CN1781200A - Negative electrode for lithium secondary cell, lithium secondary cell employing the negative electrode, film deposition material used for forming negative electrode, and process for producing negati - Google Patents
Negative electrode for lithium secondary cell, lithium secondary cell employing the negative electrode, film deposition material used for forming negative electrode, and process for producing negati Download PDFInfo
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Abstract
Greatly improved is an initial efficiency, which would be otherwise low as a fault, without reducing a magnitude of an initial charge capacity, which is a feature of a lithium secondary battery using an SiO as an negative electrode. A cycle characteristic is improved. In order to realize the improvements, a thin film of silicon oxide formed by vacuum vapor deposition or sputtering as an negative electrode active material layer 32 on a surface of a collector 31. The thin film is formed preferably by means of an ion plating method. The silicon oxide is SiOx (0.5 x < 1.0) and a film thickness is in the range of from 0.1 to 50 m. A vacuum vapor deposition source that is used is an SiO deposit having a weight decrease percent (a rattler value) in a rattler test of 1.0% or less. In vacuum vapor deposition, the surface of the collector 31 is applied with a cleaning treatment in a vacuum or an inert atmosphere and thereafter, a thin film of silicon oxide is formed on the surface of the collector without exposing the surface of the collector to the air atmosphere.
Description
Technical field
The present invention relates to be used for the negative pole of lithium storage battery, the lithium storage battery that adopts this negative pole, this negative pole and form the film forming that adopted manufacture method with material and this negative pole.
Background technology
Because absorption discharging by lithium ion, the lithium storage battery that carries out charging and discharging has the feature of high power capacity, high voltage, high-energy-density simultaneously, so in OA equipment, especially be used as the power supply of the mobile information apparatus of portable phone, personal computer etc., by very many uses.In the occasion of this lithium storage battery, when charging, lithium ion is transferred to negative pole from positive pole, and when discharge, the lithium ion transfer that is absorbed in this negative pole arrives anodal.
The negative electrode active material that constitutes the negative pole of lithium storage battery adopts carbon dust more.Its reason is the capacity of carbon negative pole, and the overall merit of the various characteristics of starting efficiency and cycle life is higher, about this point, will specifically describe in the back.In addition, this carbon dust forms negative plate by following powder coating seasoning, in this powder coating seasoning, this carbon dust mixes, forms slurries with adhesive solution, drying is carried out on the surface that these slurries is coated on collector body, then, it is pressurizeed.By the way, as constituting the oxide that anodal positive active material adopts the transition metal that comprises lithium, mainly adopt LiCoO
2Deng.
One of problem of the carbon negative poles that adopt is to compare with other negative pole more at present, and theoretical capacity is less.Although theoretical capacity is less, still carbon negative poles that adopt more, its reason is the capacity characteristic height in addition of starting efficiency, cycle life, the balance of various characteristics is good.
Just use power supply and a large amount of lithium storage battery that adopts as mobile information apparatus, capacity required further increases, and from this viewpoint, people are just at the negative electrode active material of development capacity greater than carbon dust.One of such negative electrode active material is SiO, and the theoretical capacity of SiO reaches the several times of carbon.Even now, the SiO negative pole does not drop into practicality yet.Its most important reason is that the starting efficiency of SiO negative pole is extremely low.
Starting efficiency refers to the ratio of the relative initial charge capacity of initial discharge capacity, and it is one of important battery design factor.The implication that this ratio is low refers to that by initial charge the lithium ion that is injected in the negative pole does not discharge fully when initial discharge, if this starting efficiency is lower, no matter how big theoretical capacity is, still is difficult to drop into practical.Thus, people have researched and developed the various measures of the starting efficiency that improves the SiO negative pole, and wherein a kind of to specially permit No. 2997741 document described for JP, make lithium be contained in method among the SiO in advance.By the way, required starting efficiency 75% or more than.
The SiO negative pole is identical with the carbon negative pole, and by the manufacturing of following powder coating seasoning, this mode is: the fine-powder of SiO is mixed the formation slurries with adhesive solution, these slurries is coated on the surface of collector body, it is carried out drying after, it is pressurizeed.Equally in advance lithium is being contained in the occasion of the negative pole among the SiO, by adopting same powder coating seasoning, the lip-deep mode that powder is stacked and placed on collector plate is made.
The SiO negative pole that comprises lithium of such making is effective for the raising of the starting efficiency of lithium storage battery.But the method that in advance lithium is contained among the SiO reduces initial charge capacity because of comprising this lithium, hinders the height as the theoretical capacity of SiO good characteristic in fact.Because such situation, people's expectation do not make the initial charge capacity of SiO negative pole reduce, and improve the measure of starting efficiency.
In addition, for lithium storage battery, people require miniaturization more, but in the SiO negative pole of making by this powder coating seasoning because the SiO layer is low-density porous plastid, so also have with having or not of lithium irrelevant, the problem that is difficult to miniaturization.
The 1st purpose of the present invention is not hinder SiO to be used for the value of the distinctive initial charge capacity of lithium storage battery of negative pole, improves the low situation as the starting efficiency of its shortcoming significantly.
The 2nd purpose of the present invention is to seek to adopt the negative pole miniaturization of SiO.
The improvement that the 3rd purpose of the present invention is to seek corresponding starting efficiency improves cycle characteristics.
Summary of the invention
To achieve these goals, the inventor changes former design, seeks by vacuum evaporation, forms the compacted zone of SiO on the surface of collector body.Its result distinguishes, compare with the SiO layer in the past that forms by powder coating seasoning, not only the capacity of unit volume increases, and the low situation of the starting efficiency of formation problem is improved under the situation of the reduction of not following initial charge capacity significantly in the SiO layer.Distinguish that in addition in vacuum evaporation, the performance of the film that forms by ion plating is high especially; Even be sputtered film, still obtain and the vacuum evaporation coating similar effects; The film forming that vacuum evaporation is adopted is preferably the body of separating out of SiO with material, or separates out the sintered body that system is made by this, particularly is preferably special sintering body described later.
Initial charge capacity reduces in the powder coating drying layer of SiO, and the reason that this initial charge capacity does not reduce in vacuum evaporation layer and sputtering layer is considered to following reason.
The SiO powder is such as making as following.At first, in a vacuum, to Si powder and SiO
2The mixture of powder heats, and produces SiO gas thus, in the portion of separating out of low temperature it is separated out, and obtains SiO and separates out body.The mol ratio that the SiO that obtains by this manufacture method separates out the relative Si of O in the body is 1 substantially.This SiO is separated out body pulverize, obtain the SiO powder, still, owing to increase at the occasion surface area that forms powder, so under the situation when pulverizing and during the use of powder etc., carry out oxidation by the oxygen in the atmosphere, the mol ratio of the relative Si of O in the SiO formed body is above 1.In addition, even the time, because of the size accelerating oxidation of the surface area of SiO powder by the stacked SiO powder of powder coating seasoning.Like this, in the powder coating drying layer of SiO, the mol ratio of the relative Si of O increases.In addition, if the mol ratio of the relative Si of O in the SiO powder of powder coating drying layer is higher, then the lithium ion that absorbs when initial charge is difficult to discharge when discharge, and starting efficiency reduces.
Relative therewith, in the occasion of vacuum vapour deposition, sputtering method,,, consequently, can suppress the reduction of starting efficiency so suppress the increase of oxygen mol ratio owing to form film in a vacuum.In addition, the film densification that forms by vacuum vapour deposition, sputtering method.On the other hand, only for only pressing solidly the powder aggregate of powder, the filling rate of SiO is lower for powder coating drying layer.Because initial charge capacity is the charge volume of the unit volume of negative electrode active material layer, so in the occasion of the film of densification, initial charge capacity increases, even after circulating for the 2nd time, charging capacity still rises.
In addition, the extra high reason of performance for the film that forms by ion plating it is believed that, even be under 1: 1 the situation of SiO in the mol ratio that adopts the relative Si of O, be the tendency that the oxygen among this SiO reduces and make a difference.That is, in order to wish the least possible occasion of oxygen among the SiO more by force with the associativity of lithium ion, by adopting ion plating, the mol ratio of the relative Si of O in the SiO film is reduced to 0.5 at most.By the way, in the occasion of ion plating, the reason that the oxygen mol ratio reduces is not clear under existing conditions.
In addition, in contrast, also can improve the oxygen mol ratio among the SiO by the mode of the oxygen amount in the atmosphere that increases vacuum evaporation or sputter.
In the occasion of vacuum evaporation, in a vacuum, by resistance heating, induction heating, electron beam irradiation etc., to vapor deposition source, that is, film forming heats with material, makes its fusion, and this steam is attached on the surface of matrix.The film forming here with material adopt such as, Si powder and SiO
2The mixed sintering body of powder.In addition, adopt above-mentioned SiO to separate out body and pulverize the SiO sintered body that the powder of the SiO that obtains, particle, piece etc. are made by this being separated out body.Investigation result as the inventor distinguishes, the film forming material during for the compacted zone that on the surface of collector body, forms SiO by vacuum evaporation, and from the aspect of starting efficiency and rate of film build, Si and SiO relatively
2The mixed sintering body, preferably adopt SiO to separate out body or SiO sintered body, wherein, particularly preferably adopt powder particle diameter and sintering atmosphere furtherd investigate and the sintered powder made.
That is, with regard to the film forming material that the vacuum evaporation of silica is adopted, people know when evaporation, by Si and SiO
2Composite material etc., the evaporation rate of SiO rises.Thus, if adopt the film forming material of SiO, then can improve the film forming speed of film.But, the film forming that is formed by the SiO by the sintering manufacturing depends on the various conditions of the SiO particles of powder diameter that adopted when making, manufacture method etc. with the evaporation characteristic of material, compare with the SiO before the sintering, film forming behind the sintering reduces with the evaporation rate of material, can't expect to improve the productivity of the film of the film forming usefulness material that employing forms by SiO.
According to such situation, even the inventor under the situation of sintering, still can keep evaporation rate higher SiO sintered body and manufacture method thereof to analyze.Consequently can obtain following viewpoint.
Some variations take place in the component that produces when at first, the evaporation rate of SiO different reason before and after the sintering is the sintering of SiO.On the other hand, SiO
2Comparing with SiO is the material of energy stabilization, SiO
2Evaporation rate be lower than the evaporation rate of SiO.So even supposition is used under the situation of material in the film forming of making SiO, SiO is oxidation partly still, its part becomes SiO
2, thus, produce the reduction of evaporation rate.
In addition, when autoxidation in the time of in being positioned over air and the sintering under oxygen atmosphere, the oxidation that can produce SiO.So, adopt the less SiO powder of surface area to prevent autoxidation, in addition,, then can suppress the oxidation of SiO if in non-oxidizable environment, such SiO powder is carried out sintering with doing one's utmost.The evaporation rate of the sintered powder of the SiO of such manufacturing is higher, and the evaporation residue when carrying out the thermogravimetric quantitative determination is few.In addition, be shaped if the film of the negative pole in the lithium storage battery is carried out evaporation in this occasion, then since the mol ratio of the relative Si of O reduce, so the raising of the starting efficiency of this lithium storage battery.
But, for the SiO sintered body, carry out sintering, so manufacturing cost increases in essence owing to must separate out body to SiO.Thus, from the viewpoint of economy, people wish to adopt the SiO of lower price to separate out body.But SiO separates out body and compares with the SiO sintered body, and it has the problem of cycle characteristics variation.
That is, the minimizing characteristic of the discharge capacity when cycle characteristics is called repeatedly charging and discharging is and starting efficiency, initial fill volume important battery factor arranged side by side.If on the surface of negative electrode collector, form SiO film as negative electrode active material, though starting efficiency improves, cycle characteristics reduces, the tendency that reduces whenever the discharge capacity that discharges and recharges repeatedly is stronger.It is more remarkable than the occasion that adopts the SiO sintered body that this tendency adopts SiO to separate out the occasion of body in film forming with material.The situation of the reduction of the cycle characteristics when separating out body at the such SiO of employing, the inventor finds following such measure.
The inventor is different with the exploitation of aforesaid such negative electrode for lithium secondary battery, and to as the packing material of food, pharmaceuticals etc. and the evaporated film that uses, particularly the SiO that uses as vapor deposition source when evaporation studies.In the process of this research, the inventor finds and proposes, if the weight slip (attrition value) of wear test 1.0% or following SiO separate out body and be used for evaporation source, splash (splashing) phenomenon (WO03/025246A document) when then suppressing vapor-deposited film and forming.
That is, in the occasion of vacuum evaporation, in a vacuum, by resistance heating, induction heating, electron beam irradiation etc., film forming is heated with material (evaporation source), make its fusion, its steam is attached to the surface of matrix.The film forming here adopts following SiO to separate out body with material, and this SiO separates out body and forms by following manner, and this mode is: by in a vacuum, to such as Si powder and SiO
2The mixture of powder heats, and produces SiO gas, and its portion of separating out at low temperature is separated out.But, separate out the occasion of body at SiO, have when evaporation, produce splash (splashing) phenomenon in a large number, on the vapor-deposited film of established SiO, produce the defective of pin hole etc., the problem that anti-transmissison characteristic reduces.
In order to address this problem, the inventor is conceived to the physical characteristic of film forming with material, and the correlation of this physical characteristic and splash (splashing) phenomenon has been carried out various analyses.Its result learns that film forming affects greatly splash (splashing) phenomenon with the fragility of material itself; As the metewand of the fragility of this material that is difficult to produce splash (splashing) phenomenon, powder presses the weight slip (rate of wear) of the abrasion test that the evaluation of body adopts effective.
In addition, in the process of further studying, distinguish, if the weight slip (attrition value) that wear test is adopted in the formation of the SiO film of the manufacturing of above-mentioned negative electrode for lithium secondary battery 1.0% or following SiO separate out body, then not only starting efficiency improves, and cycle characteristics also improves, that is, when adopting SiO to separate out body, suppress reduction effectively as certain cycle characteristics of intrinsic phenomenon.
Compare with the SiO sintered body, the compactness that SiO separates out body is lower, is easy to generate crack, defective.If this SiO is separated out the SiO film that body is used to form negative electrode for lithium secondary battery, then when discharging and recharging repeatedly, the tendency that discharge capacity reduces is stronger.This tendency is rare in the occasion that adopts the SiO sintered body.If the weight slip (attrition value) that adopts wear test 1.0% or following SiO separate out body, then when adopting such SiO to separate out body, suppress reduction effectively as the cycle characteristics of intrinsic phenomenon.
The inventor also pays close attention to the fitting tightly property for the SiO film of negative electrode collector as one of reason of the cycle characteristics variation of SiO membranous type negative pole.That is, think because the expansion the during charging of SiO is bigger, so after discharging and recharging repeatedly, it not is the reason of cycle characteristics variation that SiO film and collector body are peeled off.In addition,, focus on the clean of in collector body, implementing before the film forming, carried out various experimental analyses as the reason of the fitting tightly property reduction that makes the SiO film.Consequently, distinguish following situation.
In the occasion of carrying out film forming, general, the base material before the film forming is carried out clean.Specifically, in atmosphere, clean, processing such as drying.The inventor thinks, such clean may be insufficient in the manufacturing of SiO membranous type negative pole, in non-air atmosphere, the negative electrode collector as base material is carried out clean, after still do not continue to be exposed in the air atmosphere, on this substrate surface, form film.Consequently, though whether influential definite to the raising of fitting tightly property,, confirm that obviously cycle characteristics improves.
The present invention develops according to above-mentioned viewpoint, and essence of the present invention relates to the manufacture method of following negative electrode for lithium secondary battery, lithium storage battery, film forming usefulness material and lithium storage battery.
(1-1) relate to the negative electrode for lithium secondary battery that has the film of the silica that forms by vacuum evaporation or sputter on the surface of collector body.
(1-2) relate to negative electrode for lithium secondary battery, it is the SiO membranous type negative pole that forms on the surface of collector body as the silicon oxide film of negative electrode active material, as cycle characteristics, the capability retention of the 10th discharge 98% or more than.
(2) relate to the lithium storage battery that adopts these negative poles.
(3) relate to the film forming material, it is used for forming by vacuum evaporation or sputter the film of the silica of negative electrode for lithium secondary battery, and this film forming is with material separating out body or separating out the sintered body that system makes by this and form by SiO.
(3-1) relate to the film forming material, it is 1300 ℃ in particular for sintered body in heating-up temperature, and pressure is under 10Pa or the following vacuum atmosphere, the quality of the sample of evaporation residue before mensuration when carrying out the thermogravimetric quantitative determination of sintered body test 4% or below.
(3-2) relate to the film forming material, it is the sintered powder in the sintered body, the average grain diameter of this powder 250 μ m or more than.
(3-3) relate to the film forming material, it is in particular for the body of separating out of SiO, the weight slip (attrition value) of wear test 1.0% or below.Be used to form the SiO film by this SiO is separated out body, can make the negative electrode for lithium secondary battery of (1-2).
(4-1) relate to, form the manufacture method of negative electrode for lithium secondary battery of the film of silica on the surface of collector body by vacuum evaporation or sputter.
(4-2) relate to the manufacture method of negative electrode for lithium secondary battery, wherein, on the surface of negative electrode collector, formation is during as the silicon oxide film of negative electrode active material, in a vacuum or in the inert atmosphere, clean is carried out on the collector body surface, then, under the collector body surface is not exposed to situation in the air atmosphere, on this surface, form the film of silica.
With regard to the negative electrode for lithium secondary battery of (1-1), the mol ratio that forms the relative Si of O in the silica of negative electrode active material layer is preferably in 0.5～1.2 the scope, particularly is preferably in 0.5 or above below 1.That is,, can make the mol ratio of the relative Si of O in the silica that forms negative electrode active material layer be lower than the occasion that powder applies drying layer according to the present invention.Specifically, can be reduced to below 1, also can improve this value wittingly.
This mol ratio is preferably in 0.5～1.2 the scope that is enough to be lower than powder coating drying layer, particularly is preferably in 0.5 or above below 1.In other words, silica is preferably SiOx (0.5≤x≤1.2), particularly is preferably SiOx (0.5≤x＜1).That is, according to the viewpoint that is suppressed at the phenomenon that negative electrode lithium ion combines with oxygen, above-mentioned mol ratio be preferably in 1.2 or below, particularly be preferably in below 1.On the other hand, at it less than 0.5 occasion, have the volumetric expansion of lithium ion when absorbing significantly, the danger that destroys of negative electrode active material layer.
The just film forming material of (3-3), and negative electrode for lithium secondary battery (1-2), wear test are Japanese powder metallurgy industry meeting (JPMA) " metal powder is pressed the wear test method JPMA standard 4-69 of body ".This test method(s) was originally pressed the abrasion performance of body and the test method(s) of front end stability for the metal powder that is used to estimate press molding.According to the present invention, this test method(s) is used for the evaluation of the physical characteristic of SiO precipitate.Specifically,, separate out body from SiO and take its size, test film that shape is identical with wear test,, this test film is used for test, obtain the weight slip (attrition value) before and after the test by the method identical with wear test by machining etc.In original test, estimate compressibility, the formability of metal dust, still,, estimate compactness that SiO separates out body, uniformity etc. according to the present invention.
By with attrition value 1.0% or following densification, SiO separates out body and is used to form the SiO film uniformly, not only starting efficiency improves, and cycle characteristics also improves.Specifically, the capability retention of the 10th time discharge bring up to 98% or more than.Adopting general SiO to separate out the occasion of body, this capability retention be low to moderate 90% or below.The reason of the reduction influence raising cycle characteristics of attrition value is uncertain, still, in present situation, resembles following such supposition.
In lithium storage battery, constitute stacked structure by anode current collector, anode active material layer, electrolyte, chorista, negative electrode active material layer, negative electrode collector.If in negative electrode active material layer, have uneven part or jog etc. partly, think then to begin to destroy that its reduction with cycle characteristics is relevant from this part stacked structure.Thus, it is believed that, carry out the occasion that homogeneous is handled, improve cycle characteristics effectively at the anticathode active material layer.In addition, in order to form the negative electrode active material layer of homogeneous, as film forming separate out body with the SiO of material must be fine and close, evenly.It is believed that this is effective reason that the less SiO of attrition value separates out the cycle characteristics raising of body.
With regard to the manufacture method of the negative electrode for lithium secondary battery of (4-2), can enumerate as the clean in the vacuum or in the inert atmosphere, such as, the surface treatment bombardment of the direct magnetic control tube discharge in the vacuum chamber.
As film build method, can enumerate vacuum vapour deposition, sputtering method, but particularly preferably adopt the ion plating in the vacuum vapour deposition.Be to carry out in the vacuum occasion of clean, suitable mode of also carrying out in a vacuum according to continuous film forming, in identical atmosphere, implement two steps, but, also can be according in inert atmosphere, implementing clean, carry out the mode of film forming in a vacuum, in different atmosphere, implement two steps.As required, implement in a vacuum or the inert atmosphere to the operation of film forming step from the clean of collector body, during this period, the surface of collector body is not exposed in the air atmosphere.
Film forming can adopt SiO to separate out body or SiO sintered body with material, and still, in the occasion that adopts fine and close, harder SiO sintered body, cycle characteristics is good.On the other hand, manufacturing cost is lower in the occasion that SiO separates out body.Even one of great value of manufacture method (4-2) is still can guarantee good cycle characteristics adopting the lower SiO of price to separate out under the situation of body.
The thickness of the film of silica is preferably in the scope of 0.1～50 μ m.In occasion less than 0.1 μ m, though the increase of the capacity of unit volume,, the capacity of unit are reduces.On the other hand, because this film is a dielectric film,, has the problem that the current collecting efficiency from the film to the collector body reduces so surpassing the such occasion of 50 μ m.Particularly preferred thickness is in the scope of 0.1～20 μ m.
In vacuum evaporation, preferably adopt ion plating.Its reason as previously mentioned.
Collector body is preferably sheet metal.This metal can adopt Cu, Al etc.Thickness of slab is preferably in the scope of 1～50 μ m.If this plate is thin excessively, then have be difficult to make, problem that mechanical strength reduces.On the other hand, in the blocked up occasion of plate, hinder the miniaturization of negative pole.
Just very on the surface of collector body, form the structure of positive electrode active material layer.Positive active material mainly adopts LiCoO
2, LiNiO
2, LiMn
2O
4Deng the oxide of transition metal with lithium.Anodal manufacture method generally adopts powder coating seasoning, wherein, the fine-powder of oxide is mixed with adhesive solution, form slurries, these slurries are coated on the surface of collector plate, after the drying, it is pressurizeed, still, also can form by the thin film-forming method identical with negative pole.
Electrolyte can adopt such as, comprise the nonaqueous electrolyte of ethylene carbonate etc.
In addition, relate to the film forming material of (3), this film forming is effective especially with material against vacuum evaporation, even but still have effect under the situation that adopts sputtering method.This film forming is used in the material, the apparent density of the sintered body of silicon monoxide has no particular limits, and still, prevents the aspect from the effective inhibition of splash (splashing) and the rift defect when bonding, this apparent density be preferably in 80% or more than, particularly be preferably in 95% or more than.
Description of drawings
Fig. 1 is the longitudinal sectional view of the lithium storage battery of expression embodiments of the invention;
Fig. 2 is used for the cutaway view of structure of the thermogravimetric volume measuring device of thermogravimetric quantitative determination for expression;
Fig. 3 carries out the curve chart of mass change of mensuration sample of the occasion of thermogravimetric quantitative determination for expression.
Embodiment
Below with reference to the accompanying drawings, embodiments of the invention are described.
(the 1st form of implementation)
The lithium storage battery of this form of implementation is so-called button cell as shown in Figure 1, and it comprises the flat casing 10 of the circle that forms positive pole-face.This shell 10 is formed by metal, and portion within it is according to admit discoid anodal 20 and negative pole 30 overlappingly from the order of below.Anodal 20 are made of collector body 21 and positive electrode active material layer 22, and this collector body 21 is formed by the sheet metal of circle, and this positive electrode active material layer 22 is formed on the surface of this collector body 21.Equally, negative pole 30 is made of collector body 31 and negative electrode active material layer 32, and this collector body 31 is formed by the sheet metal of circle, and this negative electrode active material layer 32 is formed on the surface of this collector body 31.In addition, the two poles of the earth are according to facing at corresponding active material layer, and the state of clamping spacer body 40 is stacked between face-to-face, is received in the inside of shell 10.
Also with electrolyte with anodal 20 and negative pole 30 be received in the inside of above-mentioned shell 10.In addition, by seal member 50,, will admit thing to be sealed in the inside of above-mentioned shell 10 by the peristome sealing of lid 60 with shell 10.Lid 60 is also used as the parts that form the negative pole face, contacts with the collector body 31 of negative pole 30.The shell 10 that is also used as the parts that form positive pole-face contacts with the collector body 21 of positive pole 20.
The aspect that should note in the lithium storage battery of this form of implementation is: the negative electrode active material layer 32 of negative pole 30 is formed by the film of the densification of silica, this film is by being raw material with SiO, by vacuum evaporation or sputter, be preferably a kind of ion plating of vacuum evaporation and be formed on the collector body 31.Although this silica original material is SiO,, still can form SiOn (0.5≤n＜1.2) by the control of the oxygen concentration in the atmosphere.In addition, the thickness of film is suitable in the scope of 0.1～50 μ m.
On the other hand, anodal 20 positive electrode active material layer 22 forms by powder coating drying means, that is, as before, with LiCoO
2Deng the powder of oxide of the transition metal that comprises lithium mix with adhesive solution, form slurries, these slurries are coated on the surface of collector body 21, after the drying, its pressurization.
The feature of the lithium storage battery of this form of implementation is as described below.
The 1st, because negative electrode active material layer 32 is formed by silica, to compare with the carbon dust layer, theoretical capacity further increases.The 2nd, the film of silica for forming by vacuum evaporation or sputter, the mol ratio of the relative Si of O is lower, this film densification, thus, initial charge capacity is reduced, and can improve starting efficiency.The 3rd, because the capacity of the unit volume of film is bigger, so easy miniaturization.
In addition, in the battery terminal negative 30, the film forming that forms negative electrode active material layer 32 usefulness is as described below with material.
As this film forming as previously mentioned with the material of material, separating out body or separating out the sintered body that system is made for SiO by this, in particular for being 1300 ℃ in heating-up temperature, pressure is under 10Pa or following vacuum atmosphere, and the evaporation residue when carrying out the thermogravimetric quantitative determination of sintered body sample is 4% or following sintered body of the quality of the sample before measuring.
The thermogravimetric volume measuring device of Fig. 2 is adopted in the thermogravimetric quantitative determination of this sintered body.Specifically, in the crucible 2 on the one side in being suspended to balance 1, pack into and measure sample 3.Relative this situation, setting has the scale thallium 4 that balance is measured the quality of sample 3 in the another side in balance 1.In the thermogravimetric volume measuring device, heating furnace 5, gas introduction port 6, gas discharge outlet 7 etc. are set, by these parts, measure the adjusting of the temperature and the atmosphere of sample 3.
Because of measuring the evaporation of sample 3, measure the occasion of the quality minimizing of sample 3, electric current flows through the feedback coil that is arranged in the uniform magnetic field, produces electromagnetic force, keeps the balance with scale thallium 4.At this moment, because electromagnetic force and current value are proportional, so can measure the mass change of sample 3 according to current value.
The temperature of measuring sample 3 is 1300 ℃, and atmosphere is 10Pa or following vacuum atmosphere, carries out the thermogravimetric quantitative determination.At this moment, when the thermogravimetric quantitative determination, can't avoid measuring the slight change of the temperature of sample 3, still, if the slight change of temperature is in 1300 ± 50 ℃ scope then allow.If carry out the thermogravimetric quantitative determination under this condition, then the quality of sintered body is followed the evaporation of silicon monoxide and is reduced.Fig. 3 is 100% by the quality of the mensuration sample before measuring, and follows the variation through the evaporation residue amount of minute to represent the variation of the sample mass of this moment.In the mensuration shown in this figure, make the temperature of measuring sample from room temperature, rise to 1300 ℃.
As shown in Figure 3, will measure sample and pack in the crucible, temperature is risen, measure the sample start vaporizer, if through certain hour, measure on the quality entity of sample and do not change, can hold the residue of constant basis.Preferred film forming material is the quality of the evaporation residue of sintered body at this moment, that is, and and the sintered body of 4% or following SiO of the quality of the quality of constant basis residue before mensuration.
If satisfy this condition, the evaporation rate of SiO increases, and can make the productivity raising based on the silicon oxide film of the evaporation that evaporates.In addition, in this film, the mol ratio of the relative Si of O reduces, and can improve starting efficiency under the situation that initial charge capacity is reduced.
The sintered body of such SiO can be by the following manner manufacturing, and this mode is: to particle diameter after 250 μ m or above SiO powder carry out press molding, or in this press molding, in nonoxidizing atmosphere, carry out sintering.
The raw material of this sintered powder adopt average grain diameter to be the occasion of particle diameter less than the SiO powder of 250 μ m in the reason of 250 μ m or above SiO powder, because the surface area of SiO powder increases, particle surface at autoxidation forms silicon dioxide, so silicon dioxide occurs in sintered body, evaporation rate reduces, starting efficiency reduces.For the upper limit of above-mentioned particle diameter, preferably it is at 2000 μ m or following.In the occasion that surpasses 2000 μ m, produce the reduction of press molding, agglutinating property.
If the particle diameter of above-mentioned SiO powder on average 250 μ m or more than, needn't make the particle diameter unanimity.Such as, can mix by SiO particle 250 μ m or above various particle diameters, it is carried out the mode of sintering, improve the density of sintered body.If the density of sintered body 95% or below, then can be by the cross-section of light microscope, the particle diameter of the SiO powder of investigation sintered body can confirm whether the raw material of sintered body adopt average grain diameter at 250 μ m or above SiO powder.
Such SiO powder after according to the arbitrary shape press molding, or in press molding, sintering under nonoxidizing atmosphere.Be to carry out the occasion of sintering behind the press molding, if can be shaped according to required form by forcing press, then the method for press molding is not special concerns.In the relatively poor occasion of the zygosity of SiO particle, also can in the SiO powder, add a spot of water, behind press molding, carry out removing the operation of water etc. by processed.By at every 1cm
2Add the mode of the load of 300～1500kg, the SiO powder can be according to shape shaping arbitrarily.
On the other hand, in press molding, carry out the occasion of sintering, because the rising of the temperature of SiO powder, so at every 1cm
2Add the load of 100～300kg, just enough.
Best, sintering carries out under nonoxidizing atmosphere.This nonoxidizing atmosphere is for wrapping oxygen containing atmosphere, such as, be the inert gas atmosphere of vacuum atmosphere or argon gas etc.Particularly, be to carry out under the vacuum atmosphere occasion of sintering, because the evaporation rate of the sintered body of SiO does not become the evaporation rate of the preceding SiO powder of sintering, so best sintering carries out under vacuum atmosphere.Carry out the occasion of sintering under the oxygen containing atmosphere of bag, the combination of SiO powder, evaporation rate reduce.
For the temperature of sintering, if between the SiO particle can in conjunction with, can keep its shape, then not special relation.Under 1200～1350 ℃ temperature, the sintering that carries out 1 hour is just enough.
With regard to the 1st form of implementation, provide embodiments of the invention, by comparing, can understand effect of the present invention with existing example.
Making lithium storage battery (being of a size of: diameter 15mm, thickness 3mm) shown in Figure 1 is as following, to change the structure of negative pole according to various ways.
As embodiment, on the surface of the collector body that the Copper Foil that by thickness is 10 μ m forms, apply seasoning by ion plating, common vapour deposition method (resistance heating), sputtering method and powder as negative electrode active material layer, form the film of silica.In the occasion of ion plating, with SiO sintered powder (thin slice (tablet)) as film forming with material (evaporation source), with the EB rifle as heating source, in specified vacuum atmosphere with [10
-3Pa (10
-5Torr)] film of formation silica.
Film forming except adopting above-mentioned SiO sintered powder, also adopts aforesaid SiO to separate out body with material, that is, and and by in a vacuum to Si powder and SiO
2The mixture of powder heats, and produces SiO gas, and its portion of separating out at low temperature is separated out, and thus obtained SiO separates out the broken piece of body; Si powder and SiO
2The mixed sintering body of powder; Silico briquette.
In addition, to adopt the average grain diameter of powder be 250 μ m, 1000 μ m, 10 μ m 3 kinds for above-mentioned SiO sintered powder.For corresponding method of manufacture,, be 100kg/cm with the load in the occasion of 250 μ m
2When pressurizeing by forcing press, carrying out sintering (in a vacuum, 1200 ℃ * 1.5 hours), in the occasion of 1000 μ m, is 100kg/cm with the load
2When pressurizeing by forcing press, carrying out sintering (in a vacuum, 1200 ℃ * 1.5 hours), in the occasion of 10 μ m, is 200kg/cm with the load
2When pressurizeing, carry out sintering (1200 ℃ in a vacuum, * 1.5 hours) by forcing press.
In heating-up temperature is 1300 ℃, and the evaporation residue rate when pressure carries out the thermogravimetric quantitative determination of sintered body sample under 10Pa or following vacuum atmosphere is respectively 4%, 3%, 8%.The analyzer of Fig. 2 is adopted in the thermogravimetric quantitative determination.Heating-up temperature is for 1300 ℃ to leave the temperature of the distance of about 1mm by thermocouple 8 mensuration with measuring sample, considering that in fact will measure sample is heated to this temperature.The data that obtain by the thermogravimetric quantitative determination are put in order, and the quality when not measuring the mass change of sample in fact is as the quality of evaporation residue, calculates the ratio (evaporation residue rate) (with reference to Fig. 3) of the quality before the relative determination.
In addition, 2 kinds sample shown in Figure 3 is 2 kinds in above-mentioned 3 kinds the SiO sintered powder, specifically, for the average grain diameter of powder is the SiO sintered powder (solid line: embodiment 3) of 250 μ m, with the average grain diameter of powder be the SiO sintered powder (dotted line: embodiment 10) of 10 μ m.The former evaporation residue rate is 4%, and the latter's evaporation residue rate is 8%.
Various negative poles and anodal combination with having made are sealed in enclosure with it with electrolyte, make lithium storage battery.Measure initial charge capacity, initial discharge capacity and the starting efficiency of Manufactured each battery.In addition, the anodal LiCoO that adopts
2Fine-powder, electrolyte adopts the nonaqueous electrolyte comprise ethylene carbonate.
Table 1 expression initial charge capacity, and the starting efficiency that calculates according to initial charge capacity and initial discharge capacity.This initial charge capacity is by the magnitude of current evaluation of unit volume, and its data by embodiment 3 are that 1 o'clock ratio is represented.
Table 1
| The film forming material | Average grain diameter (μ m) | The negative pole forming method | Film thickness (μ m) | The oxygen mol ratio | Starting efficiency (%) | Initial charge capacity | The speed of | |
| Embodiment | ||||||||
| 1 | The SiO sintered body | 250 | Ion plating | 0.05 | 0.5 | 84 | 1 | |
| | ″ | ″ | ″ | 0.1 | 0.5 | 85 | 1 | |
| | ″ | ″ | ″ | 1 | 0.5 | 85 | 1 | |
| | ″ | ″ | ″ | 20 | 0.5 | 83 | 1 | |
| | ″ | ″ | ″ | 50 | 0.5 | 78 | 0.9 | |
| | ″ | ″ | ″( *1) | 1 | 0.9 | 81 | 1 | |
| | ″ | ″ | | 1 | 1.2 | 75 | 1 | Resistance heating is slow |
| Embodiment 8 | ″ | ″ | | 1 | 1.0 | 80 | 1 | Extremely slow |
| Existing example 1 | - | - | It is dry to mix coating | 200 | 1.4 | 46 | 0.6 | |
| Existing example 2 | - | - | ″( *2) | 200 | 1.4 | 84 | 0.5 | |
| Embodiment 9 | The SiO sintered | 1000 | Ion plating | 1 | 0.5 | 85 | 1 | |
| | ″ | 10 | ″ | 1 | 0.9 | 80 | 1 | |
| Embodiment 11 | SiO separates out body | - | ″ | 1 | 0.5 | 85 | 1 | Be slower than sintered body |
| Embodiment 12 | The mixed sintering body | - | ″ | 1 | 0.5 | 83 | 0.9 | Be slower than embodiment 11 |
| Embodiment 13 | The Si piece | - | ″ | 1 | 0.5 | 83 | 0.9 | Be slower than embodiment 12 |
*1: in atmosphere, add oxygen, the oxygen amount of film is increased
*2: the method that in the SiO porous layer, comprises lithium in advance
In embodiment 1～8, it is the SiO sintered powder (vacuum-sintering product) of 250 μ m that film forming adopts the average grain diameter of powder with material, changes over film method according to multiple mode.
Film build method adopts ion plating in the occasion of embodiment 1～5.The thickness of film is 0.05 μ m, 0.1 μ m, 1 μ m, 20 μ m, 50 μ m 5 kinds.In any film, the mol ratio of the relative Si of O in the silica is 0.5.
In embodiment 6, be the occasion of 1 μ m at film, in film forming atmosphere, add oxygen, increase the mol ratio of the relative Si of O in the silica wittingly.
In embodiment 7 and embodiment 8, on the surface of above-mentioned collector body, by common vacuum evaporation (resistance heating) and sputter, forming the thickness that is formed by silica is the film of 1 μ m.
Relative these embodiment in existing example 1, by powder coating seasoning, are stacked and placed on the fine-powder of powder SiO on the surface of above-mentioned collector body, and formation thickness is the negative electrode active material layer of 200 μ m.In the example 2 in the past,, be that the negative electrode active material layer of 200 μ m is formed on the surface of above-mentioned collector body with making lithium be contained in thickness among the SiO in advance by powder coating seasoning.
Adopt SiO at negative electrode active material layer, by powder coating seasoning, cambial occasion, the mol ratio of the relative Si of O in this layer is increased to 1.4.In order to make initial discharge capacity less than initial charge capacity, starting efficiency is low to moderate 46% (existing example 1).Comprise lithium among the SiO by making in advance, starting efficiency rises to 84%, but because of it is specifically designed to the minimizing of initial charge capacity, consequently, hinders the good theoretical capacity (existing example 2) of SiO.
Replace powder coating seasoning, and by the film of ion plating formation as the SiO of negative electrode active material.The mol ratio of the relative Si of O in the film is reduced to 0.5.At the bigger state of initial charge capacity, starting efficiency be improved (embodiment 1～5).But in the occasion of the bigger embodiment 5 of thickness, initial charge capacity and starting efficiency reduce slightly.The mol ratio of the relative Si of O in film is increased to the occasion of 0.99 embodiment 6, though starting efficiency reduce slightly,, this efficient is higher degree still, greater than initial charge capacity.
By common vacuum evaporation and sputter, film forming embodiment 7 and 8 occasion, the mol ratio of the relative Si of O in the film surpasses 1.If compare with ion plating, though starting efficiency reduces slightly, still be higher level, initial charge capacity also is a high level.The rate of film build of common vacuum evaporation is lower than the rate of film build of ion plating, and the rate of film build of sputtering method is lower.
On the other hand, in embodiment 9～13, film build method adopts ion plating, changes the film forming material according to multiple mode.Thickness is 1 μ m.
In the occasion of embodiment 9, the film forming material is that the average grain diameter of powder is the SiO sintered powder (vacuum-sintering product) of 1000 μ m.In the occasion of embodiment 10, it is the SiO sintered powder (vacuum-sintering product) of 10 μ m that film forming adopts the average grain diameter of powder with material.The evaporation residue rate is respectively 3%, 8%.With thickness is that the embodiment 3 of identical 1 μ m compares, and in the occasion of embodiment 9, the effect of battery performance is saturated, and in the occasion of embodiment 10, the mol ratio of the relative Si of O in the film reduces slightly.So, best, the average grain diameter of the powder of SiO sintered powder 250 μ m or more than.
In the occasion of embodiment 11, adopt SiO to separate out the broken piece (average grain diameter is about 5cm) of body.With thickness is that the embodiment 3 of identical 1 μ m compares, even for to separate out under the situation of body, still obtains starting efficiency and the initial charge capacity identical with sintered powder.On the other hand, in the occasion of sintered body, because being less than, the splash (splashing) in the film forming separates out body, so can further improve rate of film build (evaporation rate).Thus, from the productivity aspect, be preferably sintered body.In addition, in the occasion of sintered body, the continuous supply that also has the raw material of film formation device is easy to advantage.It is believed that,, pretend and separate out body with SiO for film forming securely with the SiO of material and combine because the splash (splashing) in the film forming of SiO sintered body is few.
In the occasion of embodiment 12, adopt Si powder and SiO
2The mixed sintering body of powder.Even using under the situation of material for this film forming, still obtain the effect relevant, and rate of film build be very slow with battery performance.Separate out the occasion of body, SiO sintered body at SiO, only heating-up temperature is brought up to the sublimation temperature of SiO, just can carry out film forming, but at Si powder and SiO
2The occasion of the mixed sintering body of powder, at first, Si and SiO that must be in sintered body
2Contact portion react to each other and produce SiO.Thus, the SiO generation speed in the mixed sintering body is slower than SiO and separates out body and SiO sintered body.If bigger heat is provided, then formation speed rises, and still, if like this, the splash (splashing) during owing to film forming increases, so have the restriction of having to reduce rate of film build.
In the occasion of embodiment 13, be material with the silico briquette of the cutting of adopting the silicon ingot by the casting manufacturing, under oxidizing atmosphere, carry out film forming and handle.For battery performance, obtain the identical performance of occasion with the mixed sintering body of embodiment 12.Oxidizing atmosphere forms by importing oxygen.In this occasion,,, more be easy to generate splash (splashing) so compare with the mixed sintering body because the Si atom is discharged from material surface.Thus, rate of film build is littler.
(the 2nd form of implementation)
The negative electrode active material layer 32 that the aspect that should note in the lithium storage battery of present embodiment is negative pole 30 is formed by the film of the densification of SiO, separate out body as the film forming material at this film with SiO, by vacuum evaporation or sputter, preferably be formed on the collector body 31 by a kind of ion plating as vacuum evaporation.More particularly, the negative electrode active material layer 32 of negative pole 30 is following film, and it adopts as SiO and separates out body, and the weight slip (attrition value) of wear test is 1.0% or following material.The thickness of film is adapted in the scope of 0.1～50 μ m.
On the other hand, anodal 20 positive electrode active material layer 22 forms by powder coating seasoning as before, in the method, and with LiCoO
2Deng the powder of oxide of the transition metal that comprises lithium mix with adhesive solution, form slurries, these slurries are coated on the surface of collector plate 21, after the drying, it is pressurizeed, other aspect is identical with the occasion of the 1st form of implementation.
The feature of the lithium storage battery of this form of implementation is as described below.
The 1st, because negative electrode active material layer 32 forms by SiO, so the theoretical capacity of comparing with the carbon dust layer is bigger.The 2nd, because the film of this SiO for forming by vacuum evaporation or sputter, so can under the situation that does not reduce initial charge capacity, improve starting efficiency.The 3rd, because the capacity of the unit volume of film is bigger, miniaturization easily.The 4th and since adopt film forming with the weight slip (attrition value) of fret wear test 1.0% or following SiO separate out body, cell excellent in cycle characteristics.Specifically, by the SiO layer that powder coating seasoning forms, cycle characteristics is good, and the film that forms with adopting the SiO sintered body is identical.
At the 2nd form of implementation, provide embodiments of the invention, by with the contrast of comparative example, clear and definite effect of the present invention.
Manufacturing is separated out body as film forming with the SiO of material.Specifically, in a vacuum to Si powder and SiO
2The mixture of powder heats, and thus, produces SiO gas, and its portion of separating out at low temperature is separated out, and thus, makes SiO and separates out body.At this moment, create conditions, separate out the condition of separating out of bilge construction etc., change SiO and separate out the physical characteristic (with reference to the WO03/025246A document) of body by change.
Separate out body at the various SiO that made, implement wear test, the investigation attrition value.In addition, the various SiO that made are separated out body be used for the film forming material, on the surface of the collector body that the Copper Foil that by thickness is 10 μ m forms,, form SiO film as negative electrode active material layer by ion plating.In the occasion of ion plating, with the EB rifle as heating source, in specified vacuum atmosphere [10
-3Pa (10
-5Torr)], form SiO film (thickness is 5 μ m).
Various negative poles and anodal combination with such manufacturing are sealed in enclosure with it with electrolyte and make lithium storage battery (size: diameter is 15mm, and thickness is 3mm).Measure the cycle characteristics of Manufactured various batteries.Cycle characteristics is estimated by the ratio (capability retention) of relative the 1st time discharge capacity of the 10th time discharge capacity.In addition, the anodal LiCoO that adopts
2Fine-powder, electrolyte adopts the nonaqueous electrolyte comprise ethylene carbonate.
Capability retention that table 2 expression has been measured and the relation between the attrition value.As what know according to table 2, more little with the attrition value that the SiO of material separates out body as film forming, capability retention is big more, guarantee attrition value 1.0% or below, capability retention 98% or more than.
Table 2
| Attrition value (%) | Capability retention (%) | |
| | 0.5 | 98.8 |
| | 0.8 | 98.5 |
| | 1.0 | 98.0 |
| Comparative example 1 | 1.2 | 92.7 |
| Comparative example 2 | 1.4 | 83.6 |
In addition, in the occasion of the SiO layer that forms by the powder coating mixing method, starting efficiency 50% or below.By lithium is contained among the SiO, though starting efficiency rise to 80% or more than,, it is specifically designed to initial charge capacity and reduces, and hinders the good theoretical capacity of SiO.Separate out the film formed occasion of body at SiO, at the bigger state of initial charge capacity, with starting efficiency be improved to 80% or more than.
(the 3rd form of implementation)
The active material layer 32 that the aspect that should note in the lithium storage battery of present embodiment is negative pole 30 is formed by the film of the densification of SiO, this film is separated out body as the film forming material with SiO, by vacuum evaporation or sputter, preferably, be formed on the collector body 31 by a kind of ion plating as vacuum evaporation.
More particularly, when being to form the SiO film on the collector body 31, surface treatment bombardment by the direct magnetic control tube discharge in the vacuum chamber, clean is carried out on surface to collector body 31, then, in vacuum chamber, be not exposed in the air atmosphere, by ion plating etc., on the surface of collector body 31, form the SiO film.The thickness of SiO film is suitably in the scope of 0.1～50 μ m.
On the other hand, anodal 20 positive electrode active material layer 22 forms by powder coating seasoning as before, in the method, and with LiCoO
2Deng the powder of oxide of the transition metal that comprises lithium mix with adhesive solution, form slurries, these slurries be coated on the surface of collector plate 21, carry out drying after, it is pressurizeed, and other aspect is identical with the occasion of the 1st form of implementation and the 2nd form of implementation.
The feature of the lithium storage battery of present embodiment is as described below.
The 1st, because negative electrode active material layer 32 is formed by SiO, so compare with the carbon dust layer, theoretical capacity is bigger.The 2nd, because this SiO is the film that is formed by vacuum evaporation or sputter, so can under the situation that does not reduce initial charge capacity, improve starting efficiency.The 3rd, because the capacity of the unit volume of film is bigger, miniaturization easily.The 4th, when forming the SiO film, in a vacuum clean is carried out on the surface of collector body 31, then, in a vacuum, be not exposed to and carry out film forming under the situation of air atmosphere and handle, thus, also can obtain good cycle characteristics even adopt SiO to separate out under the situation of body with material in film forming.
With regard to the 3rd form of implementation, provide embodiments of the invention, by comparing, learn effect of the present invention with comparative example.
SiO separates out body and is used for the film forming material, on the surface of the collector body that the Copper Foil that by thickness is 10 μ m forms, by ion plating, forms the SiO film as negative electrode active material layer.In the occasion of ion plating, with the EB rifle as heating source, in specified vacuum atmosphere [10
-3Pa (10
-5Torr)] form SiO film (thickness is 5 μ m).
At this moment, as a comparative example, the surface to collector body in atmosphere is cleaned, and after its drying, carries out film forming and handle in vacuum chamber.In addition,, handling, after the cleaning surfaces of collector body is handled, in this vacuum chamber, carrying out film forming and handle by the bombardment (bombard) in the vacuum chamber as embodiments of the invention.
2 kinds of negative poles having made are made up with anodal, it is sealed in enclosure with electrolyte, make lithium storage battery (size: diameter is 15mm, and thickness is 3mm).Measure the cycle characteristics of Manufactured various batteries.This cycle characteristics is estimated by the ratio (capability retention) of relative the 1st time discharge capacity of the 10th time discharge capacity.In addition, the anodal LiCoO that adopts
2Fine-powder, electrolyte adopts the nonaqueous electrolyte comprise ethylene carbonate.
In the occasion of comparative example, cycle characteristics is 85%, and still, in the occasion of embodiments of the invention, this cycle characteristics brings up to 98%.That is, in the occasion of embodiments of the invention, to the film forming step, the surface of collector body and air atmosphere are isolated from the clean of collector body, thus, although adopt SiO to separate out body, still obtain 98% higher cycle characteristics.
In the occasion of film forming with material employing SiO sintered body, identical with comparative example, the cycle characteristics when carrying out pre-treatment is 90%.If identically with embodiment carry out pre-treatment, then this cycle characteristics brings up to 99%.As what know according to this situation, it also is effective that the present invention adopts the occasion of SiO sintered body as film forming with material.
In addition, in the occasion of the SiO layer that forms by powder coating seasoning, starting efficiency 50% or below.Comprise lithium among the SiO by making in advance, reach though starting efficiency rises 80% or more than,, it is specifically designed to the minimizing of initial charge capacity, hinders the good theoretical capacity of SiO.Separate out the occasion of the film of body and SiO sintered body forming SiO, at the bigger state of initial charge capacity, with starting efficiency be improved to 80% or more than.
In addition,, in the 1st form of implementation～the 3rd form of implementation, enumerated button battery, but in the present invention for battery types because the negative pole attenuation, so can be easily by stacked and increase capacity.Thus, the present invention is particularly suitable for stacked battery, and the invention is characterized in provides to low price small-sized jumbo battery by being used for stacked battery.In addition, forming the occasion of stacked type battery, even in the part of positive electrode active material layer, collector body, slider etc., still can be identical with negative electrode active material layer, form film by film forming.
Application possibility on the industry
Negative electrode for lithium secondary battery of the present invention can be by the surface at collector body, the structure of the film of the silica that forms by vacuum evaporation or sputter is set, do not hinder the lithium battery that is used for negative pole at SiO, the value of distinctive initial charge capacity, improve significantly the lower situation as the starting efficiency of its shortcoming, performance at lithium battery improves and miniaturization, brings into play larger effect.
At negative electrode for lithium secondary battery of the present invention, or in the SiO membranous type negative pole of the surface of collector body formation as the silicon oxide film of negative electrode active material, as cycle characteristics, the capability retention of the 10th time discharge 98% or more than, starting efficiency and initial charge capacity increase thus, and cycle characteristics is also good.
Lithium storage battery of the present invention is by adopting above these negative poles, do not hinder SiO to be used for the size of distinctive initial charge capacity of the lithium battery of negative pole, can significantly improve the lower situation as the starting efficiency of its shortcoming, simultaneously, also can improve cycle characteristics, aspect the performance raising and miniaturization of lithium battery, has larger effect.
Because film-forming material of the present invention is formed by separating out body or separating out the sintered body that system makes by this of SiO, so be used for the formation of film of the silica of negative electrode for lithium secondary battery, do not hinder SiO to be used for the size of the distinctive initial charge capacity of lithium storage battery of negative pole, can improve significantly the low situation as the starting efficiency of its shortcoming, thus, the performance of lithium storage battery improve and miniaturization aspect bring into play larger effect. In addition, evaporation rate increases, and rate of film build is increased.
Film-forming material of the present invention is also for SiO separates out body, the weight slip (attrition value) of wear test be 1.0% or below, thus, can in the situation of the reduction of not following initial charge capacity, improve starting efficiency, simultaneously, can improve cycle characteristics.
The manufacture method of negative electrode for lithium secondary battery of the present invention can provide the negative pole of following good characteristic, wherein, by by vacuum evaporation or sputter, form the film of silica on the surface of collector body, do not hinder the value that SiO is used for the distinctive initial charge capacity of lithium storage battery of negative pole, can significantly improve the lower situation as the starting efficiency of its shortcoming, thus, aspect the performance raising and miniaturization of lithium battery, bring into play larger effect.
The manufacture method of negative electrode for lithium secondary battery of the present invention also can be by adopting wear test weight slip (attrition value) 1.0% or following SiO separate out body, thus, can in the situation of the reduction of not following initial charge capacity, improve starting efficiency, simultaneously, can improve cycle characteristics.
The manufacture method of negative electrode for lithium secondary battery of the present invention also can be the surface of negative electrode collector, formation is during as the silicon oxide film of negative electrode active material in a vacuum or in the inert atmosphere, cleaning is carried out on the collector body surface, then, under the collector body surface is not exposed to situation in the air atmosphere, form the film of silica on this surface, thus, it is certain adopting the occasion of SiO sintered body as film-forming material, but also can adopt SiO to separate out the occasion of body at this film-forming material, guarantee good cycle characteristics. In addition, by adopting these film-forming materials, can in the situation of not following initial charge capacity to reduce, improve starting efficiency.
Claims (17)
1. a negative electrode for lithium secondary battery in this negative electrode for lithium secondary battery, has the film of the silica that forms by vacuum evaporation or sputter on the surface of collector body.
2. negative electrode for lithium secondary battery according to claim 1, the thickness of film that it is characterized in that above-mentioned silica is in the scope of 0.1～50 μ m.
3. negative electrode for lithium secondary battery according to claim 1 is characterized in that above-mentioned vacuum evaporation is ion plating.
4. negative electrode for lithium secondary battery according to claim 1 is characterized in that above-mentioned silica is SiOx (0.5≤x≤1.2).
5. negative electrode for lithium secondary battery according to claim 4 is characterized in that above-mentioned silica is SiOx (0.5≤x＜1.0).
6. negative electrode for lithium secondary battery, this negative electrode for lithium secondary battery is on the surface of collector body, has formed the SiO membranous type negative pole of the film of silica as negative electrode active material, it is characterized in that, the capability retention of the 10th time discharge 98% or more than.
7. lithium storage battery, this lithium storage battery has any one the described negative pole in the claim 1～6.
8. film forming material, this film forming is used when forming the film of the silica in the negative electrode for lithium secondary battery by vacuum evaporation or sputter with material, and this film forming is with material separating out body or separating out the sintered body that system makes by this and form by SiO.
9. film forming material according to claim 8, it is characterized in that it is formed by sintered body, in heating-up temperature is 1300 ℃, the evaporation residue when pressure is measured the thermogravimetric amount of sintered body sample under 10Pa or following vacuum atmosphere be the sample before mensuration quality 4% or below.
10. film forming material according to claim 8 is characterized in that it is formed by sintered powder, and the average grain diameter of this powder 250 μ m or more than.
11. film forming material according to claim 8 is characterized in that its body of separating out by SiO forms, the weight slip (attrition value) of wear test 1.0% or below.
12. the manufacture method of a negative electrode for lithium secondary battery, this method by vacuum evaporation or sputter, form the film of silica on the surface of collector body.
13. the manufacture method of negative electrode for lithium secondary battery according to claim 12 is characterized in that this method adopts a kind of ion plating of above-mentioned vacuum evaporation.
14. the manufacture method of negative electrode for lithium secondary battery according to claim 12, the film forming that it is characterized in that above-mentioned vacuum evaporation or sputter adopts any one described film forming material in the claim 8～11 with material.
15. the manufacture method of a negative electrode for lithium secondary battery, it is characterized in that on the surface of negative electrode collector, formation is during as the film of the silica of negative electrode active material, in a vacuum or in the inert atmosphere clean is carried out on the collector body surface, then, under the collector body surface is not exposed to situation in the air atmosphere, on this surface, form the film of silica.
16. the manufacture method of negative electrode for lithium secondary battery according to claim 15 is characterized in that the formation method of silicon oxide film adopts vacuum vapour deposition or sputtering method.
17. the manufacture method of negative electrode for lithium secondary battery according to claim 15, the film forming when it is characterized in that forming silicon oxide film adopts SiO to separate out body with material.
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| US8309252B2 (en) | 2007-01-05 | 2012-11-13 | Samsung Sdi Co., Ltd. | Anode active material, method of preparing the same, and anode and lithium battery containing the material |
| CN101510607B (en) * | 2007-02-14 | 2013-07-03 | 三星Sdi株式会社 | Anode active material, method of preparing the same, anode and lithium battery containing the material |
| CN104966814A (en) * | 2015-07-07 | 2015-10-07 | 李震祺 | High-security metallic lithium cathode and preparation method thereof |
| CN108199031A (en) * | 2018-01-16 | 2018-06-22 | 毛伟波 | A kind of high amorphous state silicon monoxide material, preparation method and its usage |
| CN111916657A (en) * | 2020-07-24 | 2020-11-10 | 江西昌大高新能源材料技术有限公司 | Silicon monoxide/metal composite film cathode and preparation method thereof |
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| CN2390280Y (en) * | 1999-09-14 | 2000-08-02 | 珠海道元科技发展有限公司 | Internal connected stacked amorphous silicon photocell |
| JP2001185127A (en) * | 1999-12-24 | 2001-07-06 | Fdk Corp | Lithium secondary battery |
| JP2002042809A (en) * | 2000-07-31 | 2002-02-08 | Denki Kagaku Kogyo Kk | Non-aqueous secondary battery |
| JP4752992B2 (en) * | 2001-06-15 | 2011-08-17 | 信越化学工業株式会社 | Anode material for non-aqueous electrolyte secondary battery |
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2004
- 2004-04-16 CN CNB200480011532XA patent/CN100411229C/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN100438143C (en) * | 2003-08-28 | 2008-11-26 | 松下电器产业株式会社 | Negative electrode for non-aqueous electrolyte secondary battery, production method thereof and non-aqueous electrolyte secondary battery |
| US8309252B2 (en) | 2007-01-05 | 2012-11-13 | Samsung Sdi Co., Ltd. | Anode active material, method of preparing the same, and anode and lithium battery containing the material |
| CN101510607B (en) * | 2007-02-14 | 2013-07-03 | 三星Sdi株式会社 | Anode active material, method of preparing the same, anode and lithium battery containing the material |
| CN104966814A (en) * | 2015-07-07 | 2015-10-07 | 李震祺 | High-security metallic lithium cathode and preparation method thereof |
| CN108199031A (en) * | 2018-01-16 | 2018-06-22 | 毛伟波 | A kind of high amorphous state silicon monoxide material, preparation method and its usage |
| CN108199031B (en) * | 2018-01-16 | 2020-04-10 | 毛伟波 | High amorphous silicon monoxide material, preparation method and application thereof |
| CN111916657A (en) * | 2020-07-24 | 2020-11-10 | 江西昌大高新能源材料技术有限公司 | Silicon monoxide/metal composite film cathode and preparation method thereof |
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