CN100347904C - Lithium secondary battery and method for producing same - Google Patents

Abstract

A lithium secondary battery comprising a negative electrode composed of a collector on which an amorphous silicon thin film or an amorphous thin film mainly containing silicon is deposited, a positive electrode, and a nonaqueous electrolyte is characterized in that carbon dioxide is dissolved in the nonaqueous electrolyte.

Description

Lithium secondary battery and manufacture method thereof

Technical field

The present invention relates to a kind of rechargeable lithium battery and manufacture method thereof.

Background technology

Rechargeable battery as a kind of novel high-power and high-energy-density, recently used rechargeable lithium battery, this lithium rechargeable battery charges by migration in the non-aqueous electrolytic solution of lithium ion between positive electrode and negative electrode and discharges.

For this lithium rechargeable battery, after deliberation use the negative electrode of the Zinc-lithium alloy material of silicon for example as negative active core-shell material.Yet, using under the situation of Zinc-lithium alloy material as negative electrode active material of silicon for example, because active material volumetric expansion or contraction when storing or discharge lithium, this active material meeting powdered or come off in charging and discharge process from current-collector.This has reduced the current collection capacity of electrode, and has reduced the charge-discharge cycles performance characteristic thus, and this has become a problem.

The applicant has proposed a kind of use silicon as active material, and has improved the electrode (patent document 1) of the cycle performance feature of lithium rechargeable battery.More specifically, this electrode has by for example film shaped method of sputtering method, chemical vapour deposition technique (CVD method) or evaporation and is deposited on non-crystalline silicon thin-film on the current-collector.The inventor has also proposed a kind ofly to make in the silicon by cobalt or other element sneaked into, as the electrode (patent document 2) in the lithium rechargeable battery.For using material with carbon element or lithium metal, proposed carbon dioxide is dissolved in (for example, patent document 3-13) in the nonaqueous electrolyte as the lithium rechargeable battery of negative active core-shell material.

No. 01/29,913, patent document 1:PCT international application WO

No. 02/071,512, patent document 2:PCT international application WO

Patent document 3: United States Patent (USP) the 4th, 853, No. 304

Patent document 4: Japanese kokai publication hei 6-150975 number

Patent document 5: Japanese kokai publication hei 6-124700 number

Patent document 6: Japanese kokai publication hei 7-176323 number

Patent document 7: Japanese kokai publication hei 7-249431 number

Patent document 8: Japanese kokai publication hei 8-64246 number

Patent document 9: Japanese kokai publication hei 9-63649 number

Patent document 10: Japanese kokai publication hei 10-40958 number

Patent document 11: TOHKEMY 2001-307771 number

Patent document 12: TOHKEMY 2002-329502 number

Patent document 13: TOHKEMY 2003-86243 number

Summary of the invention

Propose as the applicant, use the lithium rechargeable battery of non-crystalline silicon thin-film, show high charge-discharge capacity and excellent cycle performance feature as negative active core-shell material.Yet along with charge-discharge cycles repeatedly, the porosity of active material layer increases, thereby causes the active material layer thickness to increase, and this has become a problem.

An object of the present invention is to provide a kind of lithium rechargeable battery and manufacture method thereof, this lithium battery uses by making non-crystal thin film complete or that mainly be made of silicon deposit the negative electrode that makes on current-collector, this lithium battery shows the cycle specificity of high charge-discharge capacity and improvement, and can suppress the porosity of active material behind the charging and discharging and the increase of thickness.

Lithium rechargeable battery of the present invention comprises by making non-crystal thin film complete or that mainly be made of silicon deposit the negative electrode that makes, positive electrode and nonaqueous electrolyte on current-collector.The feature of this nonaqueous electrolyte is to contain the carbon dioxide that is dissolved in wherein.

In the present invention, nonaqueous electrolyte contains the carbon dioxide that is dissolved in wherein.This means that this nonaqueous electrolyte contains expressly or on purpose is dissolved in wherein carbon dioxide.Although in the general manufacture process of lithium rechargeable battery, carbon dioxide is dissolved in the nonaqueous electrolyte inevitably, and this type of carbon dioxide dissolved is not included in this scope.Carbon dioxide is dissolved in the solvent of nonaqueous electrolyte usually.Therefore, can prepare this nonaqueous electrolyte in the solvent by solute is dissolved into carbon dioxide then.Perhaps, can prepare this nonaqueous electrolyte in the solvent by carbon dioxide is dissolved into solute then.

Can be by carbon dioxide being dissolved in nonaqueous electrolyte to stop the raising of the active material layer porosity that takes place with charging-exoelectrical reaction.Also can be suppressed at the increase of active material layer thickness in charging-discharge process thus, thereby improve the volume energy density of lithium rechargeable battery.

As disclosed in the patent document 1, if the known slit that forms in the upwardly extending mode in film thickness side is divided into the hurdle with film, use non-crystal thin film complete or that mainly constitute to show the charging-discharge performance feature of improvement as the electrode of active material so by silicon.Delimitation is limit and around hurdle shape space partly, is used in charging and discharge process, provides the space for changing of its volume when film expansion or contraction, and suppresses the generation of stress thus, so just can prevent that film breaks away from from current-collector.On the film thickness direction, extend and the slit of formation, originate from the recess of out-of-flatness place on the film surface.

The present inventor finds that when kind electrode charged repeatedly and discharges, the film with layer structure showed the porosity that inwardly progressively increases from its surface.Along with porosity improves, the thickness of film increases.Thus, the volume energy density of film reduces.The raising of this film porosity is considered to because the performance change that the silicon active material takes place when standing irreversible reaction.

According to the present invention, the dissolving of carbon dioxide in nonaqueous electrolyte suppressed the raising of film porosity.This has correspondingly suppressed the raising of thickness, and has improved the volume energy density of film thus.The dissolving of carbon dioxide in nonaqueous electrolyte stoped the raising of film porosity, and its detailed reason it be unclear that, but most possibly is owing to formed the stabilizing films with high-lithium ion conducting power at film surface.

In the present invention, the amount that is dissolved in the carbon dioxide of nonaqueous electrolyte preferably is at least 0.001wt.%, more preferably is at least 0.01wt.%, further preferably is at least 0.1wt.%.Usually preferably, carbon dioxide is dissolved in the nonaqueous electrolyte until saturated.Above the meltage of carbon dioxide of appointment do not comprise the amount that is dissolved in the carbon dioxide in the nonaqueous electrolyte inevitably, that is to say, do not comprise the amount that is dissolved in the carbon dioxide of nonaqueous electrolyte in the general manufacture process of lithium rechargeable battery.Can by measure carbon dioxide is dissolved in nonaqueous electrolyte after with before its weight, the meltage of the carbon dioxide that mensuration proposes above.Particularly, it can use following formula to calculate:

Be dissolved in amount (wt.%)=[(carbon dioxide is dissolved in nonaqueous electrolyte its weight afterwards)-(carbon dioxide is dissolved in nonaqueous electrolyte its weight before)]/(carbon dioxide is dissolved in nonaqueous electrolyte its weight afterwards) * 100 of the carbon dioxide of nonaqueous electrolyte.

In the present invention, use by non-crystal thin film complete or that mainly be made of silicon is deposited the negative electrode of making on current-collector.Term used herein is noncrystal, is to comprise amorphous thin film and the microcrystalline film that has up to the crystallite size of 100nm.Can pass through to observe the existence at peak in the X-ray diffraction spectrum, and half frequency range at peak is applied to the Scherrer formula, judge thus whether film is crystallite size amorphous and that measure microcrystalline film.Be appreciated that from above-mentioned definition the non-crystal thin film among the present invention does not comprise monocrystalline and polycrystal film.

Mainly the non-crystal thin film that is made of silicon is meant and contains the amorphous alloy film of 50atomic% silicon at least.The example of this type of alloy comprises that those contain silicon and at least a alloy that is selected from cobalt, iron, zinc and zirconium.Object lesson comprises Si-Co, Si-Fe, Si-Zn and Si-Zr alloy firm.

In the present invention, the current-collector surface of deposit film preferably has the arithmetic average roughness Ra of at least 0.1 μ m.Arithmetic average roughness Ra defines in Japanese Industrial Standards (JIS B 0601-1994), and can measure by the sonde-type surface roughness tester.Film deposits on this type of extremely irregular current-collector, causes forming on the deposit film surface corresponding out-of-flatness.As mentioned above, using under the situation of the extremely irregular non-crystal thin film of this class as active material, when battery charge and discharge, concentrating on the recess of film out-of-flatness place because of the stress that film expands or contraction produces, thereby on the film thickness direction, form the slit, film is divided into the hurdle.As a result, the stress that produces is disperseed the reversible construction to promote non-crystal thin film to change charging and when discharge.

On the other hand, the film that is divided into the hurdle has obviously improved the contact area of itself and nonaqueous electrolyte.As mentioned above, have been found that the performance change that has electrode active material now starts from the film surface that directly contacts with nonaqueous electrolyte, and cause the raising of film porosity.The present invention can suppress the raising of this type of porosity, improves the charge-discharge cycles performance characteristic, suppresses the increase of film thickness, and improves the volume of battery energy density.

There is no particular limitation to the upper limit of the arithmetic average roughness on current-collector surface.But because the thickness of current-collector is preferably between 10-100 μ m, the essence value of arithmetic average roughness is preferably 10 μ m or lower.

In the present invention, preferably use the heat resistant copper alloy paper tinsel as current-collector.Heat resistant copper alloy used herein refers in annealing under 200 ℃ and shows the copper alloy of 300Mpa tensile strength at least after one hour.The example of available heat resistant copper alloy is listed in the table 1.

[table 1]

(% is based on weight)

Type	Form
		The copper of stanniferous	The Sn of 0.05-0.2% and 0.04% or P still less join among the Cu
The copper of argentiferous	The Ag of 0.08-0.25% joins among the Cu
		Zirconium-copper (being used for embodiment)	The Zr of 0.02-0.2% joins among the Cu
Chromium-copper	The Cr of 0.4-1.2% joins among the Cu
		Titanium-copper	The Ti of 1.0-4.0% joins among the Cu
Beryllium-copper	The Be of 0.4-2.2%, Co, Ni and the Fe of trace join among the Cu
		The copper of iron content	The iron of 0.1-2.6% and the P of 0.01-0.3% join among the Cu
High-strength brass	2.0% or Al still less, 3.0% or Mn still less and 1.5% or Fe still less join in the brass of the Cu that contains 55.0-60.5%
		The brass of stanniferous	The Cu of 80.0-95.0%, the Sn of 1.5-3.5%, all the other are Zn
Phosphor bronze	Be mainly Cu, contain the Sn of 3.5-9.0% and the P of 0.03-0.35%
		Aluminium bronze	The Fe, 7.0 or Ni still less and 2.0% or Mn still less of Al, 1.5-6.0% that contains Cu, the 6.0-12.0% of 77.0-92.5%
Copper-nickel alloy	Be mainly Cu, contain the Mn and 1.0% or Zn still less of Fe, 0.20-2.5% of Ni, the 0.40-2.3% of 9.0-33.0%
		The Ke Sen corson alloy	Contain 3% Ni, 0.65% Si and 0.15% Mg in the copper
The Cr-Zr-Cu alloy	Contain 0.2% Cr, 0.1% Zr and 0.2% Zn in the copper

In the manufacturing of negative electrode, the variations in temperature that takes place during deposit film on current-collector may make the mechanical strength of current-collector be reduced to a certain degree, and makes processing in the battery manufacturing subsequently difficulty that becomes.Use the heat resistant copper alloy paper tinsel as current-collector, prevented and to have changed and the reduction of the current-collector mechanical strength that cause by aforementioned temperature, and guaranteed that thus current-collector has enough conductivity.

As mentioned above, current-collector preferred surface used in this invention is extremely irregular.Unless the arithmetic average roughness Ra of heat resistant copper alloy paper tinsel is enough big, otherwise can on the surface of paper tinsel, superpose cathode copper or copper alloy, so that big out-of-flatness is provided from the teeth outwards.This type of cathode copper and copper alloy layer can form by electrolysis.

Method of the present invention can be made above-mentioned lithium rechargeable battery of the present invention, specifically is used to make the lithium rechargeable battery that comprises negative electrode, positive electrode and nonaqueous electrolyte.The method is characterized in that and may further comprise the steps: non-crystal thin film complete or that mainly be made of silicon is deposited on current-collector be dissolved in nonaqueous electrolyte with the preparation negative electrode, with carbon dioxide and use this negative electrode, positive electrode and nonaqueous electrolyte assembling lithium rechargeable battery.

Can utilize the whole bag of tricks that carbon dioxide is dissolved in the nonaqueous electrolyte.For example, force carbon dioxide to contact with nonaqueous electrolyte.Particularly, carbon dioxide is fed in the nonaqueous electrolyte.This is a kind of effective and easy method, can obtain to contain the nonaqueous electrolyte of carbon dioxide dissolved thus.Other available method is included in and stirs nonaqueous electrolyte under the carbon dioxide atmosphere, and the high pressure draught of carbon dioxide is contacted with nonaqueous electrolyte.Perhaps, can add carbon dioxide and generate agent so that carbon dioxide is dissolved in the nonaqueous electrolyte.The example that carbon dioxide generates agent comprises Merlon and carbonate.Also can use dry ice.

When use contained the nonaqueous electrolyte manufacturing lithium rechargeable battery of carbon dioxide dissolved, preferred control stably was dissolved in the amount of the carbon dioxide in the nonaqueous electrolyte.For this purpose, preferably assemble lithium rechargeable battery containing under the atmosphere of carbon dioxide.For example, the nonaqueous electrolyte that will contain carbon dioxide dissolved adds step in the battery and step subsequently, preferably carries out containing under the atmosphere of carbon dioxide.Equally preferably, in adding battery after, the nonaqueous electrolyte that will contain carbon dioxide dissolved is exposed under the high-pressure carbon dioxide atmosphere, so that make the meltage of carbon dioxide stable.The amount that is dissolved to saturated carbon dioxide changes along with the temperature of nonaqueous electrolyte.It is therefore preferable that in manufacturing step, provide and regulate so that the temperature change of lithium rechargeable battery is minimized.

In manufacture method of the present invention,, non-crystal thin film complete or that mainly be made of silicon prepares negative electrode on current-collector by being deposited.In the deposition process of non-crystal thin film, preferably supply with raw material by gas phase.This method can make non-crystal thin film be deposited on substantially equably on the irregular surface of current-collector, and cause thus form on the non-crystal thin film surface usually with below the consistent out-of-flatness of the lip-deep out-of-flatness shape of current-collector.Can will be deposited on the non-crystal thin film from the raw material of gas phase by for example sputtering method, chemical vapour deposition technique or evaporation.Especially from practical term, preferably use evaporation to make the non-crystal thin film deposition.Evaporation is because its high film production rate is more suitable for making electrode than other method.

In lithium rechargeable battery of the present invention, the discharge capacity of negative electrode per unit volume is no more than 0.7 (mAh/cm ²μ m).Can make electrode by adopting evaporation that non-crystal thin film is deposited with this discharge capacity.The discharge capacity of per unit volume can be by calculating the discharge capacity of the per unit area thickness divided by non-crystal thin film.The discharge capacity of per unit volume stores in the active material or the amount of the lithium that discharges no better than.Therefore it is believed that the discharge capacity of per unit volume is low more, the change in volume that the per unit volume of active material produces is more little, can obtain the better cycle ability feature thus.

Do not limit the type of solvent of the nonaqueous electrolyte that uses in the lithium rechargeable battery of the present invention especially, but can be example with the mixed solvent of cyclic carbonate and linear carbonate.The example of cyclic carbonate comprises ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate.The example of linear carbonate comprises dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate.Same available be to contain any above-named cyclic carbonate and for example 1,2-dimethoxy-ethane or 1, the mixed solvent of the ether solvents of 2-diethoxyethane.Contain at solvent under the situation of the cyclic carbonate with unsaturated carbon bond of vinylene carbonate for example, the content of this type of cyclic carbonate is preferably the 0.1-10wt.% of cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) and linear carbonate total weight.Preferably, the volume content of described cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) is no more than 70% of cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) and linear carbonate cumulative volume; Further preferably, the volume content of described cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) is the 0.1-20% of cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) and linear carbonate cumulative volume; Perhaps, the volume content of described cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) is the 50-70% of cyclic carbonate (not comprising the cyclic carbonate with unsaturated carbon bond) and linear carbonate cumulative volume.Other example with cyclic carbonate of unsaturated carbon bond is an ethylene thiazolinyl ethyl.

The solute of nonaqueous electrolyte can be exemplified as LiPF ₆, LiBF ₄, LiCF ₃SO ₃, LiN (CF ₃SO ₂) ₂, LiN (C ₂F ₅SO ₂) ₂, LiN (CF ₃SO ₂) (C ₄F ₉SO ₂), LiC (CF ₃SO ₂) ₃, LiC (C ₂F ₅SO ₂) ₃, LiAsF ₆, LiClO ₄, Li ₂B ₁₀Cl ₁₀, Li ₂B ₁₂Cl ₁₂And composition thereof.That be preferably used as solute is LiXF _y(wherein X is P, As, Sb, B, Bi, Al, Ga or In; If X is P, As or Sb, y is 6, and if X is B, Bi, Al, Ga or In, y is 4); Perfluoroalkyl group sulfonyl imines lithium LiN (C _mF _2m+1SO ₂) (C _nF _2n+1SO ₂) (wherein m and n are the integer of 1-4 independently); With perfluoroalkyl group sulfonyl lithium methide LiN (C _pF _2p+1SO ₂) (C _qF _2q+1SO ₂) (C _rF _2r+1SO ₂) (wherein p, q and r are the integer of 1-4 independently).Wherein, especially preferably use LiPF ₆Other available electrolyte comprises, for example, and the gum polymers electrolyte that constitutes by the electrolyte solution in the polymer dielectric that is impregnated into for example polyoxyethylene and polyacrylonitrile.The electrolyte of lithium rechargeable battery of the present invention can use without restriction, as long as in charging, discharge and the storage process of battery, give the lithium compound of ionic conductance and the solvent of dissolving and maintenance lithium compound as solute, under voltage, can not decompose.

Equally in the present invention, nonaqueous electrolyte preferably contains fluorochemical or LiClO ₄The example of this type of fluorochemical comprises LiXF _y(wherein X is P, As, Sb, B, Bi, Al, Ga or In; If X is P, As or Sb, y is 6, if X is B, Bi, Al, Ga or In, y is 4) and LiN (C _pF _2p+1SO ₂) (C _qF _2q+1SO ₂) (C _rF _2r+1SO ₂) (wherein p, q and r are the integer of 1-4 independently), they all can be used as aforesaid solute, also comprise containing lithium fluoroborate.Contain lithium fluoroborate and can be exemplified as LiBF ₂(O _x).

The example of the suitable positive electrode material of lithium rechargeable battery of the present invention comprises for example LiCoO ₂, LiNiO ₂, LiMn ₂O ₄, LiMnO ₂, LiCo _0.5Ni _0.5O ₂And LiNi _0.7Co _0.2Mn _0.1O ₂Lithium-containing transition metal oxide; And MnO for example ₂Do not contain lithium metal oxide.Other material also can use without restriction, as long as they can and deviate from lithium by the electrochemistry insertion.

According to the present invention, lithium rechargeable battery with high charge-discharge capacity can be provided, and in this battery, can suppress to charge and discharge process in the increase of active material layer porosity, and can suppress thus to charge and discharge the increase of active material layer thickness afterwards.

Description of drawings

[Fig. 1] Fig. 1 is the FIB-SIM figure that shows according to the negative electrode cross section of lithium rechargeable battery A1 of the present invention;

[Fig. 2] Fig. 2 shows the relatively FIB-SIM figure in the negative electrode cross section of battery B2;

[Fig. 3] Fig. 3 is the spectrogram that shows the TOF-SIMS surface analysis result (cation) of negative electrode;

[Fig. 4] Fig. 4 is the spectrogram that shows the TOF-SIMS surface analysis result (anion) of negative electrode;

[Fig. 5] Fig. 5 is the schematic diagram that shows according to the sputter equipment that uses in the embodiments of the invention;

[Fig. 6] Fig. 6 is the perspective view that shows according to the lithium rechargeable battery of making in the embodiments of the invention;

[Fig. 7] Fig. 7 is the schematic cross-section that shows according to the lithium rechargeable battery of making in the embodiments of the invention;

[Fig. 8] Fig. 8 is the schematic diagram that shows according to the double source sputter equipment that uses in the embodiments of the invention;

[Fig. 9] Fig. 9 shows according to the electron beam deposition schematic representation of apparatus of using in the embodiments of the invention;

[Figure 10] Figure 10 is the curve chart that shows according to concerning between the charging capacity of the lithium rechargeable battery of the embodiment of the invention and the circulation;

[Figure 11] Figure 11 is the schematic diagram that shows according to the three electrode beaker batteries of constructing in the embodiments of the invention;

[Figure 12] Figure 12 shows to scheme according near the TEM the negative electrode film surface of lithium rechargeable battery A1 of the present invention;

[Figure 13] Figure 13 shows near the relatively TEM figure of negative electrode film surface of battery B1;

[Figure 14] Figure 14 is presented at according on the negative electrode film surface of lithium rechargeable battery A1 of the present invention and near the figure of oxygen concentration;

[Figure 15] Figure 15 is presented on the negative electrode film surface of comparison battery B1 and near the figure of oxygen concentration;

[Figure 16] Figure 16 is presented at according on the negative electrode film surface of lithium rechargeable battery A1 of the present invention and near the Si concentration and the figure of silica concentration;

[Figure 17] Figure 17 is negative electrode film surface place and near the Si concentration and the figure of silica concentration that is presented at comparison battery B1.

The reference number note

1... chamber

2... base sheet rack

3...Si sputtering source

4...DC the pulse power

5... plasma

6... gas access

7... gas vent

8...Co sputtering source

9...RF power supply

10... shell

11... anode collector

12... silicon thin film

13... cathode collector

14... anode active material layer

15... interlayer

16... nonaqueous electrolyte

17... negative plate

18... positive plate

21... electron beam deposition device

22... chamber

23... sedimentary origin

24... rotating cylinder

25... radiant heat barricade

26... flashboard

27... vacuum extractor

32... current-collector

43... beaker battery

44... work electrode

45... container

46... auxiliary electrode

47... reference electrode

48... non-aqueous electrolytic solution

Embodiment

The present invention illustrates in greater detail below by embodiment.Following examples only are used to illustrate practice of the present invention, rather than will limit it.Can carry out suitable change and modification without departing from the present invention.

(experiment 1)

(manufacturing of negative electrode)

By electrolysis with copper be deposited on constitute by zirconium-copper alloy (zirconium content is 0.015-0.03wt.%), on heat-resisting, the rolling copper alloy foil surface, thereby provide shaggy, heat resistant copper alloy paper tinsel (having the arithmetic average roughness Ra of 0.25 μ m and the thickness of 31 μ m) as current-collector.Use the sputter equipment shown in Fig. 5 that non-crystalline silicon thin-film is deposited on the current-collector.

As shown in Figure 5, pack in the chamber 1 cylindrical shape base sheet rack 2 of a rotation.Current-collector is placed on the surface of base sheet rack 2.The Si sputtering source 3 of also packing in the chamber 1 is connected with the DC pulse power 4 on it.Chamber 1 is furnished with the gas access 6 that is used to import Ar gas and is used for emptying chamber 1 gas inside outlet 7.

By gas vent 7 chamber interior is evacuated to 1 * 10 ^-4Pa.Pass through gas access 6 subsequently with Ar gas flood chamber 1 inside.After the stable gas pressure, apply electric pulse with generation plasma 5 from 4 pairs of Si sputtering sources 3 of the DC pulse power, thereby non-crystalline silicon thin-film is deposited on the current-collector that is positioned at base sheet rack 2 surfaces.Concrete film deposition conditions is listed in table 2.

[table 2]

The DC pulse frequency	100kHz
		The DC pulse duration	1856ns
The DC pulse power	2000W
		The argon gas flow velocity	60sccm
Air pressure	2-2.5×10 -1Pa
		Sedimentation time	146min
Film thickness	5μm

After thin film deposition to thickness is 5 μ m, current-collector is removed from base sheet rack 2.The size of 2.5cm * 2.5cm will be cut into the current-collector of film on it.Negative plate is attached thereon to make negative electrode.

(manufacturing of positive electrode)

LiCoO with 90 weight portions ₂Powder and as 5 weight portion graphous graphite powders of conductor is mixed in the 5wt.%N-methyl pyrrolidone aqueous solution that contains as the polytetrafluoroethylene of 5 weight portions of adhesive, thereby the negative pole mixed slurry is provided.This slurry is applied on the 2cm * 2cm surf zone of the aluminium foil (18 μ m are thick) as cathode collector by doctor blade method, subsequent drying is to form anode active material layer.Positive plate is invested the remaining aluminium foil zone of anode active material layer that do not scribble with the preparation positive electrode.

(manufacturing of nonaqueous electrolyte)

With 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate and diethyl carbonate, with preparation nonaqueous electrolyte b1.

The vinylene carbonate of 20wt.% is added among this nonaqueous electrolyte b1 with preparation nonaqueous electrolyte b2.

Carbon dioxide fed among the nonaqueous electrolyte b1 30 minutes at 25 ℃, be dissolved to saturated therein up to carbon dioxide.Obtain nonaqueous electrolyte a1 thus.Measure the weight of dissolved carbon dioxide front and back nonaqueous electrolyte, determine that thus the meltage of carbon dioxide is 0.37wt.%.

Nonaqueous electrolyte a1, b1 and b2 are described in detail as follows:

Nonaqueous electrolyte a1: wherein dissolved CO ₂Nonaqueous electrolyte

Nonaqueous electrolyte b1: wherein do not dissolve CO ₂Nonaqueous electrolyte

Nonaqueous electrolyte b2: the nonaqueous electrolyte that adds 20wt.% vinylene carbonate (VC).

(manufacturing of battery)

The negative electrode that use is made above, positive electrode and nonaqueous electrolyte are made lithium rechargeable battery.Fig. 6 and Fig. 7 are respectively perspective view and the schematic cross-section that shows the lithium rechargeable battery that makes.As shown in Figure 7, positive electrode and negative electrode are embedded in the shell of being made by the aluminium lamination press mold 10.Assembling is as the silicon thin film 12 of negative active core-shell material on anode collector 11.Assembling anode active material layer 14 on cathode collector 13.The position of silicon thin film 12 and anode active material layer 14 is over against the relative both sides of interlayer 15.Nonaqueous electrolyte 16 is injected shell 10.At shell 10 ends it is welded to define hermetic unit 10a.Negative plate 17 is connected on the anode collector 11, makes its front end pass hermetic unit 10a and extend to the outside.Although be not shown in Fig. 7, positive plate 18 is connected on the cathode collector 13, make its front end also pass hermetic unit 10a and extend to the outside.

The battery mark of using nonaqueous electrolyte a1 to make is A1.The battery mark of using nonaqueous electrolyte b1 to make is B1.The battery mark of using nonaqueous electrolyte b2 to make is B2.Lithium rechargeable battery A1 makes under high-purity carbon dioxide atmosphere.

(charge-discharge cycles test)

Lithium rechargeable battery A1, B1 and the B2 that makes thus carried out the charge-discharge cycles test.Each battery is at 25 ℃, with the current charges of 13mA to 4.2V, subsequently with the current discharge of 13mA to 2.75V.This is recorded as a unit circulation of charging and discharge.The maximum discharge capacity of every kind of battery, and the discharge capacity of the 100th circulation and the 200th circulation, and the capacity retention rate is listed in table 3.Maximum discharge capacity is the peak of the discharge capacity that records in all circulations.Maximum discharge capacity is considered as 100%, thus the calculated capacity retention rate.

[table 3]

Battery	Maximum discharge capacity (mAh)	The 100th circulation		The 200th circulation
						Discharge capacity (mAh)	Capacity retention rate (%)	Discharge capacity (mAh)	Capacity retention rate (%)
		A1	11.17	9.89	88.5					8.66	77.5
B1	12.17					2.14	17.6	0.58	4.8
		B2	11.42	8.41	73.6					5.33	46.7

Can clearly be seen that from table 3 the battery B1 of the nonaqueous electrolyte of dissolved carbon dioxide compares with containing wherein not, according to of the present invention, contain the battery A1 of the nonaqueous electrolyte that has dissolved carbon dioxide, the capacity that demonstrates obvious improvement keeps.Equally, compare with the battery B2 that contains vinylene carbonate, battery A1 according to the present invention shows the capacity retention rate of obvious improvement.

After 200 charge-discharge cycles, each battery is taken apart, and its negative electrode is shifted out.Use SEM (scanning electron microscopy) to observe the cross section of negative electrode, thereby measure the thickness of non-crystalline silicon thin-film.The thickness of the non-crystalline silicon thin-film that records is shown in table 4.The discharge capacity that in table 4, has also shown 200 circulation accumulative totals.The accumulated discharge capacity almost with non-crystalline silicon thin-film in the reaction weight of storage and the lithium that discharges proportional.Therefore the accumulated discharge capacity is considered to improve with the porosity that increases non-crystalline silicon thin-film thickness the substantial connection that has of reaction.

[table 4]

Battery	Accumulated discharge capacity (mAh)	The thickness of non-crystalline silicon thin-film (μ m)
			A1	1949	25
B1	851	22
			B2	1657	42

Can clearly be seen that from result shown in the table 4 although the difference between both thickness is very little, B1 compares with battery, show much higher accumulated discharge capacity according to the non-crystalline silicon thin-film among the battery A1 of the present invention.The battery B2 that use contains the nonaqueous electrolyte of vinylene carbonate shows the accumulated discharge capacity higher than battery B1, but shows bigger amorphous si film thickness.It is reported, for the lithium rechargeable battery that uses the carbon back negative electrode, owing to, in nonaqueous electrolyte, add vinylene carbonate and improved cycle characteristics at the negative electrode surface produced film.But, clearly show as comparative example, add the increase that vinylene carbonate can not suppress silicon thin film thickness in fact.On the other hand,, use and contain in the lithium rechargeable battery of the nonaqueous electrolyte that has dissolved carbon dioxide, obviously suppressed the increase of non-crystal thin film thickness according to of the present invention.

(FIB-SIM observation)

After the same loop condition is carried out 200 charge-discharge cycles as described above, take and take out battery A1 apart its negative electrode.After the same loop condition is carried out 100 charge-discharge cycles as described above, take and take out battery B1 apart its negative electrode.Observe the cross section of each negative electrode with FIB-SIM.FIB-SIM observation is meant with focused ion beam (FIB) and handles negative electrode so that outside its cross section is exposed to, use the cross section of scanning ion microscope (SIM) observation exposure subsequently.

In SIM observation, above the cross section that exposes and from the angles that are 45 degree with it, the cross section that exposes is observed.

Fig. 1 and Fig. 2 show SIM figure respectively.

Fig. 1 shows the negative electrode of battery A1, and Fig. 2 shows the negative electrode of battery B2.Can clearly be seen that from Fig. 2 show in the negative electrode of thickness increase owing to adding vinylene carbonate, owing to there is hole, the surface portion of each row of film all presents white.Owing to there is not hole, the top interior section of film presents dimness to a certain degree.But near the film portion current-collector mainly is white in color.This proof, the part adjacent with current-collector at film has obvious greater porosity.

On the other hand, can use in the negative electrode of the lithium rechargeable battery that contains the nonaqueous electrolyte that has dissolved carbon dioxide, from Fig. 1 finding owing to the film portion that exists hole to be white in color is considerably less.Particularly, find that this negative electrode has low-down porosity in its part adjacent with current-collector.

(TEM observation)

After carrying out 50 charge-discharge cycles according to identical as mentioned above charging and discharging condition, in argon atmospher, battery A1 is taken apart to take out its negative electrode.After carrying out 30 charge-discharge cycles according to identical as mentioned above charging and discharging condition, in argon atmospher, battery B2 is taken apart to take out its negative electrode.

The negative electrode of every kind of taking-up is processed into the form of slice, and observes the far-end of negative electrode film hurdle shape structure with transmission electron microscope (TEM).Figure 12 has shown the TEM figure of the negative electrode of battery A1, and Figure 13 has shown the TEM figure of the negative electrode of battery B1.In Figure 12 and 13, whole black regions comprise dark and shallow zone, the tangent plane of film in the expression negative electrode.The upper end of black region, the boundary of black and white portion just, the contact surface of the critical surfaces inclusive NAND Water-Electrolyte of film in the expression negative electrode.From Figure 12 and 13, can obviously find out, near the film surface of negative electrode, observe pitch black zone.This pitch black zone is approximately 50nm in battery A1 thick, and it is thick to be approximately 150nm in battery B1.Thus, the negative electrode film according to battery A1 of the present invention has the pitch black zone thinner than battery B1.

By the X-ray energy scatter spectroscopic methodology (EDX) to battery A1 and B1 separately the film surface of negative electrode analyze.Figure 14 is presented on the negative electrode film surface of battery A1 and the oxygen concentration of near surface.Figure 15 is presented on the negative electrode film surface of battery B1 and the oxygen concentration of near surface.In Figure 14 and 15, represent the boundary in pitch black zone and somber zone at the vertical line of the 0nm degree of depth.Can clearly be seen that from Figure 14 and 15 than battery B1, it is less that battery A1 has the thickness of negative electrode area of hyperoxia concentration.

Carry out etching by Ar (argon) ion at the surface portion of battery A1 and B1 negative electrode film separately, and it is analyzed along the composition on the surface portion depth direction by x-ray photoelectron spectroscopy.Figure 16 is presented on the negative electrode film surface of battery A1 and the Si concentration and the silica concentration of near surface.Figure 17 is presented on the negative electrode film surface of battery B1 and the Si concentration and the silica concentration of near surface.From Figure 16 and 17, can clearly be seen that, compare with the situation that exists of silica in the surface portion of battery B1 negative electrode, silica is present in the thin zone in the surface portion of battery A1 negative electrode in a large number, and this oxidation reaction that has proved Si in battery A1 has been subjected to obstruction.

Be appreciated that nonaqueous electrolyte from aforementioned result,, can hinder the oxidation reaction of the Si that in charging and discharge process, takes place if contain carbon dioxide dissolved.In battery B1, the oxidation reaction of Si has obviously taken place.As if this has increased the porosity of silicon thin film, and makes its volumetric expansion.Believe by carbon dioxide being dissolved in the nonaqueous electrolyte, can hinder this type of oxidation reaction of silicon and the raising of silicon thin film internal void degree according to the present invention.

Be appreciated that according to the present invention from foregoing carbon dioxide is dissolved in the raising that can stop the film porosity the nonaqueous electrolyte, and suppress the increase of non-crystalline silicon thin-film thickness thus.

(TOF-SIMS observation)

For battery A1, B1 and the B2 of initial charge, each negative electrode surface is analyzed by TOF-SIMS (time of flight secondary ion massspectrometry).Fig. 3 is a cation TOF-SIMS spectrogram, and Fig. 4 is an anion TOF-SIMS spectrogram.In Fig. 3 and Fig. 4, " LiPF ₆+ CO ₂" show the spectrogram of battery A1 of the present invention, " LiPF ₆" show the spectrogram of battery B1, " LiPF ₆+ VC20wt.% " show the spectrogram of battery B2.

From Fig. 3 and 4, can clearly be seen that,, can detect than battery B1 and B2 Si ion that obviously reduces and the Li that contains silicon ion and increase at its negative electrode surface for battery A1 according to the present invention ₂F ⁺Ion.This shows, uses according to the nonaqueous electrolyte that has dissolved carbon dioxide that contains of the present invention, causes the Si concentration of film surface significantly to reduce.This most possibly is owing to formed not siliceous film on the film surface that is made of active material.Believe that this film is a kind of stabilising membrane with high-lithium ion conducting power, and generate the performance change that this film has suppressed film, and stoped at lithium and store and the increase of film porosity from charging-discharge process that film discharges at film surface.

On the other hand, very likely in the negative electrode of battery B1 and B2, formed the film that contains the Si active material.The formation of this type of film may be the reason that the surface of active material porosity increases.Believe that the present invention has prevented the generation of this type of film, thereby successfully stoped the increase of active material porosity.

(reference experiment)

(manufacturing of carbon negative electrode)

In carboxymethyl cellulose aqueous solution as thickener, will mix with styrene butadiene rubbers as the Delanium of negative active core-shell material as adhesive, making mixture contain weight ratio is 95: 3: 2 active material, adhesive and thickener.Stir with preparation negative electrode slurry with being about to mixture.With the slurry coating that makes on Copper Foil as current-collector, drying, and rolling with pressure roll.Connect subsequently and go up collector plate, make negative electrode.

(manufacturing of positive electrode)

In the 5wt.%N-methyl pyrrolidone aqueous solution that contains as the polytetrafluoroethylene of 5 weight portions of adhesive, with the LiCoO of 90 weight portions ₂Powder and mix as the graphous graphite powder of 5 weight portions of electric conductor, thus make the negative electrode mixed pulp.By doctor blade method this slurry is applied on the aluminium foil as cathode collector, subsequent drying is to form anode active material layer.Positive plate is invested the remaining aluminium foil zone of anode active material layer that do not scribble with the preparation positive electrode.

(manufacturing of nonaqueous electrolyte)

With 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate and diethyl carbonate, with preparation solution.

The vinylene carbonate that adds 2wt.% in this solution is with preparation nonaqueous electrolyte c2.

Carbon dioxide fed among the nonaqueous electrolyte c2 30 minutes at 25 ℃, be dissolved to saturated therein up to carbon dioxide.Obtain nonaqueous electrolyte c1 thus.The meltage of carbon dioxide is 0.37wt.%.

Nonaqueous electrolyte c1 and c2 are described in detail as follows:

Nonaqueous electrolyte c1: wherein dissolved CO ₂Nonaqueous electrolyte

Nonaqueous electrolyte c2: wherein do not dissolve CO ₂Nonaqueous electrolyte

(manufacturing of battery)

Use the negative electrode, positive electrode and the nonaqueous electrolyte that as above make to make lithium rechargeable battery.

Positive electrode and negative electrode are rolled into columnar structured, the porous polyethylene barrier film is arranged between them.This electrode group and each nonaqueous electrolyte are introduced in the shell of being made by aluminium flake.Outer rim at shell seals shell, and order front end anodal and the negative pole collector plate is protruding from shell thus, finishes the manufacturing of battery thus.

The details of the battery that makes is listed in table 5.

[table 5]

Thickness (mm)	3.6
		Width (mm)	35
Highly (mm)	62
		Design capacity (mAh)	600
The number of turn	9
		Anode active material layer thickness (μ m)	53.5

The battery mark of using nonaqueous electrolyte c1 to make is C1.The battery mark of using nonaqueous electrolyte c2 to make is C2.Battery C1 makes under high-purity carbon dioxide atmosphere.

(charge-discharge cycles test)

Lithium rechargeable battery C1 and the C2 that makes thus carried out the charge-discharge cycles test.Each battery to 4.2V, charges to 30mA with the constant current charge of 600mA all under 25 ℃ under the constant voltage of 4.2V, immediately with the current discharge of 600mA to 2.75V.This is recorded as a unit circulation of charging and discharge.With the 500th time the circulation discharge capacity divided by the 1st time the circulation discharge capacity to obtain capacity retention rate as shown in table 6.Table 6 has also shown the increase of 500 circulation back cell thickness, and the thickness added value of every layer of the electrode active material that is calculated by the added value of cell thickness.

[table 6]

Battery	Capacity after 500 circulations keeps (%)	The thickness of 500 circulation back batteries increases (μ m)	The thickness that electrode active material layers is every layer increases (μ m)
				C1	88.9	148	8
C2	88.2	150	8

Can clearly be seen that from the result shown in the table 6, when using material with carbon element, carbon dioxide is dissolved in the nonaqueous electrolyte, almost can not stop the degeneration of cycle performance and the increase of inhibition cell thickness as negative active core-shell material.

(experiment 2)

(manufacturing of negative electrode a3)

Copper is deposited on heat-resisting, the rolling copper alloy foil surface that constitutes by zirconium-copper alloy (zirconium content is 0.03wt.%) by electrolysis, thereby provide shaggy, heat resistant copper alloy paper tinsel (having the arithmetic average roughness Ra of 0.25 μ m and the thickness of 26 μ m) as current-collector.According to the condition shown in the table 7 amorphous si film is deposited on the current-collector.In this experiment, apply electric pulse to cause sputter.But, also can under condition of similarity, carry out thin film deposition by direct current or radio frequency sputtering method.In table 7, sccm is the unit of flow velocity, and it is the abbreviation of per minute standard milliliter.

[table 7]

The DC pulse frequency	100kHz
		The DC pulse duration	1856ns
The DC pulse power	2000W
		The argon gas flow velocity	60sccm
Air pressure	2.0-2.5×10 -1Pa
		Curring time	146min.
Film thickness	5μm

The film that makes is cut to the size of 25mm * 25mm, with as negative electrode a3.

(manufacturing of negative electrode a4)

Use double source sputter equipment shown in Figure 8, amorphous Si-Co alloy firm is deposited on the same set electrical equipment used in making with negative electrode a3, wherein respectively Si target and Co target are applied DC pulse and radio frequency.Specific sedimentary condition is listed in table 8.

In sputter equipment shown in Figure 8, the cylindrical shape base sheet rack of packing into and rotate in chamber 12.Current-collector is placed on the surface of base sheet rack 2.The chamber 1 Si sputtering source 3 of also packing into is connected with the DC pulse power 4 on it.Co sputtering source 8 also is equipped with in chamber 1, is connected with RF power supply 9 on it.On chamber 1, equipped and be used to import the gas access 6 of Ar gas and be used for emptying chamber 1 gas inside outlet 7.

After the stable gas pressure in the chamber 1, apply electric pulse from 4 pairs of Si sputtering sources 3 of the DC pulse power, apply radio frequency from 9 pairs of Co sputtering sources 8 of RF power supply simultaneously,, thus noncrystal Si-Co alloy firm is deposited on the current-collector that is positioned at base sheet rack 2 surfaces with the plasma 5 that produces them respectively.Concrete sedimentary condition is listed in table 8.

[table 8]

The Si target	The DC pulse frequency	100kHz
			The DC pulse duration	1856ns
	The DC pulse power	2000W
			The Co target	High frequency power	400W
High-frequency	13.56MHz
		The argon gas flow velocity		50sccm
Air pressure					1.7-2.2×10 -1Pa
		Curring time		172min.
Film thickness					6.5μm

When measuring by x-ray fluorescence analysis, the Co concentration of the alloy firm that discovery makes is 30wt.%.Equally, determined the amorphous property of film by the X-ray diffraction analysis.

Be cut into the size of 2.5cm * 2.5cm with loading on the Si-Co film that makes on the current-collector, so that negative electrode a4 to be provided.

(manufacturing of negative electrode a5)

Use the double source sputter equipment identical, just replace the Co sputtering source, amorphous Si-Fe alloy firm is deposited on the same set electrical equipment used in the preparation with negative electrode a3 and a4 with the Fe sputtering source with device shown in Figure 8.By respectively Si target and Fe target being applied the deposition that DC pulse and radio frequency cause amorphous Si-Fe alloy firm.Concrete sedimentary condition is listed in table 9.

[table 9]

The Si target	The DC pulse frequency	100kHz
			The DC pulse duration	1856ns
	The DC pulse power	2000W
			The Fe target	High frequency power	300W
High-frequency	13.56MHz
		The argon gas flow velocity		50sccm
Air pressure					1.7-2.2×10 -1Pa
		Curring time		165min.
Film thickness					6.0μm

When measuring by x-ray fluorescence analysis, the Fe concentration of the alloy firm that discovery makes is 17wt.%.Equally, determined the amorphous property of film by the X-ray diffraction analysis.

Be cut into the size of 2.5cm * 2.5cm with loading on the Si-Fe film that makes on the current-collector, so that negative electrode a5 to be provided.

(manufacturing of positive electrode)

With raw material Li ₂CO ₃And CoCO ₃Weigh, make the ratio Li of Li and Co atom: Co reaches 1: 1, mixes in mortar with being about to it.At diameter is compacted mixture in the mould of 17mm, in 800 ℃ of calcinings 24 hours, grinds with being about to it in air, and obtaining average grain diameter is the positive electrode active materials of 20 μ m.With 90: 5: 5 weight ratio, with the gained positive electrode active materials, add in the N-N-methyl-2-2-pyrrolidone N-, mixed to make the negative electrode mixed pulp with being about to it as the carbon of electric conductor with as the polyvinylidene fluoride of adhesive.

The slurry that makes is coated on the aluminium foil as current-collector, is dried, and uses the calender roll calendering.To make the size that thing is cut into 20mm * 20mm, so that positive electrode to be provided.

(manufacturing of battery)

According to the step of experiment 1, only be to use positive electrode and negative electrode a3, a4 and the a5 manufacturing battery made above.The nonaqueous electrolyte a1 and the b1 of use preparation in experiment 1.

Negative electrode a3, a4 and a5 are used with nonaqueous electrolyte a1 respectively, make lithium rechargeable battery A3, A4 and A5.

Negative electrode a3, a4 and a5 are used with nonaqueous electrolyte b1 respectively, make lithium rechargeable battery B3, B4 and B5.

(charge-discharge cycles test)

With experiment in 1 under the identical condition, battery A3-A5 and the B3-B5 that makes thus carried out the charge-discharge cycles test.Their discharge capacity, and the capacity retention rate of the 100th circulation and 200 circulations is listed in the table 10.

[table 10]

Battery	Maximum discharge capacity (mAh)	100 circulations		200 circulations
						Discharge capacity (mAh)	Capacity retention rate (%)	Discharge capacity (mAh)	Capacity retention rate (%)
		A3	11.17	9.89	88.5					8.66	77.5
A4	11.45					10.3	90.0	9.55	83.4
		A5	12.30	10.8	87.9					9.96	80.8
B3	12.17					2.14	17.6	0.58	4.80
		B4	12.0	5.32	44.3					1.06	8.86
B5	11.67					3.85	33.0	0.78	6.68

Can clearly be seen that from result shown in the table 10, even using under silicon-cobalt and the situation of silicon-ferroalloy as negative active core-shell material, the battery B4 of the nonaqueous electrolyte of dissolved carbon dioxide compares with B5 with using not, contain the battery A4 and the A5 of the nonaqueous electrolyte that has dissolved carbon dioxide according to use of the present invention, show the capability retention of obvious improvement.

After 200 charge-discharge cycles, battery A4 and B4 are taken apart to take out their negative electrode.Use SEM (scanning electron microscopy) to observe the cross section of each negative electrode to measure the thickness of its non-crystalline silicon alloy firm.The thickness of the non-crystalline silicon alloy firm that records is listed in the table 11.The discharge capacity that in table 11, has also shown accumulative total in 200 circulations.

[table 11]

Battery	Accumulated discharge capacity (mAh)	The thickness of non-crystalline silicon thin-film (μ m)
			A4	1960	19
B4	1191	28

Can clearly be seen that from result shown in the table 11,,, show the accumulated discharge capacity more much higher than battery B4 according to the non-crystalline silicon among the battery A4 of the present invention-cobalt alloy film although thickness increases very for a short time.The increase of film thickness when using non-crystalline silicon-cobalt alloy, film thickness must increase when using non-crystalline silicon, and this shows that the effect of using carbon dioxide is more obvious.

(experiment 3)

(manufacturing of nonaqueous electrolyte a6)

Under carbon dioxide atmosphere, with 1 mol LiClO ₄Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and diethyl carbonate (DEC).With the electrolyte solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved in wherein, prepare nonaqueous electrolyte a6 thus.

(manufacturing of nonaqueous electrolyte b6)

Under argon atmospher, with 1 mol LiClO ₄Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and diethyl carbonate (DEC), with preparation nonaqueous electrolyte b6.

(manufacturing of nonaqueous electrolyte b7)

Under carbon dioxide atmosphere, with the fluorine-containing lithium borate derivative of 1 mol, LiBF ₂(O _X) (Central Glass Co., the product of Ltd.) be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and diethyl carbonate (DEC).With the electrolyte solution that makes with the carbon dioxide bubbling so that carbon dioxide is dissolved in wherein, prepare nonaqueous electrolyte a7 thus.

(manufacturing of nonaqueous electrolyte b7)

Under argon atmospher, with 1 mol LiBF ₂(O _X) be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and diethyl carbonate (DEC), with preparation nonaqueous electrolyte b7.

(manufacturing of battery)

According to the step of experiment 1, different positive electrodes that is to use manufacturing in the experiment 2 and negative electrode a3 and the nonaqueous electrolyte a6, the a7 that prepare above, b6 and b7 make battery A6, A7, B6 and B7.

(charge-discharge cycles test)

With experiment in 1 under the identical condition, lithium rechargeable battery A6, A7, B6 and the B7 that makes thus carried out the charge-discharge cycles test.Test result is listed in the table 12.In table 12, also listed the result of battery A3 and B3.

[table 12]

Battery	Maximum discharge capacity (mAh)	100 circulations		200 circulations
						Discharge capacity (mAh)	Capacity retention rate (%)	Discharge capacity (mAh)	Capacity retention rate (%)
		A3	11.17	9.89	88.5					8.66	77.5
A6	12.45					8.78	70.5	6.18	49.6
		A7	11.13	8.98	80.7					8.01	72.0
B3	12.17					2.14	17.6	0.58	4.80
		B6	11.74	4.57	38.1					1.94	16.2
B7	12.01					8.78	73.1	4.42	36.8

From result shown in the table 12 as can be seen, using LiPF ₆, LiBF ₂(O _X) and LiClO ₄Under the situation that joins the solute in the nonaqueous electrolyte, battery B3, the B6 of the nonaqueous electrolyte of dissolved carbon dioxide compare with B7 with using not, contain battery A3, A6 and the A7 of the nonaqueous electrolyte that has dissolved carbon dioxide according to use of the present invention, show the capacity retention rate of obvious improvement.When nonaqueous electrolyte contained fluorochemical, this difference was especially remarkable.

(experiment 4)

(manufacturing of nonaqueous electrolyte a8-a10)

As shown in table 13, with 0: 100-100: the different volumes ratio in 0 scope, mix the nonaqueous electrolyte a1 (wherein having dissolved carbon dioxide) of preparation in the experiment 1 and nonaqueous electrolyte b1 (wherein not dissolved carbon dioxide) to prepare nonaqueous electrolyte a8 to a10.

[table 13]

The CO of dissolving 2Gas flow (wt.%)	Nonaqueous electrolyte	B1 content (vol.%)	A1 content (vol.%)
				0.37	a1	0	100
0.185	a8	50	50
				0.0925	a9	75	25
0.037	a10	90	10
				0	b1	100	0

(manufacturing of battery)

According to experiment 1 step, the different nonaqueous electrolyte a8-a10 that are to use the positive electrode made in the experiment 1 and negative electrode a1 and prepare above are to make battery A8-A10.

(charge-discharge cycles test)

With experiment in 1 under the identical condition, the lithium rechargeable battery A8-A10 that makes is thus carried out the charge-discharge cycles test.Test result is listed in the table 14.In table 14, listed the result of battery A1 and B1 equally.

[table 14]

Battery	The CO of dissolving 2The amount of gas (wt.%)	Maximum discharge capacity (mAh)	After 100 circulations
					Discharge capacity (mAh)	Capacity retention rate (%)
			A1	0.37			11.17	9.89	88.5
A8	0.185	12.5			9.67	77.4
			A9	0.0925			12.3	5.85	47.6
A10	0.037	12.4			4.27	34.4
			B1	0			12.2	2.14	17.6

Can clearly be seen that by table 14, use the battery A1 and the A8-A10 that contain the nonaqueous electrolyte that has dissolved carbon dioxide, show higher than battery B1 capacity retention rate frequently.Equally as can be seen, the amount that is dissolved in the carbon dioxide in the nonaqueous electrolyte preferably is at least 0.01wt.%, more preferably is at least 0.1wt.%.

(experiment 5)

(preparation of nonaqueous electrolyte a11)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 propylene carbonate (PC) and diethyl carbonate (DEC).With the electrolyte solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturated therein.Prepare nonaqueous electrolyte a11 thus.

When identical mode was measured in 1 with experiment, the carbon dioxide dissolved amount was 0.36wt.% in the nonaqueous electrolyte.

(preparation of nonaqueous electrolyte a12-a14)

Under carbon dioxide atmosphere, vinylene carbonate (VC) added contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and diethyl carbonate (DEC), to prepare three kinds of different solvents that contain respectively based on 1%, 5% and 10% vinylene carbonate of EC and DEC total weight.Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in every kind of solvent.With each personal carbon dioxide bubbling of these electrolyte solutions so that carbon dioxide is dissolved to saturated therein.Thus, nonaqueous electrolyte a12 (containing 1wt.%VC), a13 (containing 5wt.%VC) and a14 (containing 10wt.%VC) have been prepared.

When identical mode was measured in 1 with experiment, the amount of all nonaqueous electrolyte a12-a14 carbon dioxide dissolved was 0.37wt.%.

(manufacturing of battery)

According to the step of experiment 1, the different nonaqueous electrolyte a11-a14 that as above make that are to use make battery A11-A14

(charge-discharge cycles test)

With experiment in 1 under the identical condition, the lithium rechargeable battery A11-A14 that makes is thus charged-the discharge cycle test.They are listed in the table 15 at the discharge capacity and the capacity retention rate of the 100th circulation and 300 circulations.In table 15, listed the result of battery A1 and B1 equally.

[table 15]

Battery	Solvent	Maximum discharge capacity (mAh)	The 100th circulation		The 300th circulation
							Discharge capacity (mAh)	Capacity retention rate (%)	Discharge capacity (mAh)	Capacity retention rate (%)
			A1	(there is CO in EC/DEC 2)	11.17	9.89					88.5	3.52	31.5
A11	(there is CO in PC/DEC 2)	12.57					10.55	83.9	7.77	61.8
			A12	(there is CO in EC/DEC/ VC-1wt.% 2)	12.50	9.85					78.8	6.27	50.2
A13	(there is CO in EC/DEC/ VC-5wt.% 2)	12.17					9.64	79.2	4.85	39.9
			A14	(there is CO in EC/DEC/ VC-10wt.% 2)	12.41	8.58					69.1	2.06	16.6
B1	(there is not CO in EC/DEC 2)	12.17					2.14	17.6	0.16	1.3

As can be seen from Table 15, when using, nonaqueous electrolyte contains the mixed solvent of ethylene carbonate and propylene carbonate as cyclic solvent, and when using diethyl carbonate as linear carbonate, by carbon dioxide is dissolved in nonaqueous electrolyte, the charge-discharge cycles performance that has obtained to improve improve effect.

It can also be seen that from the result of battery A12-A14,, also obtain gratifying charge-discharge cycles performance characteristic even in vinylene carbonate being added ethylene carbonate and diethyl carbonate mixed solvent the time.Be further appreciated that the amount of the vinylene carbonate that adds in mixed solvent, based on the total weight of cyclic carbonate except that the carbonic acid vinylene and linear carbonate, the 10wt.% that preferably reaches more preferably reaches 5wt.%.

(experiment 6)

(manufacturing of nonaqueous electrolyte a15-a19)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in the mixed solvent that contains volume ratio ethylene carbonate as follows (EC) and diethyl carbonate (DEC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, prepare nonaqueous electrolyte a15-a19 thus.

Nonaqueous electrolyte a15 EC: DEC=0: 10

Nonaqueous electrolyte a16 EC: DEC=1: 9

Nonaqueous electrolyte a17 EC: DEC=2: 8

Nonaqueous electrolyte a18 EC: DEC=5: 5

Nonaqueous electrolyte a19 EC: DEC=7: 3

(manufacturing of nonaqueous electrolyte a20)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 1: 9 butylene carbonate (BC) and diethyl carbonate (DEC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a20 thus.

(manufacturing of nonaqueous electrolyte a21)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 butylene carbonate (BC) and diethyl carbonate (DEC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a21 thus.

(manufacturing of nonaqueous electrolyte a22)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and dimethyl carbonate (DMC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a22 thus.

(manufacturing of nonaqueous electrolyte a23)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in and contain in the mixed solvent that volume ratio is 3: 7 ethylene carbonate (EC) and methyl ethyl carbonate (MEC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a23 thus.

(manufacturing of nonaqueous electrolyte a24)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in the mixed solvent that contains 5 weight portion vinylene carbonates (VC) and 100 weight portion diethyl carbonates (DEC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a24 thus.

(manufacturing of nonaqueous electrolyte a25)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in the mixed solvent that contains 5 weight portion vinylene carbonates (VC) and 100 weight portion dimethyl carbonates (DMC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a25 thus.

(preparation of nonaqueous electrolyte a26)

Under carbon dioxide atmosphere, with 1 mol LiPF ₆Be dissolved in the mixed solvent that contains 5 weight portion vinylene carbonates (VC) and 100 weight portion methyl ethyl carbonates (MEC).With the solution made with the carbon dioxide bubbling so that carbon dioxide is dissolved to saturatedly therein, make nonaqueous electrolyte a26 thus.

(manufacturing of battery)

According to the step of experiment 1, the different nonaqueous electrolyte a15-a26 that as above make that are to use make battery A15-A26.

(charge-discharge cycles test)

With experiment 1 different condition under, the lithium rechargeable battery A15-A26 that makes is thus carried out the charge-discharge cycles test.As pre-circulation, be each battery charge and three voltage ranges of discharge to 4.2-2.75V with the constant current of 9.1mA.Next circulation is as the circulation first of record.In circulation and subsequently circulation first, with the constant current of 9.1mA with battery charge to 4.2V.Behind further constant voltage charge (cut-off current of 0.45mA), be discharged to 2.75V with constant current.Calculate its capacity retention rate by following formula at the 200th circulation time:

Capacity retention rate (%)=(the 200th cyclic discharge capacity)/(cyclic discharge capacity first) * 100.

Measurement result is listed among the table 16-18.In table 16, also listed the result of battery A1.

[table 16]

Battery	Solvent	The capacity retention rate (%) of the 200th circulation
			A15	EC∶DEC＝0∶10	77
A16	EC∶DEC＝1∶9	76
			A17	EC∶DEC＝2∶8	70
A1	EC∶DEC＝3∶7	66
			A18	EC∶DEC＝5∶5	69
A19	EC∶DEC＝7∶3	68

Shown in table 16, when ethylene carbonate content less (0.1-20vol.%) or relatively large (50-70vol.%), the cycle performance feature slightly improves.

The excellent cycle performance feature can obtain in higher diethyl carbonate content range.This may be because higher diethyl carbonate content has improved the amount of carbon dioxide that is dissolvable in water in the solvent, and this can be from hereinafter inferring.

In the EC/DEC mixed solvent, be dissolved to saturated amount of carbon dioxide:

EC∶DEC＝1∶9 0.42wt.％

EC∶DEC＝3∶7 0.37wt.％

EC∶DEC＝5∶5 0.32wt.％

EC∶DEC＝7∶3 0.29wt.％

[table 17]

Battery	Solvent	The capacity retention rate (%) of the 200th circulation
			A20	BC∶DEC＝1∶9	74
A21	BC∶DEC＝3∶7	68
			A22	EC∶DMC＝3∶7	70
A23	EC∶MEC＝3∶7	72

Shown in table 17, when using butylene carbonate (BC), obtain the excellent cycle performance feature as cyclic carbonate.When using dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC), obtain the excellent cycle performance feature equally as cyclic carbonate.

[table 18]

Battery	Solvent	The capacity retention rate (%) of the 200th circulation
			A24	DEC/VC-5wt.％	70
A25	DMC/VC-5wt.％	82
			A26	MEC/VC-5wt.％	70

As can be seen from Table 18, when diethyl carbonate (DEC), dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC) separately with vinylene carbonate (VC) when mixing, obtained the excellent cycle performance feature equally.

(experiment 7)

(manufacturing of negative electrode)

Copper is deposited on the surface heat-resisting, rolling copper alloy foil that constitutes by zirconium-copper alloy (zirconium content is 0.03wt.%) by electrolysis, thereby provide shaggy, heat resistant copper alloy paper tinsel (having the arithmetic average roughness Ra of 0.25 μ m and the thickness of 31 μ m) as current-collector.Use electron beam deposition device shown in Figure 9 that non-crystalline silicon thin-film is deposited on this current-collector.

As shown in Figure 9, electron beam deposition device 21 comprises chamber 22, sedimentary origin 23, rotating cylinder 24, radiant heat barricade 25, flashboard 26 and vacuum extractor 27.Radiant heat barricade 25 is separated into 22 inside, chamber the chamber 22a that settles sedimentary origin 23 and is positioned at the chamber 22b that rotating cylinder 24 is settled in sedimentary origin 23 tops.Sedimentary origin 23 comprises electron gun 28, smelting furnace 29, burner hearth lining 30 and deposition materials 31.Electron gun 28 can operate with emission is enough to heat electron beam with hydatogenesis material 31.The burner hearth lining 30 that smelting furnace 29 is collected deposition materials 31 covers.The structure of rotating cylinder 24 makes it rotate along predetermined direction, and can cool off through rotating cylinder inside by making circulating water flow.Current-collector 32 is positioned on the peripheral surface of rotating cylinder 24.The radiant heat barricade of being made by stainless steel 25 is used to stop the radiant heat that produces on the sedimentary origin 23 to transfer to current-collector 32.Radiant heat barricade 25 heart therein has an opening 25a, and this opening can be closed by flashboard 26.Flashboard 26 has a stainless steel cover plate 26a, and this cover plate 26a can move to and make the complete covered position of opening 25a also close thus.

As mentioned above, use electron beam deposition device shown in Figure 9 that non-crystalline silicon thin-film is deposited on the current-collector.Chamber interior is evacuated to 1 * 10 ^-4Pa.When flashboard cuts out, shone deposition materials 10 minutes with electron beam, thereby make its hot melt and remove internal gas.Simultaneously, smelting furnace, burner hearth lining, chamber interior walls, radiant heat barricade and flashboard are exposed in the radiant heat from deposition materials, make by absorb and absorption introduce wherein for example oxygen and the impurity of moisture discharge.Then, stop the electron beam irradiation, use vacuum extractor that chamber interior is found time continuously simultaneously so that they leave standstill and heat release.

After they were fully cooled off, the film deposition conditions according to shown in the table 19 was deposited on non-crystalline silicon thin-film on the current-collector.In thin film deposition, after melting fully, deposition materials opens flashboard.

[table 19]

Deposition materials	Silicon (purity 99.999%)
		Current-collector	Shaggy heat-resisting rolling copper alloy (zirconium-copper alloy) paper tinsel
Beam power	4.7kW
		Sedimentation time	15min.
The Si film thickness	6μm

With the size of making that film on the current-collector cuts into 2.5cm * 2.5cm that is carried on.Connect negative plate subsequently, make negative electrode a27 thus.

(manufacturing of battery)

According to the step of experiment 1, different is to use the negative electrode a27 that as above makes and tests the CO that contains dissolving in 1 ₂Nonaqueous electrolyte a1 make battery A27.

According to the step of experiment 1, CO is not dissolved in different being to use the negative electrode a27 that as above makes and testing in 1 ₂Nonaqueous electrolyte b1 make battery B8.

According to the step of experiment 1, different is to use the negative electrode a27 that as above makes and tests the nonaqueous electrolyte b2 manufacturing battery B9 that contains 20wt.% vinylene carbonate (VC) in 1.

(charge-discharge cycles test)

With experiment 1 identical condition under, lithium rechargeable battery A27, the B8 and the B9 that make thus and the battery A1 that tests in 1 are carried out the charge-discharge cycles test.They list in table 20 at the discharge capacity and the capacity retention rate of the 100th circulation, 200 circulations and 300 circulation times.For each battery, the relation between circulation and the discharge capacity is listed in Figure 10.For battery B8 and B9, after 200 circulations, stop test.For battery A27 and A1, after 300 circulations, stop test.

[table 20]

Battery	Maximum discharge capacity (mAh)	The 100th circulation		The 200th circulation		The 300th circulation
								Discharge capacity (mAh)	Capacity retention rate (%)	Discharge capacity (mAh)	Capacity retention rate (%)	Discharge capacity (mAh)	Capacity retention rate (%)
		A27	11.38	9.54	83.8	8.46	74.3							7.51	66.0
A1	11.17							9.89	88.5	8.66	77.5	3.52	31.5
		B8	11.26	3.64	32.3	0.59	5.2							Experiment stops
B9	9.62							7.70	83.9	3.6	37.4	Experiment stops

From table 20 and Figure 10, can clearly be seen that, show good charging-discharge performance feature according to battery A27 of the present invention and A1.Can obviously find out to have from the comparison between battery A27 and the A1, show better charging-discharge performance feature by the film forming battery A27 of evaporation.

Table 21 has been listed the accumulated discharge capacity of each battery, and this is total discharge capacities of all circulation accumulative totals in the loop test, and table 21 has also been listed the electrode measured by micrometer before charge-discharge cycles and varied in thickness afterwards.

[table 21]

Battery	Accumulated discharge capacity (mAh)	The varied in thickness (μ m) of electrode before and after the circulation
			A27	2.711	+12
A1	2.586	+21
			B8	0.945	+57
B9	1.437	+45

From table 21, can clearly be seen that, show higher accumulated discharge capacity, and their electrode shows littler thickness increase according to battery A27 of the present invention and A1.Find out that from apparent in view between battery A27 and the A1 battery A27 with the film that forms by evaporation shows higher accumulated discharge capacity and littler thickness of electrode variation.Since the accumulated discharge capacity almost with 300 circulations in store and the lithium amount that discharges proportional, therefore certain than storage in battery A1 with discharged more lithium in battery A27.And A1 compares with battery, has suppressed better to be improved and the increase of the thickness of electrode that causes by film internal void degree in battery A27.

(manufacturings of three electrode beaker batteries)

Use negative electrode a27 and negative electrode a1 (being used for battery A1's) manufacturing three electrode beaker batteries shown in Figure 11.Place container 45 to be used as work electrode 44 negative electrode a27 or a1.To place container 45 by auxiliary electrode 46 and the reference electrode 47 that lithium metal forms.In container 45, add non-aqueous electrolytic solution 48 then to obtain beaker battery 43.Use in the experiment 1 and do not dissolve CO ₂Nonaqueous electrolyte b1 as non-aqueous electrolytic solution 48.

Use the beaker battery that makes thus to charge-discharge test.With this battery charge, reach 0V with respect to the standard electrode potential of reference electrode 47 with the constant current of 4mA, with the constant current discharge, bring up to 2.0V then until work electrode 44 electromotive forces until the electromotive force of work electrode 44.Such charge-discharge cycles is registered as a unit circulation.After 10 circulations, stop charge-discharge cycles.The maximum discharge capacity that records in these 10 times circulations divided by electrode area, obtains the maximum discharge capacity of per unit area, and this is worth further divided by film thickness, obtains the maximum discharge capacity of per unit volume.Per unit area maximum discharge capacity and the per unit volume maximum discharge capacity of each electrode a27 and a1 are listed in the table 22.

[table 22]

Battery	Maximum area discharge capacity (the mAh/cm that uses three-electrode battery to measure 2)	Maximum area discharge capacity/film thickness (per unit volume maximum discharge capacity) (mAh/cm 2μm)
			A27 (electron beam evaporation)	3.81	0.63
A1 (sputter)	3.82	0.76

Can clearly be seen that to have the electrode a27 of the film that forms by electron-beam vapor deposition method from result shown in the table 22, compare, show lower discharge capacity with electrode a1 with the film that forms by sputtering method.This is that the electrode per unit volume stores and discharged result than lithium in small amounts.Therefore, believe that electrode a27 when storing and discharge lithium, relatively is not easy to be subjected to the volume variable effect.This possible explanation the variation of the thickness of electrode before circulation and afterwards shown in the table 21 less.

Electrode 27a shows than electrode a1 better cycle ability feature.Most likely because smaller volume changes, this has reduced the appearance of non-crystalline silicon from the current-collector obscission, and has reduced the ruined possibility of stable diaphragm that forms on the non-crystalline silicon surface for this.Understand thus, the maximum discharge capacity of active material film per unit volume is preferably at 0.7mAh/cm ²Within the μ m, be dissolved in the effect of the carbon dioxide in the nonaqueous electrolyte with abundant acquisition.

Claims (27)

1. lithium rechargeable battery, comprise by making non-crystal thin film complete or that mainly constitute on current-collector, deposit negative electrode, positive electrode and the nonaqueous electrolyte that makes by silicon, it is characterized in that described nonaqueous electrolyte contains the carbon dioxide that is dissolved in wherein, and the amount that is dissolved in the carbon dioxide in the described nonaqueous electrolyte is at least 0.001wt.%.

2. lithium rechargeable battery as claimed in claim 1 is characterized in that the amount that is dissolved in the carbon dioxide in the described nonaqueous electrolyte is at least 0.01wt.%.

3. lithium rechargeable battery as claimed in claim 1 is characterized in that the amount that is dissolved in the carbon dioxide in the described nonaqueous electrolyte is at least 0.1wt.%.

4. as any one described lithium rechargeable battery among the claim 1-3, it is characterized in that the surface of described current-collector has the arithmetic average roughness Ra of at least 0.1 μ m.

5. lithium rechargeable battery as claimed in claim 1 is characterized in that described current-collector contains the heat resistant copper alloy paper tinsel.

6. lithium rechargeable battery as claimed in claim 5 is characterized in that described current-collector contains the heat resistant copper alloy paper tinsel, deposits cathode copper or copper alloy surface layer on described heat resistant copper alloy paper tinsel surface.

7. lithium rechargeable battery as claimed in claim 1 is characterized in that the described non-crystal thin film that mainly is made of silicon contains at least a in cobalt and the iron.

8. lithium rechargeable battery as claimed in claim 1 is characterized in that described nonaqueous electrolyte contains fluorochemical or LiClO ₄

9. lithium rechargeable battery as claimed in claim 8 is characterized in that described fluorochemical is LiXF _y, wherein X is P, As, Sb, B, Bi, Al, Ga or In, if X is P, As or Sb, then y is 6, and if X is B, Bi, Al, Ga or In, then y is 4; LiN (C _mF _2m+1SO ₂) (C _nF _2n+1SO ₂), wherein m and n are the integer of 1-4 independently; Or fluorine-containing lithium borate derivative.

10. lithium rechargeable battery as claimed in claim 9 is characterized in that described fluorine-containing lithium borate derivative is LiBF ₂(O _x).

11. lithium rechargeable battery as claimed in claim 1 is characterized in that described nonaqueous electrolyte contains cyclic carbonate and linear carbonate.

12. lithium rechargeable battery as claimed in claim 1, the solvent that it is characterized in that described nonaqueous electrolyte are the mixed solvents of cyclic carbonate and linear carbonate.

13., it is characterized in that containing at least a in ethylene carbonate and the propylene carbonate as described cyclic carbonate as claim 11 or 12 described lithium rechargeable batteries.

14., it is characterized in that containing diethyl carbonate as described linear carbonate as claim 11 or 12 described lithium rechargeable batteries.

15., it is characterized in that containing cyclic carbonate with unsaturated carbon bond and other cyclic carbonate except aforementioned cyclic carbonate with unsaturated carbon bond as described cyclic carbonate as claim 11 or 12 described lithium rechargeable batteries.

16. lithium rechargeable battery as claimed in claim 15 is characterized in that described cyclic carbonate with unsaturated carbon bond is a vinylene carbonate.

17., it is characterized in that when disregarding the cyclic carbonate with unsaturated carbon bond, the volume content of described cyclic carbonate is no more than 70% of cyclic carbonate and linear carbonate cumulative volume as claim 11 or 12 described lithium rechargeable batteries.

18., it is characterized in that when disregarding the cyclic carbonate with unsaturated carbon bond, the volume content of described cyclic carbonate is the 0.1-20% of cyclic carbonate and linear carbonate cumulative volume as claim 11 or 12 described lithium rechargeable batteries.

19., it is characterized in that when disregarding the cyclic carbonate with unsaturated carbon bond, the volume content of described cyclic carbonate is the 50-70% of cyclic carbonate and linear carbonate cumulative volume as claim 11 or 12 described lithium rechargeable batteries.

20. lithium rechargeable battery as claimed in claim 15 is characterized in that described weight content with cyclic carbonate of unsaturated carbon bond is the cyclic carbonate except the cyclic carbonate with unsaturated carbon bond and the 0.1-10% of linear carbonate total weight.

21. lithium rechargeable battery as claimed in claim 1 is characterized in that described non-crystal thin film forms by evaporation.

22. a manufacturing contains the method for the lithium rechargeable battery of negative electrode, positive electrode and nonaqueous electrolyte, it is characterized in that may further comprise the steps:

Make fully or the non-crystal thin film that mainly is made of silicon deposits on current-collector and prepares described negative electrode;

Carbon dioxide is dissolved in described nonaqueous electrolyte, and the amount that is dissolved in the carbon dioxide in the described nonaqueous electrolyte is at least 0.001wt.%; With

Use described negative electrode, positive electrode and nonaqueous electrolyte assembling lithium rechargeable battery.

23. the method for manufacturing lithium rechargeable battery as claimed in claim 22 is characterized in that the step that carbon dioxide is dissolved in nonaqueous electrolyte comprises the step that gaseous carbon dioxide is fed this nonaqueous electrolyte.

24., it is characterized in that the step of assembling lithium rechargeable battery is included in the step of assembling lithium rechargeable battery under the atmosphere that contains carbon dioxide as the method for claim 22 or 23 described manufacturing lithium rechargeable batteries.

25. the method for manufacturing lithium rechargeable battery as claimed in claim 22 is characterized in that described non-crystal thin film deposits by supplying with raw material from gas phase.

26. the method for manufacturing lithium rechargeable battery as claimed in claim 25 is characterized in that described non-crystal thin film is by sputter, chemical vapour deposition (CVD) or evaporation deposition.

27. the method for manufacturing lithium rechargeable battery as claimed in claim 25 is characterized in that described non-crystal thin film deposits by evaporation.

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