WO2012063745A1 - 蓄電デバイス用負極材料およびそれを用いた蓄電デバイス用負極 - Google Patents
蓄電デバイス用負極材料およびそれを用いた蓄電デバイス用負極 Download PDFInfo
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- WO2012063745A1 WO2012063745A1 PCT/JP2011/075498 JP2011075498W WO2012063745A1 WO 2012063745 A1 WO2012063745 A1 WO 2012063745A1 JP 2011075498 W JP2011075498 W JP 2011075498W WO 2012063745 A1 WO2012063745 A1 WO 2012063745A1
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
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- H01M4/00—Electrodes
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- H—ELECTRICITY
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- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/04—Hybrid capacitors
- H01G11/06—Hybrid capacitors with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
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- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/46—Metal oxides
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- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/22—Electrodes
- H01G11/30—Electrodes characterised by their material
- H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
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- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
- H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
- H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- H—ELECTRICITY
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- 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
- H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
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- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
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- H—ELECTRICITY
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- 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
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
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- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/13—Energy storage using capacitors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Definitions
- the present invention relates to a negative electrode material for an electricity storage device (hereinafter also simply referred to as “negative electrode material”) such as a lithium ion non-aqueous secondary battery used for a portable electronic device or an electric vehicle, and an anode for an electricity storage device using the same.
- negative electrode material such as a lithium ion non-aqueous secondary battery used for a portable electronic device or an electric vehicle, and an anode for an electricity storage device using the same.
- LiCoO 2 LiCo 1-x Ni x O 2 , LiNiO 2 , LiMn 2 O 4 and the like are widely used as positive electrode materials for lithium ion secondary batteries.
- a carbonaceous material is generally used as the negative electrode material. These materials function as electrode active materials that reversibly occlude and release lithium ions by charging and discharging, and constitute so-called rocking chair type secondary batteries that are electrochemically connected by a non-aqueous electrolyte or a solid electrolyte. .
- Examples of the carbonaceous material used for the negative electrode material include graphitic carbon material, pitch coke, fibrous carbon, and high-capacity soft carbon fired at a low temperature.
- the carbon material has a relatively small lithium insertion capacity, there is a problem that the capacity is low. Specifically, even if a stoichiometric amount of lithium insertion capacity can be realized, the capacity of the carbon material is limited to about 372 mAh / g.
- Patent Literature 1 Japanese Patent Literature 1
- Non-Patent Literature 1 a negative electrode active material that can occlude and release lithium ions and has a high capacity density exceeding that of a carbon-based material and contains a metal such as Si or Sn or SnO has been proposed (for example, see Patent Literature 1 and Non-Patent Literature 1).
- a negative electrode active material containing a metal such as Si or Sn or SnO is excellent in initial charge / discharge efficiency (ratio of discharge capacity to initial charge capacity), but is a volume resulting from occlusion and release reactions of lithium ions during charge / discharge. Since the change is remarkably large, the structure of the negative electrode material is easily deteriorated when repeatedly charged and discharged, and cracks are likely to occur. As cracks progress, in some cases, cavities are formed in the negative electrode material and may be pulverized. When a crack occurs in the negative electrode material, the electron conduction network is divided, which causes a problem of reduction in discharge capacity (cycle characteristics) after repeated charge and discharge.
- thermoplastic linear polymers such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE) are used as binders.
- PVDF polyvinylidene fluoride
- PTFE polytetrafluoroethylene
- SBR styrene-butadiene rubber
- the above polymer may be used by dissolving it in a non-polar organic solvent such as N-methylpyrrolidinone.
- a non-polar organic solvent such as N-methylpyrrolidinone.
- using an organic solvent has a large environmental impact.
- thermoplastic polymers and organic solvents are expensive, there is also a problem that the electricity storage device is expensive.
- the present invention has been made in view of the above situation, has a high capacity and excellent initial charge / discharge characteristics, is excellent in cycle characteristics and high rate characteristics, and is also excellent in safety.
- An object is to provide a negative electrode material for an electricity storage device and an anode for an electricity storage device using the same, which is an environmental load and is low in cost.
- the present invention relates to a negative electrode material for an electricity storage device, comprising a negative electrode active material containing an oxide material and a binder made of a water-soluble polymer.
- a water-soluble polymer is used as a binder.
- the negative electrode active material containing an oxide material has a hydroxyl group (—OH) on the outermost surface, while the water-soluble polymer also has a hydroxyl group.
- the hydroxyl group on the outermost surface of the negative electrode active material and the hydroxyl group in the water-soluble polymer are dehydrated and condensed, so that the negative electrode active materials can be firmly bound to each other in the negative electrode material. Can be suppressed.
- the use of a water-soluble polymer as a binder can reduce the resistance of the negative electrode and improve the high rate characteristics.
- water-soluble polymers are highly soluble in water, they are uniformly dispersed in solvents without using nonpolar organic solvents, unlike the thermoplastic linear polymers and SBR polymers described above. It is possible to make it. Therefore, it is possible to manufacture a negative electrode material that has low environmental burden, low cost, and excellent safety.
- the negative electrode material for an electricity storage device of the present invention is characterized in that the water-soluble polymer is a cellulose derivative or polyvinyl alcohol.
- cellulose derivatives (cellulose ester, cellulose ether, etc.) constitute a strong skeleton with glucose units, and have a hydroxyl group or a carboxyl group (—COOH) in a part of the side chain.
- Polyvinyl alcohol has many hydroxyl groups in the side chain. Therefore, these water-soluble polymers have excellent affinity for the surface of the negative electrode active material and tend to form strong bonds. For this reason, the negative electrode active materials are firmly bonded to each other, and the negative electrode material can be prevented from peeling off due to the volume change of the negative electrode active material accompanying charge / discharge.
- cellulose derivatives and polyvinyl alcohol are particularly low in environmental burden and are inexpensive because they are mass-produced.
- the negative electrode material for an electricity storage device of the present invention is characterized by containing 2 to 30% by mass of a binder.
- the negative electrode material for an electricity storage device of the present invention is characterized in that the oxide material contains P 2 O 5 and / or B 2 O 3 .
- the negative electrode active material containing an oxide material containing P 2 O 5 and / or B 2 O 3 has many hydroxyl groups on the outermost surface, the number of binding sites with a water-soluble polymer increases, and the negative electrode material The binding between the negative electrode active materials in the inside can be made extremely strong. Further, as will be described later, since the negative electrode active material containing an oxide material containing P 2 O 5 and / or B 2 O 3 has a small volume change of the negative electrode active material accompanying the charge / discharge reaction, The negative electrode active material can be prevented from peeling off.
- the negative electrode material for an electricity storage device of the present invention is characterized in that the oxide material is composed of a compound containing P 2 O 5 and / or B 2 O 3 and SnO.
- a lithium ion secondary battery undergoes the following reaction at the negative electrode during charge and discharge.
- Li y Sn alloy formation occurs from Sn x + ions during the initial charge, the negative electrode material occludes y lithium ions released from the positive electrode material and causes volume expansion.
- This volume change can be estimated from the viewpoint of crystal structure.
- SnO crystal because the length of the crystal unit cell is tetragonal in 3.802 ⁇ ⁇ 3.802 ⁇ ⁇ 4.836 ⁇ , crystal unit volume becomes 69.9 ⁇ 3. Since Sn atoms are present twice in the crystal unit cell, the occupied volume per Sn1 atoms becomes 34.95 ⁇ 3.
- Li 2.6 Sn, Li 3.5 Sn, Li 4.4 Sn, and the like are known as Li y Sn alloys formed during charging.
- the length of the unit cell of Li 4.4 Sn (cubic system, space group F23) is 19.78 ⁇ ⁇ 19.78 ⁇ ⁇ 19. because it is 78A, the lattice unit volume becomes 7739 ⁇ 3. Since Sn atoms are present 80 to the unit cell volume occupied per Sn1 atoms becomes 96.7 ⁇ 3. For this reason, when SnO crystal is used for the negative electrode material, the occupied volume of Sn atoms expands 2.77 times (96.7 ⁇ 3 /34.95 ⁇ 3 ) at the first charge.
- the reaction formula (2) proceeds to the left and y lithium ions and electrons are released from the Li y Sn alloy to form metal Sn, so that the negative electrode material shrinks in volume.
- the shrinkage rate in this case is obtained from the crystallographic viewpoint as described above.
- Length of the unit lattice of the metal Sn is tetragonal in 5.831 ⁇ ⁇ 5.831 ⁇ ⁇ 3.182 ⁇ , unit cell volume becomes 108.2 ⁇ 3. Since Sn atoms are present four in this lattice, the volume occupied per Sn1 atoms becomes 27.05 ⁇ 3.
- the Li y Sn alloy is Li 4.4 Sn
- the discharge reaction in the negative electrode material proceeds and metal Sn is generated, the occupied volume of Sn atoms is 0.28 times (27.5 ⁇ 3 /96.7 cm 3 ).
- reaction formula (2) proceeds in the right direction, and the metal Sn occludes y lithium ions and electrons, and an Li y Sn alloy is formed. Inflate. At this time, when Li 4.4 Sn is formed from the metal Sn, the occupied volume of Sn atoms expands to 3.52 times (96.7 / 3 /27.5 ⁇ 3 ).
- the negative electrode material containing SnO is remarkably accompanied by a volume change during charge and discharge, the negative electrode material is easily cracked when repeatedly charged and discharged. As cracks progress, in some cases, cavities are formed in the negative electrode material and may be pulverized. When a crack occurs in the negative electrode material, the electron conduction network is divided, so that the charge / discharge capacity is liable to be reduced, which causes a decrease in cycle characteristics.
- Sn x + ions in the negative electrode material exist in a state of being included in the phosphate network and / or boric acid network, and therefore, the volume change of Sn atoms associated with charge / discharge is related to the phosphate network and / or boric acid. Can be relaxed on the network. As a result, it is possible to obtain an electricity storage device having excellent cycle characteristics when repeatedly charged and discharged.
- the negative electrode material for an electricity storage device of the present invention is characterized in that the oxide material contains SnO 45 to 95% and P 2 O 5 5 to 55% in terms of the composition.
- the oxide material has a composition of mol%, SnO 10 to 85%, B 2 O 3 3 to 90%, P 2 O 5 0 to 55% (however, , B 2 O 3 + P 2 O 5 15% or more).
- the negative electrode material for an electricity storage device of the present invention further includes that the negative electrode active material further contains at least one metal material selected from Si, Sn, Al, and an alloy containing any of these.
- At least one metal material selected from Si, Sn, Al, and an alloy containing any one of these that can occlude and release lithium ions and electrons functions as a negative electrode active material, further improving the initial charge and discharge efficiency. It becomes possible to plan. About these metal materials, it is known that the following reaction will occur at the time of charging / discharging.
- At least one metal material selected from Si, Sn, Al, and an alloy containing any one of these has a large amount of occlusion of lithium ions, it is remarkable when a Li z M alloy is formed during charging.
- volume expansion For example, when metal Sn is used as the negative electrode active material, 4.4 lithium ions and electrons are occluded from the positive electrode during charging, and at this time, the volume expansion is approximately 3.52 times.
- the negative electrode active material is used alone, cracks are likely to occur in the negative electrode material when it is repeatedly charged and discharged, causing cycle characteristics to deteriorate.
- An oxide material in which the metal material is composed of a phosphate network and / or a borate network by compounding an oxide material containing P 2 O 5 and / or B 2 O 3 with the metal material Therefore, the volume change of the metal material accompanying charge / discharge can be mitigated by the oxide material composed of the phosphate network and / or the borate network. Furthermore, in the phosphate network and the borate network, lithium ions having a small ionic radius and a positive electric field are occluded, and the network contracts, resulting in a decrease in the molar volume. That is, the phosphoric acid network and the boric acid network not only relieve the volume increase of the metal material accompanying charging but also have a function of suppressing. Therefore, even when repeatedly charged and discharged, cracking of the negative electrode material due to volume change can be suppressed, and deterioration of cycle characteristics can be prevented.
- the negative electrode material for an electricity storage device of the present invention is characterized by further containing a conductive additive.
- the conductive auxiliary agent forms an electron conduction network in the negative electrode material, and makes it possible to increase the capacity and the rate of the negative electrode material.
- the present invention relates to a negative electrode for an electricity storage device, characterized in that any one of the negative electrode materials for an electricity storage device is applied to the surface of a current collector.
- Example 6 is a graph showing the discharge capacity of the negative electrode active material when the current during discharge was changed from 0.2 C to 20 C in Example 8 and Comparative Example 1.
- the negative electrode material for an electricity storage device of the present invention is characterized by containing a negative electrode active material containing an oxide material and a binder made of a water-soluble polymer.
- a water-soluble polymer As the binder, a water-soluble polymer is used.
- water-soluble polymers include cellulose derivatives such as carboxymethylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, ethylcellulose and hydroxymethylcellulose; starch derivatives such as starch, carboxymethyl starch, phosphate starch and cationic starch; xanthan gum and guar gum Natural vegetable polymers such as alginic acid, gum arabic, carrageenan, chondroitin sulfate soda, sodium hyaluronate, chitosan, gelatin; polyvinyl alcohol, polyacrylamide, polyvinyl pyrrolidone and copolymers thereof, polyethylene glycol, polymethyl vinyl ether, polyisopropyl Nonionic synthetic polymers such as acrylamide; poly (sodium acrylate) And its copolymers, polystyrene sulfonate sodium, polyisopren
- cellulose derivatives such as carboxymethylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, hydroxyethylcellulose, ethylcellulose, and hydroxymethylcellulose, or polyvinyl alcohol are preferable, and carboxymethylcellulose or polyvinyl alcohol that is widely used industrially and is inexpensive. It is.
- carboxymethylcellulose shall also contain carboxymethylcellulose salts, such as carboxymethylcellulose sodium.
- the said binder may be used by 1 type and may be used in mixture of 2 or more types.
- the content of the binder in the negative electrode material is preferably 2 to 30% by mass, 3 to 28% by mass, particularly 4 to 25% by mass.
- the binder content is less than 2% by mass, the binding between the negative electrode active material and the conductive additive is insufficient, and therefore the negative electrode active material peels off from the negative electrode material due to its volume change when repeatedly charged and discharged. This tends to reduce the cycle characteristics.
- the content of the binder is more than 30% by mass, the amount of the binder interposed between the negative electrode active materials (or conductive assistants) in the negative electrode material is increased, so that the electron conduction network is reduced. As a result, the capacity cannot be increased and the high rate characteristic tends to be remarkably deteriorated.
- an oxide material contained in the negative electrode active material for example, a material containing P 2 O 5 and / or B 2 O 3 , particularly a compound containing P 2 O 5 and / or B 2 O 3 and SnO is used. be able to.
- a composition containing mol% of SnO 45 to 95% and P 2 O 5 5 to 55% composition A
- composition of mol% of SnO 10 Examples include those containing 85 to 85%, 3 to 90% B 2 O 3, and 0 to 55% P 2 O 5 (however, B 2 O 3 + P 2 O 5 15% or more) (composition B). The reason why each composition is limited in this way will be described below.
- SnO is an active material component that serves as a site for occluding and releasing lithium ions.
- the SnO content is preferably 45 to 95%, 50 to 90%, 55 to 87%, 60 to 85%, 68 to 83%, particularly 71 to 82%.
- the content of SnO is less than 45%, the charge / discharge capacity per unit mass of the oxide material is reduced, and as a result, the charge / discharge capacity of the negative electrode active material is also reduced.
- the SnO content is more than 95%, the amorphous component in the negative electrode active material decreases, so that the volume change associated with insertion and extraction of lithium ions during charge and discharge cannot be reduced, and the discharge capacity is increased. May drop rapidly.
- SnO ingredient content in the present invention the tin oxide component other than SnO (SnO 2, etc.) also refers to that summed in terms of SnO.
- P 2 O 5 is a network-forming oxide, encompassing the insertion and extraction sites of lithium in SnO ions, lithium ions serve as a solid electrolyte movable.
- the content of P 2 O 5 is preferably 5 to 55%, 10 to 50%, 13 to 45%, 15 to 40%, 17 to 32, particularly 18 to 29%. If the content of P 2 O 5 is less than 5%, the change in volume of SnO that accompanies occlusion and release of lithium ions during charge / discharge cannot be mitigated, resulting in structural deterioration, and the discharge capacity tends to decrease during repeated charge / discharge. Become. On the other hand, if the content of P 2 O 5 is more than 55%, the water resistance tends to deteriorate.
- various components can be further added to the oxide material.
- CuO, ZnO, B 2 O 3 , MgO, CaO, Al 2 O 3 , SiO 2 , R 2 O (R represents Li, Na, K or Cs) in a total amount of 0 to 20%, 0 to It can be contained in an amount of 10%, particularly 0.1 to 7%.
- R represents Li, Na, K or Cs
- the total amount of these components is more than 20%, the structure tends to be disordered and an amorphous material is easily obtained, but the phosphate network is likely to be cut.
- the volume change of the negative electrode active material accompanying charge / discharge cannot be relaxed, and the cycle characteristics may be deteriorated.
- the SnO / P 2 O 5 (molar ratio) is preferably 0.8 to 19, 1 to 18, and particularly preferably 1.2 to 17.
- SnO / P 2 O 5 is smaller than 0.8, Sn atoms in SnO are easily affected by the coordination of P 2 O 5 , and the initial charge / discharge efficiency tends to be reduced.
- SnO / P 2 O 5 is greater than 19, the discharge capacity tends to decrease when charging and discharging are repeated. This can not comprehensively thoroughly SnO is less P 2 O 5 to coordinate the SnO in the oxide, as a result, will not be able to reduce the volume change SnO accompanying occlusion and release of lithium ions, structural deterioration It is thought to be caused.
- SnO is an active material component that serves as a site for occluding and releasing lithium ions.
- the SnO content is preferably 10 to 85%, 30 to 83%, 40 to 80%, and particularly preferably 50 to 75%.
- the content of SnO is less than 10%, the charge / discharge capacity per unit mass of the oxide material is reduced, and as a result, the charge / discharge capacity of the negative electrode active material is also reduced.
- the SnO content is more than 85%, the amorphous component in the negative electrode active material is reduced, so that the volume change associated with insertion and extraction of lithium ions during charge and discharge cannot be reduced, and the discharge capacity is increased. May drop rapidly.
- B 2 O 3 is a network-forming oxide that covers the storage and release sites of SnO lithium ions, mitigates volume changes associated with storage and release of lithium ions during charge and discharge, and maintains the structure of the oxide material To play a role.
- the content of B 2 O 3 is preferably 3 to 90%, 5 to 70%, 7 to 60%, particularly 9 to 55%. If the content of B 2 O 3 is less than 3%, the change in volume of SnO that accompanies occlusion and release of lithium ions during charge / discharge cannot be alleviated, resulting in structural deterioration, and the discharge capacity tends to decrease during repeated charge / discharge. Become.
- P 2 O 5 is a network-forming oxide, and can entangle the lithium ion storage and release sites of SnO by forming a composite network intertwined with the boric acid network in a three-dimensional manner. It plays the role of relaxing the volume change accompanying the release and maintaining the structure of the oxide material.
- the content of P 2 O 5 is preferably 0 to 55%, 5 to 50%, particularly preferably 10 to 45%. When the content of P 2 O 5 is more than 55%, the water resistance tends to deteriorate.
- B 2 O 3 and P 2 O total content of 5 15% or more, 20% or more, particularly preferably 30% or more. If the total amount of B 2 O 3 and P 2 O 5 is less than 15%, the volume change of SnO that accompanies occlusion and release of lithium ions during charge / discharge cannot be mitigated, resulting in structural deterioration. The capacity tends to decrease.
- various components can be further added to the oxide material to facilitate vitrification.
- CuO, ZnO, MgO, CaO, Al 2 O 3 , SiO 2 , R 2 O (R represents Li, Na, K or Cs) in a total amount of 0-20%, 0-10%, especially 0 1 to 7% can be contained.
- R represents Li, Na, K or Cs
- the total amount of these components is more than 20%, the structure becomes disordered and an amorphous material is easily obtained.
- the phosphate network or the boric acid network is easily cut. As a result, the volume change of the negative electrode active material accompanying charge / discharge cannot be relaxed, and the cycle characteristics may be deteriorated.
- the crystallinity of the oxide material is preferably 95% or less, 80% or less, 70% or less, 50% or less, particularly 40% or less, and substantially amorphous before the charge / discharge reaction. Most preferred.
- the degree of crystallinity the larger the proportion of the amorphous phase, the more advantageous is the reduction in volume during repeated charge / discharge, which is advantageous from the viewpoint of suppressing a decrease in discharge capacity. .
- the crystallinity is obtained by separating the peak into a crystalline diffraction line and an amorphous halo in a diffraction line profile of 10 to 60 ° with a 2 ⁇ value obtained by powder X-ray diffraction measurement using CuK ⁇ ray.
- the integrated intensity obtained by peak-separating a broad diffraction line (amorphous halo) at 10 to 45 ° from the total scattering curve obtained by subtracting the background from the diffraction line profile is Ia, 10
- the degree of crystallinity Xc can be obtained from the following equation.
- substantially amorphous means that the crystallinity is substantially 0% (specifically, the crystallinity is 0.1% or less), and CuK ⁇ radiation is used. In a powder X-ray diffraction measurement, a crystalline diffraction line is not detected.
- the negative electrode active material of the present invention may contain a phase composed of a complex oxide of metal and oxide or an alloy phase of metal and metal.
- the particle size is 0.1 to 10 ⁇ m and the maximum particle size is 75 ⁇ m or less, and the average particle size is 0.3 to 9 ⁇ m and the maximum. It is preferable that the particle size is 65 ⁇ m or less, the average particle size is 0.5 to 8 ⁇ m and the maximum particle size is 55 ⁇ m or less, and particularly the average particle size is 1 to 5 ⁇ m and the maximum particle size is 45 ⁇ m or less. If the average particle size of the oxide material contained in the negative electrode active material is larger than 10 ⁇ m or the maximum particle size is larger than 75 ⁇ m, the volume change of the negative electrode active material due to insertion and extraction of lithium ions cannot be reduced when charging / discharging.
- the negative electrode material is easily peeled off from the current collector.
- the capacity tends to be significantly reduced.
- it becomes difficult to uniformly enclose between the particles of the metal material with the oxide material, and the volume change of the metal material due to insertion and extraction of lithium ions when charged and discharged Can not be relaxed, and the negative electrode material is easily peeled off from the current collector.
- the capacity tends to be significantly reduced.
- the average particle diameter of the powder is smaller than 0.1 ⁇ m, the powder is in a poorly dispersed state when formed into a paste, and it tends to be difficult to produce a uniform electrode.
- the average particle size and the maximum particle size are respectively the primary median diameter D50 (50% volume cumulative diameter) and D100 (100% volume cumulative diameter), and a laser diffraction particle size distribution analyzer (Shimadzu Corporation). The value measured by SALD-2000 series.
- a BET specific surface area of the powdered oxide material is 0.1 ⁇ 20m 2 /g,0.15 ⁇ 15m 2 / g , particularly 0.2 ⁇ 10m 2 / g.
- the specific surface area of the oxide material is smaller than 0.1 m 2 / g, lithium ions cannot be absorbed and released quickly, and the charge / discharge time tends to be long.
- the specific surface area of the oxide material is larger than 20 m 2 / g, when producing a paste for forming an electrode containing a binder and water, the dispersion state of the powder is inferior. There is a need to increase the amount of addition, or lack of coatability tends to make it difficult to form a uniform electrode.
- the tap density of the powdered oxide material is preferably 0.5 to 2.5 g / cm 3 , particularly preferably 1 to 2 g / cm 3 .
- the tap density of the oxide material is smaller than 0.5 g / cm 3 , the filling amount of the negative electrode material per electrode unit volume is reduced, so that the electrode density is inferior and it is difficult to achieve high capacity.
- the tap density of the oxide material is larger than 2.5 g / cm 3 , the filling state of the negative electrode material is too high, and the electrolyte does not easily permeate, and a sufficient capacity may not be obtained.
- the tap density here means a value measured under the conditions of tapping stroke: 18 mm, tapping frequency: 180 times, and tapping speed: 1 time / 1 second.
- a general pulverizer or classifier is used.
- a mortar, a ball mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a jet mill, a sieve, a centrifugal separator, an air classification, or the like is used.
- the oxide material is manufactured, for example, by heating and melting raw material powder to vitrify it.
- melting of the raw material powder containing Sn is particularly preferably performed in a reducing atmosphere or an inert atmosphere.
- the oxidation state of Sn atoms easily changes depending on the melting conditions.
- unwanted crystals such as SnO 2 and SnP 2 O 7 are formed on the surface of the glass melt or in the glass melt. It is easy to be formed.
- the initial charge / discharge efficiency and cycle characteristics of the negative electrode material are likely to deteriorate. Therefore, by performing melting in a reducing atmosphere or an inert atmosphere, it is possible to suppress an increase in the valence of Sn ions in the oxide material, to suppress formation of unwanted crystals, and to be excellent in initial charge / discharge efficiency and cycle characteristics. It is possible to obtain an electricity storage device.
- a reducing gas In order to melt in a reducing atmosphere, it is preferable to supply a reducing gas into the melting tank.
- a reducing gas As the reducing gas, it is preferable to use a mixed gas of N 2 90 to 99.5%, H 2 0.5 to 10%, particularly N 2 92 to 99%, H 2 1 to 8% by volume%. .
- an inert gas When melting in an inert atmosphere, it is preferable to supply an inert gas into the melting tank.
- the inert gas it is preferable to use any of nitrogen, argon, and helium.
- the reducing gas or the inert gas may be supplied to the upper atmosphere of the molten glass in the melting tank, may be supplied directly from the bubbling nozzle into the molten glass, or both methods may be performed simultaneously.
- a negative electrode active material having few devitrified foreign matters and excellent uniformity can be easily obtained.
- a negative electrode active material containing the oxide material an electricity storage device with a stable discharge capacity can be easily obtained.
- complex oxides include stannous pyrophosphate (Sn 2 P 2 O 7 ).
- the raw material powder contains metal powder or carbon powder.
- Sn atoms in the oxide material can be shifted to a reduced state.
- the valence of Sn in the oxide material is reduced, and the initial charge efficiency of the electricity storage device can be improved.
- the metal powder it is preferable to use any powder of Sn, Al, Si, and Ti. Among these, it is preferable to use Sn, Al, and Si powders.
- the content of the metal powder is preferably 0 to 20%, more preferably 0.1 to 10%, in terms of mol% in terms of oxide in the oxide material. If the content of the metal powder is more than 20%, an excess metal lump may be precipitated from the oxide material, or SnO in the oxide material may be reduced and precipitated as lumped Sn particles.
- the carbon powder is preferably added to the raw material powder in an amount of 0 to 20% by mass, particularly 0.05 to 10% by mass.
- the negative electrode active material further contains at least one metal material selected from Si, Sn, Al, and alloys containing any of these (for example, Sn—Cu alloys). May be.
- Si, Sn, Al having a large lithium ion storage capacity and a high capacity, or an alloy containing any of these is preferable, and Si having the highest theoretical capacity is particularly preferable.
- the average particle size is preferably 0.01 to 30 ⁇ m, 0.05 to 20 ⁇ m, 0.1 to 10 ⁇ m, and particularly preferably 0.15 to 5 ⁇ m.
- the average particle diameter of the metal material is larger than 30 ⁇ m, the negative electrode material is easily peeled off from the current collector due to a volume change associated with insertion and extraction of lithium ions during charge and discharge. As a result, when the charge / discharge is repeated, the capacity tends to be remarkably reduced.
- the average particle size of the metal material is smaller than 0.01 ⁇ m, it is difficult to uniformly mix with an oxide containing at least P 2 O 5 and / or B 2 O 3, and it is difficult to manufacture a uniform electrode.
- the maximum particle size of the metal material is preferably 200 ⁇ m or less, 150 ⁇ m or less, 100 ⁇ m or less, 50 ⁇ m or less, 30 ⁇ m or less, and particularly preferably 25 ⁇ m or less.
- the maximum particle size of the metal material is larger than 200 ⁇ m, the volume change accompanying the insertion and extraction of lithium ions during charging and discharging is remarkably large, so that the negative electrode material is easily peeled off from the current collector.
- cracks are likely to occur in the particles of the metal material with repeated charge and discharge, and as a result, the particles are further pulverized, so that the electron conduction network in the electrode material is easily divided. As a result, when the charge / discharge is repeated, the capacity tends to be remarkably reduced.
- the content of the metal material in the negative electrode active material is preferably 5 to 90%, 10 to 70%, 10 to 50%, particularly 20 to 40%.
- the content of the metal material is less than 5%, the initial charge / discharge efficiency tends to be low.
- the content of the metal material is more than 90%, the volume change accompanying charging / discharging is large, and the capacity is likely to decrease when repeatedly charging / discharging.
- the method for combining the oxide material and the metal material is not particularly limited, but is preferably a mixed powder containing the powdered oxide material and the metal material in terms of easy handling. Further, the mixed powder may be heated to the softening point or higher of the oxide material to disperse the metal material in the oxide material. In addition, the powdery metal material surface may be coated with an oxide material.
- a mixed powder containing a powdered metal material and an oxide material can be manufactured using a general method. For example, dry mixing using a ball mill, tumbler mixer, vibration mill, planetary ball mill or the like, or wet mixing to which an auxiliary agent such as water or alcohol is added, a revolving mixer, propeller stirrer, bead mill, jet mill, etc. Wet mixing is applicable.
- the negative electrode material preferably contains a conductive additive.
- the conductive additive is a component added to achieve high capacity and high rate of the negative electrode material.
- Specific examples of the conductive aid include highly conductive carbon black such as acetylene black and ketjen black, and metal powder such as Ni powder, Cu powder, and Ag powder. Among them, it is preferable to use any one of highly conductive carbon black, Ni powder, and Cu powder that exhibits excellent conductivity when added in a very small amount.
- the content of the conductive additive in the negative electrode material is preferably 3 to 20% by mass, 4 to 15% by mass, and particularly preferably 5 to 13% by mass.
- the content of the conductive auxiliary is less than 3% by mass, an electron conductive network that only includes the negative electrode active material cannot be formed, the capacity is reduced, and the high rate characteristics are also significantly reduced.
- there is more content of a conductive support agent than 20 mass% the bulk density of negative electrode material will fall, and as a result, there exists a tendency for the charge / discharge capacity per unit volume of negative electrode material to fall. In addition, the strength of the negative electrode material tends to decrease.
- the negative electrode material may be in a paste state in which, for example, a negative electrode active material and a binder, and further a material containing a conductive auxiliary agent as required are dispersed in water and uniformly mixed.
- It can be used as a negative electrode for an electricity storage device by applying the negative electrode material for an electricity storage device to the surface of a metal foil or the like that serves as a current collector.
- the thickness of the negative electrode material in the negative electrode for an electricity storage device may be appropriately adjusted according to the target capacity, and is preferably 1 to 250 ⁇ m, 2 to 200 ⁇ m, particularly 3 to 150 ⁇ m, for example.
- the thickness of the negative electrode material is smaller than 1 ⁇ m, a portion where the negative electrode active material cannot be included by the binder is partially generated, and as a result, the cycle characteristics tend to be deteriorated.
- the thickness of the negative electrode material is larger than 250 ⁇ m, when the negative electrode is used as a battery in a folded state, tensile stress is likely to be generated on the surface of the negative electrode material. Therefore, cracks are likely to occur due to a volume change of the negative electrode active material when repeatedly charged and discharged, and the cycle characteristics tend to be remarkably deteriorated.
- the drying method after applying the negative electrode material to the surface of the current collector is not particularly limited, but is 100 to 400 ° C., 120 to 380 ° C., particularly 140 to 140 ° C. under reduced pressure or in an inert or reducing atmosphere.
- Heat treatment is preferably performed at 360 ° C.
- the heat treatment temperature is lower than 100 ° C.
- the moisture adsorbed on the negative electrode material is not sufficiently removed, so that the moisture is decomposed inside the electricity storage device and ruptures due to the release of oxygen or the heat generated by the reaction between lithium and water. Because it ignites due to the cause, it lacks safety.
- the heat treatment temperature is higher than 400 ° C., the binder is easily decomposed. As a result, the binding property is lowered, or a part where the negative electrode active material is not included by the binder is partially generated, so that the cycle characteristics are easily lowered.
- the negative electrode material for lithium ion secondary batteries has been mainly described.
- the negative electrode material for an electricity storage device of the present invention and the negative electrode for an electricity storage device using the same are not limited thereto, and other non-aqueous materials are used.
- the present invention can also be applied to a secondary battery or a hybrid capacitor that combines a negative electrode material for a lithium ion secondary battery and a positive electrode material for a non-aqueous electric double layer capacitor.
- the lithium ion capacitor which is a hybrid capacitor, is a kind of asymmetric capacitor that has different charge / discharge principles for the positive and negative electrodes.
- the lithium ion capacitor has a structure in which a negative electrode for a lithium ion secondary battery and a positive electrode for an electric double layer capacitor are combined.
- the positive electrode forms an electric double layer on the surface and is charged / discharged by utilizing a physical action (electrostatic action), whereas the negative electrode has a lithium ion chemistry similar to the lithium ion secondary battery described above. Charge and discharge by reaction (occlusion and release).
- a positive electrode material made of carbonaceous powder having a high specific surface area such as activated carbon, polyacene, or mesophase carbon is used.
- the negative electrode the negative electrode material of the present invention in which lithium ions and electrons are occluded can be used.
- the means for occluding lithium ions and electrons in the negative electrode material is not particularly limited.
- a metal lithium electrode that is a supply source of lithium ions and electrons may be disposed in a capacitor cell, and may be brought into contact with a negative electrode including the negative electrode material of the present invention directly or through a conductor.
- the negative electrode material may be preliminarily occluded with lithium ions and electrons and then incorporated into the capacitor cell.
- the negative electrode material for an electricity storage device of the present invention the negative electrode material for a non-aqueous secondary battery will be described in detail using examples, but the present invention is not limited to these examples.
- the molten glass was poured out between a pair of rotating rollers and molded while being rapidly cooled to obtain a film-like glass having a thickness of 0.1 to 2 mm.
- the film-like glass was pulverized at 100 rpm for 3 hours using a ball mill containing zirconia balls having a diameter of 2 to 3 cm and then passed through a resin sieve having an opening of 120 ⁇ m to obtain a glass coarse powder having an average particle size of 3 to 15 ⁇ m. Subsequently, this coarse powder glass was air classified to obtain a glass powder (oxide material powder) having an average particle diameter of 2 ⁇ m and a maximum particle diameter of 28 ⁇ m.
- the raw material of stannous oxide was used as it was for the oxide material described in Comparative Example 7.
- stannous oxide one having an average particle size of 2.5 ⁇ m and a maximum particle size of 28 ⁇ m was used.
- the structure was identified by powder X-ray diffraction measurement for each oxide material powder.
- the oxide materials of Examples 1 to 16 and Comparative Examples 1 and 2 were amorphous, and no crystals were detected.
- Examples 12 to 14 and Comparative Examples 2 to 6 the metal material powders listed in Tables 2 and 4 were charged into the container in the proportions shown in the same table, and mixed using a ball mill. As a result, a negative electrode active material was obtained.
- As the Si powder one having an average particle diameter of 2.1 ⁇ m and a maximum particle diameter of 8.9 ⁇ m was used.
- the obtained slurry was coated on a 20 ⁇ m thick copper foil as a negative electrode current collector, dried with a dryer at 70 ° C., and then passed between a pair of rotating rollers. To obtain an electrode sheet.
- the electrode sheet was punched to a diameter of 11 mm with an electrode punching machine and dried under reduced pressure to obtain a circular working electrode (a negative electrode for a non-aqueous secondary battery).
- the electrode sheets were dried at a temperature of 160 ° C. for Examples 1 to 16 and Comparative Examples 3 to 7 for 3 hours, and for Comparative Examples 1 and 2 at a temperature of 140 ° C. for 4 hours.
- test battery (3) Preparation of test battery The above working electrode was placed on the lower lid of the coin cell with the copper foil surface facing down, and dried on a reduced pressure at 70 ° C. for 8 hours on a polypropylene porous membrane having a diameter of 16 mm (Hoechst Cera A separator comprising Cellguard # 2400 manufactured by Needs Co., Ltd. and metallic lithium as a counter electrode were laminated to prepare a test battery.
- the test battery was assembled in an environment with a dew point temperature of ⁇ 50 ° C. or lower.
- Charging / discharging test Charging (Occlusion of Li ions in the negative electrode active material) was performed by CC (constant current) charging from 1 V to 0 V at 0.2 mA. Next, discharge (release of Li ions from the negative electrode active material) was discharged from 0 V to 1 V at a constant current of 0.2 mA. This charge / discharge cycle was repeated, and the charge capacity and discharge capacity per unit mass of the negative electrode active material were measured.
- Tables 1 to 4 show the results of the initial charge / discharge characteristics when the charge / discharge test was conducted and the cycle characteristics when the battery was repeatedly charged / discharged. It was expressed as (ratio of discharge capacity after 100 cycles to initial discharge capacity).
- (5) High-rate test The high-rate test was conducted on the test battery using the negative electrode for the non-aqueous secondary battery of Example 8 and Comparative Example 1. The test condition is that charging is performed at a constant current of 0.2 C from 1 V to 0 V, and discharging is set to current rates of 0.2 C, 0.5 C, 1 C, 2 C, 5 C, 10 C, and 20 C, respectively. The battery was discharged from 0V to 1V with a constant current. The results are shown in FIG.
- the initial discharge capacity was 463 mAh / g or more, the initial charge / discharge efficiency was 47.9% or more, and the discharge capacity retention rate was 72.9% or more.
- the initial discharge capacity is 1970 mAh / g or more, the initial charge / discharge efficiency is 67.9% or more, and the discharge capacity maintenance rate is also high. A very good characteristic of 75.1% or more was exhibited.
- Comparative Examples 1 and 2 using PVDF as a binder and Comparative Examples 3 to 7 not using an oxide material containing P 2 O 5 and / or B 2 O 3 as a negative electrode active material The discharge capacity was 452 mAh / g or more and the initial charge / discharge efficiency was 44.5% or more, but the discharge capacity retention rate after 100 cycles was significantly reduced to 23.2% or less.
- Example 8 using CMC as the binder the discharge capacity at 20C rate is 253 mAh / g, whereas in Comparative Example 1 using PVDF as the binder, It was remarkably reduced to 0 mAh / g.
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Abstract
Description
Sn+yLi++ye-←→LiySn ・・・(2)
(M=Si、Sn、Alおよびこれらのうちいずれかを含む合金から選択される少なくとも1種)
上記結着剤は一種類で使用してもよいし二種類以上を混合して用いてもよい。
SnOはリチウムイオンを吸蔵および放出するサイトとなる活物質成分である。SnOの含有量は45~95%、50~90%、55~87%、60~85%、68~83%、特に71~82%であることが好ましい。SnOの含有量が45%より少ないと、酸化物材料の単位質量当たりの充放電容量が小さくなるため、結果的に負極活物質の充放電容量も小さくなる。一方、SnOの含有量が95%より多いと、負極活物質中の非晶質成分が少なくなるため、充放電時のリチウムイオンの吸蔵および放出に伴う体積変化を緩和できずに、放電容量が急速に低下するおそれがある。なお、本発明においてSnO成分含有量は、SnO以外の酸化スズ成分(SnO2等)もSnOに換算して合算したものを指す。
SnOはリチウムイオンを吸蔵および放出するサイトとなる活物質成分である。SnOの含有量は10~85%、30~83%、40~80%、特に50~75%であることが好ましい。SnOの含有量が10%より少ないと、酸化物材料の単位質量当たりの充放電容量が小さくなるため、結果的に負極活物質の充放電容量も小さくなる。一方、SnOの含有量が85%より多いと、負極活物質中の非晶質成分が少なくなるため、充放電時のリチウムイオンの吸蔵および放出に伴う体積変化を緩和できずに、放電容量が急速に低下するおそれがある。
実施例1~13、15、16および比較例1、2の酸化物材料について、表1~4に示す組成となるように、主原料としてスズとリンの複合酸化物(ピロリン酸第一錫:Sn2P2O7)を用い、各種酸化物、炭酸塩原料などで原料を調製した。原料を石英ルツボに投入し、電気炉を用いて窒素雰囲気にて950℃、40分間の溶融を行い、ガラス化した。また、実施例14の酸化物材料について、表2に示す組成となるように、各種酸化物、炭酸塩原料などで原料を調整し、白金ルツボに投入し電気炉を用いて大気雰囲気中で1400℃、40分間の溶融を行い、ガラス化した。
上記で得られた負極活物質と導電助剤と結着剤を表1~4に示す負極材料組成になるように秤量し、溶媒に分散した後、自転・公転ミキサーで十分に撹拌してスラリー化した。ここで、結着剤としては、実施例1~14および比較例3~7ではカルボキシメチルセルロース(CMC)(ダイセルファインケム社製)、実施例15および16ではCMCとポリビニルアルコール(PVA)(クラレ社製)を混合したものを使用し、比較例1、2ではポリフッ化ビニリデン(PVDF)(キシダ化学社製)を使用した。また、導電助剤としてはケッチェンブラック(KB)(ライオン社製)を用いた。なお、CMCは純水に分散させたものを用い、PVDFはN-メチルピロリジノン溶媒に分散させたものを用いた
コインセルの下蓋に、上記作用極を銅箔面を下に向けて載置し、その上に70℃で8時間減圧乾燥した直径16mmのポリプロピレン多孔質膜(ヘキストセラニーズ社製 セルガード#2400)からなるセパレータ、および対極である金属リチウムを積層し、試験電池を作製した。電解液としては、1M LiPF6溶液/EC:DEC=1:1(EC=エチレンカーボネート、DEC=ジエチルカーボネート)を用いた。なお試験電池の組み立ては露点温度-50℃以下の環境で行った。
充電(負極活物質へのLiイオンの吸蔵)は、0.2mAで1Vから0VまでCC(定電流)充電を行った。次に、放電(負極活物質からのLiイオンの放出)は、0.2mAの定電流で0Vから1Vまで放電させた。この充放電サイクルを繰り返し行い、負極活物質の単位質量あたりの充電容量および放電容量を測定した。
(5)ハイレート試験
実施例8および比較例1の非水二次電池用負極を用いた試験電池に関し、ハイレート試験を行なった。試験条件は充電を0.2Cの定電流で1Vから0Vまで行い、放電はそれぞれ0.2C、0.5C、1C、2C、5C、10C、20Cの各レートになるよう電流値を設定し、定電流で0Vから1Vまで放電させた。結果を図1に示した。
Claims (10)
- 酸化物材料を含む負極活物質と、水溶性高分子からなる結着剤とを含有することを特徴とする蓄電デバイス用負極材料。
- 水溶性高分子が、セルロース誘導体またはポリビニルアルコールであることを特徴とする請求項1に記載の蓄電デバイス用負極材料。
- 結着剤を2~30質量%含有することを特徴とする請求項1または2に記載の蓄電デバイス用負極材料。
- 酸化物材料が、P2O5および/またはB2O3を含有することを特徴とする請求項1~3のいずれかに記載の蓄電デバイス用負極材料。
- 酸化物材料が、P2O5および/またはB2O3とSnOとを含有する化合物からなることを特徴とする請求項4に記載の蓄電デバイス用負極材料。
- 酸化物材料が、組成としてモル%で、SnO 45~95%、P2O5 5~55%を含有することを特徴とする請求項5に記載の蓄電デバイス用負極材料。
- 酸化物材料が、組成としてモル%で、SnO 10~85%、B2O3 3~90%、P2O5 0~55%(ただし、B2O3+P2O5 15%以上)を含有することを特徴とする請求項5に記載の蓄電デバイス用負極材料。
- 負極活物質が、さらに、Si、Sn、Alおよびこれらのうちいずれかを含む合金から選択される少なくとも1種の金属材料を含有することを特徴とする請求項1~7のいずれかに記載の蓄電デバイス用負極材料。
- さらに、導電助剤を含有することを特徴とする請求項1~8のいずれかに記載の蓄電デバイス用負極材料。
- 請求項1~9のいずれかに記載の蓄電デバイス用負極材料が集電体表面に塗布されてなることを特徴とする蓄電デバイス用負極。
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JP2014116273A (ja) * | 2012-12-12 | 2014-06-26 | Nippon Telegr & Teleph Corp <Ntt> | ナトリウム二次電池 |
JP2014154217A (ja) * | 2013-02-05 | 2014-08-25 | Nippon Electric Glass Co Ltd | 蓄電デバイス用負極活物質粉末、ならびに、それを用いた蓄電デバイス用負極材料および蓄電デバイス用負極 |
JP2015041455A (ja) * | 2013-08-21 | 2015-03-02 | 日本電気硝子株式会社 | ナトリウムイオン二次電池用負極活物質、ならびに、それを用いたナトリウムイオン二次電池用負極及びナトリウムイオン二次電池 |
JP2015173201A (ja) * | 2014-03-12 | 2015-10-01 | 日本電気硝子株式会社 | リチウムイオンキャパシタ |
JP2015198000A (ja) * | 2014-04-01 | 2015-11-09 | 日本電気硝子株式会社 | 蓄電デバイス用負極活物質、蓄電デバイス用負極材料および蓄電デバイス |
JPWO2014119157A1 (ja) * | 2013-02-04 | 2017-01-26 | 住友電気工業株式会社 | ナトリウム溶融塩電池用電極およびナトリウム溶融塩電池 |
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JP6222433B2 (ja) * | 2013-08-08 | 2017-11-01 | 日本電気硝子株式会社 | 蓄電デバイス用負極活物質の製造方法 |
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- 2011-11-04 KR KR1020137003831A patent/KR20140001197A/ko not_active Application Discontinuation
- 2011-11-04 CN CN2011800500806A patent/CN103155231A/zh active Pending
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JP2014116273A (ja) * | 2012-12-12 | 2014-06-26 | Nippon Telegr & Teleph Corp <Ntt> | ナトリウム二次電池 |
JPWO2014119157A1 (ja) * | 2013-02-04 | 2017-01-26 | 住友電気工業株式会社 | ナトリウム溶融塩電池用電極およびナトリウム溶融塩電池 |
JP2014154217A (ja) * | 2013-02-05 | 2014-08-25 | Nippon Electric Glass Co Ltd | 蓄電デバイス用負極活物質粉末、ならびに、それを用いた蓄電デバイス用負極材料および蓄電デバイス用負極 |
JP2015041455A (ja) * | 2013-08-21 | 2015-03-02 | 日本電気硝子株式会社 | ナトリウムイオン二次電池用負極活物質、ならびに、それを用いたナトリウムイオン二次電池用負極及びナトリウムイオン二次電池 |
JP2015173201A (ja) * | 2014-03-12 | 2015-10-01 | 日本電気硝子株式会社 | リチウムイオンキャパシタ |
JP2015198000A (ja) * | 2014-04-01 | 2015-11-09 | 日本電気硝子株式会社 | 蓄電デバイス用負極活物質、蓄電デバイス用負極材料および蓄電デバイス |
Also Published As
Publication number | Publication date |
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US20130260236A1 (en) | 2013-10-03 |
KR20140001197A (ko) | 2014-01-06 |
CN103155231A (zh) | 2013-06-12 |
JPWO2012063745A1 (ja) | 2014-05-12 |
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