Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
  • H01M10/0569—Liquid materials characterised by the solvents
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
  • H01M10/0567—Liquid materials characterised by the additives
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
  • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
  • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M2004/021—Physical characteristics, e.g. porosity, surface area
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0017—Non-aqueous electrolytes
  • H01M2300/0025—Organic electrolyte
  • H01M2300/0028—Organic electrolyte characterised by the solvent
  • H01M2300/0037—Mixture of solvents
  • H01M2300/0042—Four or more solvents
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates to a non-aqueous electrolyte secondary battery.
• primary batteries such as Al-Rimang batteries
• secondary batteries such as nickel-power dome batteries and lead-acid batteries.
• non-aqueous electrolyte secondary batteries that use lithium composite oxide for the positive electrode and occlude and release lithium ion for the negative electrode are small, lightweight, have high single-cell voltage, and have high energy density. It is noticed that it is possible to obtain.
• a lithium-lithium alloy can be used instead of the carbonaceous material.
• the dissolution and precipitation of lithium are repeated, and it is desired to grow into a needle shape.
• loose dendrites are formed, and the dendrites may cause an internal short circuit by penetrating the senore.
• a negative electrode containing a carbonaceous material causes dendrite formation as compared with a negative electrode containing lithium or a lithium alloy.
• the negative electrode capacity can be made close to the theoretical capacity of 372 mAh / g, and a high-capacity lithium ion secondary battery can be realized. Is possible.
• the graphite material has high activity with respect to many of the nonaqueous electrolytes used in lithium ion secondary batteries, and desorption due to exfoliation of the material itself.
• An object of the present invention is to provide a nonaqueous electrolyte secondary battery that simultaneously satisfies initial charge / discharge efficiency, discharge capacity, and cycle characteristics.
• a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode including a carbonaceous substance capable of inserting and extracting lithium ions, and a non-aqueous electrolyte including a non-aqueous solvent.
• the non-aqueous solvent contains a sulfonate compound having at least one double bond in a ring,
• the carbonaceous material has a specific surface area Ru good to BET method 1. 5 m 2 / g or more, 1 0 m 2 / g or less, 0 in powder X-ray diffractometry. 3 3 6 nm following interplanar spacing d. .
• the peak derived from 2 appears, and in X-ray diffraction measurement using Cu- ⁇ ray, the diffraction angle 2 ⁇ becomes 42.8 ° to 44.0 ° and 45.5 ° to 46.6 °.
• a non-aqueous electrolyte secondary battery including a graphitic material whose peak is detected and whose R value measured by Raman spectrum is 0.3 or more in intensity ratio and 1 or more in area ratio is provided.
• a non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode containing a carbonaceous substance capable of inserting and extracting lithium ions, and a non-aqueous electrolyte containing a non-aqueous solvent.
• the non-aqueous solvent contains a sluton compound having at least one double bond in a ring,
• the carbonaceous material has a specific surface area Ru good to BET method 1. 5 m 2 / g or more, 1 0 m 2 / g or less, 0 in powder X-ray diffractometry. 3 3 6 nm following interplanar spacing d. Appear a peak derived from a Q 2, has a rhombohedral structure, with zeros. 3 or by that R value is an intensity ratio to a wig Ma Nsupeku preparative Le measurements, graphite is one or more in area ratio A non-aqueous electrolyte secondary battery including the material is provided.
• FIG. 1 is a perspective view showing a thin non-aqueous electrolyte secondary battery which is an example of the non-aqueous electrolyte secondary battery according to the present invention.
• FIG. 2 is a partial cross-sectional view of the thin nonaqueous electrolyte secondary battery of FIG. 1 taken along the line II-II.
• FIG. 3 is a partial cross-sectional view showing a cylindrical nonaqueous electrolyte secondary battery which is an example of the nonaqueous electrolyte secondary battery according to the present invention.
• FIG. 4 is a schematic diagram showing a diffraction pattern obtained by X-ray diffraction measurement using a Cu u ⁇ ray on the graphite material of the nonaqueous electrolyte secondary battery of Example 1.
• FIG. 5 is a characteristic diagram showing the 1H NMR spectrum of the PRS included in the nonaqueous electrolyte of the nonaqueous electrolyte secondary battery of Example 1.
• the non-aqueous electrolyte secondary battery includes a container, an electrode group housed in the container and including a positive electrode and a negative electrode, and a non-aqueous electrolyte held by the electrode group and including a non-aqueous solvent. It is.
• the non-aqueous solvent contains a sulfonate compound having at least one double bond in a ring, and a specific surface area of the carbonaceous material measured by the BET method is 1.5 m 2 / g. As mentioned above, it is within the range of 10 m 2 / g or less.
• Sulfon compounds having at least one double bond in the ring can form a protective film on the surface of the carbonaceous material.
• the specific surface area of the carbonaceous material by the BET method to be 1.5 m 2 / g or more and 1 O m 2 / g or less, it is formed on the surface of the carbonaceous material.
• the uniformity of the distribution of the protective film can be improved, and the inhibition of the lithium-intercalation reaction related to charging and discharging by the protective film can be suppressed.
• a non-aqueous electrolyte secondary battery that simultaneously satisfies discharge capacity and cycle characteristics can be provided.
• the electrode group the positive electrode, the negative electrode, the separator, the nonaqueous electrolyte, and the container will be described.
• This electrode group may be formed, for example, by (i) winding a positive electrode and a negative electrode in a flat shape or a spiral shape with a separator interposed therebetween, or (ii) interposing a separator between the positive electrode and the negative electrode. (Iii) bending the positive and negative electrodes one or more times with a separator between them, or (iv) separating the positive and negative electrodes from each other. Meanwhile through the separator It is manufactured by the method of laminating while existing.
• the electrode group may not be pressurized, but may be pressurized in order to increase the integration strength of the positive electrode, the negative electrode, and the sensor. It is also possible to apply heating during pressing.
• the positive electrode includes a current collector and a positive electrode layer that is supported on one or both surfaces of the current collector and contains an active material.
• the positive electrode layer includes a positive electrode active material, a binder, and a conductive agent.
• the positive electrode active material include various oxides such as manganese dioxide, lithium manganese composite oxide, lithium-containing nickel oxide, lithium-containing cobalt oxide, and lithium-containing cobalt oxide.
• Nickel cobalt oxide containing lithium, iron oxide containing lithium, vanadium oxide containing lithium, chalcogen compounds such as titanium disulfide, molybdenum disulfide, etc. be able to.
• lithium cobalt oxide eg, LiCoO 2
• lithium nickel cobalt oxide eg, LiNi 0.8 Co 0.
• Li Ji U Muma Nga down composite oxide for example, L i when M n 2 ⁇ 4, L i M n O 2
• Ru use Rere and arbitrarily preferred for high voltage.
• the positive electrode active material one kind of oxide may be used alone, or two or more kinds of oxides may be mixed and used.
• Examples of the conductive agent include acetylene black, carbon black, and graphite.
• the binder has a function of holding the active material on the current collector and connecting the active materials.
• the binder for example, poly Tetra phenolic ethylene (PTFE), polyolefin vinylidene (PVdF), polyethersanolone, ethylene-propylene copolymer (EPDM), styrene It is possible to use monobutadiene rubber (SBR).
• PTFE Tetra phenolic ethylene
• PVdF polyolefin vinylidene
• EPDM ethylene-propylene copolymer
• SBR monobutadiene rubber
• the mixing ratio of the positive electrode active material, the conductive agent and the binder is set in the range of 80 to 95% by weight of the positive electrode active material, 3 to 20% by weight of the conductive agent, and 2 to 7% by weight of the binder. Is preferred.
• a conductive substrate having a porous structure or a non-porous conductive substrate can be used as the current collector.
• These conductive substrates can be formed from, for example, aluminum, stainless steel, or nickel silicate.
• the positive electrode is manufactured, for example, by suspending a conductive agent and a binder in a suitable solvent in a positive electrode active material, applying the suspension to a current collector, drying and pressing. .
• the negative electrode includes a current collector and a negative electrode layer supported on one or both surfaces of the current collector.
• the negative electrode layer contains a carbonaceous substance that occludes and releases lithium ions and a binder.
• the specific surface area of the carbonaceous material measured by the BET method is in the range of 1.5 m 2 / g or more and 1 O m 2 / g or less. In other words, if the specific surface area is less than 1.5 m 2 / g, the protective film derived from the sulfur compound will act as a resistance component against the lithium intercalation reaction, so that the secondary battery , The discharge capacity decreases. On the other hand, when the specific surface area exceeds 10 m 2 / g, the uniformity of As a result, the initial charge / discharge efficiency, discharge capacity, and charge / discharge cycle life of the secondary battery decrease.
• the protective film made of the cyclic sulfur compound can be made uniform and thin. It is possible to efficiently perform lithium intercalation while suppressing side reactions caused by contact between the nonaqueous electrolyte and the negative electrode active material.
• a more preferable range of the specific surface area is 1.5 to 10 m 2 / g, and a more preferable range is 1.5 to 6 m 2 / g.
• the carbonaceous material has an interplanar spacing d of 0.336 nm or less in powder X-ray diffraction measurement. .
• a peak derived from 2 appears. That is, according to the carbonaceous substance in which no peak derived from the interplanar spacing dQQ2 of 0.336 nm or less is detected in the powder X-ray diffraction measurement, the decomposition reaction of the non-aqueous solvent other than the sulfonic acid compound is caused. As a result, the discharge capacity or cycle life may be reduced.
• a plane spacing d of 0.336 nm or less. .
• the carbonaceous material showing the peak derived from 2 can narrow the decomposition potential width of the sluton compound, the sluton compound is selectively decomposed at the first charge to form a protective film. In addition to this, it is possible to increase the rate of the protective film formation reaction by the sulfuron compound. As a result, the charge / discharge cycle life of the secondary battery can be further improved. Further, it is preferable that the lower limit value of the interplanar spacing d 002 is set to the interplanar spacing d 002 of the ( 002 ) plane in perfect graphite crystal, that is, 0.3354 nm. Note that the carbonaceous material, 0.3 3 exceeds 6 nm interplanar spacing d 0.
• a peak derived from 2 may be detected.
• peaks were detected at diffraction angles of 26 and 42.8 ° to 44.0 ° and 45.5 ° to 46.6 ° in X-ray diffraction measurement using Cu K rays. It is desirable to be done. Since such a carbonaceous material has a rhombohedral structure, the decomposition potential width of the sluton compound can be narrowed, and the decomposition reaction of a solvent other than the sluton compound is suppressed. This makes it possible to further improve the cycle life of the secondary battery.
• the carbonaceous material with peaks derived from (2) enhances the effect of promoting the formation of a protective film derived from the sulfuric acid compound and the effect of suppressing the decomposition reaction of non-aqueous solvents other than the sulfuric acid compound. As a result, the initial charge / discharge efficiency and discharge capacity of the secondary battery can be further improved.
• a peak derived from 2 or (b) a rhombohedral structure, or a carbonaceous material satisfying both the conditions (a) and (b) Natural graphite that satisfies at least one of the conditions (b) and (b) can be used.
• such a carbonaceous material is subjected to heat treatment at 280 to 300 ° C., for example, to a cox, a pitch, a thermosetting resin, or to a natural graphite. It can be obtained by adding a substance, pitch, thermosetting resin, etc. and subjecting them to a heat treatment.
• the R value measured by Raman spectrum is the intensity ratio.
• the ratio be 0.3 or more and the area ratio be 1 or more.
• Such carbonaceous materials can have a low crystalline structure on some or all of the surface while maintaining the specific surface area and the internal graphitic structure.
• the decomposition reaction of propylene carbonate (PC) can be suppressed, so that the initial charge and discharge efficiency when using a non-aqueous solvent containing PC can be improved, and the discharge capacity can be improved.
• Rechargeable batteries that have both excellent battery life and total cycle life.In addition, if the strength ratio becomes larger than 1.5 and the area ratio becomes larger than 4.0.
• the ratio of the low crystalline structure region in the carbonaceous material is increased, a decomposition reaction of a solvent other than the sultone compound may be accelerated. Therefore, it is desirable to set the upper limit of the intensity ratio to 1.5 and the upper limit of the area ratio to 4.0.
• a more preferable range of the intensity ratio is 0.3 to 1.5, and a more preferable range of the area ratio is 1.0 to 3.0.
• a carbonaceous material whose R value by Raman spectrum measurement is 0.3 or more in intensity ratio and 1 or more in area ratio is produced, for example, by the method described below. That is, natural graphite is mixed with a carbonaceous material such as coke, pitch thermosetting resin or a carbon precursor, and is mixed with a graphite material which is liquid or pulverized and pulverized and then molded. It can be obtained by performing a heat treatment at a temperature of 2500 ° C. or less in an inert atmosphere. Alternatively, a material obtained by performing chemical vapor deposition using benzene, toluene, or the like on a graphitic material to deposit a low-crystalline carbon layer on the surface may be used.
• binder examples include polytetrafluoroethylene (PTFE), polyolefin bilidene (PVdF), ethylene-propylene-gene, and the like.
• PTFE polytetrafluoroethylene
• PVdF polyolefin bilidene
• EPDM styrene One-butadiene rubber
• CMC canoleboximetinolosenorreose
• the mixing ratio of the carbonaceous material and the binder is preferably in the range of 90 to 98% by weight of the carbonaceous material and 2 to 20% by weight / 0 of the binder.
• a conductive substrate having a porous structure or a non-porous conductive substrate can be used as the current collector.
• These conductive substrates can be formed from, for example, copper, stainless steel, or nickel.
• a carbonaceous substance that occludes and releases lithium ion and a binder are kneaded in the presence of a solvent, and the resulting suspension is applied to a current collector, dried, and then dried. It is produced by pressing once or two to five times at multiple pressures.
• a microporous membrane, a woven fabric, a nonwoven fabric, a laminate of the same or different materials, or the like can be used.
• the material for forming the separator include polyethylene propylene, ethylene-propylene copolymer, ethylene butene copolymer, and the like. You.
• the material for forming the separator one or two or more kinds selected from the above-mentioned types can be used.
• the thickness of the separator is preferably 30 / xm or less, more preferably, 25 zm or less.
• the lower limit of the thickness is preferably set to 5 ⁇ m, and the more preferable lower limit is 8 ⁇ m. It is preferable that the sensor has a heat shrinkage of not more than 20% at 120 ° C. for one hour. The heat shrinkage is preferably 15% or less, more preferably than the force S.
• the porosity of the senor is in the range of 30 to 60%.
• a more preferred range of porosity is between 35 and 50%.
• the separator has an air permeability of 600 seconds / 100 cm 3 or less.
• Air permeability refers to the time (seconds) required for 100 cm 3 of air to pass through the separator. More preferably, the upper limit of the air permeability is 500 seconds / 100 cm 3 .
• the lower limit of the air permeability is preferably set to 50 seconds / 100 cm 3 , and the more preferable lower limit is 80 seconds / 100 cm 3 .
• the width of the separator be wider than the width of the positive and negative electrodes. With such a configuration, it is possible to prevent the positive electrode and the negative electrode from directly contacting each other without passing through the separator.
• non-aqueous electrolyte those having a substantially liquid or gel-like form can be used.
• the gel non-aqueous electrolyte can reduce the possibility that the non-aqueous electrolyte leaks to the outside when the container is damaged by some external force.
• liquid non-aqueous electrolytes can have higher ion conductivity than gelled non-aqueous electrolytes, so that the capacity when discharging a non-aqueous electrolyte secondary battery with a large current and the low temperature The capacity at the time of discharging can be improved.
• the non-aqueous electrolyte is prepared, for example, by the methods described in the following (I) to (VI).
• a non-aqueous electrolyte is obtained by dissolving an electrolyte (for example, a lithium salt) in the above-mentioned non-aqueous solvent (liquid non-aqueous electrolyte).
• an electrolyte for example, a lithium salt
• (II) Dissolve the organic polymer compound and the lithium salt in a solvent to prepare a polymer solution.
• the polymer solution is applied or impregnated to the electrode (at least one of the positive electrode and the negative electrode), the separator, or both the electrode and the separator, and the solvent is evaporated to be cast.
• an electrode group is obtained by interposing a separator between the positive electrode and the negative electrode. This is accommodated in a container, and a non-aqueous electrolyte is injected and held on the cast polymer membrane, whereby a secondary battery having a gel non-aqueous electrolyte is obtained.
• a cross-linked polymer may be used instead of the organic polymer compound.
• a cross-linked polymer may be used instead of the organic polymer compound.
• a prepolymer solution is prepared from a compound having a crosslinkable functional group, a lithium salt, and a solvent, and the solution is prepared by using an electrode (at least one of the positive electrode and the negative electrode) or a seno. After coating or impregnating on the separator or on both the electrode and the separator, the compound having a crosslinkable functional group is crosslinked. Next, an electrode group is obtained by interposing a separator between the positive electrode and the negative electrode.
• the cross-linking step may be performed before or after the solvent is volatilized. When the cross-linking is performed by heating, the cross-linking may be performed while evaporating the solvent.
• (b) apply the prepolymer solution to an electrode (at least one of the positive electrode and the negative electrode), a separator, or an electrode and a separator. After coating or impregnating both of the separators, a positive electrode and a negative electrode are interposed between them to obtain an electrode group with a separator interposed therebetween. After that, it is possible to carry out a cross-linking process.
• the method of crosslinking is not particularly limited, but heat polymerization or photopolymerization by ultraviolet rays is preferred in view of the simplicity of the apparatus and the cost.
• cross-linking is performed by heating or irradiation with ultraviolet light, it is necessary to add a polymerization initiator suitable for the polymerization method to the prepolymer solution.
• the polymerization initiator is not limited to one kind, and two or more kinds may be used as a mixture.
• a secondary battery comprising a gelled non-aqueous electrolyte is obtained.
• a crosslinked polymer can be used instead of the organic polymer compound.
• a pregel solution is prepared from a compound having a bridging functional group, a lithium salt, and an electrolytic solution, and this is used as an electrode (at least one of the positive electrode and the negative electrode), a separator, Alternatively, after coating or impregnating both the electrode and the separator, the compound having a crosslinkable functional group is crosslinked. This cross-linking step may be performed before or after the production of the electrode group.
• the method of crosslinking is not particularly limited, but considering the simplicity of the apparatus and the cost, the polymerization by heat or ultraviolet light is considered. Is preferred.
• crosslinking is performed by heating or irradiation with ultraviolet rays, it is necessary to add a polymerization initiator suitable for the polymerization method to the pregel solution.
• the polymerization initiator is not limited to one kind, and two or more kinds may be used in combination.
• organic polymer compound in (II) and (IV) described above examples include, for example, a polymer having a skeleton of an alkylene oxide such as polyethylene oxide or polypropylene oxide or a derivative thereof; Vinylidene fluoride, 6 futsuidani propylene, 4 futihiethylene, no.
• prepolymer solutions (III) and pregel solutions (V) can be prepared from monomers and oligomers that are precursors of these polymers.
• the present invention is characterized in that the above-mentioned electrolyte contains a sulfur compound having at least one double bond in the ring.
• the sultone compound having at least one double bond in the ring may be a snorethone compound A represented by the following general formula 1 or a sultone compound A: Sulfon compound B in which at least one H of sulfon compound A is substituted with a hydrocarbon group can be used.
• the sulfone compound A or the snorretone compound B may be used alone, or both the sulfone compound A and the sulfone compound B may be used.
• C m H n is a linear hydrocarbon group
• m and n are integers of 2 or more that satisfy 2 m> n.
• snorethone compounds having a double bond in the ring open the double bond during the reduction reaction with the negative electrode, causing a polymerization reaction, and without causing gas generation, a dense protective film on the negative electrode surface Can be formed. At this time, if EC and PC are present, it is possible to form a dense protective film having excellent lithium ion permeability.
• the protective coating derived from these compounds has the highest effect of suppressing side reactions due to contact between Li + in the graphite material and the non-aqueous electrolyte.
• 1,3—Proprous Tolutone (PRS) or 1,4-Plethylene Sultone (BTS) can be used alone or in combination. You may.
• the ratio of the sultone compound be 10% by weight or less. This is because, when the ratio of the sluton compound exceeds 10% by weight, the lithium ion permeability of the protective film decreases, the impedance of the negative electrode increases, and sufficient capacity and charge / discharge efficiency can be obtained. May not be available. Furthermore, in order to maintain the design capacity of the electrode and to keep the initial charge / discharge efficiency high, it is desirable that the ratio of the sluton compound be 4% by weight or less. In addition, in order to sufficiently secure the formation amount of the protective film, it is desirable to secure at least 0.01% by weight of the ratio of the sulfur compound. Further, if the ratio of the sultone compound is 0.1% by weight or more, the protective function such as suppressing gas generation at the time of the first charge by the protective film can be made sufficient. You.
• the non-aqueous solvent preferably contains another solvent in addition to the slutone compound.
• Other solvents include, for example, cyclic carbonates such as ethylene carbonate (EC) and propylene carbonate (PC), chain carbonates (e.g., Chinole Chinore Carbonate (MEC), Getinore Carbonate (DEC), Dimethyl Carbonate (DMC) ⁇ , ⁇ -butyrolactone (GBL), Vinylene Carbonate (VC), Vininole Carbonate (VEC), phenylethylene force-ponate (phEC), V-inlet rattan (VL), methyl propionate (MP), ethyl propionate (EP), 2-Methynolefuran (2 Me-F), Fran (F), Tiophen (TIOP), Katecole Carbonate (CATC), Echilensanoleitate (ES), 1 2 — Crown 4 (Terown), Tetra ethylene glycol resin regimen (Ether), and the like.
• Other solvent types can
• vinylene carbonate can increase the denseness of the protective film without greatly reducing the lithium ion permeability of the carbonaceous material, so that the initial charge / discharge efficiency, discharge capacity, and cycle The tool life and the life can be further improved.
• Non-aqueous solvents 1 0 by weight 0/0 following this and is desired arbitrary to within the range.
• the weight ratio of vinylene carbonate is 10 weight. If the ratio is more than / 0 , the lithium ion permeability of the protective film on the negative electrode surface is reduced, and the initial charge / discharge efficiency, discharge capacity, or cycle life may be significantly impaired. It is.
• a further preferred range of the weight ratio of vinylene carbonate is 0.01 to 5% by weight.
• a preferred composition of the non-aqueous solvent includes (I) a cyclic carbonate and ⁇ -butyric acid. Lorataton (GBL) and snoreton compounds A non-aqueous solvent containing (11) EC, a chain carbonate containing at least MEC, and a sluton compound;
• the cyclic carbonate of the non-aqueous solvent (I) preferably contains EC, and more preferably contains PC in addition to EC. According to the nonaqueous solvent (I), the high-temperature storage characteristics and cycle life of the secondary battery can be further improved.
• vinylene carbonate (VC) is added to this non-aqueous solvent (I)
• the low-temperature discharge characteristics of the secondary battery can be improved
• the chain carbonate of the non-aqueous solvent (II) can be improved.
• methyl carbonate (MEC) is contained as an essential component, and MEC alone may be used as a chain carbonate, or another chain carbonate may be used in combination with MEC. According to the non-aqueous solvent (II), gas generation during initial charging can be suppressed, and the low-temperature discharge characteristics and cycle life can be improved.
• chain carbonates used in combination with MEC desirably have a low freezing point and a low viscosity. Further, a solvent having a relatively small molecular weight is desirable. This is because the discharge characteristics at low temperatures become better.
• a chained carbonates at least one of Jetilka-Polynate (DEC) and Dimethylcarbonate (DMC) is preferred.
• DEC Jetilka-Polynate
• DMC Dimethylcarbonate
• a chain car containing MEC and DEC is used from the viewpoint of obtaining excellent charge / discharge cycle characteristics.
• a boat is preferred, while a chain carbonate containing MEC and DMC is desirable from the viewpoint of obtaining excellent low-temperature discharge characteristics.
• the non-aqueous solvent (ill) can reduce the amount of gas generated during the initial charging of the secondary battery, and at the same time, can improve the high-temperature storage characteristics.
• vinylene carbonate (VC) is further added to the non-aqueous solvent (II)
• the high-temperature storage characteristics of the secondary battery can be further improved.
• the non-aqueous solvent (IV) can suppress the amount of gas generated at the time of the first charge, and can also improve the initial charge / discharge efficiency. If vinylene carbonate (VC) is further added to the non-aqueous solvent (IV), the initial charge / discharge efficiency can be further improved.
• Is the electrolyte to be dissolved in the nonaqueous solvent for example, perchlorate Li Ji U beam (L i C 1 0 4) , six full Tsu reduction-phosphate Li Ji U beam (L i PF 6), four full Tsuihiho c acid Li Ji U beam (L i BF 4), six full Tsu arsenic Li Ji U beam (L i A s F 6) , Application Benefits Furuo b meth scan Noreho phosphate Li Ji U beam (L i CF 3 SO 3), bi be sampled Li full O b menu Chirusu sulfo Ninorei Mi drill Ji U beam [(L i N (CF 3 SO 2) 2], L i N (C 2 F 5 SO 2) 2 Lithium salts can be mentioned, etc.
• the type of electrolyte used can be one, two or more.
• those with Li PF 6 are preferably those containing Li BF 4.
• (L i N (CF ⁇ SO 2 ) 2 and L i N (C F 5 SO 2 ) 2 containing at least one of the imido salts and i BF 4 and / or L i PF 6 at least one of the salts or mixed salts a there have in the use of mixed salt B containing L i BF 4 and L i PF 6, Ru can and this to improve Ri by the cycle life at high temperatures.
• the thermal stability of the electrolyte is improved, it is possible to suppress a voltage drop due to self-discharge during storage in a high-temperature environment.
• the amount of the electrolyte dissolved in the non-aqueous solvent is desirably 0.5 to 25 mol / L. A more preferred range is 1 to 2.5 monoles / L.
• the liquid non-aqueous electrolyte contains a surfactant such as trioctyl phosphate (TOP) in order to improve the wettability with the separator.
• a surfactant such as trioctyl phosphate (TOP)
• TOP trioctyl phosphate
• the addition amount of the surfactant is preferably 3% or less, and more preferably 0.1 to 1%.
• the amount of the liquid non-aqueous electrolyte is 0.2 to 0.6 g per 100 mAh of battery unit capacity.
• a more preferred range for the mass of the liquid non-aqueous electrolyte is from 0.25 to 0.55 g / 100 mAh.
• the shape of the container can be, for example, a cylindrical shape with a bottom, a rectangular tube with a bottom, a bag-like cup shape, or the like.
• This container can be formed, for example, from a sheet including a resin layer, a metal plate, a metal finolem, or the like.
• the resin layer contained in the sheet is, for example, a polyolefin. It can be composed of polyamides.
• the metal plate and the metal fin can be formed, for example, of iron, stainless steel, and anolem metal.
• the thickness of the container should be less than 0.3 mm. This is a force that makes it difficult to obtain high weight energy density and volume energy density when the thickness force is more than 0.3 mm.
• a preferred range for the thickness of the container is less than 0.25 in, a more preferred range is less than 0.15 mm, and a most preferred range is less than 0.12 mm.
• the thickness force is smaller than SO 0.05 mm, the container is liable to be deformed or damaged. Therefore, the lower limit of the thickness of the container is preferably set to. 0.05 mm.
• a thin lithium secondary battery and a cylindrical lithium secondary battery which are examples of the nonaqueous electrolyte secondary battery according to the present invention, will be described in detail with reference to FIGS.
• FIG. 1 is a perspective view showing a thin lithium ion secondary battery which is an example of the nonaqueous electrolyte secondary battery according to the present invention
• FIG. 2 is an enlarged sectional view of a main part of the nonaqueous electrolyte secondary battery shown in FIG.
• FIG. 3 is a partially cutaway perspective view showing a cylindrical non-aqueous electrolyte secondary battery which is an example of the non-aqueous electrolyte secondary battery according to the present invention.
• an electrode group 2 is accommodated in a container body 1 having a long box-shaped cup shape.
• the electrode group 2 has a structure in which a laminate including the positive electrode 3, the negative electrode 4, and the separator 5 disposed between the positive electrode 3 and the negative electrode 4 is wound into a flat shape.
• Non-aqueous electrolysis The quality is retained in electrode group 2.
• a part of the edge of the container body 1 is wide and functions as a cover plate 6.
• the container body 1 and the lid plate 6 are each composed of a laminate finolem force.
• This laminated film includes an outer protective layer 7, an inner protective layer 8 containing a thermoplastic resin, and a metal layer 9 disposed between the outer protective layer 7 and the inner protective layer 8.
• a lid 6 is fixed to the container body 1 by a heat seal using the thermoplastic resin of the inner protective layer 8, whereby the electrode group 2 is sealed in the container.
• a positive electrode tab 10 is connected to the positive electrode 3, and a negative electrode tab 11 is connected to the negative electrode 4.
• Each of the negative electrodes 4 is drawn out of the container and serves as a positive electrode terminal and a negative electrode terminal.
• a cylindrical container 21 made of stainless steel and having a bottom has an insulator 22 disposed at the bottom.
• the electrode group 23 is housed in the container 21.
• the electrode group 23 includes: a positive electrode 24; Lator 2
• a belt-like material in which the negative electrode 26 and the separator 25 are laminated is wound in a spiral shape so that the separator 25 is located outside.
• the container 21 contains a non-aqueous electrolyte.
• the insulating paper 27 having an opening at the center is provided with the electrode group in the container 21.
• the insulating sealing plate 28 is the container
• the sealing plate 28 is disposed at the upper opening of the container 2 and the vicinity of the upper opening is caulked inward, whereby the sealing plate 28 is
• the positive electrode terminal 29 is the insulating sealing plate 28 It is fitted in the center of One end of the positive electrode lead 30 is connected to the positive electrode 24, and the other end is connected to the positive electrode terminal 29.
• the negative electrode 26 is connected to the container 21 serving as a negative electrode terminal via a negative electrode lead (not shown).
• the non-aqueous electrolyte secondary battery according to the present invention described above has a non-aqueous electrolyte including a positive electrode, a negative electrode including a carbonaceous substance capable of inserting and extracting lithium ions, and a non-aqueous electrolyte including a non-aqueous solvent.
• Rechargeable battery a non-aqueous electrolyte including a positive electrode, a negative electrode including a carbonaceous substance capable of inserting and extracting lithium ions, and a non-aqueous electrolyte including a non-aqueous solvent.
• the non-aqueous solvent contains a sulfonate compound having at least one double bond in a ring, and a specific surface area of the carbonaceous material measured by a BET method is 1.5 m 2 / g. As described above, the characteristic is within the range of 10 m 2 / g or less.
• the interplanar spacing d of 0.336 nm or less in powder X-ray diffraction measurement. . 2 or a diffraction angle 20 in the X-ray diffraction measurement using the CuKa line S 42.8 ° to 44.0 ° and 45.5 ° and 45.5 ° — 46.6 ° peaks can promote the decomposition reaction of sultone compounds, so that a protective film can be formed while suppressing side reactions with coexisting solvents. it can. Therefore, the initial charge / discharge efficiency and discharge capacity of the secondary battery can be further improved.
• the R value measured by the Raman spectrum By setting the ratio to 0.3 or more and the area ratio to 1.0 or more, it is possible to suppress the decomposition reaction of a solvent (particularly, propylene carbonate) other than the sulfuric acid compound.
• the initial charging and discharging efficiency of the secondary battery can be further improved.
• the carbonaceous material has a specific surface area of not less than 1.5 m 2 / g and not more than 10 m 2 / g, and a plane distance d of not more than 0.336 nm in powder X-ray diffraction measurement. .
• the peak derived from No. 2 appears, and the R value by Raman spectrum measurement is 0.3 or more in intensity ratio and 1 or more in area ratio, and X using Cu K line Peaks are detected at 2 diffraction angles of 42.8 ° to 44.0 ° and 45.5 ° to 46.6 ° in X-ray diffraction measurement or graphite material with rhombohedral structure
• the charge / discharge cycle life of the secondary battery can be further improved.
• the graphite material having the plane spacing, the specific surface area and the R value in the above-mentioned range, and having the above-mentioned diffraction peak or rhombohedral structure preferentially reacts with the sulfonate compound to form a lithium on the negative electrode surface.
• the protective film can be formed uniformly without impairing the umion permeability. Since the reaction with the sulfur compound occurs preferentially and a dense protective film is formed from the first charge, the decomposition reaction of cyclic carbonate such as PC can be suppressed. As a result, the amount of gas generated at the time of the first charge can be reduced. As a result, the initial charge / discharge efficiency can be increased, so that the discharge capacity and the charge / discharge cycle life can be further improved.
• Lithium cobalt oxide (L i x C o 0 2 ; and ⁇ , X is 0 rather X ⁇ 1) to the powder 9 0 wt 0/0, and acetyl Renbura click 5 weight 0/0, polyunsaturated Kka vinylene Li Den (PV d F) 5 wt 0/0 was added a dimethyl Chirufuorumua mi de (DMF) solution were mixed to prepare a scan la rie. The slurry is applied to both sides of a current collector made of an aluminum foil having a thickness of S i 5 / m, dried, and pressed to collect the positive electrode layer. A positive electrode having a structure supported on both sides of the body was produced. The thickness of the positive electrode layer was 60 ⁇ m per side.
• FIG. 4 shows the results of X-ray diffraction measurement of the graphite material used in Example 1 using Cu ⁇ ⁇ ⁇ ⁇ rays.
• the plane distance d of the (002) plane is a value obtained from the powder X-ray diffraction spectrum by the half-width width midpoint method. At this time, scattering correction such as Lorentz scattering was not performed.
• a product name “Cancer Sorb” manufactured by Weursa Ionics was used as a measuring device.
• the sample amount was set to around 0.5 g, and the sample was degassed at 120 ° C for 15 minutes as a pretreatment.
• Graphitic material Nirre, La Ma Nsupeku preparative Le hands perform peak separation
• D Graphene graphite carbon Peak derived from structural disorder
• G Amorphous carbon
• the peaks derived from the fight structure were obtained. The intensity of each peak was calculated, and the sum of the intensities of the peaks derived from the D band was obtained.The ID and the intensity of the peak derived from the G band were obtained.
• a separator made of a microporous polyethylene film with a thickness of 25 m was prepared.
• EC ethylene carbonate
• GBL ⁇ _petit mouth rattan
• PRS Le tons
• VC Nkabone capital
• TOP door re-octene Chirufu O scan off E over bets the (TOP) 0 5
• a non-aqueous solvent was prepared by adding the weight ° / 0 .
• a positive electrode lead made of a strip of aluminum foil (100 ⁇ m in thickness) is ultrasonically welded to the current collector of the positive electrode, and a strip of nickel foil (thickness) is formed on the current collector of the negative electrode.
• the negative electrode lead made of ⁇ ⁇ ) is ultrasonically welded, the positive electrode and the negative electrode are spirally wound therebetween through the separator, and then formed into a flat shape. Then, an electrode group was prepared.
• a 100- jum-thick laminating finolem with both sides of an aluminum foil covered with polyethylene is rectangular-shaped by a press machine.
• the electrode group was housed in the obtained container.
• the electrode group in the container was subjected to vacuum drying at 80 ° C. for 12 hours to remove water contained in the electrode group and the laminate.
• the liquid non-aqueous electrolyte was injected into the electrode group in the container so that the amount per battery capacity of 1 Ah was 4.8 g, and sealed with a heat seal.
• a thin non-aqueous electrolyte secondary battery with the structure shown in 1 and 2, having a thickness of 3.6 mm, a width of 35 mm, a height of 62 mm, and a nominal capacity of 0.65 Ah. Assembled.
• the following treatment was performed on this nonaqueous electrolyte secondary battery as the first charge / discharge step.
• 1 C is the current required to discharge the nominal capacity (Ah) in one hour.
• 0.2 C is the current required to discharge the nominal capacity (A h) in 5 hours.
• a thin non-aqueous electrolyte secondary battery was manufactured in the same manner as described in Example 1 above. Manufactured.
• a negative electrode was manufactured in the same manner as described in Example 1 except that such a graphitic material was used.
• a liquid nonaqueous electrolyte was prepared by dissolving it to 1 mol / L.
• a thin nonaqueous electrolyte secondary battery was manufactured in the same manner as described in Example 1 except that the obtained negative electrode and the nonaqueous electrolyte were used.
• a liquid non-aqueous electrolyte was prepared in the same manner as described in Example 6 described above.
• a thin nonaqueous electrolyte secondary battery was manufactured in the same manner as described in Example 1 except that the obtained negative electrode and the nonaqueous electrolyte were used. ⁇
• a negative electrode was produced in the same manner as described in Example 1 except that such a graphitic material was used.
• a liquid nonaqueous electrolyte was prepared in the same manner as described in Example 6 described above.
• a thin nonaqueous electrolyte secondary battery was manufactured in the same manner as described in Example 1 except that the obtained negative electrode and the nonaqueous electrolyte were used.
• the thin non-aqueous electrolyte was prepared in the same manner as described in Example 1 except that the parameters of the graphite material and the composition of the non-aqueous electrolyte were set as shown in Table 1 below. Secondary batteries were manufactured. The graphitic materials used in Examples 9 to 11 were produced by the methods described below.
• Example 9 a graphite material was obtained by pitch coating natural graphite similar to that described in Example 1 and then firing at 150 ° C.
• Example 10 in the powder X-ray diffraction, a peak derived from the ( 002 ) plane spacing (d 002 ) force of SO.33656 nm was detected in the powder X-ray diffraction. were prepared natural graphite peaks appear in the diffraction angle 2 0 force S 4 3. 3 5 ° at a linear diffraction measurement (P 4) and 4 6. 1 9 ° (P 5).
• Example 11 natural graphite similar to that described in Example 10 was spheroidized, then pitch-coated, and fired at 100 ° C. to obtain a graphitic material.
• a negative electrode was produced in the same manner as described in Example 1 except that such artificial graphite was used.
• EC ethylene carbonate
• MEC methyl carbonate
• PRS 1,3-prosone nortone
• VC vinylene carbonate
• a non-aqueous solvent was prepared.
• a liquid non-aqueous electrolyte was prepared by dissolving lithium phosphate (LiPF6) in the obtained non-aqueous solvent so as to have a concentration of 1 mol / L. did.
• a thin non-aqueous electrolyte secondary battery was manufactured in the same manner as described in Example 1 except that the obtained negative electrode and the non-aqueous electrolyte were used.
• a thin non-aqueous electrolyte secondary battery having the same configuration as that described in Comparative Example 1 was manufactured except that the specific surface area of the carbonaceous material by the BET method was changed as shown in Table 2 below. did.
• a negative electrode was fabricated in the same manner as described in Example 1 described above, and this anode was used to fabricate a negative electrode in the same manner as described in Example 1 described above.
• a thin non-aqueous electrolyte secondary battery with a simple configuration was manufactured.
• the secondary batteries of Comparative Examples 1 to 3 using a carbonaceous material having a specific surface area of less than 1.5 m2 / g by the BET method have both a discharge capacity and a capacity retention rate during 300 cycles.
• the charge-discharge reaction could not be performed.
• the secondary battery of Comparative Example 4 had a high capacity retention rate during 300 cycles, but had a low discharge capacity.
• the secondary batteries of Examples 1 to 5 and 9 to 11 had a high capacity retention rate of 90% or more in 50 cycles, whereas the secondary batteries of Examples 6 to 8 had a capacity retention rate of 90% or more.
• the capacity retention rate during 0 cycles was less than 90%. The main causes are explained below.
• the Ar concentration was 99.9% or more and the dew point was 1-5.
• the electrode group was taken out by disassembly in a glove box below 0 ° C. Packed the electrode group in a centrifuge tube, dimethyl Chirusunorehokishi de (DMSO) - was sealed by adding d 6, then Eject Ri by the glove box, was centrifugal away. Then, in the glow Bubokku scan, the said electrolyte DMSO from said spun down tube - were taken mixed solution of d 6.
• DMSO dimethyl Chirusunorehokishi de
• the apparatus used for the NMR measurement was JNM-LA400WB manufactured by JEOL Ltd., the observation nucleus was 1 H, the observation frequency was 400 MHz, and dimethylsulfoxide (DMSO)- d
• DMSO dimethylsulfoxide
• the temperature was 25 ° C.
• a peak corresponding to EC was observed at around 4.5 ppm, and a peak corresponding to VC was observed at around 7.7 pm.
• the peak corresponding to PRS is As in the case of the stick figure shown in FIG. ! ! ! near ? ,
• the ratio of the integrated NMR intensity of VC to the integrated intensity of EC and the ratio of the integrated intensity of PRS to the integrated intensity of EC were calculated for the non-aqueous solution. It was confirmed that both the ratio of VC and the ratio of PRS to the entire solvent were lower than before assembling the secondary battery.
• the present invention is not limited to the above-described embodiment, and can be similarly applied to a combination of another type of positive electrode / negative electrode / separator / container. Further, the present invention is applicable not only to the nonaqueous electrolyte secondary battery in which the container is formed from the laminated film as in the above embodiment, but also to a secondary battery having a cylindrical or rectangular container. It is possible. Industrial applicability

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