The contained theme of the present invention relates to Japanese patent application JP 2007-019722, Japanese patent application JP 2007-083569 that submitted to Japan Patent office on March 28th, 2007 that submitted to Japan Patent office on January 30th, 2007 and the Japanese patent application JP2007-307478 that submitted to Japan Patent office on November 28th, 2007, and the full content with above-mentioned document is combined in herein by reference.
Embodiment
Describe embodiments of the present invention with reference to the accompanying drawings in detail.
Fig. 1 shows the cross-section structure of the negative pole of one embodiment of the present invention.This negative pole for example is used for the electrochemical apparatus such as battery.This negative pole comprises collector body 1 with a pair of surface and anode active material layer 2 disposed thereon.
Negative electrode collector 1 is preferably made by the metal material with good electrical chemical stability, conductivity and mechanical strength.As metal material, for example can use copper, nickel, stainless steel etc.Especially, as metal material, copper is preferred, because can obtain high conductivity.
Especially, as the metal material that constitutes negative electrode collector 1, comprising one or more is not preferred with the metal material that the electrode reaction thing forms the metallic element of intermetallic compound.If metal material and electrode reaction thing form intermetallic compound, then since anode active material layer 2 (for example, when battery charging and discharging) when electrochemical apparatus operate expand and shrink and generation stress, thereby structural failure appears.The result causes the current collection reduction, and anode active material layer 2 is peeled off easily.As metallic element, for example can use copper, nickel, titanium, iron, chromium etc.
Above-mentioned metal material preferably comprises one or more and anode active material layer 2 alloyed metal (AM) elements.Improve the contact performance between negative electrode collector 1 and the anode active material layer 2 thus, so that anode active material layer 2 is difficult to peel off from negative electrode collector 1.Negative active core-shell material in anode active material layer 2 comprises under the situation of silicon, with anode active material layer 2 alloyed metal (AM) elements, for example can use copper, nickel, iron etc. as not forming intermetallic compound with the electrode reaction thing.Aspect intensity and conductivity, such metallic element also is preferred.
Negative electrode collector 1 can have single layer structure or sandwich construction.If negative electrode collector 1 has sandwich construction, then preferably contact with anode active material layer 2 layer by making with anode active material layer 2 alloyed metal (AM) materials, and layer making of not contacting by other metal material with anode active material layer 2.
The surface of negative electrode collector 1 is preferably coarse.Thereby owing to so-called grappling effect is improved contact performance between negative electrode collector 1 and the anode active material layer 2.In the case, promptly enough to major general's collector body 1 with respect to the surface roughening of anode active material layer 2.As the roughening method, for example can use the method etc. that forms particle by electrolytic treatments.Electrolytic processing method provides non-planarization by form particle on negative electrode collector 1 surface in electrolysis tank.Copper Foil through electrolytic treatments is commonly referred to as " electrolytic copper foil ".
10 mean roughness Rz on negative electrode collector 1 surface are preferably 1.5-6.5 μ m.Further improve the contact performance between negative electrode collector 1 and the anode active material layer 2 thus.
Anode active material layer 2 comprises metal material and as a plurality of negative active core-shell material particles of negative active core-shell material, wherein metal material comprises the metallic element that does not form alloy with the electrode reaction thing, and the negative active core-shell material particle can absorb and discharge the electrode reaction thing.When anode active material layer 2 comprises this metal material,, also can obtain higher binding characteristic even the negative active core-shell material particle is formed by for example vapour deposition process etc.
The negative active core-shell material particle contains element silicon.Silicon absorbs and discharges the ability height of electrode reaction thing, thereby high-energy-density can be provided.The negative active core-shell material particle can be simple substance, alloy or silicon compound, perhaps is the material with one or more above-mentioned phases at least in part.These phases can be used separately, also can two or more be used in combination.In the present invention, except the alloy that comprises two or more metallic elements, alloy also comprises the alloy that contains one or more metallic elements and one or more metalloid elements.Obviously, alloy of the present invention can comprise nonmetalloid.Its composition can be solid solution, eutectic (eutectic mixture), intermetallic compound or above-mentioned two or more coexistences.
As silicon alloy, for example can use silica removal also to comprise at least a alloy that is selected from the element of tin (Sn), nickel, copper, iron, cobalt, manganese (Mn), zinc, indium (In), silver (Ag), titanium, germanium (Ge), bismuth (Bi), antimony (Sb) and chromium in addition.
As silicon compound, for example can use silica removal also to comprise the compound of oxygen and carbon (C) element outward.The silicon compound silica removal also can comprise outward more than one or more the described element of silicon alloy.
Negative active core-shell material particle and negative electrode collector 1 link.That is, the negative active core-shell material particle is grown along the thickness direction of anode active material layer 2 from the surface of negative electrode collector 1.In the case, preferred negative pole active material particles forms by vapour deposition process, and between negative electrode collector 1 and the anode active material layer 2 (negative active core-shell material particle) to the small part interface by alloying.Particularly, on this interface, the element of negative electrode collector 1 can be spread in the negative active core-shell material particle, and perhaps the element of negative active core-shell material particle can be spread in the negative electrode collector 1, during perhaps above-mentioned two kinds of elements are diffused into each other mutually.Therefore, the breakage that expansion or contraction owing to negative active core-shell material cause can take place when discharging and recharging hardly, and improved the conductivity between negative electrode collector 1 and the anode active material layer 2.
As above-mentioned vapour deposition process, for example can use physical deposition method or chemical deposition.More specifically, can use vacuum vapour deposition, sputtering method, ion plating, laser ablation method, hot CVD (chemical vapour deposition (CVD)) method, plasma CVD method etc.
The negative active core-shell material particle can have by single film and forms the single layer structure that step forms.Perhaps, the negative active core-shell material particle can have by a plurality of films and forms the sandwich construction that step forms.Yet, for prevent negative electrode collector 1 when forming the negative active core-shell material particle by vapour deposition method since film when forming high heat and heat damage, the negative active core-shell material particle preferably has sandwich construction.When the film formation of negative active core-shell material particle is divided into several steps (the negative active core-shell material particle forms and lamination in proper order), form step with the negative active core-shell material particle by single film and compare, the time that negative electrode collector 1 is exposed under the high heat shortens.
In addition, the negative active core-shell material particle preferably comprises oxygen, thereby prevents that anode active material layer 2 from expanding or contraction.In anode active material layer 2, at least a portion oxygen preferably combines with a part of silicon.In the case, can be the form of silicon monoxide, silicon dioxide in conjunction with attitude, or other metastable state form.
Oxygen content in the negative active core-shell material particle is preferably 3-40 atom %, to obtain better effect.More specifically, if oxygen content less than 3 atom %, then can not fully avoid anode active material layer 2 to expand or shrink, on the other hand, if oxygen content greater than 40 atom %, then resistance excessively increases.For example, when in electrochemical apparatus negative pole being used with electrolyte, anode active material layer 2 does not comprise the coating that forms by deposited electrolyte etc.That is, when the oxygen content in the calculating anode active material layer 2, the oxygen in the above-mentioned coating does not count.
Contain oxygen negative active core-shell material particle by when forming the negative active core-shell material particle, oxygen being introduced in the chamber continuously, can being formed with vapour deposition process.Especially, when required oxygen content can't be only when introducing oxygen and obtain, liquid (for example, steam etc.) can be introduced this chamber as the oxygen supply source.
The negative active core-shell material particle preferably also contains the metallic element of at least a chosen from Fe, cobalt, nickel, titanium, chromium and molybdenum, thereby prevents the expansion and the contraction of anode active material layer 2.Metal element content in the negative active core-shell material particle can be set arbitrarily.Yet, if negative pole is used for battery, the metallic element of crossing a large amount is unpractiaca, because in the case, the thickness of anode active material layer 2 should increase the battery capacity of expecting to obtain, so anode active material layer 2 is easy to peel off or breakage from negative electrode collector 1.
When forming the negative active core-shell material particle, for example, can form the negative active core-shell material particle that contains above-mentioned metallic element by using the vapor deposition source of mixing or using a plurality of vapor deposition source with metallic element by vapour deposition method as vapour deposition process.
Negative active core-shell material preferably has the oxygen of containing district, and wherein the negative active core-shell material particle also contains aerobic on thickness direction, and the oxygen content that contains the oxygen district is greater than other regional oxygen content.Can prevent the expansion or the contraction of anode active material layer 2 thus.Except that containing the oxygen district, other zone can contain oxygen also can oxygen-free.Obviously, if other zone except that containing the oxygen district contains aerobic, then its oxygen content is lower than the oxygen content that contains the oxygen district.
In the case, expand or contraction in order further to prevent anode active material layer 2, other zone except that containing the oxygen district preferably contains aerobic.That is, the negative active core-shell material particle preferably includes first and contains oxygen district (zone that oxygen content is lower) and second and contain oxygen district (zone that oxygen content is higher).In the case, preferred second contains the oxygen district and is clipped in first and contains between the oxygen district.More preferably, first contains oxygen district and second and contains the oxygen district and alternately repeat lamination.Obtain better effect thus.First oxygen content that contains in the oxygen district is preferably as much as possible little.The oxygen content that second oxygen content that contains the oxygen district and top described negative active core-shell material particle contain under the situation of aerobic is similar.
For example comprise that by oxygen being introduced off and on the chamber or changed the amount of oxygen (when forming the negative active core-shell material particle) of introducing the chamber, can forming first contains the negative active core-shell material particle that oxygen district and second contains the oxygen district with vapour deposition process.Obviously, if can't be only by introducing the oxygen content that oxygen obtains expectation, then liquid (for example, steam etc.) can be introduced this chamber.
First oxygen content and second that contains the oxygen district contains the difference of the oxygen content in oxygen district can obviously also can be not obvious.Especially, when the introducing amount of oxygen changed as mentioned above continuously, oxygen content also can change continuously.When oxygen introducing amount intermittently changed, first contains oxygen district and second contained the oxygen district and forms so-called " floor ".On the other hand, when oxygen introducing amount changed continuously, first contains oxygen district and second contained the oxygen district and becomes " laminar " (" lamellar state ") but not " floor ".Under latter event, the oxygen content in the negative active core-shell material particle is fluctuation and distributes.In the case, preferably, oxygen content contains oxygen district and second first and contains graded or variation continuously between the oxygen district.If the oxygen content acute variation then can reduce the ions diffusion characteristic or increase resistance.
The metal material that is contained in the anode active material layer 2 with the negative active core-shell material particle comprises the metallic element that does not form alloy with the electrode reaction thing, thereby prevents that anode active material layer 2 from expanding or contraction.The example of metallic element comprises the element of at least a chosen from Fe, cobalt, nickel, zinc, copper, chromium, titanium, magnesium and manganese.Especially, at least a in preferred iron, cobalt, nickel, zinc and the copper, more preferably cobalt.Obviously, metal material can comprise other metallic element except that above-mentioned metallic element, and prerequisite is that this metallic element does not form alloy with the electrode reaction thing.In the present invention, the metal material that is contained in the anode active material layer 2 with the negative active core-shell material particle is a broad sense, this metal material can be simple substance, alloy or compound, and prerequisite is that this metal material contains the metallic element that does not form alloy with the electrode reaction thing.
The situation that does not have crystallinity (amorphous state) with metal material is compared, and above-mentioned metal material preferably has crystallinity, thereby reduces the resistance of whole negative pole, and makes the electrode reaction thing in the negative pole be easy to absorb and discharge.In addition, in the case, in the initial operation (for example, the initial charge of battery) of electrochemical apparatus, absorb equably and discharge the electrode reaction thing, in negative pole, produce local stress hardly, thereby prevent to produce fold.In the case, half-band width 2 θ that the crystal plane (111) of the metal material that obtains by X-ray diffraction is gone up the peak that produces are preferably 20 degree or littler, to obtain better effect.
As mentioned above, under the situation of the thickness direction growth of negative active core-shell material particle from negative electrode collector 1 surface along anode active material layer 2, metal material is arranged in the gap between the adjacent negative active core-shell material particle.In addition, metal material covers at least a portion exposure of negative active core-shell material particle, the i.e. at least a portion on the surface that the negative active core-shell material particle is not adjacent with other negative active core-shell material particle.In addition, have at the negative active core-shell material particle under the situation of sandwich construction, metal material is arranged in the gap of particle inside.
Fig. 2 A and 2B show the cross-section structure of negative pole.Fig. 2 A is the photo (secondary electron image) of scanning electron microscopy (SEM).Fig. 2 B schematically shows the SEM image of Fig. 2 A.In Fig. 2 B, the clear area is a negative active core-shell material particle 201, and the shadow region is a metal material 202.Fig. 2 A and 2B show the situation that negative active core-shell material particle 201 has sandwich construction.
Shown in Fig. 2 A and 2B, when on the rough surface of negative electrode collector 1, having projection (for example, the formed particulate of electrolytic treatments), negative active core-shell material by for several times deposition and lamination on the surface of negative electrode collector 1.Therefore, a plurality of negative active core-shell material particles 201 are growth gradually on the thickness direction of each above-mentioned projection, and arranges on negative electrode collector 1.In the case, for example, metal material 202 is arranged in the gap between the adjacent negative active core-shell material particle 201 (metal material 202A), metal material 202 partly covers the exposure (metal material 202B) of negative active core-shell material particle 201, and metal material 202 is arranged in the gap of negative active core-shell material particle 201 inside (metal material 202C).In the structure of the metal material 202 that comprises metal material 202A and 202C, metal material 202A is as trunk, and a plurality of metal material 202C is as the branch of trunk.
Metal material 202A gets involved in the gap between the adjacent negative active core-shell material particle, to improve the binding characteristic of anode active material layer 2.More particularly, if negative active core-shell material particle 201 is formed by vapour deposition process etc., then negative active core-shell material particle 201 was grown in aforesaid being present on negative electrode collector 1 lip-deep each projection, thereby formed the gap between negative active core-shell material particle 201.The gap causes the binding characteristic of anode active material layer 2 to reduce.Therefore, in order to improve binding characteristic, metal material 202A is filled in the above-mentioned gap.In the case, the filling part gap is promptly enough, but preferred loading is bigger, because can further improve the binding characteristic of anode active material layer 2.The loading of metal material 202A is preferably 20% or bigger, and more preferably 40% or bigger, also more preferably 80% or bigger.
Metal material 202B covers projection and has a negative impact with the fibrous micro crowning (not shown) that prevents to generate on the outermost exposure in the negative active core-shell material particle 201 performance to electrochemical apparatus.More particularly, if negative active core-shell material particle 201 is formed by vapour deposition process etc., then generate fibrous micro crowning in its surface, thereby between projection, form the space.The space causes the surface area of negative active core-shell material to increase, thereby has increased the surperficial irreversible coating that forms, the electrode reaction that may the slow down progress of going up.Therefore, slow down, fill above-mentioned space with metal material 202B for fear of the electrode reaction progress.In the case, the filling part space is promptly enough, but in order to prevent that further the electrode reaction progress from slowing down, bigger loading is preferred.In Fig. 2 A and 2B, metal material 202B intersperses among the outermost surface of negative active core-shell material particle 201, this means that above-mentioned micro crowning is present in the position that metal material 202B scatters.Obviously, metal material 202B needn't always intersperse among negative active core-shell material particle 201 surfaces, also can cover whole surface.
In the gap in the metal material 202C intervention negative active core-shell material particle 201, to improve the binding characteristic of anode active material layer 2.More particularly, have at negative active core-shell material particle 201 under the situation of sandwich construction, form the gap between each layer.The same binding characteristic of anode active material layer 2 that also can cause with the gap between the above-mentioned adjacent negative active core-shell material particle 201 in this gap reduces.Therefore, in order to improve binding characteristic, fill above-mentioned gap with metal material 202C.In the case, the filling part gap is promptly enough, but in order further to improve and chemistry 2 the binding characteristic that come out, bigger loading is preferred.
Especially, the effect of metal material 202C is similar to metal material 202B.More particularly, if negative active core-shell material is deposited and lamination for several times, then when each deposition, generate above-mentioned micro crowning in its surface.Therefore, metal material 202C not only fills the gap in the negative active core-shell material particle 201, also fills above-mentioned fine voids.
Metal material forms by at least a method of for example vapour deposition process and liquid phase deposition.Especially, metal material is preferably formed by liquid phase deposition.Therefore, be easy to the gap shown in metal material blank map 2A and Fig. 2 B.In addition, in the case, metal material is easy to fill the space, and improves the crystallinity of metal material.
The example of above-mentioned vapour deposition process comprises and used similar method in forming the negative active core-shell material particle.The example of liquid phase deposition comprises plating method, covers method as electrolytic plating method and electroless plating.Especially, as liquid phase deposition, electrolytic plating method covers method more preferably than electroless plating.Thereby more easily in gap and space, fill metal material, and further improve the crystallinity of metal material.
The molal quantity M1 of unit are negative active core-shell material particle and ratio (mol ratio) M2/M1 of the molal quantity M2 of unit are metal material are preferably 1/15-7/1.The shared atomicity ratio (metal material occupation rate) of metal material on the negative terminal surface is preferably 2-82 atom %, more preferably 2.3-82 atom %.Prevent the expansion and the contraction of anode active material layer 2 thus.For example, analyze the negative terminal surface element, can measure the occupation rate of metal material by using energy-dispersive X-ray fluorescence spectroscopic methodology (EDX).
Particularly preferably be, metal material also contains oxygen element, with expansion and the contraction that prevents anode active material layer 2.Oxygen content in the metal material is preferably 1.5-30 atom %, thereby can obtain higher effect.More particularly, if, then can not fully preventing anode active material layer 2 less than 1.5 atom %, oxygen content expands and contraction.On the other hand, if oxygen content greater than 30 atom %, then resistance increases excessive.The oxygen metal material can be for example forms by being similar to that used method forms when containing oxygen negative active core-shell material particle.
Fig. 3 A and 3B show the particle structure on anode active material layer 2 surfaces.Fig. 3 A is the SEM photo.Fig. 3 B schematically shows the SEM image shown in Fig. 3 A.Fig. 4 A and 4B show the profile of the anode active material layer 2 among Fig. 3 A and Fig. 3 B.Fig. 4 A is the SEM photo.Fig. 4 B schematically shows SEM image shown in Figure 4.Fig. 5 A and 5B show the amplifier section of particle structure shown in Fig. 3 A and the 3B.Fig. 5 A is scanning ion microscope (SIM) photo.Fig. 5 B schematically shows the SIM photo shown in Fig. 5 A.Fig. 3 A to Fig. 5 B shows the situation that the negative active core-shell material particle has single layer structure.
Shadow region among Fig. 3 B is an offspring 205, and the particulate matter among Fig. 3 A is a primary particle.Shadow region among Fig. 4 B is primary particle 204 (the negative active core-shell material particle of single layer structure).
Shown in Fig. 3 A-Fig. 5 B, by have the groove of the degree of depth on the thickness direction of anode active material layer 2, offspring 205 separates on the direction in the face of anode active material layer 2.Shown in Fig. 4 A-Fig. 5 B, each primary particle 204 is not only adjacent one another are, and at least a portion of each primary particle 204 is engaged with each other forming offspring 205, and groove 203 almost reaches negative electrode collector 1.The degree of depth of groove 203 and width for example are respectively 5 μ m or bigger and 1 μ m or bigger.Groove 203 forms by electrode reaction (negative pole is used for the reaction that discharges and recharges under the battery situation).Groove 203 does not rupture along primary particle 204, and shape linearly relatively.Therefore, shown in Fig. 3 A, 3B, 5A and 5B, part primary particle 204 divided by groove 203 and form the division particle 206.Mesh-like area among Fig. 5 B is division particle 206.
The quantity of division particle 206 is preferably: for five adjacent or more a plurality of offspring 205, each offspring 205 on average has 10 or more a plurality of division particle 206.If primary particle 204 engages with the contact performance of certain level, with the offspring 205 that formation has the above size of certain level, the stress that expansion and contraction caused of anode active material layer 2 is released when then discharging and recharging.The average that the middle part of negative pole reaches above-mentioned division particle 206 is enough.At the peripheral part of negative pole, current concentration takes place easily, and the generation of groove 203 changes easily.
In addition, as offspring 205, on the section on the thickness direction shown in Fig. 4 B, in continuous 10 offsprings 205, length T 2 is preferably about 50% or bigger greater than the quantity ratio of the offspring of length T 1, wherein length T 1 is on thickness direction, and the direction of length T 2 is perpendicular to length T 1.Therefore, the stress due to the expansion of anode active material layer 2 and the contraction is further discharged.It is enough than promptly that the middle part of negative pole reaches this quantity, as above-mentioned division particle 206.For the length T on the thickness direction 1 with perpendicular to the length T on the direction of T1 2, measure the maximum of each offspring 205 on section.
For example, these particle structures can use SEM to observe shown in Fig. 3 A and Fig. 4 A, perhaps can use SIM to observe shown in Fig. 5 A.The observation section is preferably used incisions such as focused ion beam (FIB), microtome.
Fig. 6 schematically shows the cross-section structure of the negative pole shown in Fig. 1, Fig. 2 A and Fig. 2 B.Fig. 6 shows the situation that negative active core-shell material particle 201 has single layer structure.
As shown in Figure 6, in anode active material layer 2, a plurality of negative active core-shell material particles 201 are grown on each projection 1R of negative electrode collector 1, and arrange on negative electrode collector 1.Comprise metal material 202 (202A) in the gap of anode active material layer 2 between negative active core-shell material particle 201.
If anode active material layer 2 comprises metal material 202 and negative active core-shell material particle 201, then metal material 202 can be distributed in the anode active material layer 2 by any way.Yet especially, a large amount of metal materials 202 preferably are present near negative electrode collector 1 one sides.More particularly, in the section of the anode active material layer 2 in the orientation of a plurality of negative active core-shell material particles 201, the existence district that is present in the metal material 202 in the gap between two given negative active core-shell material particles 201 is counted as given area S, when region S is vertically divided equally, metal material 202 occupied area ratios among the inferior segment SB are preferably 60% or bigger, and more preferably 70% or bigger.Reason is as follows.That is, most of metal material 202 is present in (near negative electrode collector 1 one sides) in the anode active material layer 2.Therefore, in this way, in the binding characteristic that guarantees the negative active core-shell material particle, can prevent under most of metal material 202 is present in the situation of adjacent domain (away from a side of negative electrode collector 1) on anode active material layer 2 surfaces, to have problems for example electrode sclerosis, short circuit etc.Especially, if metal material 202 is formed by coating method, prevent that then metal material 202 from being isolated (excessive formation) on negative active core-shell material particle 201.Therefore, can prevent owing to isolate the short circuit that causes.For example by using SEM to observe the negative pole section, can determine the shared area ratio of metal material 202 among the inferior segment SB.
Above-mentioned " region S " is meant two straight line LP1 and LP2 and two straight line LT and LB institute area surrounded, wherein LP1 and LP2 with the direction of negative electrode collector 1 surface crosswise on extend and pass the summit 201P of two adjacent negative active core-shell material particles 201, LT and LB extend and pass the upper extreme point 202T and the lower extreme point 202B of metal material 202 on the direction on negative electrode collector 1 surface, and wherein the surface of negative electrode collector 1 is counted as almost plane." inferior segment SB " is meant four straight line LP1, LP2, LH and LB institute area surrounded, and wherein region S is vertically divided equally (being divided into district ST and inferior segment SB) by straight line LH." on " be meant that the side away from negative electrode collector 1, D score are meant the side near negative electrode collector 1.Therefore, " the metal material 202 shared areas among the inferior segment SB compare " is (metal material 202 area occupied in the metal material 202 area occupied/region S among the inferior segment SB) * 100 resulting values (%).
When determining region S, need only two adjacent negative active core-shell material particle 201 combinations, select the combination in any of given negative active core-shell material particle 201 in a plurality of combinations of the negative active core-shell material particle 201 that can from anode active material layer 2, exist.Yet region S is preferably determined on the regularly arranged to a certain extent position of negative active core-shell material particle 201.More particularly, region S is to determine on the position of 1-30 μ m in the distance between the summit 201P of two adjacent negative active core-shell material particles 201 preferably.Therefore, determine region S, and calculate the shared area ratio of metal material 202 among the inferior segment SB with good repeatability with good repeatability.
In Fig. 6, only the situation of anticathode active material particles 201 with single layer structure is described.Therefore, in the case, metal material 202 only comprises metal material 202A, and straight line LT and LB are determined by upper extreme point and the lower extreme point of metal material 202A.On the other hand, have at negative active core-shell material particle 201 under the situation of sandwich construction, metal material 202 comprises metal material 202A and 202C.Therefore, straight line LT and LB are determined by the upper extreme point and the lower extreme point of the aggregate that comprises metal material 202A and 202C.As mentioned above, when determining region S, attentiveness concentrates between negative active core-shell material particle 201 and is positioned at the metal material 202A and the 202C of particle, but not concentrates on the metal material 202B on the outermost surface that is positioned at negative active core-shell material particle 201.
If the 202 shared areas of the metal material among the inferior segment SB compare in above-mentioned scope, then the molal quantity M1 of unit are negative active core-shell material particle 201 is preferably 1/100-1/1 with ratio (mol ratio) M2/M1 of the molal quantity M2 of unit are metal material, more preferably 1/50-1/2.If the 202 shared areas of the metal material among the inferior segment SB compare in above-mentioned scope, then the amount of metal material 202 is suitable, thereby in the binding characteristic that guarantees negative active core-shell material particle 201, prevents electrode sclerosis, short circuit etc.
For example, form negative pole by the following method.
At first, preparation negative electrode collector 1.If desired, roughened is carried out on the surface of anticathode collector body 1.Subsequently, on negative electrode collector 1, form a plurality of siliceous negative active core-shell material particles by vapour deposition process etc.In the case, can form step by single film the negative active core-shell material particle is formed single layer structure.Perhaps, can form step by a plurality of films the negative active core-shell material particle is formed sandwich construction.Subsequently, wait to form by liquid phase deposition and contain not the metal material that forms the metallic element of alloy with the electrode reaction thing.Then metal material is introduced in the gap between the negative active core-shell material particle, thereby formed anode active material layer 2.In the case, for example, at least a portion exposed surface of negative active core-shell material particle is covered by metal material.Simultaneously, for example,, then metal material is introduced in the gap in the negative active core-shell material particle if the negative active core-shell material particle forms sandwich construction.
Under the situation that forms metal material, the formation scope of preferably regulating metal material is so that the shared area ratio of the metal material among the inferior segment SB shown in Figure 6 is 60% or bigger.For example when using electrolytic plating method to form metal material, pass through to regulate current density, can control the area ratio of metal material.More particularly, if current density reduces, then plated film fine and close growth on the surface of negative electrode collector 1, so the area of the metal material among the inferior segment SB is than increasing.On the other hand, if current density raises, then the plated film growth is fine and close but along negative active core-shell material particle surface local growth, so the area of the metal material among the inferior segment SB is than reducing.
Then, preferably with negative pole heating (so-called annealing), so that the metal material crystallization, thereby improve crystallinity.Can set temperature, time etc. in the annealing arbitrarily according to the conditions such as crystallinity of metal material.Yet, should be noted that if annealing temperature is too high alloying on the interface between negative electrode collector 1 and the negative active core-shell material particle may be carried out excessively.
Especially, forming under the situation of metal material by liquid phase deposition, the necessity of annealing is explained as follows.That is,, then can under the condition of not annealing, obtain enough crystallinity, but crystallinity is improved further because of annealing if use electrolytic plating method.On the other hand,, then do not anneal and possibly can't obtain enough crystallinity, but in this case, can obtain enough crystallinity by annealing if use electroless plating to cover method.
According to negative pole and manufacture method thereof, after being formed on siliceous negative active core-shell material particle on the negative electrode collector 1, forming and contain the metal material that does not form the metallic element of alloy with the electrode reaction thing.Therefore, metallic element is introduced in the gap between the adjacent negative active core-shell material particle.Then by metal material with the combination of negative active core-shell material particle, so that anode active material layer 2 is difficult to pulverize and come off.Therefore, in the electrochemical apparatus that uses this negative pole, cycle characteristics can be enhanced.In addition,, therefore not only cycle characteristics can be improved, expansion characteristics can also be improved because electrochemical apparatus expands in operation hardly.
Especially, when metal material covers at least a portion exposed surface of negative active core-shell material particle, prevented the negative effect that fibrous micro crowning caused that generates on the exposed surface.In addition, when the negative active core-shell material particle has sandwich construction and metal material when entering intragranular gap, anode active material layer 2 is difficult to pulverize and come off, and electrochemical apparatus is difficult to expand, and is similar to the situation that metal material enters the gap between the adjacent negative active core-shell material particle.Therefore, in the case, can further improve cycle characteristics and expansion characteristics.
In addition, if the mol ratio M2/M1 of negative active core-shell material particle and metal material is 1/15-7/1, perhaps the shared atomicity of anode active material layer 2 lip-deep metal materials is 2-82 atom %, then can obtain better effect.
If the oxygen content that the negative active core-shell material particle also contains in aerobic and the negative active core-shell material is 3-40 atom %, perhaps when the negative active core-shell material particle also contains the metallic element of at least a chosen from Fe, cobalt, nickel, titanium, chromium and molybdenum, perhaps, the negative active core-shell material particle contains oxygen district (containing the zone that aerobic and oxygen content are higher than other zone) on thickness direction when having, perhaps when metal also contains oxygen content in aerobic and the metal material and is 1.5-30 atom %, can obtain better effect.
In addition, when anode active material layer 2 on average has 10 or more a plurality of division particle 206 for each offspring 205 in adjacent five or the more a plurality of offspring 205, contact performance between negative electrode collector 1 and the anode active material layer 2 improves, and the contact performance between each primary particle 204 (negative active core-shell material particle) in the anode active material layer 2 improves.Therefore, the expansion of anode active material layer 2 and shrink due to stress be released so that anode active material layer 2 is difficult to pulverize and come off.Therefore, can further improve cycle characteristics.In the case, as offspring 205, if in continuous 10 offsprings 205 in the section on the thickness direction of anode active material layer 2, is 50% or bigger perpendicular to the length of thickness direction greater than the quantity ratio of the offspring of the length of thickness direction, then can obtain better effect.
In addition, when metal material had crystallinity, the resistance of whole negative pole reduced, and cathode reactant is easy to absorb and discharge, and is difficult to produce fold in the negative pole.Therefore can obtain better effect.In the case, half-band width 2 θ that the crystal plane (111) of the metal material that obtains by X-ray diffraction is gone up the peak that produces are 20 degree or littler, can further improve cycle characteristics.
In addition, when metal material is formed by liquid phase deposition, metal material is easy to enter gap and the interior gap of negative active core-shell material particle between the adjacent cathode active material particles, the space between the easy fiberfill fibers shape of the metal material micro crowning, and the crystallinity of metal material improves.Therefore can obtain better effect in the case.In the case, if after forming metal material negative pole is annealed, then the crystallinity of metal material improves, thereby can obtain better effect.
In addition, in a plurality of negative active core-shell material particle alignment under the situation on the negative electrode collector 1, if on the section of the anode active material layer 2 of a plurality of negative active core-shell material particle alignment directions, the shared area ratio of metal material among the inferior segment SB shown in Figure 6 be 60% or bigger, more preferably 70% or bigger, then can further improve cycle characteristics and prevent for example electrode sclerosis and problem of short-circuit.In the case, be 1/100-1/1, more preferably during 1/50-1/2, can obtain better effect as the mol ratio M2/M1 of negative active core-shell material particle and metal material.
In addition, if with respect to the surface of the negative electrode collector 1 of anode active material layer 2 by the formed particulate roughening of electrolytic treatments, then can improve the contact performance between negative electrode collector 1 and the anode active material layer 2.In the case, when 10 mean roughness Rz on negative electrode collector 1 surface are 1.5-6.5 μ m, can obtain better effect.
The application example of above-mentioned negative pole hereinafter will be described.Here use the example of battery as electrochemical apparatus.The negative pole battery that is used for as described below.
First battery
Fig. 7 and Fig. 8 show the cross-section structure of first battery.Fig. 8 shows along the section of the straight line VIII-VIII among Fig. 7.Battery described here for example is a lithium rechargeable battery, and wherein the capacity of negative pole 22 is represented as based on as the absorption of the lithium of electrode reaction thing and the voxel of release.
Secondary cell comprises the cell device with flat wound winding arrangement 20 that is positioned at battery case 11 inside.
Battery case 11 for example is square packing component.As shown in Figure 8, the longitudinal profile of this packing component is shaped as rectangle or approximate rectangular (comprising the part curve).Battery case 11 not only constitutes rectangle side's battery, also constitutes oval side's battery.That is, square packing component is meant the rectangular vessel shape member with bottom or has the elliptical vessel shape member of bottom to have rectangular aperture or approximate rectangular (ellipse) opening by forming with straight line connection circular arc respectively.Fig. 8 shows the situation that battery case 11 has the rectangular section shape.The battery structure that comprises battery case 11 is called as the square structure.
Battery case 11 is for example made by the metal material that comprises iron, aluminium (Al) or its alloy.Battery case 11 also can be used as negative terminal.In the case, expand for the rigidity (almost indeformable characteristic) of utilizing battery case 11 when discharging and recharging prevents secondary cell, battery case 11 preferably by the iron of rigidity but not aluminium make.If battery case 11 is fabricated from iron, then can wait plating iron with nickel (Ni).
Battery case 11 also has end sealing and the unlimited hollow structure of the other end.At the openend of battery case 11, connect insulation board 12 and battery cover 13, so that battery case 11 is inner airtight.Insulation board 12 perpendicular to the spiral winding side face setting of cell device 20, is for example made by polypropylene between cell device 20 and battery cover 13.Battery cover is for example made by the material that is similar to battery case 11, also can be as battery case 11 as negative terminal.
In battery cover 13 outsides, be provided as the terminal board 14 of positive terminal.There are insulating case 16 in terminal board and battery cover 13 electric insulations between the two.Insulating case 16 is for example made by Polybutylene Terephthalate etc.Substantial middle place at battery cover 13 is provided with through hole.Anodal pin 15 inserts this through hole so that anodal pin is electrically connected with terminal board 14, and by pad 17 and battery cover 13 electric insulations.Pad 17 is for example made by insulating material, and its surface-coated pitch.
Flow divider 18 and hand-hole 19 are set near battery cover 13 edges.Split valve 18 is electrically connected with battery cover 13.If the internal pressure of battery is owing to internal short-circuit, external heat etc. reaches more than the certain level, then split valve 18 breaks away to discharge internal pressure from battery valve 13.The containment member 19A sealing that hand-hole 19 is made by for example stainless steel ball.
In cell device 20, positive pole 21 and negative pole 22 laminations (having dividing plate 23 between the two) and spiral twine.Cell device 20 is flat, and is consistent with the shape of battery case 11.The positive wire of being made by the metal material of for example aluminium 24 is connected to an end (for example, the inner) of anodal 21.The negative wire of being made by the metal material of for example nickel 25 is connected to an end (for example, outer end) of negative pole 22.By positive wire 24 being welded to an end of anodal pin 15, it is electrically connected with terminal board 14.Negative wire 25 is welded and is electrically connected to battery case 11.
In anodal 21, for example, anode active material layer 21B is arranged on two surfaces of banded positive electrode collector 21A.For example, positive electrode collector 21A is made by the metal material such as aluminium, nickel and stainless steel.Anode active material layer 21B comprises positive electrode active materials, also can comprise adhesive, electric conducting material etc. if desired.
Positive electrode active materials comprises one or more can absorb and discharge positive electrode as the lithium of electrode reaction thing.The example of positive electrode is the lithium complex oxide, for example lithium and cobalt oxides, lithium nickel oxide, comprise their solid solution (Li (Ni
xCo
yMn
z) O
2, wherein 0<x<1,0<y<1,0<z<1, and x+y+z=1), have the lithium manganese oxide (LiMn of spinel structure
2O
4) and solid solution (Li (Mn
2-vNi
v) O
4, v<2 wherein).In addition, as positive electrode, for example can use phosphate compounds such as LiFePO4 (LiFePO with olivine structural
4).Can obtain high-energy-density thus.In addition, as positive electrode, for example can use oxide, as titanium oxide, vanadium oxide and manganese dioxide; Disulphide is as ferrous disulfide, titanium disulfide and molybdenum sulfide; Sulfur; Conducting polymer is as polyaniline and polythiophene.
Negative pole 22 has and the similar structure of above-mentioned negative pole.For example, in negative pole 22, anode active material layer 22B is arranged on two surfaces of banded negative electrode collector 22A.The structure of negative electrode collector 22A and anode active material layer 22B is similar to the negative electrode collector 1 in the above-mentioned negative pole and the structure of anode active material layer 2 respectively.
Separator 23 separates with negative pole 22 anodal 21 and carries ion as the electrode reaction thing, prevents from simultaneously to contact the short circuit current that causes by two electrodes.Separator 23 is for example made by perforated membrane or ceramic membrane, and wherein perforated membrane is made by for example polytetrafluoroethylene, polypropylene and poly synthetic resin.Separator 23 can have the structure of above-mentioned two or more perforated membrane laminations.
Electrolyte as liquid electrolyte is immersed in the separator 23.Electrolyte for example comprises solvent and the electrolytic salt that is dissolved in wherein.
Solvent for example comprises one or more nonaqueous solventss, for example organic solvent.Nonaqueous solvents for example comprises carbonic ester, as ethylene carbonate (ethylene carbonate), propylene carbonate (propylenecarbonate), carbonic acid fourth diester (butylene carbonate), dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate and carbonic acid third methyl esters.Obtain excellent capacity characteristic, storage characteristics and cycle characteristics thus.Above-mentioned solvent can be used alone, but also also mix together.Especially, as solvent, the mixture of high viscosity solvent (for example ethylene carbonate and propylene carbonate) and low viscosity solvent (for example dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate) is preferred.Improve electrolytical character and the ion transport of dissociating thus, thereby can obtain better effect.
Especially, solvent preferably comprises the halo carbonic ester, for example contains the linear carbonate and the cyclic carbonate that contains halogen element of halogen element, thereby form stable coating on negative pole 22 surfaces, and then prevent the decomposition reaction of electrolyte and improve cycle characteristics.As the halo carbonic ester, the fluoro carbonic ester is preferred, and owing to can obtain better effect, the difluoro ethylene carbonate than single fluorine ethylene carbonate more preferably.As single fluorine ethylene carbonate, for example can use 4-fluoro-1,3-dioxane penta-2-ketone.As the difluoro ethylene carbonate, for example can use 4,5-two fluoro-1,3-dioxane penta-2-ketone.
In addition, solvent preferably comprise contain unsaturated bond cyclic carbonate to improve cycle characteristics.As the cyclic carbonate that contains unsaturated bond, for example can use vinylene carbonate (vinylenecarbonate), vinyl ethylene carbonate (vinyl ethylene carbonate) etc.
In addition, solvent preferably comprises sultone, to improve cycle characteristics and to prevent that secondary cell from expanding.As sultone, for example can use 1,3-propylene sultone etc.
Electrolytic salt comprises for example one or more light metal salt, as lithium salts.The example of lithium salts is hexafluorophosphate (LiPF
6), lithium perchlorate (LiClO
4), hexafluoroarsenate lithium (LiAsF
6) etc.Obtain excellent capacity characteristic, storage characteristics and cycle characteristics thus.Electrolytic salt can use separately, also can two or more mix use, and especially, as electrolytic salt, lithium hexafluoro phosphate is preferred, and reason is to reduce internal resistance, thereby obtains better effect.
Especially, electrolytic salt preferably comprises the compound that contains boron and fluorine, to improve cycle characteristics and to prevent that secondary cell from expanding.As the compound that contains boron and fluorine, for example can use LiBF4.
The content of the electrolytic salt in the solvent for example is 0.3-3.0mol/kg, thereby can obtain excellent capacity characteristic.
For example make secondary cell by the following method.
At first, form anodal 21.That is, positive electrode active materials, adhesive and electric conductor are mixed with the preparation cathode mix, this mixture is dispersed in the organic solvent to form pasty state cathode mix slurries.Then, the cathode mix slurries evenly are coated on two surfaces of positive electrode collector 21A by doctor etc. and dry.At last, in heating as required by roll squeezer with gains compression moulding to form anode active material layer 21B.In the case, gains can be by several compression moulding.
Then, by with the identical method of above-mentioned formation negative pole, on two surfaces of negative electrode collector 22A, form anode active material layer 22B, form negative pole 22 thus.
Then, form electrode member 20.That is, positive wire 24 and negative wire 25 are connected to positive electrode collector 21A and negative electrode collector 22A respectively by welding etc.Then, twine with positive pole 21 and negative pole 22 (having separator 23 between the two) lamination and at longitudinal spiral.At last, gains are formed flat pattern, form cell device 20 thus.
At last, secondary cell for assembling.That is, after being contained in cell device 20 in the battery case 11, insulation board 12 is arranged on the cell device 20.Then, by welding etc. positive wire 24 and negative wire 25 are connected to anodal pin 15 and battery case 11 respectively.Subsequently, by laser welding etc. battery cover 13 is fixed on the open end of battery case 11.At last, electrolyte is injected battery case 11 from hand-hole 19, and be immersed in the separator 23.Subsequently, with containment member 19A hand-hole 19 is sealed.Shop drawings 7 and secondary cell shown in Figure 8 thus.
In secondary cell, for example when charging, lithium ion discharges from positive pole 21, and is absorbed in the negative pole 22 by the electrolyte that is immersed in the separator 23.On the other hand, for example when discharge, lithium ion discharges from negative pole 22, and is absorbed in anodal 21 by the electrolyte that is immersed in the separator 23.
According to the square secondary cell, because the similar of negative pole 22 is in the structure of above-mentioned negative pole, even therefore when repeating to discharge and recharge, discharge capacity also reduces hardly, and battery expands hardly when discharging and recharging.Therefore, can improve cycle characteristics and expansion characteristics.In the case, if negative pole 22 comprises silicon to obtain high power capacity, then cycle characteristics improves.Therefore, the situation that comprises other negative material (for example material with carbon element) with negative pole is compared, and can obtain better effect.Especially, comprise metal material, also can prevent negative pole 22 sclerosis even work as anode active material layer 22B.Therefore,, then negative pole 22 spirals can be twined, and prevent anode active material layer 22B division and come off if form cell device 20.Other effect except that above-mentioned effect of this secondary cell is similar to above-mentioned negative pole.
Second battery
Fig. 9 and Figure 10 show the cross-section structure of secondary cell.Figure 10 shows the amplifier section that spiral shown in Figure 9 twines electrode body 40.This battery is the lithium rechargeable battery as above-mentioned first battery.Secondary cell comprises that spiral twines a pair of insulation board 32 and 33 of the approximate hollow columnar in electrode body 40 and the battery case 31, and in electrode body 40, positive pole 41 and negative pole 42 spirals twine (having separator 43 between the two).The battery structure that comprises battery case 31 is called the column type secondary cell.
Battery case 31 is for example made by the metal material of the battery case 11 that is similar to above-mentioned first battery.The one end sealing of battery case 31, and the other end opens wide.A pair of insulation board 32 and 33 twines electrode body 40 with spiral and is clipped in the middle, and twines the side face extension perpendicular to spiral.
At the open end of battery case 31, battery cover 34 and be arranged on the relief valve mechanism 35 of battery cover 34 inboards and PTC (positive temperature coefficient) device 36 is tightly connected by pad 37.Thus with battery case 31 inner sealings.Battery cover 34 is for example made by the material that is similar to battery case 31.Relief valve mechanism 35 is electrically connected with battery cover 34 by PTC device 36.In relief valve mechanism 35, if the internal pressure of battery is owing to internal short-circuit, external heat etc. reaches more than the specified level, then disc 35A upset is twined being electrically connected between the electrode body 40 to cut off battery cover 34 with spiral.If temperature raises, the PTC device then improves resistance value and then restriction electric current, to prevent big current anomaly heating.Pad 37 is for example made by insulating material and its surface coated pitch.
For example, centrepin 44 is inserted into the center that spiral twines electrode body 40.Twine in the electrode body 40 at spiral, the positive wire of being made by the metal material of for example aluminium 45 is connected with anodal 41, and the negative wire of being made by the metal material of for example nickel 46 is connected with negative pole 42.Positive wire 45 is soldered to relief valve mechanism 35, is electrically connected with battery cover 34 thus.Negative wire 46 is soldered to battery case 31, thereby is electrically connected with it.
In anodal 41 structure, for example, anode active material layer 41B is set on two surfaces of banded positive electrode collector 41A.The similar of negative pole 42 is in the structure of above-mentioned negative pole, and for example, wherein anode active material layer 42B is set on two surfaces of banded negative electrode collector 42A.The structure of positive electrode collector 41A, anode active material layer 41B, negative electrode collector 42A, anode active material layer 42B and separator 43 and the composition of electrolyte are similar to the structure of positive electrode collector 21A, anode active material layer 21B, negative electrode collector 22A, anode active material layer 22B and separator 23 of above-mentioned first battery and the composition of electrolyte respectively.
The following manufacturing of second battery.
At first, for example, form positive pole 41 and negative pole 42 by the method that forms positive pole 21 and negative pole 22 in above-mentioned first battery, in anodal 41, anode active material layer 41B is set on two surfaces of positive electrode collector 41A, in negative pole 42, anode active material layer 42B is set on two surfaces of negative electrode collector 42A.Then, positive wire 45 is connected to positive pole 41, negative wire 46 is connected to negative pole 42.Then, positive pole 41 and negative pole 42 spirals are twined (having separator 43 between the two), form spiral thus and twine electrode body 40.The end of positive wire 45 is soldered to relief valve mechanism 35, the end of negative wire 46 is soldered to battery case 31.Subsequently, spiral is twined electrode body 40 be clipped between a pair of insulation board 32 and 33, and it is contained in the battery case 31.Then, inject the electrolyte into battery case 31 and being immersed in the separator 43.At last, with pad 37 sealings battery cover 34, relief valve mechanism 35 and PTC device 36 are fixed on the open end of battery case 31.Shop drawings 9 and secondary cell shown in Figure 10 thus.
In secondary cell, for example when charging, lithium ion discharges from positive pole 41, and is absorbed in the negative pole 42 by electrolyte.On the other hand, for example when discharge, lithium ion discharges from negative pole 42, and is absorbed in anodal 41 by electrolyte.
According to the column type secondary cell, the similar of negative pole 42 is in the structure of above-mentioned negative pole.Therefore, can improve cycle characteristics and expansion characteristics.Other effect except that above-mentioned effect of this secondary cell is similar to above-mentioned first battery.
The 3rd battery
Figure 11 shows the exploded perspective structure of the 3rd battery.Figure 12 shows along the profile of straight line XII-XII shown in Figure 11.In this battery, comprise spiral in the film packing component 60 and twine electrode body 50, positive wire 51 and negative wire 52 are connected on the electrode body 50.The battery structure that comprises packing component 60 is called as the stack membrane structure.
Positive wire 51 and negative wire 52 are derived to the outside from packing component 60 inside respectively with equidirectional.Positive wire 51 is made by the metal material of for example aluminium, and negative wire 52 is made by for example copper, nickel and stainless metal material.Metal material is plate-shaped or grid.
Packing component 60 is made by the rectangular aluminum stack membrane, and wherein for example nylon membrane, aluminium foil and polyethylene film combine successively.For example, packing component 60 is set so that polyethylene film and spiral twine electrode body 50 toward each other, and the outward flange of two rectangular aluminum stack membranes is contacted with each other by fusion or adhesive.
Inserting bonding film 61 between packing component 60 and positive wire 51, negative wire 52 enters to prevent extraneous air.Bonding film 61 is made by the material that positive wire 51 and negative wire 52 is had contact performance.The example of this material comprises vistanex, as polyethylene, polypropylene, modified poly ethylene and modified polypropene.
Packing component 60 can be by the stack membrane with other structure (for example polyacrylic polymer film or metal film) but not above-mentioned aluminium stack membrane make.
Twine in the electrode body 50 at spiral, with positive pole 53 and negative pole 54 (having separator 55 and electrolyte 56 between the two) lamination, spiral twines then.Its outermost is by boundary belt 57 protections.
In anodal 53 structure, for example, anode active material layer 53B is set on two surfaces of the positive electrode collector 53A with a pair of apparent surface.The similar of negative pole 54 is in the structure of above-mentioned negative pole, and for example, wherein anode active material layer 54B is set on two surfaces of banded negative electrode collector 54A.The structure of positive electrode collector 53A, anode active material layer 53B, negative electrode collector 54A, anode active material layer 54B and separator 55 is similar to the structure of positive electrode collector 21A, anode active material layer 21B, negative electrode collector 22A, anode active material layer 22B and the separator 23 of above-mentioned first battery respectively.
Electrolyte 56 is so-called gel electrolyte, comprises electrolyte and the polymer compound that holds this electrolyte.Gel electrolyte is preferred, because can obtain high ion-conductivity (for example, 1mS/cm or bigger under the room temperature) and prevent that battery liquid from leaking.For example, can and provide electrolyte 56 between negative pole 54 and the separator 55 between positive pole 53 and separator 55.
As polymer compound, for example can use copolymer, polytetrafluoroethylene, polyhexafluoropropylene, poly(ethylene oxide), PPOX, polyphosphazene, polysiloxanes, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethylacrylic acid, styrene butadiene rubbers, nitrile-butadiene rubber, polystyrene, Merlon of polyacrylonitrile, polyvinylidene fluoride, polyvinylidene fluoride and polyhexafluoropropylene etc.These polymer compounds can use separately, also can two or more mix use.Especially, preferably use polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene or poly(ethylene oxide) as polymer compound, reason is to obtain electrochemical stability.
The composition of electrolyte is similar to the electrolyte of first battery and forms.Yet in the case, solvent is a broad sense, not only comprises liquid flux, also comprises the solvent with ionic conductivity that electrolytic salt is dissociated.Therefore, if use the polymer compound with ionic conductivity, then this polymer compound is also included within the solvent.
Electrolyte also can directly use, but not keeps electrolyte by polymer compound in gel electrolyte 56.In the case, electrolyte is submerged in the separator 55.
Comprise the following manufacturing of battery of gel electrolyte 56.
At first, form positive pole 53 and negative pole 54 by being similar to the method that forms positive pole 21 and negative pole 22 in above-mentioned first battery, in anodal 53, anode active material layer 53B is set on two surfaces of positive electrode collector 53A, in negative pole 54, anode active material layer 54B is set on two surfaces of negative electrode collector 54A.Then, preparation comprises the precursor solution of electrolyte, polymer compound and solvent.Then, apply positive pole 53 and negative pole 54 respectively with this precursor solution.Subsequently, make solvent evaporates to form gel electrolyte 56.Then, positive wire 51 is connected to positive electrode collector 53A, negative wire 52 is connected to negative electrode collector 54A.Then, positive pole 53 that will form with electrolyte 56 and negative pole 54 (having separator 55 between the two) lamination are to obtain lamination.Subsequently, this lamination longitudinal spiral is twined, boundary belt 57 is bonded to its outermost twines electrode body 50 to form spiral.Then, for example, spiral is twined electrode body 50 be clipped between the packing component 60, and make the outward flange contact of packing component 60 so that spiral twines electrode body 50 sealings by heat fused etc.Bonding film 61 is inserted between positive wire 51/ negative wire 52 and the packing component 60.Make Figure 11 and secondary cell shown in Figure 12 thus.
Perhaps, above-mentioned battery can followingly be made.At first, positive wire 51 and negative wire 52 are connected on positive pole 53 and the negative pole 54.Subsequently, with positive pole 53 and negative pole 54 (having separator 55 between the two) lamination and spiral winding.At the bonding boundary belt 57 of its outermost, and form spiral winding body, twine the precursor of electrode body 50 as spiral.Then, this spiral is twined body is clipped between the packing component 60, with its periphery except that a side by contacts such as heat fuseds with the shape pouch, and spiral winding body is included in bag shape packing component 60.Then, preparation comprises the electrolyte composition of electrolyte, the monomer as the polymer compound raw material, polymerization initiator and other material (as polymerization inhibitor) as required, and is injected into a bag shape packing component 60.Subsequently, by the opening sealing with packing component 60 such as for example heat fused.At last, make the monomer thermal polymerization to obtain polymer compound.Form gel electrolyte 56 thus.Thereby make Figure 11 and secondary cell shown in Figure 12.
According to the stack membrane secondary cell, the similar of negative pole 54 is in the structure of above-mentioned negative pole.Therefore, can improve cycle characteristics and expansion characteristics.Other effect except that above-mentioned effect of this secondary cell is similar to first battery.
Embodiment
Describe embodiments of the invention below in detail.
Embodiment 1-1
Make Figure 11 and stack membrane secondary cell shown in Figure 12 by the following method.This secondary cell is as the lithium rechargeable battery manufacturing, and wherein the capacity of negative pole 54 is represented as the voxel based on the absorption and the release of lithium.
At first, form anodal 53.That is, with lithium carbonate (Li
2CO
3) and cobalt carbonate (CoCO
3) with 0.5: 1 mixed in molar ratio.Subsequently, under 900 ℃, with mixture calcining 5 hours.Obtain lithium cobalt complex oxide (LiCoO thus
2).Then, mixing to obtain cathode mix the lithium cobalt complex oxide as positive electrode active materials of 91 weight portions, 6 weight portions as the graphite of electric conductor and the polyvinylidene fluoride as binding agent of 3 weight portions.Subsequently, cathode mix is dispersed in the N-N-methyl-2-2-pyrrolidone N-, to obtain pasty state cathode mix slurries.At last, evenly apply two surfaces and the drying of the positive electrode collector 53A that makes by banded aluminium foil (12 μ m are thick) with these cathode mix slurries.Subsequently, with roll squeezer with gains compression moulding, to form anode active material layer 53B.Subsequently, positive wire made of aluminum 51 is soldered to the end of positive electrode collector 53A.
Next, form negative pole 54.That is, prepare the negative electrode collector 54A (thickness of making by the electrolyte Copper Foil: 18 μ m; 10 mean roughness: 3.5 μ m).Subsequently, by the electron beam evaporation plating method, use the deflection beam vapor deposition source, continuously oxygen is introduced simultaneously in the chamber (if desired, introduce steam), will be on two surfaces of negative electrode collector 54A, so that a side thickness of negative active core-shell material is 6 μ m as the siliceous deposits of negative active core-shell material.Thus the negative active core-shell material particle is formed single layer structure.Use purity be 99% silicon as vapor deposition source, deposition rate is 10nm/s, the oxygen content in the negative active core-shell material particle is 3 atom %.Then, by electrolytic plating method (supplying air to coating bath simultaneously) cobalt is deposited on two surfaces of negative electrode collector 54A and forms metal material, form anode active material layer 54B thus.Plating bath uses Japan Pure Chemical Co., the cobalt plating bath that Ltd. produces, and current density is 2-5A/dm
2, plating rate is 10nm/s.Oxygen content in the metal material is 5 atom %, and the molal quantity M1 of unit are negative active core-shell material particle and ratio (mol ratio) M2/M1 of the molal quantity M2 of unit are metal material are 1/50.Content with ICP (inductively coupled plasma) emission spectrographic determination metal material.For the negative pole 54 that forms, by FIB section is exposed, use AES (Auger electronic spectrograph) to carry out local elementary analysis then.The result shows, element counterdiffusion mutually, the i.e. alloying on its interface of the element of negative electrode collector 54A and anode active material layer 54B.Subsequently, will be soldered to the end of negative electrode collector 54A by the negative wire 52 that nickel is made.
23 μ m), negative pole 54 and above-mentioned polymer separator 55 next, anodal 53, three strata compound (wherein porous polyethylene membrane is clipped between the porous polypropylene film) separators 55 of deposition (thickness: successively.Gained lamination longitudinal spiral is twined, use the fixedly spiral end of twining body of the boundary belt 57 made by adhesive tape, form spiral thus and twine body, as the precursor of spiral winding electrode body.Then, spiral being twined body is clipped in by (the gross thickness: 100 μ m) between the packing component of making 60, in stack membrane, from outside deposition nylon (30 μ m are thick), aluminium (40 μ m are thick) and non-resilient polypropylene (30 μ m are thick) of the stack membrane with three-decker.Subsequently, with the external margin except that a side of packing component heat fused each other.Thereby making spiral twine body is included in bag shape packing component 60.Then, by the opening injection electrolyte of packing component 60, electrolyte is immersed in the separator 55, forms spiral thus and twines electrode body 50.
During preparation electrolyte, use the mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC), and use lithium hexafluoro phosphate (LiPF
6) as electrolytic salt.The composition of mixed solvent (EC: DEC) be 50: 50 (weight ratio).The concentration of electrolytic salt is 1mol/kg.
At last, in vacuum atmosphere, the opening hot melt of packing component 60 is merged sealing.Make the stack membrane secondary cell thus.For this secondary cell, regulate the thickness of anode active material layer 53B, make the charge/discharge capacity of negative pole 54 greater than anodal 54 charge/discharge capacity, so that the lithium metal is not separated out on negative pole 54 in charging/discharging thereof.
Embodiment 1-2~1-15
Carry out the method for embodiment 1 in the same manner, difference is that mol ratio M2/M1 becomes 1/30 (embodiment 1-2), 1/20 (embodiment 1-3), 1/15 (embodiment 1-4), 1/10 (embodiment 1-5), 1/5 (embodiment 1-6), 1/2 (embodiment 1-7), 1/1 (embodiment 1-8), 2/1 (embodiment 1-9), 3/1 (embodiment 1-10), 4/1 (embodiment 1-11), 5/1 (embodiment 1-12), 6/1 (embodiment 1-13), 7/1 (embodiment 1-14) and 8/1 (embodiment 1-15) from 1/50.
Comparative Examples 1
Carry out the method for embodiment 1-1 in the same manner, difference is not form metal material.
The cycle characteristics and the expansion characteristics of the secondary cell of check embodiment 1-1~1-15 and Comparative Examples 1 obtain the result shown in the table 1.In the case, for the amount of checking metal material and the relation between the cycle characteristics, also checked the shared atomicity ratio of negative pole 54 lip-deep metal materials.
When the check cycle characteristics, carry out loop test by the following method, and obtain the discharge capacity sustainment rate thus.At first, stable in order to make battery status, in 23 ℃ atmosphere, carry out discharging and recharging again after the discharging and recharging of 1 circulation.Measure the discharge capacity of second circulation.Then, in identical atmosphere, secondary cell is carried out discharging and recharging of 99 circulations, and measure the discharge capacity of the 101st circulation time.At last, calculate discharge capacity sustainment rate (%)=(discharge capacity of the discharge capacity of the 101st circulation time/2nd circulation time) * 100.Charge condition is as follows: at first at 3mA/cm
3Constant current density under charge, reach 4.2V up to cell voltage, under the constant voltage of 4.2V, carry out trickle charge then, reach 0.3mA/cm up to cell density
3Discharging condition is as follows: at 3mA/cm
3Constant current density under discharge, reach 2.5V up to cell voltage.
In check during expansion characteristics, by following method by secondary cell charge is obtained expansion ratio.At first, stable in order to make battery status, in 23 ℃ atmosphere, carry out before second cycle charging, measuring thickness after the discharging and recharging of 1 circulation.Then, in identical atmosphere, charge.Subsequently, measure thickness behind second cycle charging.At last, calculate expansion ratio (%)=[thickness before (thickness before the thickness-charging after the charging)/charging] * 100.Charge condition is similar to the situation of check cycle characteristics.
In order to check the shared atomicity ratio of negative pole 54 lip-deep metal materials, carry out elementary analysis with the surface of EDX anticathode 54, measure the occupation rate (atom %) of metal material thus.
The method of cycle characteristics, expansion characteristics etc. and the identical characteristics that condition is used to estimate following examples and Comparative Examples similarly will be checked.
Table 1
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 1-1 |
1 |
Co |
Electrolytic plating method |
1/50 |
0.5 |
55 |
19.6 |
Embodiment 1-2 |
1/30 |
1.1 |
60 |
17.5 |
Embodiment 1-3 |
1/20 |
1.8 |
65 |
14.6 |
Embodiment 1-4 |
1/15 |
2.3 |
80 |
9.6 |
Embodiment 1-5 |
1/10 |
4.3 |
83 |
6 |
Embodiment 1-6 |
1/5 |
6.8 |
84 |
4.2 |
Embodiment 1-7 |
1/2 |
9.1 |
85 |
3.5 |
Embodiment 1-8 |
1/1 |
12.1 |
85 |
3.3 |
Embodiment 1-9 |
2/1 |
22.4 |
84 |
3.2 |
Embodiment 1-10 |
3/1 |
32.6 |
83 |
3.2 |
Embodiment 1-11 |
4/1 |
37.5 |
83 |
3.1 |
Embodiment 1-12 |
5/1 |
43.1 |
82 |
3.1 |
Embodiment 1-13 |
6/1 |
62.5 |
81 |
3.1 |
Embodiment 1-14 |
7/1 |
82 |
80 |
3 |
Embodiment 1-15 |
8/1 |
95.5 |
74 |
3 |
Comparative Examples 1 |
1 |
- |
- |
- |
- |
45 |
24.6 |
As shown in table 1,, to compare by separating among embodiment 1-1~1-15 that plating method forms at metal material with the Comparative Examples 1 that does not form metal material, the discharge capacity sustainment rate is higher and expansion ratio is less, and this and mol ratio M2/M1 are irrelevant.These results mean that because metal material forms, the binding characteristic of anode active material layer 54B improves after forming the negative active core-shell material particle.Show thus, in secondary cell of the present invention, comprise at anode active material layer 54B under the situation of a plurality of siliceous negative active core-shell material particles, contain the metal material that does not form the metallic element of alloy with the electrode reaction thing if wherein also comprise, then cycle characteristics and expansion characteristics improve.
Especially, in embodiment 1-1~1-15, along with mol ratio M2/M1 increases, the occupation rate of metal material raises, and discharge capacity is kept the back that takes the lead in rising and descended, and expansion ratio reduces.In the case, if mol ratio M2/M1 less than 1/15 and the occupation rate of metal material less than 2 atom % (strictly) less than 2.3 atom %, then the discharge capacity sustainment rate reduces greatly, and expansion ratio enlarges markedly.In addition, if mol ratio M2/M1 greater than 7/1 and the occupation rate of metal material greater than 82 atom %, then the discharge capacity sustainment rate reduces greatly, and expansion ratio is constant.Show thus, in order further to improve cycle characteristics and expansion characteristics, mol ratio M2/M1 should be in the scope of 1/15-7/1, and the shared atomicity of negative pole 54 lip-deep metal materials is than should be in the scope of 2-82 atom %, more preferably in the scope of 2.3-82 atom %.
Embodiment 2-1~2-8
Carry out the method for embodiment 1-4~1-11 in the same manner, difference is by depositing negative active core-shell material 6 times the negative active core-shell material particle to be formed six layers of structure, and a side gross thickness is 6 μ m.Deposition rate is 100nm/s.
Embodiment 2-9~2-12
Carry out the method for embodiment 2-4 in the same manner, difference is to use iron plating bath (embodiment 2-9), nickel plating bath (embodiment 2-10), zinc plating bath (embodiment 2-11) or copper electrolyte (embodiment 2-12) to replace the cobalt plating bath as the raw material that forms metal material.Current density is 2-5A/dm when using the iron plating bath
2, when using nickel plating bath, be 2-10A/dm
2, when using the zinc plating bath, be 1-3A/dm
2, when using copper electrolyte, be 2-8A/dm
2Above plating bath is by Japan Pure ChemicalCo., and Ltd. produces.
Embodiment 2-13~2-16
Carry out the method for embodiment 2-9~2-12 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
Comparative Examples 2
Carry out the method for embodiment 2-1~2-8 in the same manner, difference is not form metal material.
The cycle characteristics of the secondary cell of check embodiment 2-1~2-16 and Comparative Examples 2, expansion characteristics etc. obtain the result shown in the table 2.
Table 2
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 2-1 |
6 |
Co |
Electrolytic plating method |
1/15 |
1.5 |
83 |
8.1 |
Embodiment 2-2 |
1/10 |
4.1 |
86 |
5.2 |
Embodiment 2-3 |
1/5 |
6.3 |
88 |
3.3 |
Embodiment 2-4 |
1/2 |
8.3 |
90 |
3 |
Embodiment 2-5 |
1/1 |
10.3 |
90 |
3.1 |
Embodiment 2-6 |
2/1 |
18 |
89 |
2.7 |
Embodiment 2-7 |
3/1 |
26 |
88 |
2.7 |
Embodiment 2-8 |
4/1 |
33 |
88 |
2.6 |
Embodiment 2-9 |
6 |
Fe |
Electrolytic plating method |
1/2 |
11.2 |
89 |
3.4 |
Embodiment 2-10 |
Ni |
9.5 |
88 |
3.4 |
Embodiment 2-11 |
Zn |
8.5 |
87 |
3.5 |
Embodiment 2-12 |
Cu |
8.9 |
85 |
3.6 |
Embodiment 2-13 |
6 |
Fe |
Electrolytic plating method |
1/1 |
10.4 |
90 |
3.3 |
Embodiment 2-14 |
Ni |
10.8 |
89 |
3.4 |
Embodiment 2-15 |
Zn |
9.9 |
88 |
36 |
Embodiment 2-16 |
Cu |
9.8 |
87.5 |
37 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 2, form among the embodiment 2-1~2-8 of six layers of structure at the negative active core-shell material particle, to compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion ratio is less, forms the embodiment 1-4~1-11 of single layer structure as the negative active core-shell material particle.In addition, in the different embodiment 2-9~2-16 of the material that forms metal material, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion ratio is less, as embodiment 2-4 and 2-5.Show that thus in secondary cell of the present invention, if the number of plies of negative active core-shell material particle changes, cycle characteristics also improves.Show that in addition change if form the material of metal material, as long as this material is selected from cobalt, iron, nickel and copper, then cycle characteristics and expansion characteristics also improve.
Especially, in mol ratio M2/M1 was 1/2 embodiment 2-4 and 2-9~2-12, the discharge capacity sustainment rate raise by the order as the material zinc, nickel, iron and the cobalt that form metal material.It is among 1/1 the embodiment 2-5 and 2-13~2-16 that this trend almost appears at M2/M1 equally.Therefore show,, preferably use cobalt as the material that forms metal material in order further to improve cycle characteristics.
Embodiment 3-1~3-4
Carry out the method for embodiment 1-7~1-10 in the same manner, difference is by the electroless method but not electrolytic plating method forms metal material.Use Japan Pure Chemical Co., the nothing electricity cobalt plating bath that Ltd. produces, the plating time is 60 minutes.
The cycle characteristics of the secondary cell of check embodiment 3-1~3-4, expansion characteristics etc. obtain the result shown in the table 3.Table 3 also shows the result of Comparative Examples 2.
Table 3
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 3-1 |
6 |
Co |
The electroless method |
1/2 |
7.8 |
72 |
9.5 |
Embodiment 3-2 |
1/1 |
9.5 |
73 |
9.2 |
Embodiment 3-3 |
2/1 |
16 |
72 |
9.6 |
Embodiment 3-4 |
3/1 |
22 |
72 |
9.9 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 3, forming among the embodiment 3-1~3-4 of metal material, to compare with Comparative Examples 2 by the electroless method, the discharge capacity sustainment rate is higher and expansion ratio is less, as the embodiment 1-7~1-10 that forms metal material by electrolytic plating method.Show that thus in secondary cell of the present invention, if use the electroless method as the method that forms metal material, then cycle characteristics and expansion characteristics also improve.
Embodiment 4-1~4-5
Carry out the method for embodiment 3-2 in the same manner, difference is to form metal material to form negative pole 54 by the electroless method, under reduced atmosphere negative pole 54 is annealed then.Pressure is 10
-2Pa or littler, annealing time are 3 hours.Annealing temperature is 100 ℃ (embodiment 4-1), 150 ℃ (embodiment 4-2), 200 ℃ (embodiment 4-3), 250 ℃ (embodiment 4-4), 300 ℃ (embodiment 4-5).
The cycle characteristics of the secondary cell of check embodiment 4-1~4-5, expansion characteristics etc. obtain the result shown in the table 4.Table 4 also shows the result of embodiment 3-2 and Comparative Examples 2.
Table 4
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Annealing temperature (℃) |
Embodiment 3-2 |
6 |
Co |
The electroless method |
- |
1/1 |
9.5 |
73 |
9.2 |
Embodiment 4-1 |
100 |
81 |
8.5 |
Embodiment 4-2 |
150 |
82 |
7.6 |
Embodiment 4-3 |
200 |
84 |
6.5 |
Embodiment 4-4 |
250 |
86 |
5.1 |
Embodiment 4-5 |
300 |
89 |
4.6 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 4, in embodiment 4-1~4-5 that negative pole 54 is annealed,, to compare with Comparative Examples 2 as embodiment 3-2, the discharge capacity sustainment rate is higher and expansion ratio is less.Show that thus in secondary cell of the present invention, if with negative pole 54 annealing, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 4-1~4-5, compare with embodiment 3-2, the discharge capacity sustainment rate is higher and expansion ratio is less.In addition, in the case, along with annealing temperature raises, the discharge capacity sustainment rate increases and expansion ratio reduces.The result shows, with the crystallinity of negative pole 54 annealing raising metal material.Show that thus cycle characteristics and expansion characteristics can further improve by anticathode 54 annealing, and this two specific character is also improved by the rising annealing temperature.The embodiment that does not have the public use electrolytic plating method to be annealed as the negative pole 54 under the situation of the method that forms metal material.Yet for the situation of using electrolytic plating method, if with negative pole 54 annealing and check cycle characteristics and expansion characteristics similarly, also this two specific character of susceptible of proof also improves.
Embodiment 5-1~5-4
Carry out the method for embodiment 1-7~1-10 in the same manner, difference is by being similar to the electron beam evaporation plating method that forms the negative active core-shell material particle but not electrolytic plating method forms metal material.Use purity be 99.9% cobalt as vapor deposition source, deposition rate is 5nm/s.Especially, when forming metal material, after forming the negative active core-shell material particle, repeat the step of evaporation cobalt in identical chamber so that every layer thickness becomes 830nm, and outermost layer is made by the negative active core-shell material particle.
The cycle characteristics of the secondary cell of check embodiment 5-1~5-4, expansion characteristics etc. obtain the result shown in the table 5.Table 5 also shows the result of Comparative Examples 2.
Table 5
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 5-1 |
6 |
Co |
The electron beam evaporation plating method |
1/2 |
8.8 |
82 |
11.5 |
Embodiment 5-2 |
1/1 |
10.5 |
83 |
10.9 |
Embodiment 5-3 |
2/1 |
19.8 |
83 |
11.2 |
Embodiment 5-4 |
3/1 |
28.6 |
81 |
11.6 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
42 |
21.3 |
As shown in Figure 5, forming by the electron beam evaporation plating method among the embodiment 5-1~5-4 of metal material, the embodiment 1-7~1-10 as form metal by electrolytic plating method compares with Comparative Examples 2, and the discharge capacity sustainment rate is higher and expansion ratio is less.Show that thus in secondary cell of the present invention, if use the electron beam evaporation plating method as the method that forms metal material, then cycle characteristics and expansion characteristics also improve.
Embodiment 6-1
Carry out the method for embodiment 3-1 in the same manner, difference is to form metal material with after the formation negative pole 54 by the electroless method, under 300 ℃ negative pole 54 is annealed in reduced atmosphere.Pressure and annealing time are similar to embodiment 4-1~4-5.
Embodiment 6-2
Carry out the method for embodiment 2-4 in the same manner, difference is by the RF magnetron sputtering method but not electrolytic plating method forms metal material.With purity be 99.9% cobalt as target, deposition rate is 3nm/s.
Embodiment 6-3
Carry out the method for embodiment 2-4 in the same manner, difference is by the CVD method but not electrolytic plating method forms metal material.Use silane (SiH respectively
4) and argon (Ar) as raw material and excited gas.Deposition rate and base material temperature are respectively 1.5nm/s and 200 ℃.
The cycle characteristics of the secondary cell of check embodiment 6-1~6-3, expansion characteristics etc. obtain the result shown in the table 6.Table 6 also shows the result of embodiment 2-4,3-1,5-1 and Comparative Examples 2.
Table 6
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 2-4 |
6 |
Co |
Electrolytic plating method |
1/2 |
8.3 |
90 |
3 |
Embodiment 3-1 |
Electroless method (unannealed) |
7.8 |
72 |
9.5 |
Embodiment 6-1 |
Electroless method (annealing) |
7.8 |
87 |
4.8 |
Embodiment 5-1 |
The electron beam evaporation plating method |
8.8 |
82 |
11.5 |
Embodiment 6-2 |
Sputtering method |
8.1 |
89 |
10.6 |
Embodiment 6-3 |
The CVD method |
8.6 |
88 |
10.9 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
42 |
21.3 |
As shown in Figure 6, in the embodiment 6-1 with negative pole 54 annealing, as embodiment 3-1, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion ratio is less.In the case, especially, 54 unannealed embodiment 3-1 compare with negative pole, and the discharge capacity sustainment rate is higher and expansion ratio is less.In addition, forming among the embodiment 6-2 and 6-3 of metal material by sputtering method or CVD method, embodiment 2-4,3-1,5-1 and 6-1 as by formation metal materials such as electrolytic plating methods compare with Comparative Examples 2, and the discharge capacity sustainment rate is higher and expansion ratio is less.Show that thus in secondary cell of the present invention, if use sputtering method or CVD method as the method that forms metal material, then cycle characteristics and expansion characteristics also improve.Show in addition, if, then obtain better effect negative pole 54 annealing.
Especially, in embodiment 2-4,3-1,5-1 and 6-1~6-3, under the situation of using liquid phase deposition (electrolytic plating method or electroless method) as the method that forms metal material, expansion ratio is less than the expansion ratio under the situation of using vapour deposition process (electron beam evaporation plating method, sputtering method or CVD method).And in the case, the expansion ratio of the expansion ratio when using electrolytic plating method when using the electroless method.As mentioned above, under the situation of using the electroless method, the expansion ratio of the expansion ratio when using annealing when not using annealing.In addition, in embodiment 2-4,3-1,5-1 and 6-1~6-3, the discharge capacity sustainment rate when using liquid phase deposition (electrolytic plating method) is higher than the discharge capacity sustainment rate when using above-mentioned vapour deposition process.Under the situation of not using annealing, the discharge capacity sustainment rate when using liquid phase deposition (electroless method) is lower than the discharge capacity sustainment rate when using vapour deposition process; And under the situation of using annealing, the discharge capacity sustainment rate when the discharge capacity sustainment rate uses vapour deposition process no better than.These results show, if use vapour deposition process to form metal material, because metal material is an amorphous state, the advantage that binding characteristic brought of the anode active material layer 54B that therefore can be improved, and the advantage that the crystallinity of the metal material that can't be improved is brought.On the other hand, if form metal material by liquid phase deposition, because metal material has crystallinity, the advantage that binding characteristic brought of the metal material that therefore both can be improved, the advantage that the crystallinity of the metal material that also can be improved is brought.Therefore show that if use liquid phase deposition as the method that forms metal material, then cycle characteristics and expansion characteristics further improve.Show in addition,, compare, more preferably use electrolytic plating method with the electroless method in order to improve this two specific character.
Embodiment 7-1~7-6
Carry out the method for embodiment 4-1~4-5 in the same manner, difference is to change annealing temperature goes up the peak that produces with the crystal plane (111) that changes the metal material that obtains by X-ray diffraction half-band width 2 θ.Annealing temperature is 70 ℃ (embodiment 7-1), 80 ℃ (embodiment 7-2), 90 ℃ (embodiment 7-3), 125 ℃ (embodiment 7-4), 175 ℃ (embodiment 7-5), 225 ℃ (embodiment 7-6).
Embodiment 7-7
Carry out the method for embodiment 2-5 in the same manner, difference is in order to change half-band width 2 θ, forming metal material by electrolytic plating method with after forming negative pole 54, with negative pole 54 annealing.Annealing temperature is 200 ℃, and other condition is similar to embodiment 4-1~4-5.
The cycle characteristics of the secondary cell of check embodiment 7-1~7-7 obtains table 7 and result shown in Figure 13.Table 7 also shows the result of embodiment 2-5,3-2 and 4-1~4-5.
Table 7
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Discharge capacity sustainment rate (%) |
The number of plies (layer) |
Type |
The formation method |
Annealing temperature (℃) |
Half-band width 2 θ (°) |
Embodiment 3-2 |
6 |
Co |
The electroless method |
- |
25 |
1/1 |
73 |
Embodiment 7-1 |
70 |
24 |
75 |
Embodiment 7-2 |
80 |
22 |
78 |
Embodiment 7-3 |
90 |
20 |
80 |
Embodiment 4-1 |
100 |
18 |
81 |
Embodiment 7-4 |
125 |
14 |
82 |
Embodiment 4-2 |
150 |
10 |
82 |
Embodiment 7-5 |
175 |
7 |
83 |
Embodiment 4-3 |
200 |
5 |
84 |
Embodiment 7-6 |
225 |
4 |
85 |
Embodiment 4-4 |
250 |
3 |
86 |
Embodiment 4-5 |
300 |
1 |
89 |
Embodiment 2-5 |
- |
0.4 |
90 |
Embodiment 7-7 |
Electrolytic plating method |
200 |
0.1 |
93 |
As table 7 and shown in Figure 13, in embodiment 2-5, the 3-2,4-1~4-5 and the 7-1~7-7 that use liquid phase deposition (electroless method or electrolytic plating method) and as required negative pole 54 is annealed, metal material has crystallinity, and the excursion of half-band width 2 θ is 0.1-25.In the case, 2 θ diminish along with half-band width, and discharge capacity is kept and taken the lead in increasing, keeps constant substantially afterwards and then increase.If half-band width 2 θ become 20 ° or littler, then obtain 80% or bigger high discharge capacity sustainment rate.Therefore show, in secondary cell of the present invention, having under the crystalline situation at metal material, is 20 ° or littler if the crystal plane (111) of the metal material that obtains by X-ray diffraction is gone up half-band width 2 θ at the peak that produces, and then cycle characteristics further improves.
As the representative of the foregoing description and Comparative Examples, use SEM to observe the section of the negative pole 54 in the secondary cell of embodiment 2-4 and Comparative Examples 2, obtain the result shown in Figure 14 A~16B.
Figure 14 A and 14B are the SEM photos of the cross-section structure of negative pole 54 before the loop test.Figure 14 A shows the observed result of Comparative Examples 2, and Figure 14 B shows the observed result of embodiment 2-4.Shown in Figure 14 A and 14B, in Comparative Examples 2 and embodiment 2-4, in being formed on the lip-deep anode active material layer 54B of coarse negative electrode collector 54A, observing the negative active core-shell material particle and form six layers of structure on its surface.Yet in Comparative Examples 2, shown in Figure 14 A, between adjacent negative active core-shell material particle and in the inner formation of negative active core-shell material particle gap, so anode active material layer 54B does not have abundant combination.On the other hand, in embodiment 2-4, as shown in Figure 14B, metal material is filled in the above-mentioned gap, and anode active material layer 54B is by the abundant combination of this metal material.Especially, in embodiment 2-4, cover a part of exposed surface of negative active core-shell material particle with metal material.Therefore show that in secondary cell of the present invention, the binding characteristic of anode active material layer 54B improves by metal material.
Figure 15 A and 15B are the results who the section of the negative pole 54 among the embodiment 2-4 shown in Figure 14 B is carried out element distribution analysis (so-called element distributes and videos) with EDX.In Figure 15 A, represent the silicon distribution by the light areas that 15A represents.In Figure 15 B, represent the cobalt distribution by the light areas that 15B represents.Shown in Figure 15 A and 15B, as the non-existent scope of the silicon of negative active core-shell material particle (darker regions that the zone of being represented by the 15A among Figure 15 A surrounds) corresponding to there being scope as the cobalt of metal material (light areas of representing by the 15B among Figure 15 B).This scope comprises the gap between the adjacent negative active core-shell material particle and the gap of negative active core-shell material particle inside.Therefore show that in secondary cell of the present invention, metal material enters the gap between the adjacent negative active core-shell material particle and the gap of negative active core-shell material particle inside, and the part exposed surface of negative active core-shell material particle is covered by metal material.
Figure 16 A and 16B are the SEM photo of the cross-section structure of the negative pole 54 behind the loop test.Figure 16 A shows the observed result of Comparative Examples 2, and Figure 16 B shows the observed result of embodiment 2-4.Shown in Figure 16 A and 16B, in Comparative Examples 2 and embodiment 2-4, all observe, anode active material layer 54B is tending towards breaking by a plurality of expansion and contractions that discharge and recharge step.Yet in Comparative Examples 2, shown in Figure 16 A, anode active material layer 54B breaks on a plurality of positions and therefore pulverizes, and then anode active material layer 54B is easily partly come off.On the other hand, in embodiment 2-4, shown in Figure 16 B, anode active material layer 54B does not almost break, thereby anode active material layer 54B does not almost come off.Show that thus in secondary cell of the present invention, the binding characteristic of anode active material layer 54B improves by metal, so anode active material layer 54B pulverizes hardly and comes off.
Embodiment 8-1~8-6
Carry out the method for embodiment 2-4 in the same manner, difference is that the oxygen content in the negative active core-shell material particle is 2 atom % (embodiment 8-1), 10 atom % (embodiment 8-2), 20 atom % (embodiment 8-3), 30 atom % (embodiment 8-4), 40 atom % (embodiment 8-5) and 45 atom % (embodiment 8-6), but not 3 atom %.
The cycle characteristics of the secondary cell of check embodiment 8-1~8-6, expansion characteristics etc. obtain the result shown in the table 8.Table 8 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 8
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Oxygen content (atom %) |
Type |
The formation method |
Embodiment 8-1 |
6 |
2 |
Co |
Electrolytic plating method |
1/2 |
8 |
82 |
4.3 |
Embodiment 2-4 |
3 |
8.3 |
90 |
3 |
Embodiment 8-2 |
10 |
8.5 |
92 |
2.9 |
Embodiment 8-3 |
20 |
8.4 |
93 |
2.7 |
Embodiment 8-4 |
30 |
8.2 |
92 |
2.6 |
Embodiment 8-5 |
40 |
8.3 |
91 |
2.5 |
Embodiment 8-6 |
45 |
8.2 |
88 |
2.3 |
Comparative Examples 2 |
6 |
3 |
- |
- |
- |
- |
42 |
21.3 |
As shown in Figure 8, among the different embodiment 8-1~8-6 of the oxygen content in the negative active core-shell material particle, as embodiment 2-4, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion ratio is less.Show that thus in secondary cell of the present invention, if the oxygen content in the negative active core-shell material particle changes, cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 2-4 and 8-1~8-6, along with oxygen content increases, discharge capacity reduces after keeping and taking the lead in increasing.In the case, if oxygen content less than 3 atom %, then the discharge capacity sustainment rate obviously reduces.If oxygen content is greater than 40 atom %, although obtain enough discharge capacity sustainment rates, battery capacity reduces greatly, and is therefore also impracticable.Show that thus in order further to improve cycle characteristics, the oxygen content in the negative active core-shell material particle is preferably 3-40 atom %.
Embodiment 9-1~9-6
Carry out the method for embodiment 8-1~8-6 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
The cycle characteristics of the secondary cell of check embodiment 9-1~9-6, expansion characteristics etc. obtain the result shown in the table 9.Table 9 also shows the result of embodiment 2-5 and Comparative Examples 2.
Table 9
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Oxygen content (atom %) |
Type |
The formation method |
Embodiment 9-1 |
6 |
2 |
Co |
Electrolytic plating method |
1/1 |
10.5 |
83 |
3.1 |
Embodiment 2-5 |
3 |
10.3 |
90 |
3.1 |
Embodiment 9-2 |
10 |
10.1 |
92 |
3 |
Embodiment 9-3 |
20 |
10 |
93 |
3 |
Embodiment 9-4 |
30 |
10 |
92 |
2.9 |
Embodiment 9-5 |
40 |
10.1 |
91 |
2.9 |
Embodiment 9-6 |
45 |
10.2 |
83 |
2.8 |
Comparative Examples 2 |
6 |
3 |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 9, in embodiment 2-5 and 9-1~9-6 that mol ratio M2/M1 changes, obtain being similar to the result of embodiment 2-4 and 8-1~8-6.That is, in embodiment 2-5 and 9-1~9-6, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.In the case, if oxygen content is 3-40 atom %, then obtain higher discharge capacity sustainment rate, and obtain enough battery capacities.Show that thus in secondary cell of the present invention, under the situation that oxygen content in negative active core-shell material changes, even when mol ratio M2/M1 changes, cycle characteristics and expansion characteristics also improve.
Embodiment 10-1~10-6
Carry out the method for execution mode 2-4 in the same manner, difference is that the oxygen content in the metal material is 1 atom % (embodiment 10-1), 1.5 atom % (embodiment 10-2), 10 atom % (embodiment 10-3), 20 atom % (embodiment 10-4), 30 atom % (embodiment 10-5) and 35 atom % (embodiment 10-6), but not 5 atom %.
The cycle characteristics of the secondary cell of check embodiment 10-1~10-6, expansion characteristics etc. obtain the result shown in the table 10.Table 10 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 10
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
Oxygen content (atom %) |
The formation method |
Embodiment 10-1 |
6 |
Co |
1 |
Electrolytic plating method |
1/2 |
13.5 |
82 |
5.3 |
Embodiment 10-2 |
1.5 |
10.9 |
88 |
4.2 |
Embodiment 2-4 |
5 |
8.3 |
90 |
3 |
Embodiment 10-3 |
10 |
6.2 |
92 |
2.8 |
Embodiment 10-4 |
20 |
3.4 |
91 |
2.8 |
Embodiment 10-5 |
30 |
2.1 |
91 |
2.9 |
Embodiment 10-6 |
35 |
1.8 |
84 |
3 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 10, among the different embodiment 10-1~10-6 of the oxygen content in metal material,, to compare with Comparative Examples 2 as embodiment 2-4, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, if the oxygen content in the metal material changes, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 2-4 and 10-1~10-6, along with oxygen content increases, discharge capacity reduces after keeping and taking the lead in increasing.In the case, if oxygen content less than 1.5 atom % or greater than 30 atom %, then the discharge capacity sustainment rate obviously reduces.Show that thus in order further to improve cycle characteristics, the oxygen content in the metal material is preferably 3-30 atom %.
Embodiment 11-1~11-3
Carry out the method for embodiment 2-4 in the same manner, difference be to use the mixture that comprises silicon and metallic element but not purity be 99% silicon as vapor deposition source be 6.5 μ m so that comprise the negative active core-shell material particle one side thickness of this mixture.Use iron as metallic element, ratio (mol ratio) M2/M3/M1 of the molal quantity M3 of the metallic element that comprises in the molal quantity M1 of unit are negative active core-shell material particle, the molal quantity M2 of unit are metal material, the unit are negative active core-shell material particle is 1/0.1/2 (embodiment 11-1), 1/0.2/2 (embodiment 11-2) and 1/0.4/2 (embodiment 11-3).In the case, regulate the thickness of anode active material layer 53B, so that the charge/discharge capacity of negative pole 54 is greater than anodal 53 charge/discharge capacity, therefore the lithium metal is not separated out on negative pole 54 in charge and discharge process.
Embodiment 11-4~11-7
Carry out the method for embodiment 11-2 in the same manner, difference be to use cobalt (embodiment 11-4), nickel (embodiment 11-5), titanium (11-6) and chromium (embodiment 11-7) but not iron as metallic element.
Comparative Examples 11
Carry out the method for embodiment 11-4 in the same manner, difference is not form metal material.
The cycle characteristics of the secondary cell of check embodiment 11-1~11-7 and Comparative Examples 11, expansion characteristics etc. obtain the result shown in the table 11.Table 11 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 11
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M3/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer)) |
Metallic element |
Type |
The formation method |
Type |
Embodiment 2-4 |
6 |
- |
Co |
Electrolytic plating method |
1/0/2 |
8.3 |
90 |
3 |
Embodiment 11-1 |
Fe |
1/0.1/2 |
8 |
92 |
3 |
Embodiment 11-2 |
1/0.2/2 |
7.9 |
94 |
2.9 |
Embodiment 11-3 |
1/0.4/2 |
7.5 |
93 |
2.8 |
Embodiment 11-4 |
Co |
1/0.2/2 |
10.5 |
95 |
2.8 |
Embodiment 11-5 |
Ni |
8 |
94 |
3 |
Embodiment 11-6 |
Ti |
7.8 |
94 |
3.1 |
Embodiment 11-7 |
Cr |
8.1 |
93 |
3.2 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
Comparative Examples 11 |
6 |
Co |
- |
- |
0/0.2/2 |
- |
61 |
19 |
As shown in table 11, contain among the embodiment 11-1~11-7 of metallic element and silicon at the negative active core-shell material particle, as embodiment 2-4, to compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.Obviously, contain among the embodiment 11-4 of cobalt and silicon at the negative active core-shell material particle, compare with Comparative Examples 11, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, if the negative active core-shell material particle comprises metallic element, then cycle characteristics and expansion characteristics also improve.Although there be not the embodiment of public use molybdenum, when the situation of using molybdenum is checked cycle characteristics and expansion characteristics similarly, confirm that equally this two specific character improves as metallic element.
Especially, in embodiment 11-1~11-7, compare with embodiment 2-4, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, if the negative active core-shell material particle comprises metallic element, then cycle characteristics and expansion characteristics further improve.
As the representative of the foregoing description and Comparative Examples, analyze the electrode 54 in the secondary cell of embodiment 2-5,5-2 and Comparative Examples 11 with X-ray diffraction (XRD), obtain Figure 17~result shown in Figure 19.Intensity shown in the longitudinal axis of Figure 17~Figure 19 is the normalized value as the crystal plane of the copper of negative electrode collector 54A (011).
Forming by electrolytic plating method among the embodiment 2-5 of metal material (cobalt), as shown in figure 17, observing as the peak P1 of the copper of negative electrode collector 54A with as the peak P2 of the cobalt of metal material.Forming by the electron beam evaporation plating method among the embodiment 5-2 of metal material (cobalt), as shown in figure 18, only observing the peak P1 of copper and do not observe the peak P2 of cobalt.Negative active core-shell material particle (silicon and cobalt) being total to evaporation and not forming in the Comparative Examples 11 of metal material, as shown in figure 19, only observe the peak P1 of copper.With the fact that the order of Comparative Examples 11, embodiment 5-2 and embodiment 2-5 increases, can obtain following inference from these XRD analysis result and discharge capacity sustainment rate.
That is, in embodiment 2-5, the metal material that forms by electrolytic plating method has crystallinity.Therefore, in the XRD analysis result, observe the peak P2 of cobalt.In the case, the negative active core-shell material particle is by metal material fully combination each other, and the resistance of metal material is enough low, so the discharge capacity sustainment rate is higher than embodiment 5-2 and Comparative Examples 11.In embodiment 5-2,, in the XRD analysis result, do not observe peak P2 because the metal material that forms by the electron beam evaporation plating method is an amorphous state.In the case, the resistance of metal material is not low to moderate the same degree of embodiment 2-5.Yet in the case, because the fully combination by metal material of negative active core-shell material particle, so the discharge capacity sustainment rate is lower than embodiment 2-5, but is higher than Comparative Examples 11.In Comparative Examples 11, obviously,, therefore in the XRD analysis result, do not observe peak P2 owing to do not form metal material.In the case, because the binding characteristic of negative active core-shell material particle does not improve by metal material and resistance does not reduce, so the discharge capacity sustainment rate is lower than embodiment 2-5 and 5-2.
Show that thus the formation of metal material can influence cycle characteristics.In addition, XRD analysis is the result show, in order to improve cycle characteristics, more preferably uses for example liquid phase deposition of electrolytic plating method, but not the vapour deposition process of electron beam evaporation plating method for example.
Embodiment 12-1~12-3
Carry out the method for embodiment 2-4 in the same manner, difference is to form the negative active core-shell material particle, by deposition negative active core-shell material when intermittently introducing oxygen etc. in the chamber, so that first contain oxygen district and second and contain alternately lamination of oxygen district (oxygen content is higher than first and contains the oxygen district), but not when introducing oxygen etc. in the chamber continuously deposition negative active core-shell material (so that comprising oxygen in the negative active core-shell material particle).Second oxygen content that contains the oxygen district is 3 atom %, and second quantity that contains the oxygen district is 2 (embodiment 12-1), 4 (embodiment 12-2) and 6 (embodiment 12-3).
The cycle characteristics of the secondary cell of check embodiment 12-1~12-3, expansion characteristics etc. obtain the result shown in the table 12.Table 12 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 12
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Second contains oxygen district quantity |
Type |
The formation method |
Embodiment 2-4 |
6 |
- |
Co |
Electrolytic plating method |
1/2 |
8.3 |
90 |
3 |
Embodiment 12-1 |
2 |
8.3 |
91 |
2.8 |
Embodiment 12-2 |
4 |
8.2 |
93 |
2.6 |
Embodiment 12-3 |
6 |
8.6 |
94 |
2.1 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 12, have first and second at the negative active core-shell material particle and contain among the embodiment 12-1~12-3 in oxygen district, as embodiment 2-4, to compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, contain the oxygen district if form negative active core-shell material to have first and second, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 12-1~12-3, the discharge capacity sustainment rate is higher than embodiment 2-4.In addition, in the case, the discharge capacity sustainment rate increases with the order of embodiment 12-1 (wherein second quantity that contains the oxygen district is 2), embodiment 12-2 (wherein second quantity that contains the oxygen district is 4), embodiment 12-3 (wherein second quantity that contains the oxygen district is 6).Show that thus in secondary cell of the present invention, contain the oxygen district by forming the negative active core-shell material particle to have first and second, cycle characteristics further improves.Show that in addition if second quantity that contains the oxygen district increases, then cycle characteristics and expansion characteristics all further improve.
Embodiment 13-1~13-3
Carry out the method for embodiment 12-1~12-3 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
The cycle characteristics of the secondary cell of check embodiment 13-1~13-3, expansion characteristics etc. obtain the result shown in the table 13.Table 13 also shows the result of embodiment 2-5 and Comparative Examples 2.
Table 13
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Second contains oxygen district quantity |
Type |
The formation method |
Embodiment 2-5 |
6 |
- |
Co |
Electrolytic plating method |
1/1 |
10.3 |
90 |
3.1 |
Embodiment 13-1 |
2 |
10.1 |
92 |
3 |
Embodiment 13-2 |
4 |
10 |
94 |
2.9 |
Embodiment 13-3 |
6 |
9.8 |
95 |
2.8 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 13, in embodiment 2-5 and 13-1~13-3 that mol ratio changes, obtain being similar to the result of embodiment 2-4 and 12-1~12-3.That is, in embodiment 2-5 and 13-1~13-3, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.In the case, along with second quantity that contains the oxygen district increases, the discharge capacity sustainment rate increases.Show that thus in secondary cell of the present invention, contain under the situation in oxygen district to have first and second at formation negative active core-shell material particle, even mol ratio changes, cycle characteristics and expansion characteristics also improve.
Embodiment 14-1~14-8
Carry out the method for embodiment 2-4 in the same manner, difference is 10 mean roughness Rz on negative electrode collector 54A surface are become 1 μ m (embodiment 14-1), 1.5 μ m (embodiment 14-2), 2.5 μ m (embodiment 14-3), 4.5 μ m (embodiment 14-4), 5 μ m (embodiment 14-5), 5.5 μ m (embodiment 14-6), 6.5 μ m (embodiment 14-7) and 7 μ m (embodiment 14-8), but not 3.5 μ m.
The cycle characteristics of the secondary cell of check embodiment 14-1~14-8, expansion characteristics etc. obtain the result shown in the table 14.Table 14 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 14
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Anode active material layer |
Negative electrode collector |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
10 mean roughness Rz (μ m) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 14-1 |
6 |
Co |
Electrolytic plating method |
1/2 |
8.3 |
1 |
79 |
3.3 |
Embodiment 14-2 |
1.5 |
85 |
3.3 |
Embodiment 14-3 |
2.5 |
88 |
3.3 |
Embodiment 2-4 |
3.5 |
90 |
3 |
Embodiment 14-4 |
4.5 |
89 |
3.3 |
Embodiment 14-5 |
5 |
88 |
3.3 |
Embodiment 14-6 |
5.5 |
87 |
3.3 |
Embodiment 14-7 |
6.5 |
86 |
3.3 |
Embodiment 14-8 |
7 |
80 |
3.3 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
As shown in table 14, in the different embodiment 14-1~14-8 of 10 mean roughness Rz,, to compare with Comparative Examples 2 as embodiment 2-4, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, if 10 mean roughness Rz change, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 2-4 and 14-1~14-8, along with 10 mean roughness Rz increase, discharge capacity is kept the back that takes the lead in raising and is reduced.In the case, if 10 mean roughness Rz less than 1.5 μ m or greater than 6.5 μ m, then the discharge capacity sustainment rate obviously reduces.Show that thus 10 mean roughness Rz are preferably 1.5-6.5 μ m.
Embodiment 15-1~15-7
Carry out the method for embodiment 14-1~14-4 and 14-6~14-8 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
The cycle characteristics of the secondary cell of check embodiment 15-1~15-7, expansion characteristics etc. obtain the result shown in the table 15.Table 15 also shows the result of embodiment 2-5 and Comparative Examples 2.
Table 15
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Anode active material layer |
Negative electrode collector |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
10 mean roughness Rz (μ m) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 15-1 |
6 |
Co |
Electrolytic plating method |
1/1 |
10.3 |
1 |
78 |
3.1 |
Embodiment 15-2 |
1.5 |
84 |
3.1 |
Embodiment 15-3 |
2.5 |
87 |
3.1 |
Embodiment 2-5 |
3.5 |
90 |
3.1 |
Embodiment 15-4 |
4.5 |
88 |
3.1 |
Embodiment 15-5 |
5.5 |
90 |
3.1 |
Embodiment 15-6 |
6.5 |
89 |
3.1 |
Embodiment 15-7 |
7 |
77 |
3.1 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
- |
42 |
21.3 |
As shown in Table 15, in embodiment 2-5 and 15-1~15-7 that mol ratio changes, obtain being similar to the result of embodiment 2-4,14-1~14-4 and 14-6~14-8.That is, in embodiment 2-5 and 15-1~15-7, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.In the case, if 10 mean roughness Rz are 1.5-6.5 μ m, then the discharge capacity sustainment rate is higher.Show that thus in secondary cell of the present invention, under the situation that 10 mean roughness Rz change, even mol ratio changes, cycle characteristics and expansion characteristics also improve.
Embodiment 16-1
Carry out the method for embodiment 2-4 in the same manner, difference is that one side thickness is 6.5 μ m but not the electron beam evaporation plating method forms the negative active core-shell material particle by the RF magnetron sputtering method.Use purity be 99.99% silicon as target, deposition rate is 0.5nm/s.In the case, regulate the thickness of anode active material layer 53B, so that the charge/discharge capacity of negative pole 54 is greater than anodal 53 charge/discharge capacity, thereby in charge and discharge process, the lithium metal is not separated out on negative pole 54.
Embodiment 16-2
Carry out the method for embodiment 2-4 in the same manner, difference is that one side thickness is 6 μ m but not the electron beam evaporation plating method forms the negative active core-shell material particle by the CVD method.Use silane and argon as raw material and excited gas respectively.Deposition rate and base material temperature are respectively 1.5nm/s and 200 ℃.In the case, regulate the charge/discharge capacity of negative pole 54 and anodal 53 charge/discharge capacity with the same way as of embodiment 16-1, so that the lithium metal is not separated out in charge and discharge process on negative pole 54.
The cycle characteristics of the secondary cell of check embodiment 16-1~16-2, expansion characteristics etc. obtain the result shown in the table 16.
Table 16
Negative active core-shell material particle: silicon
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
The formation method |
Type |
The formation method |
Embodiment 2-4 |
6 |
The electron beam evaporation plating method |
Co |
Electrolytic plating method |
1/2 |
8.3 |
90 |
3 |
Embodiment 16-1 |
Sputtering method |
89 |
3.5 |
Embodiment 16-2 |
The CVD method |
88 |
3.8 |
Comparative Examples 2 |
6 |
The electron beam evaporation plating method |
- |
- |
- |
- |
42 |
21.3 |
Shown in table 16, in the different embodiment 16-1~16-2 of the method that forms the negative active core-shell material particle,, to compare with Comparative Examples 2 as embodiment 2-4, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, change if form the method for negative active core-shell material particle, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 2-4,16-1 and 16-2, the discharge capacity sustainment rate increases with the order of embodiment 16-2 (method that wherein forms the negative active core-shell material particle is the CVD method), embodiment 16-1 (method that forms the negative active core-shell material particle is a sputtering method) and embodiment 2-4 (method that wherein forms the negative active core-shell material particle is the electron beam evaporation plating method).Show thus,, preferably use vapour deposition method as the method that forms the negative active core-shell material particle in order further to improve cycle characteristics.
Embodiment 17-1~17-2
Carry out the method for embodiment 16-1~16-2 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
The cycle characteristics of the secondary cell of check embodiment 17-1~17-2, expansion characteristics etc. obtain the result shown in the table 17.Table 17 also shows the result of embodiment 2-5 and Comparative Examples 2.
Table 17
Negative active core-shell material particle: silicon
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
The formation method |
Type |
The formation method |
Embodiment 2-5 |
6 |
The electron beam evaporation plating method |
Co |
Electrolytic plating method |
1/1 |
10.3 |
90 |
3.1 |
Embodiment 17-1 |
Sputtering method |
89 |
3.3 |
Embodiment 17-2 |
The CVD method |
88 |
3.5 |
Comparative Examples 2 |
6 |
The electron beam evaporation plating method |
- |
- |
- |
- |
42 |
21.3 |
Shown in table 17, in embodiment 2-5,17-1 and 17-2 that mol ratio changes, obtain being similar to the result of embodiment 2-4,16-1 and 16-2.That is, in embodiment 2-5,17-1 and 17-2, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.In the case, the discharge capacity sustainment rate increases with the order as CVD method, sputtering method and the electron beam evaporation plating method of the method that forms the negative active core-shell material particle.Show that thus in secondary cell of the present invention, under the situation that the method that forms the negative active core-shell material particle changes, even mol ratio changes, cycle characteristics and expansion characteristics also improve.
Embodiment 18-1
Carry out the method for embodiment 2-4 in the same manner, difference is to use the 4-fluoro-1 as fluoro carbonic ester (single fluorine ethylene carbonate), and 3-dioxane penta-2-ketone (FEC) but not EC are as solvent.
Embodiment 18-2
Carry out the method for embodiment 2-4 in the same manner, difference is to add as 4 of fluoro carbonic ester (difluoro ethylene carbonate) with solvent version, 5-two fluoro-1,3-dioxane penta-2-ketone (DFEC), and mixed solvent (EC: DFEC: consisting of DEC) 25: 5: 70 (weight ratio).
Embodiment 18-3
Carry out the method for embodiment 18-1 in the same manner, difference is in electrolyte with the vinylene carbonate (VC) of solvent version interpolation as the cyclic carbonate that contains unsaturated bond.VC content in the electrolyte is 10wt%.
Embodiment 18-4
Carry out the method for embodiment 18-1 in the same manner, difference is in electrolyte with the vinyl ethylene carbonate (VEC) of solvent version interpolation as the cyclic carbonate that contains unsaturated bond.VEC content in the electrolyte is 10wt%.
Embodiment 18-5
Carry out the method for embodiment 18-1 in the same manner, difference is to add as 1 of sultone 3-propylene sultone (PRS) with solvent version in electrolyte.PRS content in the electrolyte is 1wt%.
Embodiment 18-6
Carry out the method for embodiment 18-1 in the same manner, difference is to add the LiBF4 (LiBF as electrolytic salt in electrolyte
4).LiBF in the electrolyte
4Content is 0.1mol/kg.
The cycle characteristics of the secondary cell of check embodiment 18-1~18-6, expansion characteristics etc. obtain the result shown in the table 18.Table 18 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 18
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Negative pole |
Electrolyte |
Discharge capacity efficient (%) |
Expansion ratio (%) |
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M 1 |
Metal material occupation rate (atom %) |
Solvent (wt%) |
Other |
The number of plies (layer) |
Type |
The formation method |
EC |
FEC |
DFE C |
DEC |
Embodiment 2-4 |
6 |
Co |
Electrolytic plating method |
1/2 |
8.3 |
50 |
- |
- |
50 |
- |
90 |
3 |
Embodiment 18-1 |
- |
50 |
- |
50 |
92 |
3.1 |
Embodiment 18-2 |
25 |
- |
5 |
70 |
93 |
3.1 |
Embodiment 18-3 |
- |
50 |
- |
50 |
VC |
94 |
3 |
Embodiment 18-4 |
VEC |
95 |
3.1 |
Embodiment 18-5 |
PRS |
93 |
0.4 |
Embodiment 18-6 |
LiBF
4 |
92 |
0.9 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
50 |
- |
50 |
- |
- |
42 |
21.3 |
Shown in table 18, in the solvent composition embodiment 18-1~18-6 different,, to compare with Comparative Examples 2 as embodiment 2-4 with the electrolytic salt type, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, if solvent composition and electrolytic salt type change, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 18-1 and 18-2, the discharge capacity sustainment rate is higher than embodiment 2-4.In addition, in the case, comprise among the embodiment 18-2 of DFEC at solvent, the discharge capacity sustainment rate is higher than the embodiment 18-1 that solvent comprises FEC.Show thus,, preferably comprise the fluoro carbonic ester in the solvent in order further to improve cycle characteristics.Show that in addition in order further to improve cycle characteristics again, as the fluoro carbonic ester, the difluoro ethylene carbonate than single fluorine ethylene carbonate more preferably.
In addition, in embodiment 18-3~18-6, the discharge capacity sustainment rate is higher than embodiment 2-4.In addition, in the case, comprise among the embodiment 18-3 and 18-4 of VC or VEC at solvent, the discharge capacity sustainment rate is higher than solvent and comprises PRS or LiBF
4Embodiment 18-5 and 18-6.Show that thus in order further to improve cycle characteristics, solvent preferably comprises cyclic carbonate, sultone or the boracic with unsaturated bond and the electrolytic salt of fluorine.Show in addition, in order further to improve cycle characteristics again, the preferred cyclic carbonate that uses with unsaturated bond.
Comprise PRS or LiBF at solvent
4Embodiment 18-5 and 18-6 in, do not comprise PRS or LiBF with solvent
4Embodiment 2-4 compare, expansion ratio significantly reduces.Expansion ratio when in the case, comprising PRS is less than comprising LiBF
4The time expansion ratio.Show that thus in secondary cell of the present invention, if solvent comprises sultone etc., then expansion characteristics improves.Show in addition,, then obtain better effect if solvent comprises sultone.
Embodiment 19-1~19-6
Carry out the method for embodiment 18-1~18-6 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
The cycle characteristics of the secondary cell of check embodiment 19-1~19-6, expansion characteristics etc. obtain the result shown in the table 19.Table 19 also shows the result of embodiment 2-5 and Comparative Examples 2.
Table 19
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Negative pole |
Electrolyte |
Discharge capacity efficient (%) |
Expansion ratio (%) |
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M 1 |
Metal material occupation rate (atom %) |
Solvent (wt%) |
Other |
The number of plies (layer) |
Type |
The formation method |
EC |
FEC |
DFEC |
DEC |
|
|
|
Embodiment 2-5 |
6 |
Co |
Electrolytic plating method |
1/1 |
10.3 |
50 |
- |
- |
50 |
- |
90 |
3.1 |
Embodiment 19-1 |
- |
50 |
- |
50 |
93 |
3.1 |
Embodiment 19-2 |
25 |
- |
5 |
70 |
94 |
3 |
Embodiment 19-3 |
- |
50 |
- |
50 |
VC |
95 |
3 |
Embodiment 19-4 |
VEC |
96 |
3 |
Embodiment 19-5 |
PRS |
94 |
0.3 |
Embodiment 19-6 |
LiBF
4 |
93 |
2.8 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
50 |
- |
50 |
- |
- |
42 |
21.3 |
Shown in table 19, in embodiment 2-5 and 19-1~19-6 that mol ratio changes, obtain being similar to the result of embodiment 2-4 and 18-1~18-6.That is, in embodiment 2-5 and 19-1~19-6, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.Discharge capacity sustainment rate when in the case, comprising FEC etc. is higher.Especially, the discharge capacity sustainment rate height when comprising DFEC when comprising FEC, or comprise VC or VEC time ratio comprises PRS or LiBF
4The time discharge capacity sustainment rate height.In addition, comprise PRS or LiBF
4The time expansion ratio less.Show that thus in secondary cell of the present invention, under the situation of solvent composition and the change of electrolytic salt type, even mol ratio changes, cycle characteristics and expansion characteristics also improve.
Embodiment 20-1
Carry out the method for embodiment 2-4 in the same manner, difference is in order to the square secondary cell shown in the manufactured Fig. 7-8 of below, but not the stack membrane secondary cell.
At first, form positive pole 21 and negative pole 22.Subsequently, be respectively welded to positive electrode collector 21A and negative electrode collector 22A with positive wire made of aluminum 24 with by the negative wire 25 that nickel is made.Then, successively with positive pole 21, separator 23 and negative pole 22 laminations, and longitudinal spiral twines the formation flat pattern.Form cell device 20 thus.Then, cell device 20 is inserted in the battery case made of aluminum 11.Subsequently, insulation board 12 is set on cell device 20.Then, positive wire 24 and negative wire 25 are respectively welded to anodal pin 15 and battery case 11.Subsequently, by laser welding battery cover 13 is fixed to the openend of battery case 11.At last, inject the electrolyte into battery case 11, use containment member 19A again, thereby finish the manufacturing of square battery hand-hole 19 sealings by hand-hole 19.For this secondary cell, regulate the thickness of anode active material layer 21B, so that the charge/discharge capacity of negative pole 22 is greater than anodal 21 charge/discharge capacity, therefore in charge and discharge process, the lithium metal is not separated out on negative pole 22.
Embodiment 20-2
Carry out the method for embodiment 20-1 in the same manner, difference is to use the battery case 11 that is fabricated from iron but not battery case 11 made of aluminum.
The cycle characteristics of the secondary cell of check embodiment 20-1 and 20-2, expansion characteristics etc. obtain the result shown in the table 20.Table 20 also shows the result of embodiment 2-4 and Comparative Examples 2.
Table 20
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Battery structure |
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 2-4 |
Stack membrane |
6 |
Co |
Electrolytic plating method |
1/2 |
8.3 |
90 |
3 |
Embodiment 20-1 |
Square (aluminium) |
92 |
1.1 |
Embodiment 20-2 |
Square (iron) |
94 |
0.2 |
Comparative Examples 2 |
Stack membrane |
6 |
- |
- |
- |
- |
42 |
21.3 |
Shown in table 20, in battery structure different embodiment 20-1 and 20-2,, to compare with Comparative Examples 2 as embodiment 2-4, the discharge capacity sustainment rate is higher and expansion rate is less.Show that thus in secondary cell of the present invention, if battery structure changes, then cycle characteristics and expansion characteristics also improve.
Especially, in embodiment 20-1 and 20-2, compare with embodiment 2-4, the discharge capacity sustainment rate is higher and expansion rate is less.In addition, in the case, in the embodiment 20-2 that battery case 11 is fabricated from iron, the embodiment 20-1 made of aluminum with battery case 11 compares, and the discharge capacity sustainment rate is higher and expansion rate is less.Show thus,, compare, more preferably use the square battery structure with the stack membrane battery structure in order further to improve cycle characteristics and expansion characteristics.Show in addition, in order further to improve this two specific character, the preferred battery case 11 that is fabricated from iron that uses.Although the specific embodiment of the also unexposed here column type secondary cell of making by metal material about packing component, but the square secondary cell of making by metal material for packing component, its cycle characteristics and expansion characteristics are better than stack membrane secondary cell, so the column type secondary cell also can be obtained similar effect.
Embodiment 21-1~21-2
Carry out the method for embodiment 21-1 and 21-2 in the same manner, difference is that mol ratio M2/M1 is 1/1 but not 1/2.
The cycle characteristics of the secondary cell of check embodiment 20-1 and 20-2, expansion characteristics etc. obtain the result shown in the table 21.Table 21 also shows the result of embodiment 2-5 and Comparative Examples 2.
Table 21
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Battery structure |
The negative active core-shell material particle |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 2-5 |
Stack membrane |
6 |
Co |
Electrolytic plating method |
1/1 |
10.3 |
90 |
3.1 |
Embodiment 21-1 |
Square (aluminium) |
92 |
2.7 |
Embodiment 21-2 |
Square (iron) |
94 |
2.2 |
Comparative Examples 2 |
Stack membrane |
6 |
- |
- |
- |
- |
42 |
21.3 |
Shown in table 21, in embodiment 2-5,21-1 and 21-2 that mol ratio changes, obtain being similar to the result of embodiment 2-4 and 20-1 and 20-2.That is, in embodiment 2-5,21-1 and 21-2, compare with Comparative Examples 2, the discharge capacity sustainment rate is higher and expansion rate is less.In the case, compare with the stack membrane secondary cell, the discharge capacity sustainment rate of square secondary cell is higher and expansion rate is less.In addition, in the square secondary cell, compare with aluminium square secondary cell, the discharge capacity sustainment rate of iron square secondary cell is higher and expansion rate is less.Show that thus in secondary cell of the present invention, under the situation that battery structure changes, even mol ratio changes, cycle characteristics and expansion characteristics also improve.
Embodiment 22-1 and 22-2
Carry out the method for embodiment 2-4 in the same manner, difference is the deposition rate of negative active core-shell material particle is become 40nm/s (embodiment 22-1) and 80nm/s (embodiment 22-2), but not 100nm/s.
Embodiment 22-3~22-5
Carry out the method for embodiment 2-4 in the same manner, difference is the deposition rate of negative active core-shell material particle is become 15nm/s (embodiment 22-3), 25nm/s (embodiment 22-4) and 40nm/s (embodiment 22-5), but not 100nm/s, and form the negative active core-shell material particle, in reduced atmosphere, under 400 ℃, gains were heat-treated 5 hours then.
Comparative Examples 22-1 and 22-2
Carry out the method for embodiment 2-4 in the same manner, difference is the deposition rate of negative active core-shell material particle is become 15nm/s (Comparative Examples 22-1) and 25nm/s (Comparative Examples 22-2), but not 100nm/s.
The cycle characteristics of the secondary cell of check embodiment 22-1~22-5 and Comparative Examples 22-1 and 22-2, expansion characteristics etc. obtain the result shown in the table 22.Table 22 also shows the result of embodiment 2-4 and Comparative Examples 2.
For the secondary cell of embodiment 2-4,22-1~22-5 and Comparative Examples 22-1 and 22-2, check the particle state of negative active core-shell material particle by the following method.At first, after with 10 circulations of charging/discharging of secondary cell, secondary cell is taken and is taken out apart the negative pole 54 of discharge condition.Then, after with dimethyl carbonate washing negative pole 54, with the surface of SIM observation negative pole 54 and the section of middle body thereof.Utilize FIB that the section of negative pole 54 is exposed.At last, based on the SIM photo, check respectively: for five adjacent offsprings 205, division particle 206 averages of each offspring 205; The length that marks in the zone of 100 μ m * 70 μ m with the interval of 10 μ m is offspring 205 averages on every line segment in eight line segments of 100 μ m; Each offspring 205 be included in primary particle 204 averages in the offspring 205; Length T 2 in continuous ten offsprings 205 is greater than the ratio of the offspring 205 of length T 1 (T1 is a thickness direction, and the T2 direction is perpendicular to T1).Figure 20 A, 20B, 21A and 21B are the SEM photo on negative pole 54 surfaces behind the loop test, show the observed result of Comparative Examples 2 and embodiment 2-4 respectively.Figure 20 B and Figure 21 B show the part of image shown in Figure 20 A and Figure 21 A.
Table 22
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Negative active core-shell material |
Metal material |
Mol ratio M2/M1 |
Metal material occupation rate (atom %) |
Deposition rate (nm/s) |
Heat treatment |
SEM/SIM observation |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Division particle average |
Offspring average |
Primary particle average |
T1<T2:50% or bigger |
Embodiment 22-1 |
6 |
Co |
Electrolytic plating method |
1/2 |
8.3 |
40 |
Do not have |
16 |
6.5 |
40 |
○ |
87 |
3.5 |
Embodiment 22-2 |
80 |
Do not have |
15 |
6.1 |
37 |
○ |
89 |
3.3 |
Embodiment 2-4 |
100 |
Do not have |
13 |
5.9 |
35 |
○ |
90 |
3 |
Embodiment 22-3 |
15 |
Have |
19 |
7 |
38 |
○ |
85 |
3.2 |
Embodiment 22-4 |
25 |
Have |
18 |
6.7 |
34 |
○ |
86 |
3.4 |
Embodiment 22-5 |
40 |
Have |
15 |
6.4 |
33 |
○ |
87 |
3.6 |
Comparative Examples 2 |
6 |
- |
- |
- |
- |
100 |
Do not have |
- |
- |
- |
- |
42 |
21.3 |
Comparative Examples 22-1 |
15 |
Do not have |
- |
<5 |
- |
- |
72 |
17.3 |
Comparative Examples 22-2 |
25 |
Do not have |
- |
<5 |
- |
- |
73 |
18.5 |
Shown in table 22, in negative active core-shell material particle deposition rate the embodiment 22-1~22-5 and Comparative Examples 22-1 and 22-2 different,, to compare with Comparative Examples 2 as embodiment 2-4 with heat treatment, the discharge capacity sustainment rate is higher and expansion rate is less.In the case, division particle 206 averages be 10 or bigger and length T 2 (T1 is a thickness direction greater than length T 1, the T2 direction is perpendicular to T1) offspring 205 quantity than be 50% or bigger embodiment 2-4 and 22-1~22-5 in, the discharge capacity sustainment rate is higher than Comparative Examples 22-1 and the 22-2 that does not satisfy above-mentioned condition.In addition, in embodiment 2-4 and 22-1~22-5, the average of offspring 205 is 5-11, and the average of primary particle 204 is 20 or bigger.In Comparative Examples 22-1 and 22-2, anode active material layer 54B pulverizes after discharging and recharging and comes off, and therefore can't observe particle state.Show thus, in secondary cell of the present invention, particle state as the negative active core-shell material particle, if the average of division particle 206 is 10 or bigger, and (T1 is a thickness direction to length T 2 greater than length T 1, the T2 direction is perpendicular to T1) the quantity ratio of offspring 205 be 50% or bigger, then cycle characteristics improves.
Especially, the result of embodiment 2-4,22-1 and 22-2 and Comparative Examples 22-1 and 22-2 shows, under the situation of not heat-treating, if the deposition rate of negative active core-shell material particle is 40nm/s or bigger, can obtain above-mentioned particle state.On the other hand, the result of embodiment 22-3~22-5 shows that under the situation of heat-treating, the deposition rate of the acquisition of above-mentioned particle state and negative active core-shell material particle is irrelevant.Therefore, in order to obtain helping improving the particle state of the negative active core-shell material particle of cycle characteristics, be proved to draw a conclusion.That is, if do not heat-treat after forming the negative active core-shell material particle, then no matter how deposition rate all obtains this particle state.On the other hand, if heat-treat, be preferably 40nm/s or bigger in deposition rate.
Embodiment 23-1~23-9
Carry out the method for embodiment 1-1 in the same manner, difference is to change current density when forming metal material with electrolysis, and the shared area of the metal material among the inferior segment SB shown in Figure 6 is 15% (embodiment 23-1), 50% (embodiment 23-2), 55% (embodiment 23-3), 60% (embodiment 23-4), 65% (embodiment 23-5), 70% (embodiment 23-6), 76% (embodiment 23-7), 81% (embodiment 23-8) and 93% (embodiment 23-9) than (occupation rate of the metal material in the inferior segment).The molal quantity M1 of unit are negative active core-shell material particle and ratio (mol ratio) M2/M1 of the molal quantity M2 of unit are metal material are 1/5.
Embodiment 23-10~23-14
Carry out the method for embodiment 23-7 in the same manner, difference be to use iron plating bath (embodiment 23-10), nickel plating bath (embodiment 23-11), copper electrolyte (embodiment 23-12), chromium plating bath (23-13) and titanium plating bath (embodiment 23-14) but not the cobalt plating bath as the material that forms metal material.Above-mentioned plating bath is by Japan Pure Chemical Co., and Ltd. produces.
Comparative Examples 23
Carry out the method for embodiment 23-1~23-9 in the same manner, difference is not form metal material.
The cycle characteristics of the secondary cell of check embodiment 23-1~23-14 and Comparative Examples 23, expansion characteristics etc. obtain the result shown in the table 23.In the case, when anode active material layer 54B comprises metal material,, go back the inspecting electrode state for the rigidity (pliability) of checking negative pole 54.
For the inspecting electrode state,, use the method that presses to estimate the rigidity of negative pole 54 with the negative pole that forms 54 crooked about 90 ℃.Negative pole 54 has flexibility and is easy to crooked situation with " excellent " expression, negative pole 54 slightly the tool rigidity and when bending, present slight repellence situation represent that with " very " and the rigidity of negative pole 54 is enough to make the almost unbending situation of negative pole 54 to be represented with " poor ".The method of inspecting electrode state is similar to the method for estimating identical characteristics in the following Examples and Comparative Examples.
Table 23
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Metal material occupation rate (atom %) |
Mol ratio M2/M1 |
Electrode state |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 23-1 |
1 |
Co |
Electrolytic plating method |
15 |
1/5 |
Very |
55 |
5.5 |
Embodiment 23-2 |
50 |
Excellent |
58 |
5.3 |
Embodiment 23-3 |
55 |
Excellent |
61 |
5.1 |
Embodiment 23-4 |
60 |
Excellent |
72 |
4.9 |
Embodiment 23-5 |
65 |
Excellent |
75 |
4.3 |
Embodiment 23-6 |
70 |
Excellent |
80 |
4.1 |
Embodiment 23-7 |
76 |
Excellent |
83 |
3.9 |
Embodiment 23-8 |
81 |
Excellent |
86 |
3.7 |
Embodiment 23-9 |
93 |
Excellent |
88 |
3.5 |
Embodiment 23-10 |
1 |
Fe |
Electrolytic plating method |
76 |
1/5 |
Excellent |
78 |
3.9 |
Embodiment 23-11 |
Ni |
Excellent |
81 |
3.8 |
Embodiment 23-12 |
Cu | Excellent | |
80 |
4 |
Embodiment 23-13 |
Cr |
Excellent |
82 |
4 |
Embodiment 23-14 |
Ti | Excellent | |
80 |
4 |
Comparative Examples 23 |
1 |
- |
- |
- |
- |
Excellent |
40 |
26.2 |
Shown in table 23, forming among the embodiment 23-1~23-14 of metal material, to compare with the Comparative Examples 23 that does not form metal material by electrolytic plating method, the discharge capacity sustainment rate is higher and expansion rate is less, and does not rely on the occupation rate of the metal material in the inferior segment.Show thus, in secondary cell of the present invention, if anode active material layer 54B comprises a plurality of siliceous negative active core-shell material particles and contains the metal material that does not form the metallic element of alloy with the electrode reaction thing, then cycle characteristics and expansion characteristics improve.
Especially, in embodiment 23-1~23-9, along with the occupation rate increase of the metal material in the inferior segment, the discharge capacity sustainment rate raises and expansion ratio descends.In the case, if the metal material occupation rate less than 60%, then the discharge capacity sustainment rate significantly reduces and expansion ratio obviously increases.If occupation rate is 70% or bigger, then this trend is more obvious.In embodiment 23-1~23-9, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus in order further to improve cycle characteristics and expansion characteristics, the shared area ratio of the metal material in the inferior segment is preferably 60% or bigger, more preferably 70% or bigger.
In addition, in the different embodiment 23-10~23-14 of the material that forms metal material, compare with Comparative Examples 23, the discharge capacity sustainment rate is higher and expansion ratio is less, and obtains the good battery status as embodiment 23-7.In the case, in using the embodiment 23-7 of cobalt, the discharge capacity sustainment rate is higher than the embodiment 23-10 that uses iron etc.Show that thus if metal material changes, then cycle characteristics and expansion characteristics also improve.Show in addition,, preferably use cobalt as the material that forms metal material in order further to improve cycle characteristics.
Embodiment 24-1~24-7
Carry out the method for embodiment 23-7 in the same manner, difference is that mol ratio is 1/200 (embodiment 24-1), 1/100 (embodiment 24-2), 1/50 (embodiment 24-3), 1/20 (embodiment 24-4), 1/2 (embodiment 24-5), 1/1 (embodiment 24-6) and 2/1 (embodiment 24-7), but not 1/5, and the occupation rate of the metal material in the inferior segment in suitable scope (60% or bigger) so that mol ratio M2/M1 reaches above-mentioned each value.
Embodiment 24-8
Carry out the method for embodiment 24-6 in the same manner, difference is that the occupation rate of the metal material in the inferior segment not in above-mentioned OK range, is 21%.The electrode state of the secondary cell of check embodiment 24-1~24-8, cycle characteristics, expansion characteristics etc. obtain the result shown in the table 24.Table 24 also shows the result of embodiment 23-7 and Comparative Examples 23.
Table 24
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Metal material occupation rate (atom %) |
Mol ratio M2/M1 |
Electrode state |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Type |
The formation method |
Embodiment 24-1 |
1 |
Co |
Electrolytic plating method |
85 |
1/200 |
Excellent |
59 |
8.6 |
Embodiment 24-2 |
85 |
1/100 |
Excellent |
63 |
4.9 |
Embodiment 24-3 |
83 |
1/50 |
Excellent |
69 |
4.5 |
Embodiment 24-4 |
80 |
1/20 |
Excellent |
75 |
4.1 |
Embodiment 23-7 |
76 |
1/5 |
Excellent |
83 |
3.9 |
Embodiment 24-5 |
73 |
1/2 |
Excellent |
86 |
3.8 |
Embodiment 24-6 |
73 |
1/1 |
Very |
81 |
4 |
Embodiment 24-7 |
72 |
2/1 |
Very |
80 |
4 |
Embodiment 24-8 |
1 |
Co |
Electrolytic plating method |
21 |
1/1 |
Difference |
63 |
3.5 |
Comparative Examples 23 |
1 |
- |
- |
- |
- |
Excellent |
40 |
26.2 |
Shown in table 24, in embodiment 23-7 and 24-1~24-8, along with mol ratio M2/M1 increases, discharge capacity reduces after keeping and taking the lead in increasing, and expansion ratio reduces.In the case, if mol ratio M2/M1 is 1/100-1/1, then obtain good discharge capacity sustainment rate and expansion ratio.If mol ratio M2/M1 is 1/50-1/2, then obtain better discharge capacity sustainment rate and expansion ratio.In embodiment 24-1~24-7, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus in order further to improve cycle characteristics and expansion characteristics, mol ratio M2/M1 is preferably 1/100-1/1, more preferably 1/50-1/2.
The occupation rate of the metal material in inferior segment among the embodiment 24-8 in above-mentioned OK range, is not compared with Comparative Examples 23, and the discharge capacity sustainment rate is higher and expansion ratio is less, but in the case, negative pole 54 is a rigidity and crooked hardly.Show that thus it is influential that the shared area of the metal material in the inferior segment is compared electrode state, if this area then obtains good electrode state than in above-mentioned OK range (60% or bigger).
Embodiment 25-1 and 25-2
Carry out the method for embodiment 23-7 in the same manner, difference is by electron beam evaporation plating method (embodiment 25-1) or sputtering method (embodiment 25-2) but not electrolytic plating method forms metal material.The details of electron beam evaporation plating method or sputtering method is similar to embodiment 5-1~5-4 or 6-2.
Embodiment 25-3 and 25-4
Carry out the method for embodiment 23-7 in the same manner, difference is by sputtering method (embodiment 25-3) or CVD method (embodiment 25-4) but not the electron beam evaporation plating method forms the negative active core-shell material particle, so that the negative active core-shell material particle has the thickness of a side 6 μ m.The details of sputtering method or CVD method is similar to embodiment 16-1 and 16-2.
The electrode state of the secondary cell of check embodiment 25-1~25-4, cycle characteristics, expansion characteristics etc. obtain the result shown in the table 25.Table 25 also shows the result of embodiment 23-7 and Comparative Examples 23.
Table 25
Negative active core-shell material particle: silicon
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Metal material occupation rate (atom %) |
Mol ratio M2/M1 |
Electrode state |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
The formation method |
Type |
The formation method |
Embodiment 23-7 |
1 |
The electron beam evaporation plating method |
Co |
Electrolytic plating method |
76 |
1/5 |
Excellent |
83 |
3.9 |
Embodiment 25-1 |
The electron beam evaporation plating method |
71 |
Excellent |
43 |
6.2 |
Embodiment 25-2 |
Sputtering method |
72 |
Excellent |
41 |
6.5 |
Embodiment 25-3 |
Sputtering method |
Electrolytic plating method |
76 |
Excellent |
77 |
4.3 |
Embodiment 25-4 |
The CVD method |
76 |
Excellent |
75 |
4.2 |
Comparative Examples 23 |
1 |
The electron beam evaporation plating method |
- |
- |
- |
- |
Excellent |
40 |
26.2 |
As shown in Table 25, forming among the embodiment 25-1 and 25-2 of metal material by electron beam evaporation plating method or sputtering method, the embodiment 23-7 as metal material is formed by electrolytic plating method compares with Comparative Examples 23, and the discharge capacity sustainment rate is higher and expansion ratio is less.Especially, in embodiment 23-7,25-1 and 25-2, under the situation of using liquid phase deposition (electrolytic plating method) as the method that forms metal material, compare as the method that forms metal material with using vapour deposition process (electron beam evaporation plating method or sputtering method), the discharge capacity sustainment rate is higher and expansion ratio is less.In embodiment 25-1 and 25-2, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus if use electron beam evaporation plating method or sputtering method as the method that forms metal material, then cycle characteristics and expansion characteristics also improve.Show in addition,, preferably use liquid phase deposition as the method that forms metal material in order further to improve cycle characteristics and expansion characteristics.
In addition, forming among the embodiment 25-3 and 25-4 of negative active core-shell material particle by sputtering method or CVD method, the embodiment 23-7 as metal material is formed by electrolytic plating method compares with Comparative Examples 23, and the discharge capacity sustainment rate is higher and expansion ratio is less.Especially, in embodiment 23-7,25-3 and 25-4, under the situation of using the electron beam evaporation plating method as the method that forms the negative active core-shell material particle, to compare as the method that forms the negative active core-shell material particle with using sputtering method or CVD method, the discharge capacity sustainment rate is higher.In embodiment 25-3 and 25-4, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus change if form the method for negative active core-shell material particle, then cycle characteristics and expansion characteristics also improve.Show in addition,, preferably use vapour deposition method as the method that forms the negative active core-shell material particle in order further to improve cycle characteristics and expansion characteristics.
Embodiment 26-1~26-5
Carry out the method for embodiment 23-7 in the same manner, difference is that the oxygen content in the negative active core-shell material particle is 1 atom % (embodiment 26-1), 10 atom % (embodiment 26-2), 35 atom % (embodiment 26-3), 40 atom % (embodiment 26-4) and 50 atom % (embodiment 26-5), but not 3 atom %.
The electrode state of the secondary cell of check embodiment 26-1~26-5, cycle characteristics, expansion characteristics etc. obtain the result shown in the table 26.Table 26 also shows the result of embodiment 23-7 and Comparative Examples 23.
Table 26
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Metal material occupation rate (atom %) |
Mol ratio M2/M1 |
Electrode state |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Oxygen content (atom %) |
Type |
The formation method |
Embodiment 26-1 |
1 |
1 |
Co |
Electrolytic plating method |
76 |
1/5 |
Excellent |
72 |
4 |
Embodiment 23-7 |
3 |
Excellent |
83 |
3.9 |
Embodiment 26-2 |
10 |
Excellent |
85 |
3.8 |
Embodiment 26-3 |
35 |
Excellent |
86 |
3.7 |
Embodiment 26-4 |
40 |
Excellent |
80 |
4 |
Embodiment 26-5 |
50 |
Excellent |
70 |
4 |
Comparative Examples 23 |
1 |
3 |
- |
- |
- |
- |
Excellent |
40 |
26.2 |
Shown in table 26, among the different embodiment 26-1~26-5 of the oxygen content in the negative active core-shell material particle,, to compare with Comparative Examples 23 as embodiment 23-7, the discharge capacity sustainment rate is higher and expansion ratio is less.Especially, in embodiment 23-7 and 26-1~26-5, along with oxygen content raises, discharge capacity reduces after keeping and taking the lead in increasing.In the case, if oxygen content less than 3 atom % or greater than 40 atom %, then the discharge capacity sustainment rate significantly reduces.In embodiment 26-1~26-5, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus if the oxygen content in the negative active core-shell material particle changes, then cycle characteristics and expansion characteristics also improve.Show that in addition in order further to improve cycle characteristics, the oxygen content in the negative active core-shell material particle is preferably 3-40 atom %.
Embodiment 27-1~27-5
Carry out the method for embodiment 23-7 in the same manner, also contain iron (embodiment 27-1), cobalt (embodiment 27-2), nickel (embodiment 27-3), titanium (embodiment 27-4) and chromium (embodiment 27-5) beyond the negative active core-shell material particle silica removal that difference is to form, so that negative active core-shell material particle one side thickness is 6.5 μ m.The details that makes iron be contained in the method in the negative active core-shell material particle is similar to embodiment 11-1~11-7.
The electrode state of the secondary cell of check embodiment 27-1~27-5, cycle characteristics, expansion characteristics etc. obtain the result shown in the table 27.Table 27 also shows the result of embodiment 23-7 and Comparative Examples 23.
Table 27
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
The negative active core-shell material particle |
Metal material |
Metal material occupation rate (atom %) |
Mol ratio M2/M1 |
Electrode state |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The number of plies (layer) |
Metallic element |
Type |
The formation method |
Embodiment 23-7 |
1 |
- |
Co |
Electrolytic plating method |
76 |
1/5 |
Excellent |
83 |
3.9 |
Embodiment 27-1 |
Fe | Excellent | |
85 |
3.5 |
Embodiment 27-2 |
Co | Excellent | |
85 |
3.4 |
Embodiment 27-3 |
Ni |
Excellent |
84 |
3.4 |
Embodiment 27-4 |
Ti |
Excellent |
84 |
3.4 |
Embodiment 27-5 |
Cr |
Excellent |
84 |
3.5 |
Comparative Examples 23 |
1 |
- |
- |
- |
- |
- |
Excellent |
40 |
26.2 |
Shown in table 27, among the embodiment 27-1~27-5 of the metallic element beyond the negative active core-shell material particle contains silica removal,, to compare with Comparative Examples 23 as embodiment 23-7, the discharge capacity sustainment rate is higher and expansion ratio is less.Especially, in embodiment 27-1~27-5, compare with embodiment 23-7, the discharge capacity sustainment rate is higher and expansion ratio is less.In embodiment 27-1~27-5, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus if the negative active core-shell material particle comprises metallic element, then cycle characteristics and expansion characteristics also improve.
Embodiment 28-1
Carry out the method for embodiment 23-7 in the same manner, difference is to add DFEC as solvent, and the composition of mixed solvent (EC: DFEC: DEC) be 25: 5: 70 (weight ratio).
Embodiment 28-3~28-6
Carry out the method for embodiment 28-1 in the same manner, difference is to add VC (embodiment 28-3), VEC (embodiment 28-4), PRS (embodiment 28-5) or LiBF with solvent version in electrolyte
4(embodiment 28-6).The addition of VC etc. is similar to embodiment 18-3~18-6.
The electrode state of the secondary cell of check embodiment 28-1~28-6, cycle characteristics, expansion characteristics etc. obtain the result shown in the table 28.Table 28 also shows the result of embodiment 23-7 and Comparative Examples 23.
Table 28
Negative active core-shell material particle: silicon (electron beam evaporation plating method)
10 mean roughness Rz=3.5 μ m
Oxygen content in the negative active core-shell material particle=3 atom %
Oxygen content in the metal material=5 atom %
|
Negative pole |
Electrolyte |
Electrode state |
Discharge capacity sustainment rate (%) |
Expansion ratio (%) |
The negative active core-shell material particle |
Metal material |
Metal material occupation rate (%) in the inferior segment |
Mol ratio M2/M1 |
Solvent (wt%) |
Other |
The number of plies (layer) |
Type |
The formation method |
EC |
FEC |
DFEC |
DEC |
Embodiment 23-7 |
1 |
Co |
Electrolytic plating method |
76 |
1/5 |
50 |
- |
- |
50 |
- |
Excellent |
83 |
3.9 |
Embodiment 28-1 |
- |
50 |
- |
50 |
Excellent |
90 |
3.8 |
Embodiment 28-2 |
25 |
- |
5 |
70 |
Excellent |
91 |
3.8 |
Embodiment 28-3 |
- |
50 |
- |
50 |
VC | Excellent | |
90 |
3.8 |
Embodiment 28-4 |
VEC | Excellent | |
90 |
3.8 |
Embodiment 28-5 |
PRS |
Excellent |
91 |
3.7 |
Embodiment 28-6 |
LiBF
4 |
Excellent |
90 |
3.8 |
Comparative Examples 23 |
1 |
- |
- |
- |
- |
50 |
- |
50 |
- |
- |
Excellent |
40 |
26.2 |
Shown in table 28, in the solvent composition embodiment 28-1~28-6 different,, to compare with Comparative Examples 23 as embodiment 23-7 with the electrolytic salt type, the discharge capacity sustainment rate is higher and expansion ratio is less.Especially, comprise among the embodiment 28-1 and 28-2 of FEC or DFEC at solvent, compare with embodiment 23-7, the discharge capacity sustainment rate is higher, especially, comprises at solvent under the situation of DFEC, and the discharge capacity sustainment rate is higher.Comprise among embodiment 28-3~28-6 of VC etc. at electrolyte, compare with embodiment 23-7, the discharge capacity sustainment rate is higher.Comprise PRS or LiBF at electrolyte
4Embodiment 28-5 and 28-6 in, do not contain PRS or LiBF with electrolyte
4Embodiment 23-7 compare, expansion ratio is less.In embodiment 28-1~28-6, obtain negative pole 54 obviously being hardened with Comparative Examples 23 similar good electrode states.Show that thus if solvent composition and electrolytic salt type change, then cycle characteristics and expansion characteristics also improve.Especially, in order further to improve cycle characteristics, preferably, solvent comprises the fluoro carbonic ester and contains the cyclic carbonate of unsaturated bond, or electrolyte comprises the electrolytic salt of sultone or boracic and fluorine.Show that in addition in order further to improve expansion characteristics, preferably, electrolyte comprises the electrolytic salt of sultone or boracic and fluorine.
More than invention has been described by execution mode and embodiment.Yet the present invention is not limited to the aspect described in the above-described embodiment and examples, can also carry out various improvement to the present invention.For example, in the above-described embodiment and examples, the lithium rechargeable battery as a kind of battery types is described, wherein capacity of negative plates is expressed as the voxel based on the absorption and the release of lithium.Yet the present invention is not limited to this.Battery of the present invention is equally applicable to following secondary cell: wherein capacity of negative plates comprises based on the voxel of the absorption of lithium and release and based on the voxel of separating out and dissolving (capacity of negative plates is expressed as above-mentioned voxel sum) of lithium, and the charging capacity that can absorb and discharge the negative material of lithium is set at the value less than anodal charging capacity.
And, in the above-described embodiment and examples, be that the secondary cell of square, column type or lamination-type and battery that cell device is spiral winding structure are described to battery structure.Yet the present invention is equally applicable to have the battery of other structure, for example Coin-shaped battery and button cell; Or cell device has the battery of other structure (as laminated construction).
In addition, in the above-described embodiment and examples, be described as the situation of electrode reaction thing using lithium.Yet, as the electrode reaction thing, can also use: other 1A family element, for example sodium (Na) and potassium (K); 2A family element, for example magnesium (Mg) and calcium (Ca); Other light metal, for example aluminium.In the case, can also use negative material in the above-mentioned execution mode as negative active core-shell material.
In addition, in the above-described embodiment and examples, about the molal quantity of the unit are negative active core-shell material particle in negative pole of the present invention and the battery and the ratio (mol ratio) of the molal quantity of unit are metal material, the suitable number range that obtains has been described from embodiment result.Yet these descriptions can not be got rid of the not possibility in described scope of this content fully.That is, above-mentioned OK range only is the particularly preferred scope that adopts in order to obtain effect of the present invention.Therefore, as long as can obtain effect of the present invention, this mol ratio can depart from above-mentioned scope to a certain extent.Like this equally for other number range, for example the crystal plane (111) of the metal material that obtains than 10 mean roughness Rz on the oxygen content in, the negative active core-shell material particle, the oxygen content in the metal material, negative electrode collector surface, by X-ray diffraction of the shared atomicity of the lip-deep metal material of anode active material layer is gone up half-band width 2 θ at the peak that produces, the shared area of metal material in the inferior segment and is compared etc.
It will be appreciated by those skilled in the art that and can carry out various improvement, combination, inferior combination and replacement according to designing requirement and other factors, prerequisite is the scope that they belong to claims or its equivalent.