of the present invention, preferably the capacity of anticathode is set.Specifically, negative electrode active material to the ratio (weight) of positive active material more than 0.5, less than 1.2.If this ratio is decided to be at 1.2 o'clock, can consider in form positive active material to be set, but, because of the theoretical charge/discharge capacity of every gram negative electrode active material is higher than the theoretical charge/discharge capacity of every gram positive active material, so in fact the anticathode active material is set.
Better its reason of battery system of setting negative pole have following some.That is, anodal current potential is about 4.7V, because of used electrolyte makes the anodal oxidative resistance that lacks sometimes.Therefore, be disadvantageous with higher anodal current potential complete charge to the stability of electrolyte.In addition, if fully elemental lithium is removed from positive active material, it is contemplated that oxygen slowly emits the oxidation that the deterioration that causes active material or the oxygen of emitting cause electrolyte, cause the deterioration of cycle life and battery behavior.
(8) collector body of positive plate and negative plate
In the lithium rechargeable battery of selling on the market, adopt the collector body of aluminium usually as positive pole, adopt the collector body of copper as negative pole.This is a cause of using the collector body of excellent corrosion resistance because considering the current potential of each electrode.Put down in writing in open communique 2001-210324 number of Japan the special permission open flat 9-147867 of communique number and the Japan's special permission and used aluminium and copper collector body respectively as anodal and negative pole.
In rechargeable nonaqueous electrolytic battery of the present invention, preferably adopt aluminum or aluminum alloy as negative or positive electrode, it the reasons are as follows described.
At first, Alloy instead of Copper uses aluminium can realize the lightweight of battery, also can reduce cost simultaneously.In the battery of selling the on the market system that adopts graphite as negative pole, because of graphite with respect to the current potential of lithium metal below 0.2V, lower, so can not use aluminium to be used as collector body.This is because the cause that aluminium and lithium ion begin to react when being higher than negative pole graphite and discharging and recharging the current potential of current potential.But battery of the present invention because of negative pole discharges and recharges the current potential height, is 1.5V in being, it is following not drop to this current potential, just can use nonreactive aluminium.Use copper to carry out deep discharge etc. when the current potential of negative pole is risen, the copper ion stripping in the electrolyte.This copper ion is reflected on the negative pole and separates out because of recharging insertion prior to lithium, hinders the insertion reaction of lithium.Its as a result lithium separate out as metal form with acicular crystal on negative terminal surface.The fail safe of battery is descended, and cycle life shortens.On the other hand, the stripping of metal ion does not take place when using aluminium and separate out again.
Under the situation that the charger of the battery system of negative pole control speed etc. breaks down, because of being overcharged, superfluous lithium is provided for negative pole.When if the collector body of negative pole is copper at this moment, superfluous lithium is separated out on negative pole.The lithium metal of such acicular crystal can make the overcharge safety of battery descend.But aluminium has the ability of abundant suction storage lithium, so when using aluminium as the collector body of negative pole, the lithium metal is not separated out on negative pole yet when overcharging, and can inhale storage on collector body.Its result, the situation that does not have the overcharge safety of battery to descend.
(9) nonaqueous electrolytic solution
Best electrolyte to 3V level rechargeable nonaqueous electrolytic battery of the present invention describes.Organic solvent as electrolyte has electrochemical window.This electrochemical window is a yardstick of weighing oxidative resistance and reducing resistance, and electrochemical window is wide more, is the good more organic solvent of stability.At general LiCoO 2In the rechargeable nonaqueous electrolytic battery of/graphite-like, cobalt discharge and recharge near the current potential 4.5V time need oxidative resistance, graphite discharge and recharge near the current potential 0V time need reducing resistance (current potential is to be as the criterion with the lithium metal, below identical).Should avoid when therefore, the organic solvent that does not have the electrochemical window that satisfies above-mentioned condition being selected to use.
Particularly when using graphite that its reducing resistance is strengthened, it is difficult using the organic solvent of lactone.In addition, also because graphite is when discharging and recharging, propylene carbonate can be decomposed etc. simultaneously, so the difficult propylene carbonate that uses.No matter these solvents be cheap and dielectric constant high, the solvent with ability of abundant dissolving electrolyte (salt), or the more excellent useful solvent of oxidative resistance, it is difficult using this solvent.No matter what kind of anti-fire action and good fail safe trimethyl phosphate and triethyl phosphate have, and with same reason, are difficult to use above-mentioned solvent.
Battery of the present invention all can use aforesaid solvent with useful characteristic in being.In rechargeable nonaqueous electrolytic battery of the present invention, because of not using graphite, and use Li 4Ti 5O 12(Li[Li 1/3Ti 5/3]) O 4As negative pole, the current potential of negative side is up to 1.5V, so relaxed the required reducing resistance of solvent greatly.Also can use in addition and discharge and recharge the propylene carbonate equal solvent that on negative terminal surface, decomposes because of graphite is distinctive and be used as extremely effectively solvent.
On the other hand, because of anodal current potential up to more than 4.7V, it is more than 5V that these solvents have oxidative resistance, so can use these solvents out of questionly.Sulfolane that oxidative resistance is good or methyl diethylene glycol dimethyl ether etc. are considered to also for being suitable for the solvent of this battery system.The solvent of used all the time DEC (dimethyl carbonate), MEC (carbonic acid Methylethyl ester) and DMC (dimethyl carbonate) etc. also can be used as the diluent of the high solvent of viscosity.
There is not special restriction for the used electrolyte of the present invention, the yet available LiPF that all the time uses 6, LiBF 4With lithium salts of organic anion etc.At common in the past LiCoO 2In the rechargeable nonaqueous electrolytic battery of/graphite system, has the mixed solvent that the EC (ethylene carbonate) of high-k and high viscosity forms because of using graphite or dissolving electrolyte to be extensive use of through low-viscosity solvent dilution.In battery of the present invention is, unrestricted to the electrolyte that uses for above-mentioned reasons, can select best electrolyte according to the desirable characteristics of used equipment.
(10) interlayer
At general in the past LiCoO 2In the battery of/graphite system, use the porous film that constitutes by polyethylene or polypropylene to be used as interlayer.This interlayer is by melt extruding polymeric material to be shaped, and on biaxially oriented the shaping thing calendering of gained is made slim porous film and form, so price is very high.Need the chief reason of this film to consider as follows.
The current potential that is used as the graphite of negative pole almost drops to and approaches the current potential that the lithium metal is separated out.Cause variety of issue for this reason.Because of the charging under fierceness charging or the low temperature all makes fine lithium separate out on a part of surface of graphite.In addition, because of excessive floating charge etc. can cause cobalt or foreign metal stripping, on negative pole, separate out.
Under these circumstances, utilize above-mentioned porous film to suppress separating out of needle-like metal,, utilize the big material of fine pore such as nonwoven fabrics can cause minute short circuit in the short time this with the physical property active force with minute aperture.In addition, the overcharge safety when breaking down etc. in order to ensure the charger of imagination, also the rising of the battery temperature in order to suppress to overcharge needs interlayer to have the function of shutdown (shutdown).This is to reach uniform temperature when (being about 135 ℃) when battery, and the minute aperture of interlayer shrinks, and ends the function that electric current flows between electrode.For this reason, in the past LiCoO 2In the battery of/graphite system, used the porous film of high price.
On the other hand, in battery of the present invention system, because of the negative pole current potential is that the difference of 1.5V and the lithium current potential of separating out is bigger, so the problems referred to above can occur hardly.Because of adopting the collector body of aluminium as negative pole, lithium is inhaled storage, does not also have the problem that above-mentioned metal is separated out.Be the elemental lithium of the same surplus of battery also, have extremely excellent security on overcharging so this battery ties up to because of not containing in the positive pole of the present invention just like cobalt.That is the high-precision shutdown function that, does not need as porous film to be had.Thus, in this battery system, because of having used the collector body of aluminum or aluminum alloy, so may use nonwoven fabrics as negative pole.
Nonwoven fabrics can improve high speed characteristics, particularly pulse characteristic widely because of the amount that keeps solution is many.Thereby do not need to have the operation of the such high complexity of porous film, so the choice of interlayer material is big and cheap.If consider to be applicable to this battery system,, preferably use for example composite material of polyethylene, polypropylene, polybutylene terephthalate (PBT), these materials as the material that constitutes interlayer.Polyethylene or polypropylene are stable for electrolyte, but during the intensity when needing high temperature, the most handy polybutylene terephthalate (PBT).For fibre diameter, better use the material about 1-3 μ m, to handle through the stack of heating, the material that the fusion adhesion forms between a part of fiber is effective on slimming or lifting intensity.
(11) rechargeable nonaqueous electrolytic battery
Below when make adopting nonaqueous electrolyte (lithium) secondary cell of positive active material of the present invention operable other constituent material set forth.
Make the conductive agent in the used anode mixture of positive pole of the present invention,, this is not had special restriction so long as in the battery that constitutes, do not cause the electronic conductivity material of chemical change.The graphite-like of for example available native graphite (flaky graphite etc.) and Delanium etc.; The carbon black class of acetylene black, kitchen carbon black, channel black, furnace black, dim and thermals etc.; The conducting fibre class of carbon fiber and metallic fiber etc.; Fluorocarbon; The metal dust class of copper, nickel, aluminium and silver etc.; The conductive metal palpus class of zinc oxide, potassium titanate etc.; The organic conductive material of the conductive metal oxide of titanium dioxide etc. and polyphenylene derivative etc. etc.These can use separately, perhaps as long as in the scope of not damaging effect of the present invention, can mix use arbitrarily.
Wherein, special handy Delanium, acetylene black, nickel by powder.Addition for conductive agent does not have special restriction, is preferably 1-50 weight %, 1-30 weight % particularly preferably, and during with charcoal or graphite, 2-15 weight % particularly preferably.
Good adhesive force agent in the anode mixture of the present invention is that decomposition temperature is at the polymer more than 300 ℃.Available for example polyethylene, polypropylene, polytetrafluoroethylene (PTFE), poly-inclined to one side 1,1-difluoroethylene (PVDF), tetrafluoroethene-hexafluoroethylene copolymer, tetrafluoraoethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), 1,1-difluoroethylene one hexafluoropropylene copolymer, 1,1-difluoroethylene-chlorotrifluoroethylcopolymer copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin), polychlorotrifluoroethylene (PCTFE), 1,1-difluoroethylene-five fluorine propylene copolymer, propylene-TFE copolymer, ethylene-chlorotrifluoro-ethylene copolymer (ECTFE), 1,1-difluoroethylene-hexafluoropropylene-TFE copolymer and vinylidene fluoride one perfluoro methyl vinyl ether-TFE copolymer etc.These can use separately, in the scope of not damaging effect of the present invention, can mix use arbitrarily.
Wherein, best is poly-inclined to one side vinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).
As the collector body of positive pole,, this there is not special restriction so long as in the battery that constitutes, do not cause the electrical conductivity body of chemical change.As the material that constitutes collector body, carbon, nickel, titanium or the silver-colored complex of handling etc. have been carried out on aluminium or the stainless surface except using stainless steel, nickel, aluminium, titanium, various alloy and carbon etc., also can be used on.
Special handy aluminum or aluminum alloy.Can also carry out oxidation processes to the surface of these materials in advance.Can also on the collector body surface, form concavo-convex by surface treatment.As shape, can adopt shape used in the field of batteries.Shape, lath body, porous plastid, foaming body, fibre bundle and the nonwoven fabrics etc. that form of paper tinsel, film, net, punching for example.Do not have special restriction for thickness, be preferably the material of 1-500 μ m.
As the used negative electrode active material of the present invention (negative material), special handy Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) titanyl compound that waits.If use this negative pole, the battery of 3V level can be made, and the problem that in the past existed can be solved, greatly improved battery performance as mentioned above.On the other hand, also positive active material of the present invention can be only used, at this moment, following negative pole can be used.
As negative material, available lithium, lithium alloy, alloy, intermetallic compound, carbonaceous material, organic compound, inorganic compound, metal complex and organic high molecular compound etc., the compound of also available suction storage and release lithium ion.These can use separately, perhaps mix arbitrarily in the scope of not damaging effect of the present invention and use.
As above-mentioned lithium alloy, available Li-Al is that alloy, Li-Al-Mn are that alloy, Li-Al-Mg are that alloy, Li-Al-Sn are that alloy, Li-Al-In are that alloy, Li-Al-Cd are that alloy, Li-Al-Te are that alloy, Li-Ga are that alloy, Li-Cd are that alloy, Li-In are that alloy, Li-Pb are that alloy, Li-Bi are that alloy, Li-Mg are alloy etc.The content of lithium is more fortunately more than the 10 weight % at this moment.
As alloy and intermetallic compound, the compound of the compound of available transition metal and silicon and transition metal and tin etc., the compound of special handy nickel and silicon.
As carbonaceous material, the carbon that available coke, RESEARCH OF PYROCARBON class, native graphite, Delanium, middle carbon microballon, graphitization mesophasespherule, vapor grown carbon, vitreous carbon class, carbon fiber (polypropylene nitrile, pitch class, cellulose family carbon fiber, gas-phase growth of carbon fibre), amorphous carbon, organic substance burn till etc.Can use separately, perhaps in the scope of not damaging effect of the present invention, mix arbitrarily and use.Wherein, better use the graphite material of graphitization mesophasespherule, native graphite, Delanium etc.
In addition, in the carbonaceous material, but O, B, P, N, S, SiC and the B beyond the carbon containing also 4The different element compounds of C etc.Its content is 0-10 weight % more fortunately.
As inorganic compound, the compound of available tin and the compound of silicon etc.As inorganic oxide, except with the titanium oxide, also available tungsten oxide, molybdenum oxide, niobium oxide, barium oxide, ferriferous oxide etc.
In addition, as inorganic chalcogen compound, the inorganic chalcogen compound of for example available iron sulfide, molybdenum sulfide, titanium sulfide etc.
As organic high molecular compound, the macromolecular compound of available polythiophene, polyacetylene etc.As nitride, the nitride of the nitride of available cobalt, the nitride of copper, nickel, the nitride of iron and the nitride of manganese etc.
Above-mentioned negative material, use capable of being combined is for example with carbon and alloy combination, perhaps with carbon and inorganic compound combination etc.
The average grain diameter of the carbonaceous material that the present invention is used is 0.1-60 μ m more fortunately.0.5-30 μ m more preferably.Specific area is preferably 1-10m 2/ g.More handy following graphite, on crystal structure, the spacing (d002) on carbon hexagon plane is 3.35-3.40 , the size of the axial crystallite of c (LC) is more than 100 .
In the present invention, because of containing Li in the positive active material, so can use the negative material (carbon etc.) that does not contain Li.In addition, in such negative material that does not contain Li, contain a spot of in advance (with respect to the negative material of 100 weight portions, for about the 0.01-10 weight portion) during Li, even the Li of a part and reaction such as electrolyte and lose activity, also can replenish, so comparatively desirable with the Li that is contained in the above-mentioned negative material.
The method that contains Li as mentioned above in negative material is: pressing the lithium metal behind the coating heating and melting on the collector body of negative material attached, the method for impregnation Li on negative material; Perhaps, in electrolyte, Li is mixed in the negative material with electrochemical method by pressing attached grade that the lithium metal is sticked in the electrode group in advance.
For the conductive agent in the cathode agent, the same with conductive agent in the anode mixture, so long as in the battery that constitutes, do not cause the electrically conductive material of chemical change, this there is not special restriction.When adopting carbonaceous material,,, also can not contain conductive agent so can contain conductive agent because of carbonaceous material self has electronic conductivity as negative material.
As the adhesive in the cathode agent, use thermoplastic resin or heat-curing resin can, best adhesive is that decomposition temperature is at the polymer more than 300 ℃.Available for example polyethylene, polypropylene, polytetrafluoroethylene (PTFE), poly-inclined to one side 1,1-difluoroethylene (PVDF), styrene butadiene rubbers, tetrafluoraoethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), 1,1-difluoroethylene-hexafluoropropylene copolymer, 1,1-difluoroethylene-chlorotrifluoroethylcopolymer copolymer, ethylene-tetrafluoroethylene copolymer (ETFE resin), polychlorotrifluoroethylene (PCTFE), 1,1-difluoroethylene First Five-Year Plan fluorine propylene copolymer, propylene-TFE copolymer, ethylene-chlorotrifluoro-ethylene copolymer (ECTFE), 1,1-difluoroethylene-hexafluoropropylene-TFE copolymer and vinylidene fluoride-perfluoro methyl vinyl ether-TFE copolymer etc.Also can use styrene butadiene rubbers, poly-inclined to one side vinylidene fluoride etc.
As the collector body of negative pole, adopting Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) under the situation of titanium oxide that wait, adopt aluminum or aluminum alloy as negative electrode active material, with as above reason, special desirable.
When using other negative electrode active material, can use following material:, this is not had special restriction so long as in the battery that constitutes, do not cause the electrical conductivity body of chemical change.As the material that constitutes collector body, the complex that carbon, nickel, titanium or silver are handled, Al-Cd alloy etc. have been carried out on copper or the stainless surface except using stainless steel, nickel, copper, titanium and carbon etc., also can be used on.Special handy copper or copper alloy.The material that oxidation processes forms is carried out on also available surface to these materials.Can also on the collector body surface, form concavo-convex by surface treatment in addition.
The shape of negative electrode collector, the same with above-mentioned anodal situation, shape, lath body, porous plastid, foaming body and fibre bundle etc. that available for example paper tinsel, film, sheet, net, punching form.Do not have special restriction for thickness, be preferably the material of 1-500 μ m.
In electrode composition, except adding conductive agent and adhesive, can also add filler, dispersant, ionic conductive agent, pressure reinforcing agent and other various additives.As filler, so long as in the battery that constitutes, do not cause the fibrous material of chemical change, can with what.The fiber of common olefin polymer, glass, carbon etc. with polypropylene, polyethylene etc.Addition to filler does not have special restriction, is preferably 0-30 weight %.
On positive pole of the present invention and the negative pole except having the mixture layer that contains positive active material or negative material; also can have adhesiveness, conductivity, cycle characteristics and efficiency for charge-discharge with improvement collector body and mixture layer and be priming coat that purpose introduces and be the protective layer introduced of purpose etc. with mechanicalness or chemical protection mixture layer.Above-mentioned priming coat and protective layer can contain adhesive or conductive agent particle, not have the particle of conductivity etc.
As interlayer, adopting Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) under the situation of titanium oxide that wait as negative electrode active material, special handy above-mentioned nonwoven fabrics.When using other negative electrode active material, can use following material.Available little porous film mechanical strength, that have insulating properties that has than heavy ion permeability and regulation.Better with having plugging hole more than 80 ℃ and making the material of the function that resistance increases.From organic solvent resistance and hydrophobicity, can be used singly or in combination polypropylene or polyethylene etc. and form olefin polymer, perhaps by glass fibre etc. and sheet or the nonwoven fabrics made.
For the aperture of interlayer, wish in the scope that active material, adhesive and the conductive agent etc. that break away from from electrode slice do not see through, for example 0.1-1 μ m more fortunately.For compartment thickness, be preferably 10-300 μ m usually.Porosity is to be determined by the permeability of electronics or ion, material and mould, is preferably 30-80% usually.Improve by the nonflammable material that uses glass or metal-oxide film etc., the fail safe that incombustible material can make battery.
As the used nonaqueous electrolytic solution of the present invention, adopting Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) under the situation of titanium oxide that wait as negative electrode active material, special handy above-mentioned electrolyte.Adopt under other the situation of negative pole, can use electrolyte as described below.
Electrolyte is made of solvent and the lithium salts that is dissolved in this solvent.Solvent is single ester or mixed ester preferably.Wherein, more handy cyclic carbonate, cyclic carboxylic esters, non-annularity carbonic ester and aliphatic carboxylic acid esters, etc.Can also use mixed solvent, the mixed solvent that contains cyclic carboxylic esters that contains cyclic carbonate and non-annularity carbonic ester, the mixed solvent that contains cyclic carboxylic esters and cyclic carbonate.
The concrete example of the above-mentioned solvent of following illustration and be used for other solvent of the present invention.
As ester, the cyclic carbonate of ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC) and carbonic acid ethenylidene ester (VC) etc. can for example be used as nonaqueous solvents; Dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC) and dipropyl carbonate non-annularity carbonates such as (DPC); Methyl formate (MF), methyl acetate (MA), methyl propionate (MP), ethyl propionate aliphatic carboxylic acid esters,'s classes such as (MA); The cyclic carboxylic esters of gamma-butyrolacton (GBL) etc. etc.
As cyclic carbonate, special handy EC, PC and VC etc.As cyclic carboxylic esters, special handy GBL etc.As the non-annularity carbonic ester, more handy DMC, DEC and EMC etc.In addition, as required, be preferably the ester class that contains the aliphatic carboxylic acid esters.Aliphatic carboxylic acid esters,'s content is below 30% of weight of solvent total amount, and is better in the scope below 20%.
The solvent of electrolyte of the present invention can also contain known non-proton organic solvent except containing the above-mentioned ester class more than 80%.
As the lithium salts that is dissolved in the above-mentioned solvent, for example available, LiClO 4, LiBF 4, LiPF 6, LiAlCl 4, LiSbF 6, LiSCN, LiCF 3SO 3, LiCF 3CO 2, Li (CF 3SO 2) 2, LiAsF 6, LiN (CF 3SO 2) 2, LiB 10Cl 10, lower aliphatic carboxylic acid lithium, chloroborane lithium, tetraphenyl lithium borate, LiN (CF 3SO 2) (C 2F 5SO 2) and LiN (CF 3SO 2) 2, LiN (C 2F 5SO 2) 2And LiN (CF 3SO 2) (C 4F 9SO 2) acid imide that waits.These can be used for used electrolyte etc. separately, and perhaps combination in any is used in the scope of not damaging effect of the present invention.Wherein, the spy is to contain LiPF well 6
The good nonaqueous electrolytic solution of spy of the present invention is for containing ethylene carbonate and ethylmethyl carbonate at least, with LiPF 6Electrolyte as lithium salts.Containing with GBL is that the electrolyte of main solvent is also comparatively desirable, and at this moment, the additive that adds VC etc. is preferably several %, better adopts except LiPF 6LiBF in addition 4And LiN (C 2F 5SO 2) 2Salt-mixture as lithium salts.
Do not have special restriction for the amount of substance that is added in the electrolyte, can use required amount according to the amount and the battery size of positive active material and negative material.Be dissolved in the meltage of nonaqueous solvents for lithium salts, do not have restriction especially, be preferably 0.2-2mol/L, particularly preferably 0.5-1.5mol/L.
The common impregnation of this electrolyte or be filled in the interlayer of porous polymer, glass film, nonwoven fabrics etc. is used.In order to make electrolyte have flame retardancy, can in electrolyte, contain the Halogen solvent, for example carbon tetrachloride, chlorotrifluoroethylene.In order also to have the adaptability that high temperature is preserved, in electrolyte, contain carbon dioxide in addition.
Can also be with solid electrolyte as described below.Solid electrolyte can be divided into inorganic solid electrolyte and organic solid electrolyte based.
Known nitride, halide and the oxysalt etc. that Li is arranged of inorganic solid electrolyte.
Li wherein 4SiO 4, Li 4SiO 4-LiI-LiOH, xLi 3PO 4-(1-x) Li 4SiO 4, Li 2SiS 3, Li 3PO 4-Li 2S-SiS 2And phosphoric sulfide compound etc. is effective.
As organic solid electrolyte based, effectively have: the polymeric material of poly(ethylene oxide), PPOX, polyphosphazene, polyaziridine, poly-ethylidene thioether, polyvinyl alcohol, poly-inclined to one side vinylidene fluoride and polyhexafluoropropylene etc. and their derivative, mixture, complex etc.
The also available gel electrolyte of above-mentioned nonaqueous electrolytic solution that contains is as organic solid electrolyte based.As above-mentioned organic solid electrolyte based, effectively have: the macromolecule matrix material of poly(ethylene oxide), PPOX, polyphosphazene, polyaziridine, poly-ethylidene thioether, polyvinyl alcohol, poly-inclined to one side vinylidene fluoride and polyhexafluoropropylene etc. and their derivative, mixture, complex etc.The mixture of the copolymer of special handy vinylidene fluoride and hexafluoropropylene or poly-inclined to one side vinylidene fluoride and poly(ethylene oxide).
Cell shapes has Coin shape, button type, sheet, cylindrical shape, pancake and square etc.When cell shapes was Coin shape or button type, the mixture that contains positive active material and negative material mainly was compressed to the ball shape and uses.The thickness of this ball shape and diameter etc. depend on the size of battery.
Cell shapes is sheet, cylindrical shape or when square, contains the mixture of positive active material or negative material, mainly applied (coat) on collector body, carry out drying and compression is used.Coating process can use usual way.For example more handy reverse roll rubbing method, direct roller coat method, scraper plate coating, cutter are scraped rubbing method, extrusion coated method, curtain formula rubbing method, notch board rubbing method, excellent rubbing method, casting method, dip coated method and extrusion (squeexe) etc.Wherein especially good is that scraper plate coating, cutter are scraped rubbing method and extrusion coated method.
Coating is better carried out with the speed of O.1-100m/ dividing.At this moment, according to the rerum natura and the drying property of mixture solution, above-mentioned coating process is selected to obtain coating layer surface of good state.When on collector body, being coated with mixture, can on each face of collector body, be coated with, also can on two-sided, be coated with simultaneously.Preferably in the both sides of collector body coating layer is set, a lip-deep coating layer can be made of the multilayer that contains the mixture layer.The mixture layer except contain with the insertion of lithium ion with emit relevant material as positive active material or negative material and so on, also contain adhesive and electric conducting material etc.Except the mixture layer, the protective layer that do not contain active material also can be set, be arranged on priming coat on the collector body, be arranged on intermediate layer between the mixture layer etc.These layers that do not contain active material preferably contain electroconductive particle, insulating properties particle and adhesive etc.
Coating process can adopt continous way, batch (-type) or bar to be coated with form.The thickness of this coating layer, length and width depend on the size of battery etc., the thickness of the coating layer of single face, and under the compressed state in dry back, 1-2000 μ m particularly preferably.
As the ball of mixture or the drying or the dewatering of sheet, can use used method usually.The spy is well a method of using hot blast, vacuum, infrared ray, far infrared, electronics line and low wet wind separately, or it is used in combination.
Temperature is more fortunately in 80-350 ℃ the scope, in special 100-250 ℃ the scope fortunately.The water content of entire cell is more fortunately below the 2000ppm, and the water content in anode mixture, cathode agent and the electrolyte is respectively all below 500ppm, and is from circulative angle, comparatively desirable.
The method for press forming of sheet can adopt usually used method, and special handy metal pattern press forming method or stack press forming method do not have special restriction for the pressure of press forming, are preferably 0.2-3t/cm 2The pressing speed of stack press forming method is preferably the 0.1-50m/ branch.
Press temperature is preferably room temperature-200 ℃.The width of positive plate anticathode sheet is relatively good to be 0.9-1.1, particularly preferably 0.95-1.0.
The content ratio of positive active material and negative material, under the situation of the negative pole that uses positive pole of the present invention and constitute by titanium oxide, the design ratio of the capacity control speed of negative side as mentioned above particularly preferably.But, when only using positive active material of the present invention, this content is than can be because the prescription of the kind of compound and mixture different and different, so can not this be limited, from the angle of capacity, cyclicity and fail safe, the technical staff can set optimum value.
For the coiling body of electrode of the present invention, needn't be wound into positive cylindrically, be that electrode sections is that the prismatic shape of oval elongated cylindrical or rectangle etc. is also passable.
Below with embodiment be representative the present invention will be described, but the present invention is not subjected to the restriction of these examples.
Embodiment 1
Under as above (3) described synthesis condition, make the sample of 3 kinds of positive active materials.(the Ni that eutectic is made 1/4Mn 3/4) (OH) 2And LiOHH 2The mixture that O fully mixes is configured as the ball shape, by this pellet matter roasting is made positive active material.Therefore, the positive active material of gained consists of Li[Ni 1/2Mn 3/2] O 4The oxygen amount is different because of the difference of synthesis condition.The electrochemical gaging of the positive active material of gained is to carry out with as above (1) described method.
(1) Production Example 1
Spend about 3 hours atmosphere temperature is warming up to 1000 ℃ from room temperature, kept 12 hours, spend 2 hours again from 1000 ℃ and be cooled to room temperature at 1000 ℃.
(2) Production Example 2
Spend about 3 hours atmosphere temperature is warming up to 1000 ℃ from room temperature, kept 12 hours at 1000 ℃, spend 30 minutes from 1000 ℃ and be cooled to 700 ℃, 700 ℃ kept 48 hours, and spent 1.5 hours again from 700 ℃ and be cooled to room temperature.
(3) Production Example 3
Spend about 3 hours atmosphere temperature be warming up to 1000 ℃ from room temperature, kept 12 hours at 1000 ℃, from 1000 ℃ of quenchings to room temperature.Spend 1 hour again atmosphere temperature is warming up to 700 ℃, 700 ℃ kept 48 hours, and spent 1.5 hours again from 700 ℃ and be cooled to room temperature.
The electrochemical behavior of the positive active material of Production Example 1-3 gained is illustrated respectively in Figure 22's in (a)-(c).
As can be seen from Figure 22: the polarization of positive active material is all lacked, and has shown the favorable charge-discharge curve that flatness is fabulous.In addition, the positive active material of Production Example 1 (a) drop occurs in discharge latter stage, can utilize this drop to carry out the detection of remaining capacity.This drop is not the big drops of several V, and use equipment can not cut off the power supply because of power supply is not enough, can effectively detect remaining capacity.Under the situation of 700 ℃ of positive active materials (b) that reoxidize gained, this drop is become almost not to be had.Therefore, the temperature and time that can reoxidize operation by control with the drop of freely controlling discharge latter stage in above-mentioned scope.The positive active material (c) that gets for reoxidizing through the quenching operation does not almost observe drop too.Just can to form polarization bigger by controlling above-mentioned particle in the quenching operation, the material that flatness is higher.Also can carry out high density fills.
The above-mentioned situation that has shown the combination of adopting Ni and Mn is also carried out the mensuration of discharge capacity for the situation that adopts transition metal as shown in table 1.Roasting is to carry out under the condition of above-mentioned Production Example 3.The ratio of Mn and other transition metal is similarly 3: 1.The discharge capacity of gained is as shown in table 1 when adopting different positive active materials respectively.As known from Table 1: can make the positive active material that has the same capability difference and same characteristic is arranged.
The ratio of the transition metal of Mn and other be 3: 1 o'clock best.The ratio of transition metal be higher or lower than 3: 1 the time, the capacity of high potential reduces.
Table 1
Li[Me 1/2Mn 3/2]O 4 Capacity (mAh/g)
Me＝Ni 130
Me＝Cr 128
Me＝Co 120
Me＝Fe 118
Me＝Cu 110
Embodiment 2
Make and adopt positive active material of the present invention, adopt Li as negative electrode active material as positive pole 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) as the 3V level battery of negative pole.Use the same method with making negative plate and positive plates such as same mix proportions.The nonwoven fabrics of the 25 μ m that employing is made of polybutylene terephthalate (PBT) is as interlayer.The area that makes electrode is 3cm 2, adopt and dissolved 1 mole LiPF 6The organic electrolyte that forms of EC/DEC (3/7) mixed solvent as electrolyte.The material that employing said circumstances 3 makes is as positive active material.
Figure 23 has shown the discharge scenario of this battery system, and Figure 24 has shown high speed characteristics.From Figure 23 and Figure 24 as can be known: this battery system is the battery of 3V class, is polarization characteristic excellent in battery system.For the current potential shape, also shown unprecedented high flatness.
Figure 25 has shown pulse discharge characteristic.Figure 25 demonstrates: have the pulse characteristic of fabric width much at one latter stage to discharge from the discharge initial stage, to discharge latter stage, impulse polarization slowly increases, and is different with in the past pulse situation.The flatness of such current potential and good polarization characteristic have been considered to realize due to the optimization of synthetic method of positive active material and the big effect that region-wide 2 phase reactions are produced.
Embodiment 3
Figure 26 has shown the front view in a part of cross section of the cylindrical battery that present embodiment makes.The laminate of positive plate, interlayer and negative plate is carried out the multi-layer spiral pole plate group 4 that forms of reeling put into battery case 1.Then, draw positive wire 5 from positive plate and also be connected with hush panel 2, the bottom of drawing cathode conductor 6 and battery case 1 from negative plate is connected.Battery case and wire guide plate can be with metal and alloys with anti-organic electrolysis fluidity and electronic conductivity.For example metal or its alloy of available iron, nickel, titanium, chromium, molybdenum, copper, aluminium etc.It is special good that battery case is processed by corrosion resistant plate or Al-Mn alloying metal plate.Positive wire better is made of aluminium.Cathode conductor better is made of nickel or aluminium.As battery case, in order to realize lightweight, the material that also available engineering plastics and engineering plastics and metallic combination form.
Top and the bottom in pole plate group 4 are provided with dead ring 7 respectively.Inject electrolyte then, battery case is sealed with hush panel.At this moment, safety valve can be arranged on the hush panel.Except safety valve, can also dispose known all the time various safety elements.For example, available fuse, bimetallic, PTC element etc. are used as preventing overcurrent element.As beyond the safety valve prevent battery case in press other the countermeasure that rises, can use the method that on battery case, forms otch, sealing gasket crack method, hush panel crack method or and the method cut off of wire guide plate.Can also overcharge and overdischarge configuration protection circuit on charger for preventing, perhaps also can be with this protective circuit separate connection.
As the welding method of cap, battery case, sheet and wire guide plate, the existing known method of electric welding, laser welding or the ultrasonic bonding etc. of for example available direct current or interchange.As the sealing compound that seals usefulness, the known in the past compound or the mixture of available pitch etc.
Positive plate manufacturing as described below.In positive electrode active material powder 85 weight portions of the present invention, mix the conductive agent carbon dust of 10 weight portions and the adhesive poly-inclined to one side 1 of 5 weight portions, 1-difluoroethylene resin, the mixture of gained is scattered in the dehydration N-methyl pyrrolidone makes slurries, these slurries are coated on the positive electrode collector by aluminium foil system, after drying and the calendering, be cut into prescribed level.Except adopting Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) replace beyond the positive active material the same negative plate that makes with positive plate.
Can also use styrene butadiene rubbers class adhesive.In the present invention, the main titanium oxide that uses is as negative electrode active material, if when mainly using carbonaceous material, carbonaceous material and styrene butadiene rubbers class adhesive are that 100: 5 ratio is carried out mixed mixture with weight ratio, this mixture is coated on the two sides of Copper Foil, after drying and the calendering, be cut into prescribed level, make negative plate.
As interlayer, little porous membrane of available nonwoven fabrics or polyethylene system.
As organic electrolyte, can be used on volume ratio is in the mixed solvent that ethylene carbonate (EC) and diethyl carbonate was mixed in 3: 7, dissolving LiPF 6And the solution of the 1.0 moles/L that forms.The diameter of cylindrical battery is 14.1mm, the high 50.0mm of being.
By utilizing positive active material of the present invention, the remaining capacity alarm is carried out easily.From this angle, adjust the discharge drop size in latter stage by reoxidizing temperature.
In said circumstances 3, only changed the temperature that reoxidizes (the 2nd roasting).Adopt Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) make above-mentioned cylindrical battery as negative pole.Allow above-mentioned battery discharge with 1c speed, when cell voltage becomes 2.7V, can detect remaining capacity.After this, when being discharged to 2V, measure remaining capacity again.Its result is as shown in table 2.The numeric representation remaining capacity is to the ratio of total battery capacity.
As can be known from Table 2: battery of the present invention is the remaining capacity alarm that is produced, and does not need complicated electronic circuit or carry out complicated calculation just can be more prone to produce.Also can freely set the time of remaining capacity alarm.
Table 2
Reoxidize (the 2nd roasting) temperature (℃) Remaining capacity (mAh/g)
700 2.1
800 8.4
900 15.8
1000 17.9
Embodiment 4
Capacity design to anodal and negative pole is inquired into.The ratio of the amount of the amount of the positive active material of per unit area and negative electrode active material is carried out various variations and the cylindrical battery made, the cycle life of this battery is measured, its result is as shown in table 3.The charge and discharge cycles condition is: charging is that the constant current constant voltage with 3.5V charges, and maximum current is 1C.The condition of finishing is to cut off after 2 hours from beginning charging.Discharge is discharged for the constant current with 2C, cuts off during to 2.0V.Table 3 has shown that the capacity of keeping drops to 95% o'clock cycle-index of initial capacity.As known from Table 3: the capacity ratio is 1.2 when above, and cycle life reduces.Balanced design anodal and negative pole in fact better is decided to be negative pole control speed (capacity of negative plates setting).If exceeding to increase positive electrode, battery capacity can reduce, so actual Capacity Ratio is preferably 0.5-1.2.
Table 3
Negative electrode active material/positive active material The capacity ratio is 95% o'clock a cycle-index (inferior)
0.3 280
0.5 302
0.8 305
1.0 299
1.2 290
1.5 260
Embodiment 5
Here, the collector body of anodal and negative pole is inquired into.When adopting graphite,, adopt copper usually as collector body (core) because of reasons such as current potentials as negative pole.
Use Li as mentioned above 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) during as negative pole, can use the aluminium core.Find following advantage by the present invention:, also promoted fail safe by adopting above-mentioned material except can realizing lightweight and low cost.Its reason is as described below.That is, cause because of faults such as chargers under the situation of battery overcharge that negative terminal surface lithium metal is separated out, it is the factor that causes that fail safe descends.If use Li 4Ti 5O 12(Li[Li 1/3Ti 5/3] O 4) under the situation as negative pole, discharge and recharge the current potential height to 1.5V, exceed much than the deposition potential 0V of lithium, still, adopt copper as core, the lithium metal is considered to separate out on the surface of copper.On the other hand, this core is inhaled the storage lithium when using aluminium as core, and the lithium metal can not be separated out.To the collector body shown in the employing table 4 respectively and the cylindrical battery that makes carries out overcharge test.Measure the maximum temperature of battery surface this moment.In overcharge test, carry out constant current with the current value of 1.5C and overcharge.
As known from Table 4: by using the aluminium core, the battery heating in the time of can suppressing to overcharge.From the above,, can make the battery of 3V level, form lightweight, low cost and have the battery of bigger fail safe by adopting the aluminium core of battery of the present invention system.
Table 4
Constitute the material of collector body The battery surface temperature (℃)
Copper 45
Aluminium 81
Here, the best electrolyte of battery system of the present invention is inquired into.
In using the battery of graphite, more to the restriction of electrolyte as negative pole.Particularly from the angle of reducing resistance, it is difficult using the organic solvent of lactone.Also because of reasons such as graphite propylene carbonate when discharging and recharging can be decomposed simultaneously, it is difficult using propylene carbonate.These solvents all are cheap and have bigger dielectric constant, also have the useful solvent of the ability and the excellent oxidation-resistance of abundant dissolving electrolytic salt.Because same reason, it also is difficult using trimethyl phosphate and triethyl phosphate.These solvents are the solvents with fire extinguishing effect and good fail safe.To this, can use these useful solvents in the present invention.
Present situation is: in order to form diaphragm and electrolytic salt is dissolved on graphite surface, form the electrolyte based on the very high ethylene carbonate of viscosity (EC).In the present invention, do not need this EC.That is,, do not use graphite, just can greatly enlarge the range of choice of electrolyte though be to form to have the high-tension battery of 3V by forming this battery.Table 5 has shown the electrolyte of the best of this battery system.In table 5, the capacity of in the past electrolyte system is decided to be at 100 o'clock, the capacity of gained when representing that with index electrolyte carried out many variations.Also shown the result that following battery is estimated: in order comparing, to use cobalt acid lithium, to use graphite material as negative pole as positive pole, and the cylindrical battery that makes with same method.
The composition of in table 5, also having represented mixed solvent, the EC/DEC of mixed solvent (3/7) expression is the mixed solvent of EC and DEC, its ratio of components is 3: 7.Capacity with this electrolyte gained all is decided to be 100 in various batteries are.
As known from Table 5: in using the battery system in the past of graphite, almost can not bring into play high power capacity, can use out of use in the past electrolyte system in the present invention no problemly, and make battery cheap and that have greater security.The combination of all kinds of solvents that also can use the mixed solvent of above-mentioned solvent or use all the time etc.
Table 5
The composition of mixed solvent Electrolyte (salt) Battery of the present invention is LiCoO 2/ graphite system
EC/DEC(3/7) 1M?LiPF 6 100 100
GBL 1M?LiBF 4 102 10
GVL 1M?LiBF 4 101 12
PC 1M?LiPF 6 102 2
The methyl diethylene glycol dimethyl ether 1M?LiPF 6 100 20
Methoxyl group EMC 1M?LiPF 6 100 87
Trimethyl phosphate 1M?LiPF 6 98 18
Triethyl phosphate 1M?LiPF 6 97 20
Sulfolane 1M?LiPF 6 87 30
PC/DEC 1M?LiPF 6 100 13
PC/EMC 1M?LiPF 6 100 12
GBL/PC 1M?LiPF 6 101 8
Embodiment 7
Here, best interlayer of the present invention is inquired into.
In being, battery of the present invention do not need the same high performance interlayer of porous film.If adopt nonwoven fabrics, because of having reduced the cut-out function, so may reduce the fail safe of overcharging.On the other hand, under the situation of nonwoven fabrics, compare,, can improve the pulse performance so can expect it especially because of its electrolyte retention height with porous film.
The nonwoven fabrics that employing is made of the various polymeric materials shown in the table 6 is as interlayer, with the above-mentioned the same cylindrical battery of the present invention of making.Table 6 has shown pulse discharge characteristic and the maximum of the battery surface temperature when overcharging.Pulsed discharge be open 5 seconds of 1A, the simple pulsed discharge that closes 5 seconds, resulting pulse discharge time is decided to be 100 during with the PE porous film that uses in the past, adopts the pulse discharge time of the battery of other interlayers with exponential representation.Overcharge be utilize 1.5C constant current carried out overcharges.
As known from Table 6: in this battery system, can improve pulse discharge time greatly, and can keep and much at one the fail safe of overcharging in the past by using nonwoven fabrics.In addition, also can improve the decay of the voltage that pulse current causes by using nonwoven fabrics.
Table 6
The material of interlayer The burst length index The battery surface temperature (℃)
The polyethylene porous film 100 42
The polyethylene nonwoven fabrics 178 45
Polypropylene non-woven fabric 180 46
Polybutylene terephthalate (PBT) 181 50
Possibility of its application on the industry
By battery of the present invention system, can evenly, greatly improve flatness, high-rate discharge characteristic, the pulse characteristic of discharge voltage and the cycle life when discharging and recharging at a high speed etc.In the above-described embodiments, though the secondary cell of the present invention to the battery used as portable set is illustrated, the present invention also is suitable as power supply that the electric tool that is used for discharging and recharging at a high speed and to have extended cycle life uses, the car with mixed energy source large-sized battery with the drive system of power supply and used for electric vehicle power supply etc., and can bring into play its characteristic.The invention provides a kind of can effectively the utilization and have flatness and high-tension cheap nickel manganese composite oxide, utilize the good rechargeable nonaqueous electrolytic battery of titanium oxide as high speed characteristics and cycle life negative pole, that have good 3V level as positive active material.

Claims (24)

1. positive active material is characterized in that, by formula: Li 2 ± α(Me) 4O 8-xShown in, the reaction of its charge-discharge region be divided into before later half 2 phase reactions of carrying out respectively of half-sum, in the formula, 0≤α＜0.4,0≤x＜2, Me contains Mn and is selected from least a transition metal among Ni, Cr, Fe, Co and the Cu.
2. positive active material according to claim 1 is characterized in that, transition metal mutually in have 2 * 2 superlattice.
3. positive active material according to claim 1 is characterized in that, the ratio of Mn and other transition metal is essentially 3: 1.
4. positive active material according to claim 1 is characterized in that, has spinels like crystallization, has Li and/or Me on 16 (c) position of Fd3m space group.
5. positive active material according to claim 1 is characterized in that, has the charging and discharging curve of the drop of the current potential that has 0.2-0.8V.
6. positive active material according to claim 1 is characterized in that, the lattice constant that belongs to cubic system is below 8.3 .
7. positive active material according to claim 1 is characterized in that, is made of the crystal grain of the particle diameter with 0.1-8 μ m and the mixture of the offspring of the above-mentioned crystal grain of the particle diameter with 2-30 μ m.
8. the manufacture method of positive active material is characterized in that, contains following 3 operations: (1) synthetic operation that contains the Mn compound and be selected from least a cocrystalization compound among Ni, Cr, Fe, Co and the Cu; (2) operation that above-mentioned cocrystalization compound and lithium compound are mixed; (3) more than 600 ℃ the 1st roasting being carried out in the mixture heating of above-mentioned operation (2) gained, under than the low temperature of above-mentioned the 1st sintering temperature, carry out the 2nd roasting then, make formula: Li 2 ± α(Me) 4O 8-xShown in, the reaction of its charge-discharge region be divided into before the operation of positive active material of later half 2 phase reactions of carrying out respectively of half-sum, 0≤α in the formula＜0.4,0≤x＜2, Me contains Mn and at least a transition metal that is selected among Ni, Cr, Fe, Co and the Cu.
9. the manufacture method of positive active material according to claim 8 is characterized in that, the temperature of above-mentioned the 1st roasting is more than 900 ℃.
10. the manufacture method of positive active material according to claim 8 is characterized in that, above-mentioned the 2nd sintering temperature is 350 ℃-950 ℃.
11. the manufacture method of positive active material according to claim 10 is characterized in that, above-mentioned the 2nd sintering temperature is 650 ℃-850 ℃.
12. the manufacture method of positive active material according to claim 8 is characterized in that, after above-mentioned the 1st roasting and/or after the 2nd roasting, contains the operation with above-mentioned positive active material quenching.
13. the manufacture method of positive active material according to claim 12 is characterized in that, above-mentioned quenching carries out with the cooling rate more than 4.5 ℃/minute.
14. the manufacture method of positive active material according to claim 13 is characterized in that, above-mentioned quenching carries out with the cooling rate more than 10 ℃/minute.
15. the manufacture method of positive active material according to claim 13 is characterized in that, above-mentioned quenching proceeds to till the room temperature.
16. rechargeable nonaqueous electrolytic battery, it is characterized in that, have the positive pole that contains positive active material, contain negative pole, nonaqueous electrolyte and the interlayer of titanium oxide as negative electrode active material, have the practical average voltage of practical charge-discharge region and the 3V level of 2.5V-3.5V, described positive active material is by formula: Li 2 ± α(Me) 4O 8-xShown in, the reaction of its charge-discharge region be divided into before later half 2 phase reactions of carrying out respectively of half-sum, in the formula, 0≤α＜0.4,0≤x＜2, Me contains Mn and is selected from least a transition metal among Ni, Cr, Fe, Co and the Cu.
17. rechargeable nonaqueous electrolytic battery according to claim 16 is characterized in that, above-mentioned titanium oxide has spinel structure.
18. rechargeable nonaqueous electrolytic battery according to claim 16 is characterized in that, above-mentioned titanium oxide is Li 4Ti 5O 12
19. rechargeable nonaqueous electrolytic battery according to claim 16 is characterized in that, has the work discharge curve of the drop of the current potential that has 0.2V-0.8V.
20. rechargeable nonaqueous electrolytic battery according to claim 16 is characterized in that, above-mentioned positive pole and negative pole have the collector body that is made of aluminum or aluminum alloy.
21. rechargeable nonaqueous electrolytic battery according to claim 16, it is characterized in that above-mentioned nonaqueous electrolyte contains and is selected from least a in propylene carbonate, gamma-butyrolacton, gamma-valerolactone, methyl diethylene glycol dimethyl ether, sulfolane, trimethyl phosphate, triethyl phosphate and the carbonic acid methoxy ethyl ester.
22. rechargeable nonaqueous electrolytic battery according to claim 16 is characterized in that, above-mentioned interlayer is made of nonwoven fabrics.
23. rechargeable nonaqueous electrolytic battery according to claim 22 is characterized in that, above-mentioned nonwoven fabrics is made of at least a in polyethylene, polypropylene and the polybutylene terephthalate (PBT).
24. rechargeable nonaqueous electrolytic battery according to claim 16 is characterized in that, the weight ratio of above-mentioned negative electrode active material and above-mentioned positive active material is more than 0.5, less than 1.2.
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