WO2023097432A1 - 正极浆料及由其制备的二次电池 - Google Patents

正极浆料及由其制备的二次电池 Download PDF

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WO2023097432A1
WO2023097432A1 PCT/CN2021/134335 CN2021134335W WO2023097432A1 WO 2023097432 A1 WO2023097432 A1 WO 2023097432A1 CN 2021134335 W CN2021134335 W CN 2021134335W WO 2023097432 A1 WO2023097432 A1 WO 2023097432A1
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positive electrode
electrode slurry
additive
vinylidene fluoride
secondary battery
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PCT/CN2021/134335
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English (en)
French (fr)
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张明
张铜贤
吴启凡
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宁德时代新能源科技股份有限公司
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Priority to EP21943321.6A priority Critical patent/EP4216316A1/en
Priority to PCT/CN2021/134335 priority patent/WO2023097432A1/zh
Priority to CN202180091721.6A priority patent/CN116830317A/zh
Priority to US18/069,170 priority patent/US20230299300A1/en
Publication of WO2023097432A1 publication Critical patent/WO2023097432A1/zh

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    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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
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    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery technology, in particular to positive electrode slurry and a secondary battery prepared therefrom.
  • the commercial positive electrode active materials are mainly lithium-containing phosphate materials (such as LiFePO 4 ) and ternary (nickel, cobalt and manganese) positive electrode active materials.
  • lithium-containing phosphate materials such as LiFePO 4
  • ternary (nickel, cobalt and manganese) positive electrode active materials when used in conjunction with graphite, there is a problem of rapid decay in the early cycle of the battery.
  • adding a lithium supplement to the positive electrode is an effective means.
  • the use of lithium supplements has significantly improved the problem of rapid decay in the early cycle of the battery.
  • lithium replenishing agents are lithium-rich materials with strong alkalinity (for example, the pH value is greater than or equal to 10.0)
  • polymers containing repeating units of vinylidene fluoride (units shown in Structural Formula 3 below) are used as positive electrode slurry
  • the molecular chain of the polymer used as the binder is easy to remove HF molecules in a strong alkaline environment during the stirring process of the positive electrode slurry, and a continuous double bond is formed on the molecular chain.
  • the double bond may be broken and cross-linked with other molecular chains, which eventually leads to chemical gelation of the positive electrode slurry, thereby affecting normal compounding, coating and subsequent processes.
  • the catalytic oxidation of the above-mentioned lithium-rich materials is generally strong, which will intensify the oxidative decomposition of the electrolyte in the battery and lead to an increase in gas production.
  • the inventors of the present application have accomplished the present invention in order to solve the above-mentioned problems.
  • a positive electrode slurry comprising a lithium-containing phosphate material, a first positive electrode additive, a second positive electrode additive and a binder, wherein,
  • the first positive electrode additive is at least one of a compound represented by the following structural formula 1 and a compound represented by structural formula 2:
  • R 1 is one selected from the following: C2-C4 alkylene, alkenylene and their derivatives substituted or not substituted by halogen;
  • R 2 and R 3 are each independently substituted by halogen or unsubstituted alkyl, alkenyl, alkynyl or aryl;
  • the binder includes a polymer having a repeating unit represented by the following structural formula 3,
  • pH value of the second positive electrode additive is greater than or equal to 10.0.
  • the positive electrode slurry provided by the present application, although it contains a polymer having a repeating unit represented by the above structural formula 3 as a binder (it may also contain other types of binders) and contains a second positive electrode with a pH value greater than or equal to 10.0 additives, but it still has good fluidity within at least 24 hours of standing time after preparation, so it meets the process requirements for the actual manufacturing of secondary batteries.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive may be 0.01:100 ⁇ 100:100.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive when the mass ratio of the first positive electrode additive to the second positive electrode additive is within the above range, the effect of prolonging the static stability time of the positive electrode slurry may be more significant.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive when the mass ratio of the first positive electrode additive to the second positive electrode additive is within the above-mentioned range, even if the second positive electrode additive is a lithium replenishing agent, the first positive electrode additive will hardly consume the active lithium ions of the lithium replenishing agent, Thereby maintaining the capacity of the battery.
  • R 1 can be ethylene, propylene, butylene, vinylene or propenylene substituted or not substituted by halogen.
  • R 2 and R 3 can each independently be methyl, ethyl, propyl or butyl substituted or not substituted by halogen.
  • R 1 or R 2 and R 3 are the above-mentioned groups, on the one hand, it can be ensured that the first positive electrode additive itself will not cause the physical gelation of the slurry; on the other hand, after the first positive electrode additive reacts on the surface of the second positive electrode additive , can partially isolate the electrolyte on the surface of the second positive electrode additive.
  • the first positive electrode additive can be at least one selected from the following:
  • the binder may contain at least one selected from the following: vinylidene fluoride homopolymer, vinylidene fluoride-acrylic acid copolymer (P(VDF-co-AA)), Vinylidene fluoride-acrylate copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethane vinyl ether-tetrafluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, and optionally, the binder can be vinylidene fluoride-acrylic acid copolymer or vinylidene fluoride homopolymer.
  • the pH value of the lithium-containing phosphate material may be less than 10.0.
  • the pH value of the lithium-containing phosphate material is greater than or equal to 10.0, the positive electrode slurry is prone to chemical gelation during standing and processing after preparation.
  • the lithium-containing phosphate material may comprise LiFePO 4 , LiFeVPO 4 , LiFeMnPO 4 , carbon-coated LiFePO 4 , carbon-coated LiFeVPO 4 and carbon-coated LiFeMnPO 4 at least one of .
  • the above-mentioned lithium-containing phosphate material is used as an active material, the life characteristics and capacity characteristics of the battery can be improved.
  • the second positive electrode additive may contain at least one selected from the following: Li 2 MnO 3 , Li 2 MoO 3 , Li 2 RuO 3 , Li 3 VO 4 , Li 2 NiO 2 , Li 6 CoO 4 , Li 5 FeO 4 , Li 2 C 2 , Li 3 N, Li 2 S and materials represented by the general formula Li 1+a [ Nix Co y Mnz M b ]O 2 ,
  • M can be selected from Mg, Ca, One or more of Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo and B, optionally, 0.8 ⁇ x ⁇ 1.
  • the second positive electrode additive may include at least one selected from the following: LiNi 0.96 Co 0.02 Mn 0.02 O 2 , Li 5 FeO 4 and Li 2 NiO 2 .
  • a secondary battery which includes a positive electrode sheet containing a positive electrode active material layer, and the positive electrode active material layer is obtained by coating the positive electrode slurry described in any one of the above aspects and obtained by drying.
  • a battery module which includes the secondary battery of the above-mentioned second aspect.
  • a battery pack which includes the above-mentioned battery module of the third aspect.
  • an electrical device comprising at least one of the secondary battery of the second aspect, the battery module of the third aspect, and the battery pack of the fourth aspect.
  • the positive electrode slurry provided by the present application, although it contains a polymer having a repeating unit represented by the above structural formula 3 as a binder and contains a second positive electrode additive with a pH value greater than or equal to 10.0, it is at least 24 hours after preparation It still has good fluidity within a certain standing time, so it meets the process requirements for the actual manufacturing of secondary batteries.
  • the first positive electrode additive contained in the positive electrode slurry of the present application can be used as a base-binding agent to reduce the alkalinity of the second positive electrode additive, thereby avoiding the strong alkalinity of the second positive electrode additive on the adhesion of the positive electrode slurry during standing and processing.
  • the nucleophilic attack of the binder polymer leads to the reaction of removing HF and finally leads to the chemical gelation of the positive electrode slurry, thereby prolonging the static stability time of the positive electrode slurry.
  • the secondary battery prepared by the positive electrode slurry of the present application can greatly reduce the production rate in the chemical formation process. Air volume, and high-temperature storage characteristics have also been improved.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • Fig. 2 is an exploded view of a secondary battery according to an embodiment of the present application shown in Fig. 1;
  • Fig. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • Fig. 5 is an exploded view of a battery pack according to an embodiment of the present application shown in Fig. 4;
  • FIG. 6 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
  • the first embodiment of the present application can provide a positive electrode slurry, the positive electrode slurry includes a lithium-containing phosphate material, a first positive electrode additive, a second positive electrode additive and a binder, wherein,
  • the first positive electrode additive is at least one of a compound represented by the following structural formula 1 and a compound represented by structural formula 2:
  • R 1 is one selected from the following: C2-C4 alkylene, alkenylene and their derivatives substituted or not substituted by halogen;
  • R 2 and R 3 are each independently substituted by halogen or unsubstituted alkyl, alkenyl, alkynyl or aryl;
  • the binder includes a polymer having a repeating unit represented by the following structural formula 3:
  • pH value of the second positive electrode additive is greater than or equal to 10.0.
  • R can be ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene and their halogen substituents such as fluoroethylene, fluoropropylene group, fluorobutylene group, etc.; R1 can also be vinylidene, propenylene, butenylene, pentenylene, hexenylene, heptenylene, octenylene and its halogen substituents such as Fluorinated vinylene, fluoropropenylene, fluorobutenylene, etc.
  • R2 and R3 can be each independently: methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and their halogen substituents such as fluoromethyl, fluorine Ethyl, fluoropropyl, fluorobutyl, fluoropentyl, fluorohexyl, fluoroheptyl, fluorooctyl, etc.; vinyl, propenyl, butenyl, pentenyl, hexene Base, heptenyl, octenyl and their halogen substituents such as fluorovinyl, fluoropropenyl, fluorobutenyl, etc.; ethynyl, propynyl, butynyl, pentynyl, hexynyl , heptynyl, octynyl and their halogen substituent
  • halogen is not particularly limited, and may be, for example, fluorine, chlorine, bromine and iodine.
  • the binder includes a polymer having a repeating unit represented by Structural Formula 3 above.
  • the molar ratio of the repeating unit represented by the above Structural Formula 3 in the above polymer is preferably 90% or more. In this case, the above-mentioned polymer is more excellent in adhesiveness.
  • the pH value of the second positive electrode additive is greater than or equal to 10.0; optionally, the pH value of the second positive electrode additive may be greater than or equal to 10.5, 11.0, 11.5, 12.0, 12.5, 13.0 and 13.5.
  • the second positive electrode additive with a pH value greater than or equal to 10.0 is used in the positive electrode slurry, due to the strong alkalinity (pH>10.0) of the above-mentioned second positive electrode additive, the repeating unit represented by the following structural formula 3 is used as the binder
  • the polymer is easy to remove HF molecules and form continuous double bonds on the molecular chains, and the double bonds may be broken and cross-linked with other molecular chains, so it is prone to the problem that the positive electrode slurry is prone to chemical gelation.
  • the positive electrode slurry provided by the present application, although it contains a polymer having a repeating unit represented by the above structural formula 3 as a binder and contains a second positive electrode additive with a pH value greater than or equal to 10.0, it is at least 24 hours after preparation It still has good fluidity within a certain standing time, so it meets the process requirements for the actual manufacturing of secondary batteries.
  • the first positive electrode additive contained in the positive electrode slurry of the present application can be used as a base-binding agent to reduce the alkalinity of the second positive electrode additive, thereby avoiding the second positive electrode due to strong alkalinity during the standing and processing of the positive electrode slurry.
  • the nucleophilic attack of the additive on the binder polymer leads to the reaction of removing HF and finally leads to the chemical gelation of the positive electrode slurry, thereby prolonging the static stability time of the positive electrode slurry.
  • the secondary battery prepared from the positive electrode slurry of the present application can greatly reduce the amount of gas produced during the formation process, and the high-temperature storage characteristics are also improved. It is speculated that this may be due to the following two reasons: on the one hand, the first positive electrode additive in the positive electrode sheet forms a dense protective layer by oxidative polymerization on the surface of the second positive electrode additive during the formation of the battery.
  • the first positive electrode additive reacts on the surface of the second positive electrode additive to generate sulfur-containing substances and covers the surface of the second positive electrode additive.
  • the above-mentioned product can reduce the surface activity of the second positive electrode additive, thereby inhibiting the oxidative decomposition of the electrolyte, thereby greatly reducing the gas production during the formation process of the battery, and improving the high-temperature storage characteristics of the battery.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive may be 0.01:100 ⁇ 100:100.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive may be 0.5:100-9:100, 1:100-80:100, 4:100-65:100, 5:100- 55:100, 6:100 ⁇ 40:100, 7:100 ⁇ 36:100, 8:100 ⁇ 27:100, 9:100 ⁇ 22:100, 10:100 ⁇ 18:100, 11:100 ⁇ 17: 100, 12:100 ⁇ 19:100, 8:100 ⁇ 16:100, 9:100 ⁇ 15:100 and 7:100 ⁇ 15:100.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive when the mass ratio of the first positive electrode additive to the second positive electrode additive is within the above range, the effect of prolonging the static stability time of the positive electrode slurry may be more significant.
  • the mass ratio of the first positive electrode additive to the second positive electrode additive when the mass ratio of the first positive electrode additive to the second positive electrode additive is within the above-mentioned range, even if the second positive electrode additive is a lithium replenishing agent, the first positive electrode additive will hardly consume the active lithium ions of the lithium replenishing agent, Thereby maintaining the capacity of the battery.
  • the R 1 can be halogen substituted or unsubstituted ethylene, propylene, butylene, vinylene or propenylene.
  • R 1 can be ethylene, propylene, or butylene; or can be fluoroethylene, fluoropropylene, or fluorobutylene.
  • the R 2 and R 3 may each independently be a halogen-substituted or unsubstituted methyl, ethyl, propyl or butyl group.
  • R2 and R3 can each independently be methyl, ethyl, propyl, or butyl; or can each independently be fluoromethyl, fluoroethyl, fluoropropyl, or fluorobutyl.
  • R 1 or R 2 and R 3 are the above-mentioned groups, on the one hand, it can be ensured that the first positive electrode additive itself will not cause the physical gelation of the slurry (for example, due to the molecules of the first positive electrode additive and lithium-containing phosphate materials, etc.
  • the physical gel of the positive electrode slurry is caused by the hydrogen bond and other forces between them); on the other hand, after the first positive electrode additive reacts on the surface of the second positive electrode additive, it can partially isolate the electrolyte on the surface of the second positive electrode additive. role.
  • the first positive electrode additive can be selected from At least one of the following:
  • the binder may contain at least one selected from the following: vinylidene fluoride homopolymer, vinylidene fluoride-acrylic acid copolymer, vinylidene fluoride-acrylate copolymer, vinylidene fluoride -tetrafluoroethylene copolymer, vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, Vinyl fluoride-chlorotrifluoroethylene copolymer, optionally, the binder can be vinylidene fluoride-acrylic acid copolymer or vinylidene fluoride homopolymer.
  • the pH of the lithium-containing phosphate material may be less than 10.0.
  • the pH value of the lithium-containing phosphate material is greater than or equal to 10.0, the positive electrode slurry is prone to chemical gelation during standing and processing after preparation.
  • the lithium-containing phosphate material may comprise at least one selected from LiFePO 4 , LiFeVPO 4 , LiFeMnPO 4 , carbon-coated LiFePO 4 , carbon-coated LiFeVPO 4 and carbon-coated LiFeMnPO 4 kind.
  • LiFePO 4 LiFePO 4
  • LiFeVPO 4 LiFeMnPO 4
  • carbon-coated LiFePO 4 carbon-coated LiFeVPO 4
  • carbon-coated LiFeMnPO 4 kind carbon-coated LiFeMnPO 4 kind.
  • the second positive electrode additive may contain at least one selected from the following: Li 2 MnO 3 , Li 2 MoO 3 , Li 2 RuO 3 , Li 3 VO 4 , Li 2 NiO 2 , Li 6 CoO 4 , Li 5 FeO 4 , Li 2 C 2 , Li 3 N, Li 2 S and the general formula Li 1+a [ Nix Co y Mn z M b ] O2 represents the material,
  • M can be selected from Mg, Ca, One or more of Sb, Ce, Ti, Zr, Sr, Al, Zn, Mo and B, optionally, 0.8 ⁇ x ⁇ 1.
  • the second positive electrode additive is not particularly limited, and different materials can be used according to actual needs. For example, in order to improve the capacity characteristics of the secondary battery, the materials listed above may be used.
  • the second positive electrode additive may include at least one selected from the group consisting of LiNi 0.96 Co 0.02 Mn 0.02 O 2 , Li 5 FeO 4 and Li 2 NiO 2 .
  • a secondary battery which includes a positive electrode sheet containing a positive electrode active material layer, and the positive electrode active material layer is obtained by coating the positive electrode slurry described in any one of the above aspects and obtained by drying.
  • the electrode sheet may be a positive electrode sheet or a negative electrode sheet.
  • a secondary battery in one embodiment, includes a positive electrode sheet, a negative electrode sheet, an electrolyte, and a separator.
  • a positive electrode sheet a negative electrode sheet
  • an electrolyte a separator.
  • the electrolyte plays the role of conducting lithium ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows lithium ions to pass through.
  • the positive electrode sheet may include a positive electrode collector and a positive electrode active material layer disposed on at least one surface of the positive electrode collector.
  • the positive electrode active material layer may be obtained by coating and drying the positive electrode slurry described in any one of the above embodiments.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode active material layer is disposed on either or both of the opposing two surfaces of the positive electrode current collector.
  • the positive electrode current collector can be a metal foil or a composite current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate.
  • the composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate Formed on substrates such as polyethylene formate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.
  • PP polypropylene
  • PET polyethylene formate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive active material layer may optionally include a conductive agent.
  • conductive agents generally used in the art can be used.
  • the conductive agent may include at least one of Super P, acetylene black, carbon black, Ketjen black, carbon nanotubes, carbon nanorods, graphene and carbon nanofibers.
  • the positive electrode active material layer coated on the positive electrode current collector can be prepared in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other The components are dispersed in a solvent (the solvent may include N-methylpyrrolidone (NMP), triethyl phosphate, N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide etc.), to form a positive electrode slurry; apply the positive electrode slurry on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode coated on the positive electrode current collector can be obtained active material layer.
  • a solvent may include N-methylpyrrolidone (NMP), triethyl phosphate, N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide etc.
  • the positive electrode active material layer coated on the positive electrode current collector can be manufactured by casting the positive electrode slurry for forming the positive electrode active material layer on a separate carrier, The film obtained by peeling off from the support was then laminated on the positive electrode current collector.
  • the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative electrode active material layer may include negative electrode active materials and optional binders, conductive agents and other auxiliary agents.
  • the anode current collector has two opposing surfaces in its own thickness direction, and the anode active material layer is disposed on either or both of the two opposing surfaces of the anode current collector.
  • the negative electrode current collector may use a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate.
  • Composite current collectors can be formed by metal materials (such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) Formed on substrates such as polyethylene formate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative active material layer may further optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative active material layer may further optionally include a conductive agent.
  • the conductive agent can be selected from at least one of Super P, acetylene black, carbon black, Ketjen black, carbon nanotubes, carbon nanorods, graphene and carbon nanofibers.
  • the negative electrode active material layer may also optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode active material layer coated on the negative electrode current collector can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other The components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, it can be coated on the negative electrode current collector.
  • a solvent such as deionized water
  • the negative electrode active material layer can be manufactured by casting the negative electrode slurry for forming the negative electrode active material layer on a separate carrier, and then separating the The film is laminated on the negative electrode current collector.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid or gel.
  • the electrolyte of the embodiment of the present application may include additives.
  • the additives may include additives commonly used in this field.
  • the additives may include, for example, halogenated alkylene carbonate compounds (such as difluoroethylene carbonate), pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, (glyme) Ethers, hexamethylphosphoric triamide, nitrobenzene derivatives, sulfur, quinoneimine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts , pyrrole, 2-methoxyethanol or aluminum trichloride.
  • the additive may be included in an amount of 0.1 wt% to 5 wt%, or the amount of the additive may be adjusted by those skilled in the art according
  • the electrolyte is an electrolytic solution.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the secondary battery may include an outer package.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag can be plastic. Examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.
  • FIG. 1 shows a square-shaped secondary battery 5 as an example.
  • the outer package may include a casing 51 and a cover plate 53 .
  • the housing 51 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating chamber. Electrolyte is infiltrated in the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to actual needs.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 are arranged in sequence along the length direction of the battery module 4 .
  • multiple secondary batteries 5 may also be arranged in any other manner.
  • the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may also include a case having a housing space in which a plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 6 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is generally required to be light and thin, and a secondary battery can be used as a power source.
  • the cathode slurry was prepared as follows.
  • step 2) According to actual needs, add an appropriate amount of NMP to the dry powder mixed in step 1), and stir;
  • step 2) adding the first positive electrode additive to the slurry in step 2) and stirring;
  • composition and mass ratio of the first positive electrode additive, the second positive electrode additive, the conductive agent, the binder and the positive electrode active material in the positive electrode slurry are listed in the following table 1, and the solid content of the positive electrode slurry is 50% by weight ⁇ 80% by weight.
  • the above positive electrode slurry is evenly coated on the positive electrode current collector aluminum foil, and then dried and cold pressed to obtain a positive electrode sheet with a positive electrode active material layer.
  • Deionized water is uniformly mixed with the solvent deionized water to prepare negative electrode slurry; then the negative electrode slurry is evenly coated on the negative electrode current collector copper foil, and then dried, cold pressed, and cut to obtain the negative electrode sheet.
  • a polyethylene film with a thickness of 14 ⁇ m was used as a separator, and the above-mentioned positive electrode sheet and negative electrode sheet were wound into a bare cell with the separator interposed therebetween. Put the bare cell in the aluminum-plastic film bag of the battery case, inject the above electrolyte after drying, and then go through processes such as formation and standing to make a secondary battery.
  • the particle size of the carbon-coated LiFePO 4 used as the positive electrode active material is 1 ⁇ m
  • the carbon-coated LiFePO 4 refers to the carbon source such as sucrose, glucose, etc. during the sintering process of LiFePO 4 Carbonized coated LiFePO 4
  • the particle size of carbon-coated LiFeMnPO 4 as the positive electrode active material is 1 ⁇ m
  • carbon-coated LiFeMnPO 4 refers to LiFeMnPO 4 covered by high-temperature carbonization of carbon sources such as sucrose and glucose during the sintering process LiFeMnPO 4 .
  • the materials shown in Table 1 above are all commercially available.
  • the pH values of the second cathode additive and the cathode active material shown in Table 1 were determined as follows.
  • the positive electrode slurry has good fluidity, and the positive electrode slurry can be quickly leveled after falling on the plane after flowing down;
  • the positive electrode slurry has good fluidity, but there is obvious reflection on the surface of the positive electrode slurry, and the positive electrode slurry can be quickly leveled after falling on the plane after flowing down, and the surface of the positive electrode slurry is protruding;
  • Moderate gel the positive electrode slurry has poor fluidity and is flocculent; the positive electrode slurry is flocculent, but has no solid properties; no jelly lumps;
  • Severe gel the positive electrode slurry has no fluidity and is jelly-like; the positive electrode slurry is solid and has no fluidity, and can be picked up as a whole.
  • the volume of the secondary battery prepared above was measured by the drainage method and recorded as V 0 ; then the above secondary battery was charged to 4.5V at a constant current of 0.02C at 45°C, and the charging capacity was recorded as C 0 .
  • the volume of the above-mentioned secondary battery was measured by the drainage method and recorded as V 1 .
  • Formation gas production of the secondary battery (V 1 -V 0 )/C 0 .
  • the secondary battery prepared above was left to stand for 30 minutes, then charged at a constant current of 1C to a voltage of 3.65V, further charged at a constant voltage of 3.65V to a current of 0.05C, left to stand for 5 minutes, and then charged at a constant current of 1C to 0.05C Constant current discharge to a voltage of 2.8V, thus as a charge and discharge cycle process.
  • the discharge capacity at this time is the actual discharge capacity D0 of the secondary battery prepared above.
  • the design capacity of the secondary battery can be calculated as follows:
  • the ratio (%) of the actual capacity of the secondary battery to the design capacity (D0/design capacity) ⁇ 100%.
  • the secondary battery prepared above was left to stand for 30 minutes, then charged at a constant current of 1C to a voltage of 3.65V, and then charged at a constant voltage of 3.65V to a current of 0.05C.
  • the lithium ion was measured by the drainage method.
  • the volume of the battery is recorded as V 0 ; then the fully charged secondary battery is placed in a 60°C incubator, stored for 30 days, and the volume is measured by the drainage method and recorded as V1.
  • Volume expansion rate (%) of the secondary battery after storage at 60° C. for 30 days (V 1 ⁇ V 0 )/V 0 ⁇ 100%.
  • the secondary battery prepared from the above-mentioned positive electrode slurry of the present application can greatly reduce the amount of gas produced during the formation process while maintaining a considerable capacity, and High temperature storage characteristics are also improved.
  • Example 12 and Example 13 with Comparative Example 2 and Comparative Example 3 and the comparison of Example 1 with Comparative Example 1, it can be seen that when the positive electrode active material is the same as the second positive electrode additive, the positive electrode slurry of the present application
  • the prepared secondary battery can greatly reduce the gas production during the formation process, and the high-temperature storage characteristics are also significantly improved.
  • Example 1 Comparative Example 4
  • the secondary battery of Comparative Example 4 does not contain the second positive electrode additive with strong alkalinity in the positive electrode slurry during the preparation process, there is no gel phenomenon,
  • it is still significantly inferior to the secondary battery in Example 1 of the present application in terms of gas production through formation of the secondary battery and volume expansion rate after storage at 60° C. for 30 days.
  • the present battery prepared from the positive electrode slurry using the second positive electrode additive with strong basicity The applied secondary battery is also significantly better in terms of gas formation rate and volume expansion rate after storage at 60°C for 30 days.
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

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Abstract

本申请涉及一种正极浆料及由其制备的二次电池，所述正极浆料包含含锂磷酸盐材料、第一正极添加剂、第二正极添加剂和粘结剂，其中所述第一正极添加剂为由以下结构式（1）表示的化合物和结构式（2）表示的化合物中的至少一种：其中R1为选自如下中的一种：被卤素取代或未被卤素取代的C2-C4的亚烷基、亚烯基以及它们的衍生物；R3各自独立地为被卤素取代或未被卤素取代的烷基、烯基、炔基或芳基；所述粘结剂包括具有由如下结构式（3）表示的重复单元的聚合物，其中所述第二正极添加剂的pH值大于等于10.0。

Description

正极浆料及由其制备的二次电池 技术领域
本申请涉及电池技术领域，具体地涉及正极浆料及由其制备的二次电池。
背景技术
近年来，随着人们对清洁能源需求的日益递增，二次电池已广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、交通工具、军用设备、航空航天等多个领域。由于二次电池的应用领域得到了极大的扩展，因此对其性能也提出了更高的要求。
目前，商用的正极活性材料主要为含锂磷酸盐材料(如LiFePO 4)和三元(镍、钴和锰)正极活性材料。对于含锂磷酸盐材料(如LiFePO 4)，其与石墨配合使用时存在电池前期循环衰减较快的问题。为了解决该问题，在正极中添加补锂剂是一种有效的手段。补锂剂的使用显著改善了电池前期循环衰减较快的问题。
发明内容
技术问题
但是，由于补锂剂大多为碱性较强的富锂材料(例如pH值大于等于10.0)，因此在使用含有偏氟乙烯重复单元(下文结构式3所示的单元)的聚合物作为正极浆料用粘结剂时，在正极浆料搅拌过程中作为粘结剂的聚合物的分子链在强碱性环境下容易脱去HF分子，并在该分子链上形成连续的双键。所述双键可能断裂并与其他分子链交联，最终导致正极浆料容易发生化学凝胶，由此影响正常的配料、涂布及后续工艺。此外，上述富锂材料的催化氧化作用一般较强，由此会加剧电池中电解液的氧化分解而导致产气量增加。
技术方案
本申请的发明人为了解决上述问题而完成了本发明。
根据本申请的第一方面，提供一种正极浆料，所述正极浆料包含含锂磷酸盐材料、第一正极添加剂、第二正极添加剂和粘结剂，其中，
所述第一正极添加剂为由以下结构式1表示的化合物和结构式2表示的化合物中的至少一种：
Figure PCTCN2021134335-appb-000001
其中R 1为选自如下中的一种：被卤素取代或未被卤素取代的C2-C4的亚烷基、亚烯基以及它们的衍生物；R 2和R 3各自独立地为被卤素取代或未被卤素取代的烷基、烯基、炔基或芳基；
所述粘结剂包括具有由如下结构式3表示的重复单元的聚合物，
Figure PCTCN2021134335-appb-000002
其中所述第二正极添加剂的pH值大于等于10.0。
根据本申请提供的正极浆料，尽管其包含具有由上述结构式3表示的重复单元的聚合物作为粘结剂(同时可包含其他类型的粘结剂)并且包含pH值大于等于10.0的第二正极添加剂，但是其在制备后的至少24小时的静置时间内仍具有较好的流动性，因此满足二次电池实际制造的工艺要求。
根据本申请的任一方面，其中所述第一正极添加剂与所述第二正极添加剂的质量比可以为0.01：100～100：100。
在本申请中，当第一正极添加剂与第二正极添加剂的质量比在上述范围内时，延长正极浆料的静置稳定时间的效果可能会较显著。另一方面，当第一正极添加剂与第二正极添加剂的质量比在上述范围内时，即使第二正极添加剂为补锂剂，第一正极添加剂也几乎不会消耗补锂剂的活性锂离子，从而保持电池的容量。
根据本申请的任一方面，其中所述R 1可以为被卤素取代或未被卤素取代的亚乙基、亚丙基、亚丁基、亚乙烯基或亚丙烯基。
根据本申请的任一方面，其中所述R 2和R 3可以各自独立地为被卤素取代或未被卤素取代的甲基、乙基、丙基或丁基。
在R 1或R 2和R 3为上述基团时，一方面可以确保第一正极添加剂自身不会引起浆料的物理凝胶；另一方面第一正极添加剂在第二正极添加剂表面发生反应后，可以在第二正极添加剂表面起到部分隔绝电解液的作用。
根据本申请的任一方面，其中所述第一正极添加剂可以为选自如下中的至少一种：
Figure PCTCN2021134335-appb-000003
根据本申请的任一方面，其中所述粘结剂可以包含选自如下中的至少一种：偏氟乙烯均聚物、偏氟乙烯-丙烯酸共聚物(P(VDF-co-AA))、偏氟乙烯-丙烯酸酯共聚物、偏氟乙烯-四氟乙烯共聚物、偏氟乙烯-五氟丙烯共聚物、偏氟乙烯-五氟丙烯-四氟乙烯共聚物、偏氟 乙烯-全氟甲基乙烯基醚-四氟乙烯共聚物、偏氟乙烯-氯三氟乙烯共聚物，可选地，所述粘结剂可以为偏氟乙烯-丙烯酸共聚物或偏氟乙烯均聚物。
根据本申请的任一方面，其中所述含锂磷酸盐材料的pH值可以为小于10.0。当含锂磷酸盐材料的pH值大于等于10.0时，正极浆料在制备后的静置和处理过程中容易发生化学凝胶。
根据本申请的任一方面，其中所述含锂磷酸盐材料可以包含选自LiFePO 4、LiFeVPO 4、LiFeMnPO 4、碳包覆的LiFePO 4、碳包覆的LiFeVPO 4和碳包覆的LiFeMnPO 4中的至少一种。当采用上述含锂磷酸盐材料作为活性材料时，可以改善电池的寿命特性和容量特性。
根据本申请的任一方面，其中所述第二正极添加剂可以包含选自如下中的至少一种：Li 2MnO 3、Li 2MoO 3、Li 2RuO 3、Li 3VO 4、Li 2NiO 2、Li 6CoO 4、Li 5FeO 4、Li 2C 2、Li 3N、Li 2S和由通式Li 1+a[Ni xCo yMn zM b]O 2表示的材料，
其中0.6<x<1，0≤y<0.3，0≤z<0.3，0<a<0.2，0<b<0.2，x+y+z+b＝1，M可以为选自Mg、Ca、Sb、Ce、Ti、Zr、Sr、Al、Zn、Mo和B中的一种或多种，可选地，0.8<x<1。
根据本申请的任一方面，其中所述第二正极添加剂可以包含选自如下中的至少一种：LiNi 0.96Co 0.02Mn 0.02O 2、Li 5FeO 4和Li 2NiO 2。
根据本申请的第二方面，提供一种二次电池，其包含含有正极活性材料层的正极极片，所述正极活性材料层是通过对上述任一方面所述的正极浆料进行涂布和干燥而得到的。
根据本申请的第三方面，提供一种电池模块，其包含上述第二方面的二次电池。
根据本申请的第四方面，提供一种电池包，其包含上述第三方面的电池模块。
根据本申请的第五方面，提供一种用电装置，其包含上述第二方面的二次电池、第三方面的电池模块和第四方面的电池包中的至少一种。
有益效果
根据本申请提供的正极浆料，尽管其包含具有由上述结构式3表示的重复单元的聚合物作为粘结剂并且包含pH值大于等于10.0的第二正极添加剂，但是其在制备后的至少24小时的静置时间内仍具有较好的流动性，因此满足二次电池实际制造的工艺要求。本申请的正极浆料中包含的第一正极添加剂可以作为缚碱剂降低第二正极添加剂的碱性，由此避免正极浆料静置和处理过程中因强碱性的第二正极添加剂对粘结剂聚合物的亲核进攻而发生脱除HF的反应并最终导致正极浆料发生化学凝胶，从而延长正极浆料的静置稳定时间。
此外，与由含有第二正极添加剂和PVDF类粘结剂的正极浆料制备得到的常规的二次电池相比，由本申请的正极浆料制备得到的二次电池可以大幅降低化成过程中的产气量，并且高温存储特性也得到改善。
附图说明
图1是本申请的一个实施方式的二次电池的示意图；
图2是图1所示的本申请的一个实施方式的二次电池的分解图；
图3是本申请的一个实施方式的电池模块的示意图；
图4是本申请的一个实施方式的电池包的示意图；
图5是图4所示的本申请的一个实施方式的电池包的分解图；
图6是本申请的一个实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳体；52电极组件；53顶盖组件。
具体实施方式
以下，对本申请的电极极片进行详细说明，但是会存在省略不必要的详细说明的情况。例如，存在省略对众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，以下说明及实施例是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合而形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合而形成新的技术方案。
以下对本申请的正极浆料及由其制备的二次电池、电池模块、电池包和用电装置进行详细说明。
本申请的第一实施方式可以提供一种正极浆料，所述正极浆料包含含锂磷酸盐材料、第一正极添加剂、第二正极添加剂和粘结剂，其中，
所述第一正极添加剂为由以下结构式1表示的化合物和结构式2表示的化合物中的至少一种：
Figure PCTCN2021134335-appb-000004
其中R 1为选自如下中的一种：被卤素取代或未被卤素取代的C2-C4的亚烷基、亚烯基以及它们的衍生物；R 2和R 3各自独立地为被卤素取代或未被卤素取代的烷基、烯基、炔基或芳基；
所述粘结剂包括具有由如下结构式3表示的重复单元的聚合物：
Figure PCTCN2021134335-appb-000005
其中所述第二正极添加剂的pH值大于等于10.0。
在本申请中，R 1可以为亚乙基、亚丙基、亚丁基、亚戊基、亚己基、亚庚基、亚辛基及其卤素取代基如氟代亚乙基、氟代亚丙基、氟代亚丁基等；R 1还可以为亚乙烯基、亚丙烯基、亚丁烯基、亚戊烯基、亚己烯基、亚庚烯基、亚辛烯基及其卤素取代基如氟代亚乙烯基、氟代亚丙烯基、氟代亚丁烯基等。
在本申请中，R 2和R 3可以各自独立地为：甲基、乙基、丙基、丁基、戊基、己基、庚基、辛基及其卤素取代基如氟代甲基、氟代乙基、氟代丙基、氟代丁基、氟代戊基、氟代己基、氟代庚基、氟代辛基等；乙烯基、丙烯基、丁烯基、戊烯基、己烯基、庚烯基、辛烯基及其卤素取代基如氟代乙烯基、氟代丙烯基、氟代丁烯基等；乙炔基、丙炔基、丁炔基、戊炔基、己炔基、庚炔基、辛炔基及其卤素取代基如氟代乙炔基、氟代丙炔基、氟代丁炔基等；或者苯基、苄基、苯乙基、苯丙基、苯丁基及其卤素取代基如氟代苄基、氟代苯乙基、氟代苯丙基、氟代苯丁基等。
在本申请中，上述卤素没有特别限制，例如可以为氟、氯、溴和碘。
在本申请中，所述粘结剂包括具有由上述结构式3表示的重复单元的聚合物。考虑到所述粘结剂的粘结性，上述聚合物中由上述结构式3表示的重复单元的摩尔占比优选为90％以上。此时，上述聚合物的粘结性更优异。
在本申请中，所述第二正极添加剂的pH值大于等于10.0；可选地，所述第二正极添加剂的pH值可以大于等于10.5、11.0、11.5、12.0、12.5、13.0和13.5。当在正极浆料中使用pH值大于等于10.0的第二正极添加剂时，由于上述第二正极添加剂的强碱性(pH>10.0)作用，作为粘结剂的具有由如下结构式3表示的重复单元的聚合物易于脱去HF分子并在分子链上形成连续的双键，而所述双键可能断裂并与其它分子链发生交联，所以易于出现正极浆料容易发生化学凝胶的问题。
根据本申请提供的正极浆料，尽管其包含具有由上述结构式3表示的重复单元的聚合物作为粘结剂并且包含pH值大于等于10.0的第二正极添加剂，但是其在制备后的至少24小时的静置时间内仍具有较好的流动性，因此满足二次电池实际制造的工艺要求。这是因为本申请的正极浆料中包含的第一正极添加剂可以作为缚碱剂降低第二正极添加剂的碱性，由此避免正极浆料静置和处理过程中因强碱性的第二正极添加剂对粘结剂聚合物的亲核进攻而发生脱除HF的反应并最终导致正极浆料发生化学凝胶，从而延长正极浆料的静置稳定时间。
此外，与由含有第二正极添加剂和作为粘结剂的具有由上述结构式3表示的重复单元的聚合物的正极浆料制备得到的二次电池相比，由本申请的正极浆料制备得到的二次电池可以大幅降低化成过程中的产气量，并且高温存储特性也得到改善。据推测，这可能是由于如下两个方面的原因：一方面是正极极片中的第一正极添加剂在电池化成过程中在第二正极添加剂表面处发生氧化聚合反应而形成一层致密的保护层；另一方面是在正极浆料制备过程中第一正极添加剂在第二正极添加剂的表面发生反应生成含硫的物质并覆盖第二正极添加剂的表面。上述产物能够降低第二正极添加剂的表面活性，由此抑制电解液的氧化分解，从而大幅降低电池化成过程中的产气量，并且改善电池的高温存储特性。
在一些实施方式中，所述第一正极添加剂与所述第二正极添加剂的质量比可以为0.01：100～100：100。可选地，所述第一正极添加剂与所述第二正极添加剂的质量比可以为0.5：100～9：100，1：100～80：100，4：100～65：100，5：100～55：100，6：100～40：100，7：100～36：100，8：100～27：100，9：100～22：100，10：100～18：100，11：100～17：100，12：100～19：100，8：100～16：100，9：100～15：100和7：100～15：100。
在本申请中，当第一正极添加剂与第二正极添加剂的质量比在上述范围内时，延长正极浆料的静置稳定时间的效果可能会较显著。另一方面，当第一正极添加剂与第二正极添加剂的质量比在上述范围内时，即使第二正极添加剂为补锂剂，第一正极添加剂也几乎不会消耗补锂剂的活性锂离子，从而保持电池的容量。
在一些实施方式中，所述R 1可以为被卤素取代或未被卤素取代的亚乙基、亚丙基、亚丁基、亚乙烯基或亚丙烯基。例如，R 1可以为亚乙基、亚丙基或亚丁基；或者可以为氟代亚乙基、氟代亚丙基或氟代亚丁基。
在一些实施方式中，所述R 2和R 3可以各自独立地为被卤素取代或未被卤素取代的甲基、乙基、丙基或丁基。例如，R 2和R 3可以各自独立地为甲基、乙基、丙基或丁基；或者可以各自独立地为氟代甲基、氟代乙基、氟代丙基或氟代丁基。
在R 1或R 2和R 3为上述基团时，一方面可以确保第一正极添加剂自身不会引起浆料的物理凝胶(例如，因第一正极添加剂的分子与含锂磷酸盐材料等之间的氢键等作用力而造 成正极浆料发生的物理凝胶)；另一方面第一正极添加剂在第二正极添加剂表面发生反应后，可以在第二正极添加剂表面起到部分隔绝电解液的作用。
在一些实施方式中，从延长正极浆料的静置稳定时间、降低二次电池化成过程中的产气量以及改善二次电池的高温存储特性的观点考虑，所述第一正极添加剂可以为选自如下中的至少一种：
Figure PCTCN2021134335-appb-000006
在一些实施方式中，其中所述粘结剂可以包含选自如下中的至少一种：偏氟乙烯均聚物、偏氟乙烯-丙烯酸共聚物、偏氟乙烯-丙烯酸酯共聚物、偏氟乙烯-四氟乙烯共聚物、偏氟乙烯-五氟丙烯共聚物、偏氟乙烯-五氟丙烯-四氟乙烯共聚物、偏氟乙烯-全氟甲基乙烯基醚-四氟乙烯共聚物、偏氟乙烯-氯三氟乙烯共聚物，可选地，所述粘结剂可以为偏氟乙烯-丙烯酸共聚物或偏氟乙烯均聚物。
在一些实施方式中，所述含锂磷酸盐材料的pH值可以为小于10.0。当含锂磷酸盐材料的pH值大于等于10.0时，正极浆料在制备后的静置和处理过程中容易发生化学凝胶。
在一些实施方式中，所述含锂磷酸盐材料可以包含选自LiFePO 4、LiFeVPO 4、LiFeMnPO 4、碳包覆的LiFePO 4、碳包覆的LiFeVPO 4和碳包覆的LiFeMnPO 4中的至少一种。当采用上述含锂磷酸盐材料作为活性材料时，可以改善电池的寿命特性和容量特性。
在一些实施方式中，从改善二次电池的容量特性的观点考虑，所述第二正极添加剂可以包含选自如下中的至少一种：Li 2MnO 3、Li 2MoO 3、Li 2RuO 3、Li 3VO 4、Li 2NiO 2、Li 6CoO 4、Li 5FeO 4、Li 2C 2、Li 3N、Li 2S和由通式Li 1+a[Ni xCo yMn zM b]O 2表示的材料，
其中0.6<x<1，0≤y<0.3，0≤z<0.3，0<a<0.2，0<b<0.2，x+y+z+b＝1，M可以为选自Mg、Ca、Sb、Ce、Ti、Zr、Sr、Al、Zn、Mo和B中的一种或多种，可选地，0.8<x<1。在本申请中，所述第二正极添加剂没有特别限制，可以根据实际需要使用不同的材料。例如，为了改善二次电池的容量特性，可以使用上述列出的材料。
在一些实施方式中，所述第二正极添加剂可以包含选自如下中的至少一种：LiNi 0.96Co 0.02Mn 0.02O 2、Li 5FeO 4和Li 2NiO 2。
根据本申请的第二方面，提供一种二次电池，其包含含有正极活性材料层的正极极片，所述正极活性材料层是通过对上述任一方面所述的正极浆料进行涂布和干燥而得到的。
在本实施方式中，对所述电极极片的种类没有特别限制。例如，所述电极极片可以为正极极片或负极极片。
本发明的实施方式的详细说明
以下适当地参照附图对本申请的二次电池、电池模块、电池包和用电装置进行详细说明。
在本申请的一个实施方式中，提供一种二次电池。通常情况下，二次电池包括正极极 片、负极极片、电解质和隔离膜。在电池充放电过程中，锂离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导锂离子的作用。隔离膜设置在正极极片与负极极片之间，主要起到防止正负极短路的作用，同时可以使锂离子通过。以下对二次电池的各构成要素进行详细说明。
[正极极片]
正极极片可以包括正极集流体以及设置在正极集流体的至少一个表面上的正极活性材料层。所述正极活性材料层可以是通过对上述任一实施方式所述的正极浆料进行涂布和干燥而得到的。
作为示例，正极集流体具有在其自身厚度方向上相对的两个表面，正极活性材料层设置在正极集流体的相对的两个表面中的任一者或两者上。
在一些实施方式中，所述正极集流体可以采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铝箔。复合集流体可以包括高分子材料基材和形成于高分子材料基材的至少一个表面上的金属层。复合集流体可以通过将金属材料(如铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料层可以选择性地包括导电剂。作为示例，可以使用本领域通常使用的导电剂。所述导电剂可以包括Super P、乙炔黑、炭黑、科琴黑、碳纳米管、碳纳米棒、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，可以通过以下方式制备涂布在正极集流体上的正极活性材料层：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(所述溶剂可以包括N-甲基吡咯烷酮(NMP)、磷酸三乙酯、N,N-二甲基甲酰胺、N,N-二乙基甲酰胺、二甲亚砜等中的一种或几种)中，形成正极浆料；将正极浆料涂布在正极集流体上，经烘干、冷压等工序后，即可以得到涂布在正极集流体上的正极活性材料层。可替代地，在另一个实施方式中，可以通过如下方式来制造涂布在正极集流体上 的正极活性材料层：将用于形成正极活性材料层的正极浆料流延在单独的载体上，然后将通过从载体剥离而获得的膜层压在正极集流体上。
[负极极片]
负极极片可以包括负极集流体以及设置在负极集流体的至少一个表面上的负极活性材料层。所述负极活性材料层可以包括负极活性材料以及可选的粘结剂、导电剂和其他助剂。
作为示例，负极集流体具有在其自身厚度方向上相对的两个表面，负极活性材料层设置在负极集流体的相对的两个表面中的任一者或两者上。
在一些实施方式中，所述负极集流体可以采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可以包括高分子材料基材和形成于高分子材料基材的至少一个表面上的金属层。复合集流体可以通过将金属材料(如铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可以采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可以包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可以选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可以选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可以被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极活性材料层还可以选择性地包括粘结剂。所述粘结剂可以选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极活性材料层还可以选择性地包括导电剂。导电剂可以选自包括Super P、乙炔黑、炭黑、科琴黑、碳纳米管、碳纳米棒、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极活性材料层还可以选择性地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备涂布在负极集流体上的负极活性材料层：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂布在负极集流体上，经烘干、冷压等工序后，即可以得到涂布在负极集流体上的负极活性材料层。可替代地，在另一个实施方式中，可以通过如下方式来制造负极活性材料层：将用于形成负极活性材料层的负极浆料流延在单独的载体上，然后将通过从载体剥离而获得的膜层压在负极集流体上。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可以根据需求进行选择。例如，电解质可以是液态的或凝胶态的。
此外，本申请的实施方式的电解质可以包括添加剂。所述添加剂可以包括本领域中常用的添加剂。所述添加剂可以包括例如卤代碳酸亚烷基酯类化合物(如二氟碳酸亚乙酯)、吡啶、亚磷酸三乙酯、三乙醇胺、环醚、乙二胺、(缩)甘醇二甲醚类、六甲基磷酸三酰胺、硝基苯衍生物、硫、醌亚胺染料、N-取代的唑烷酮、N,N-取代的咪唑烷、乙二醇二烷基醚、铵盐、吡咯、2-甲氧基乙醇或三氯化铝。此时，基于电解质的总重量，可以以0.1重量％至5重量％的量包含添加剂或者由本领域技术人员根据实际需要调整添加剂的用量。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可以选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼 酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可以选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，二次电池可以包括外包装。该外包装可以用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料。作为塑料，可以列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图1是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图2，外包装可以包括壳体51和盖板53。其中，壳体51可以包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可以经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可以根据实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可以根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个二次电池5沿电池模块4的长度方向依次排列设置。当然，多个二次电池5也可以按照其他任意的方式进行排布。进一步地，可以通过紧固件将所述多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间内。
在一些实施方式中，上述电池模块还可以组装成电池包。电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可以根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块或电池包中的至少一种。所述二次电池、电池模块或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图6是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
以下详细说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请， 而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商的，均为可以通过市购获得的常规产品。
(1)正极浆料的制备
在本申请中，如下制备正极浆料。
1)在搅拌釜中添加正极活性材料、导电剂、粘结剂、第二正极添加剂，并进行搅拌；
2)根据实际需要，添加适量NMP添加到步骤1)混匀的干粉中，并进行搅拌；
3)将第一正极添加剂添加到步骤2)的浆料中并进行搅拌；
4)根据实际需要，通过NMP调整步骤3)中得到的浆料的粘度；
其中，正极浆料中的第一正极添加剂、第二正极添加剂、导电剂、粘结剂和正极活性材料的成分及质量比例列于下表1中，并且正极浆料的固含量为50重量％～80重量％。
表1
Figure PCTCN2021134335-appb-000007
Figure PCTCN2021134335-appb-000008
(2)正极极片的制备
将上述正极浆料均匀涂布于正极集流体铝箔上，然后经过烘干和冷压得到具有正极活性材料层的正极极片。
(3)负极极片的制备
将负极活性材料人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC-Na)按照质量比为94：2：2：2溶于溶剂去离子水中并与溶剂去离子水均匀混合后制备成负极浆料；然后将负极浆料均匀涂布在负极集流体铜箔上，之后经过烘干、 冷压、分切得到负极极片。
(4)电解液的制备
在氩气气氛手套箱中(气氛：H 2O<0.1ppm，O 2<0.1ppm)，将1mol/L LiPF 6溶解于有机溶剂(EC/DMC/EMC＝1/1/1(质量比))中，搅拌均匀后得到相应的电解液。
(5)二次电池的制备
采用厚度为14μm的聚乙烯膜作为隔离膜，并将上述正极极片、负极极片以隔离膜置于其间的方式卷绕成裸电芯。将裸电芯置于电池壳体铝塑膜袋中，干燥后注入上述电解液，再经过化成、静置等工艺制得二次电池。
在本申请的实施例和对比例中，作为正极活性材料的碳包覆LiFePO 4的粒径为1μm，并且碳包覆的LiFePO 4是指LiFePO 4烧结过程中被碳源如蔗糖、葡萄糖等高温炭化包覆的LiFePO 4；作为正极活性材料的碳包覆的LiFeMnPO 4的粒径为1μm，并且碳包覆的LiFeMnPO 4是指LiFeMnPO 4烧结过程中被碳源如蔗糖、葡萄糖等高温炭化包覆的LiFeMnPO 4。如无特别说明，上表1中所示的材料均为商购获得的。
实验例
在本申请中，表1中所示的第二正极添加剂和正极活性材料的pH值是如下测定的。
(1)pH值测试方法：
1)称取5g第二正极添加剂或正极活性材料的粉末样品于锥形瓶中；
2)以粉末样品与溶剂去离子水的质量比为1：9的比例将它们加入至上述锥形瓶中，放入磁力转子，用封口膜封口；
3)将上述锥形瓶放在磁力搅拌台中央，搅拌30分钟；
4)搅拌结束，静置1.5小时；
5)采用校准好的pH电极(PH测定仪型号：S220/梅特勒酸度计)浸泡于溶液中，稳定30秒后读数，得到pH值。
(2)正极浆料的稳定性表征方法
1)将正极浆料置于500mL的玻璃杯中，用保鲜膜盖上进行静置，并记录正极浆料静置的初始时间；
2)观察正极浆料静置不同时间的凝胶状态，针对凝胶状态分为以下等级：
a.无凝胶：正极浆料具有较好的流动性，正极浆料流下后落在平面可以迅速流平；
b.轻度凝胶：正极浆料具有较好的流动性，但正极浆料表面存在明显反光，并且正极浆料流下后落在平面可以迅速流平且正极浆料表面呈突起状；
c.中度凝胶：正极浆料流动性较差，呈絮状物；正极浆料类絮状型，但无固体性质；无果冻块状物；
d.严重凝胶：正极浆料无流动性，呈果冻状；正极浆料呈现固体性质，无流动性，可以整块挑起。
(3)二次电池的化成产气量测试方法
在25℃下采用排水法测定上述制备的二次电池的体积并记为V 0；然后将上述二次电池在45℃下以0.02C恒流充电至4.5V，充电容量记为C 0，此时采用排水法测定上述二次电池的体积并记为V 1。
二次电池的化成产气量＝(V 1-V 0)/C 0。
(4)二次电池的实际容量与设计容量的比值
在25℃下，将上述制备的二次电池静置30分钟，之后以1C恒流充电至电压为3.65V，进一步以3.65V恒压充电至电流为0.05C，静置5分钟，然后以1C恒流放电至电压为2.8V，由此作为一个充放电循环过程。此时的放电容量为上述制备的二次电池的实际放电容量D0。
二次电池的设计容量可以如下计算得到：
二次电池的实际容量与设计容量的比值(％)＝(D0/设计容量)×100％。
(5)锂离子电池的60℃存储产气测试方法
在25℃下，将上述制备的二次电池静置30分钟，之后以1C恒流充电至电压为3.65V，然后以3.65V恒压充电至电流为0.05C，此时采用排水法测定锂离子电池的体积并记为V 0；然后将满充的二次电池放入60℃恒温箱中，存储30天，采用排水法测定体积并记为V1。
二次电池60℃存储30天后的体积膨胀率(％)＝(V 1-V 0)/V 0×100％。
上述实验例中测定的结果示于下表2中。下表2中符号“/”表示出现凝胶后未再继续进行测试。
表2
Figure PCTCN2021134335-appb-000009
Figure PCTCN2021134335-appb-000010
由表2可以看出，实施例1至实施例22的正极浆料在制备后的24小时内均未发生凝胶现象，具有较好的流动性。
此外，与对比例1至对比例4的二次电池相比，由本申请的上述正极浆料制备得到的二次电池在保持相当的容量发挥的情况下可以大幅降低化成过程中的产气量，并且高温存储特性也得到改善。
由实施例12和实施例13与对比例2和对比例3的比较以及实施例1与对比例1的比较可知，在正极活性材料与第二正极添加剂相同的情况下，由本申请的正极浆料制备得到的二次电池可以大幅降低化成过程中的产气量，并且高温存储特性也得到明显改善。
此外，由实施例1与对比例4的比较可知，尽管对比例4的二次电池由于在制备过程中的正极浆料中不包含具有强碱性的第二正极添加剂而未出现凝胶现象，但其在二次电池的化成产气量和60℃存储30天后的体积膨胀率方面仍明显比本申请实施例1的二次电池差。换而言之，即使与由未使用具有强碱性的第二正极添加剂的正极浆料制备的二次电池相比，由使用了具有强碱性的第二正极添加剂的正极浆料制备的本申请的二次电池在化成产气量和60℃存储30天后的体积膨胀率方面也明显更优异。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (14)

  1. 一种正极浆料，所述正极浆料包含含锂磷酸盐材料、第一正极添加剂、第二正极添加剂和粘结剂，其中，
    所述第一正极添加剂为由以下结构式1表示的化合物和结构式2表示的化合物中的至少一种：
    Figure PCTCN2021134335-appb-100001
    其中R 1为选自如下中的一种：被卤素取代或未被卤素取代的C2-C4的亚烷基、亚烯基以及它们的衍生物；R 2和R 3各自独立地为被卤素取代或未被卤素取代的烷基、烯基、炔基或芳基；
    所述粘结剂包括具有由如下结构式3表示的重复单元的聚合物，
    Figure PCTCN2021134335-appb-100002
    所述第二正极添加剂的pH值大于等于10.0。
  2. 根据权利要求1所述的正极浆料，其中所述第一正极添加剂与所述第二正极添加剂的质量比为0.01：100～10：100。
  3. 根据权利要求1或2所述的正极浆料，其中所述R 1为被卤素取代或未被卤素取代的亚乙基、亚丙基、亚丁基、亚乙烯基或亚丙烯基。
  4. 根据权利要求1～3中任一项所述的正极浆料，其中所述R 2和R 3各自独立地为被卤素取代或未被卤素取代的甲基、乙基、丙基或丁基。
  5. 根据权利要求1～4中任一项所述的正极浆料，其中所述第一正极添加剂为选自如下中的至少一种：
    Figure PCTCN2021134335-appb-100003
  6. 根据权利要求1～5中任一项所述的正极浆料，其中所述粘结剂包含选自如下中的至少一种：偏氟乙烯均聚物、偏氟乙烯-丙烯酸共聚物、偏氟乙烯-丙烯酸酯共聚物、偏氟乙烯-四氟乙烯共聚物、偏氟乙烯-五氟丙烯共聚物、偏氟乙烯-五氟丙烯-四氟乙烯共聚物、偏氟乙烯-全氟甲基乙烯基醚-四氟乙烯共聚物、偏氟乙烯-氯三氟乙烯共聚物，可选地，所述粘结剂为偏氟乙烯-丙烯酸共聚物或偏氟乙烯均聚物。
  7. 根据权利要求1～6中任一项所述的正极浆料，其中所述含锂磷酸盐材料的pH值小于10.0。
  8. 根据权利要求1～7中任一项所述的正极浆料，其中所述含锂磷酸盐材料包含选自LiFePO 4、LiFeVPO 4、LiFeMnPO 4、碳包覆的LiFePO 4、碳包覆的LiFeVPO 4和碳包覆的 LiFeMnPO 4中的至少一种。
  9. 根据权利要求1～8中任一项所述的正极浆料，其中所述第二正极添加剂包含选自如下中的至少一种：Li 2MnO 3、Li 2MoO 3、Li 2RuO 3、Li 3VO 4、Li 2NiO 2、Li 6CoO 4、Li 5FeO 4、Li 2C 2、Li 3N、Li 2S和由通式Li 1+a[Ni xCo yMn zM b]O 2表示的材料，
    其中0.6<x<1，0≤y<0.3，0≤z<0.3，0<a<0.2，0<b<0.2，x+y+z+b＝1，M为选自Mg、Ca、Sb、Ce、Ti、Zr、Sr、Al、Zn、Mo和B中的一种或多种，可选地，0.8<x<1。
  10. 根据权利要求1～9中任一项所述的正极浆料，其中所述第二正极添加剂包含选自如下中的至少一种：LiNi 0.96Co 0.02Mn 0.02O 2、Li 5FeO 4和Li 2NiO 2。
  11. 一种二次电池，其包含含有正极活性材料层的正极极片，所述正极活性材料层是通过对权利要求1～10中任一项所述的正极浆料进行涂布和干燥而得到的。
  12. 一种电池模块，其包含权利要求11所述的二次电池。
  13. 一种电池包，其包含权利要求12所述的电池模块。
  14. 一种用电装置，其包含选自权利要求11所述的二次电池、权利要求12所述的电池模块或权利要求13所述的电池包中的至少一种。
PCT/CN2021/134335 2021-11-30 2021-11-30 正极浆料及由其制备的二次电池 WO2023097432A1 (zh)

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CN103262326A (zh) * 2010-11-16 2013-08-21 日立麦克赛尔株式会社 非水二次电池
CN107492660A (zh) * 2016-06-13 2017-12-19 宁德新能源科技有限公司 正极浆料、正极片及锂离子电池
CN112005418A (zh) * 2019-12-26 2020-11-27 宁德新能源科技有限公司 一种电解液及电化学装置
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CN1877897A (zh) * 2005-06-07 2006-12-13 日立麦克赛尔株式会社 非水电解液二次电池
CN103262326A (zh) * 2010-11-16 2013-08-21 日立麦克赛尔株式会社 非水二次电池
CN107492660A (zh) * 2016-06-13 2017-12-19 宁德新能源科技有限公司 正极浆料、正极片及锂离子电池
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