WO2018001274A1 - 一种氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用 - Google Patents

一种氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用 Download PDF

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WO2018001274A1
WO2018001274A1 PCT/CN2017/090557 CN2017090557W WO2018001274A1 WO 2018001274 A1 WO2018001274 A1 WO 2018001274A1 CN 2017090557 W CN2017090557 W CN 2017090557W WO 2018001274 A1 WO2018001274 A1 WO 2018001274A1
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lithium ion
ion battery
electrode
fluorophosphate
lithium
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PCT/CN2017/090557
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English (en)
French (fr)
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朱幼仙
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江苏国泰超威新材料有限公司
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention relates to the technical field of lithium ion secondary batteries, in particular to an application of a fluorophosphate in preparing an electrode of a lithium ion battery, a lithium ion battery electrode, a preparation method thereof and an application thereof.
  • Lithium-ion batteries are widely used in various fields of daily life, including various portable electronic devices and electric vehicles, because of their high operating voltage, high energy density, low self-discharge rate, no memory effect, long cycle life and no pollution. .
  • the miniaturization, long standby, long life development of portable electronic devices, and the activation of high-power and high-energy devices such as electric vehicles are all the energy of lithium-ion secondary batteries as energy storage power sources. Density, cycle life, environmental adaptability and other performance put forward higher and higher requirements.
  • the performance of the cycle life of the battery is improved by doping or coating the positive and negative materials, or adding a functional additive to the electrolyte.
  • These are the mainstream methods in the industry. It is also an effective method to increase the energy density of the battery by increasing the mass percentage of the active material or increasing the thickness of the pole piece.
  • the existing methods have the following drawbacks: 1. During the first cycle, the electrolyte and electrode materials in the lithium ion battery system react at the level of the solid-liquid phase to form a layer of SEI film, which consumes the electrode material.
  • the lithium in the active material causes the initial capacity of the lithium ion battery to be low; 2 during the charging and discharging process, the pole piece of a certain thickness causes the battery to form a large concentration polarization, which causes the battery capacity to fail to function properly and the rate performance is poor.
  • a series of problems such as low temperature lithium deposition and cycle capacity decay.
  • the Chinese patent document No. 201210415398.6 is added to the electrode material by coating a lithium source into the polymer to form a core-shell coating structure, thereby improving the battery for the first charge.
  • Capacity loss caused by discharge film formation This method can compensate for the lithium loss caused by the formation of the SEI film, but its actual industrialization cost is high.
  • the present application provides a use of a fluorophosphate in the preparation of a lithium ion battery electrode,
  • the lithium ion battery electrode, the preparation method and application thereof, and the lithium ion battery electrode provided by the invention can obtain a battery with excellent performance such as rate performance and safety performance, and the cost is low.
  • the present invention provides the use of a fluorophosphate in the preparation of a lithium ion battery electrode having the formula I:
  • M is an alkali metal element, 0 ⁇ a ⁇ 3, x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the present invention provides a lithium ion battery electrode comprising a current collector and an electrode material supported on the current collector; the electrode material being made of a slurry comprising an additive, the additive being a fluorophosphate represented by Formula I salt;
  • M is an alkali metal element, 0 ⁇ a ⁇ 3, x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the M is selected from the group consisting of Li, Na, K or Rb, y ⁇ 3, and x + y ⁇ 4.
  • the fluorophosphate accounts for 0.1 to 15% by mass of the lithium ion battery electrode material.
  • the lithium ion battery electrode material is made of a slurry including a fluorophosphate, an active material, a conductive agent, and a binder; the slurry includes: 0.1 to 15% of fluorine by mass fraction Phosphate, 55 to 99% active material, 0.1 to 15% conductive agent and 0.1 to 15% binder.
  • the lithium ion battery electrode is a positive electrode
  • the active material in the positive electrode is selected from a transition metal oxide or a transition metal sulfide.
  • the lithium ion battery electrode is a negative electrode
  • the active material in the negative electrode is selected from a lithium-containing metal, a lithium titanate material, a carbon material, a transition metal oxide material or a silicon material.
  • the invention provides a preparation method of a lithium ion battery electrode, comprising the following steps:
  • the additive is a fluorophosphate represented by Formula I;
  • M is an alkali metal element, 0 ⁇ a ⁇ 3, x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the drying temperature is from 80 to 200 °C.
  • the present invention also provides a lithium ion battery comprising the electrode described above.
  • the present invention uses the fluorophosphate shown in Formula I to prepare a lithium ion battery electrode, which can effectively improve the polarization of the pole piece, improve the stability of the SEI film, and improve the lithium deposition on the surface of the pole piece.
  • the lithium ion battery electrode provided by the invention has low manufacturing cost, and the battery rate performance is obviously improved after the battery is fabricated. The cycle life is significantly extended and the battery safety performance is improved.
  • Figure 1 is a schematic illustration of the addition of fluorophosphate in a pole piece and an electrolyte.
  • the present invention provides the use of a fluorophosphate in the preparation of a lithium ion battery electrode having the formula I:
  • M is an alkali metal element, 0 ⁇ a ⁇ 3, x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the fluorophosphate represented by the formula I is used as an electrode additive for a lithium ion battery, and is used for preparing a lithium ion battery electrode, which can effectively improve the conductivity of the pole piece, and can form a film on the surface of the pole piece, and can improve the pole piece.
  • the stability of the lithium and SEI films can fully improve the performance of the battery, and can also reduce the cost, making it suitable for use in lithium ion secondary batteries.
  • the fluorophosphate has the formula I.
  • M is an alkali metal element, preferably lithium (Li), sodium (Na), potassium (K) or ruthenium (Rb), and more preferably Li or Na.
  • Both x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the fluorophosphate may be LiPO 2 F 2 , NaPO 2 F 2 , KPO 2 F 2 , Li 2 PO 3 F, or the like.
  • the fluorophosphate represented by Formula I may be a commercially available product or may be obtained by preparation.
  • the fluorophosphate content in the lithium ion battery electrode material is preferably from 0.1 to 15%, more preferably from 0.1 to 10%, still more preferably from 0.2 to 8%, most preferably 1 to 6%.
  • the structure of the electrode sheet containing the fluorophosphate is as shown in FIG. 1(b), and FIG. 1 is a schematic view showing the comparison of the addition of the fluorophosphate to the electrode sheet and the electrolyte. In Fig.
  • the present invention provides a lithium ion battery electrode comprising a current collector and an electrode material supported on the current collector; the electrode material being made of a slurry comprising an additive, the additive being a fluorine represented by Formula I Phosphate
  • M is an alkali metal element, 0 ⁇ a ⁇ 3, x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the lithium ion battery electrode provided by the invention, a battery with excellent performance such as rate performance and safety performance can be obtained, and the cost is reduced, and it is suitable for industrial application.
  • the fluorophosphate represented by Formula I is used as a lithium ion battery electrode additive to form a lithium ion battery electrode.
  • the fluorophosphate has the formula I, and M is an alkali metal element, preferably lithium (Li), sodium (Na), potassium (K) or ruthenium (Rb), more preferably Li or Na.
  • M is an alkali metal element, preferably lithium (Li), sodium (Na), potassium (K) or ruthenium (Rb), more preferably Li or Na.
  • Both x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the fluorophosphate may be LiPO 2 F 2 , NaPO 2 F 2 , KPO 2 F 2 , Li 2 PO 3 F, or the like.
  • the fluorophosphate represented by Formula I may be a commercially available product or may be obtained by preparation.
  • the fluorophosphate content in the lithium ion battery electrode material is preferably from 0.1 to 15%, more preferably from 0.1 to 10%, still more preferably from 0.2 to 8%, most preferably 1 to 6%.
  • the present invention can obtain a battery having more excellent performance by adjusting the amount of addition of the fluorophosphate in the electrode.
  • the structure of the electrode tab containing the fluorophosphate is as shown in (b) of FIG.
  • the lithium ion battery electrode material is made of a slurry comprising a fluorophosphate, an active material, a conductive agent, and a binder.
  • the lithium ion battery electrode is a pole piece, and may be a positive electrode piece or a negative electrode piece.
  • the lithium ion battery electrode may be a positive electrode, and the active material (or active material, active component) in the positive electrode may be any transition metal oxide or transition metal sulfide commonly used in the art.
  • lithium cobaltate LiCoO 2
  • LiNi 1-t Mn t O 2 (0 ⁇ t ⁇ 1) LiNi t Co 1-t O 2 (0 ⁇ t ⁇ 1)
  • lithium nickel manganese cobalt oxide LiNi 1/3 Mn 1/3 Co 1/3 O 2 , Li 1.2 Ni 1/6 Mn 1/6 Co 4/6 O 2
  • lithium iron phosphate LiFePO 4
  • Various lithium-containing transition metal composite oxides such as various lithium-free transition metal oxides or transition metal sulfides such as MoS 2 , SnS 2 , MoO 3 , V 2 O 5 , preferably lithium-containing transitions Metal composite oxide.
  • These positive electrode active materials are commercially available or can be obtained by preparation.
  • the lithium ion battery electrode may also be a negative electrode
  • the active material in the negative electrode may be any negative electrode active material commercially available in the prior art, including metallic lithium or lithium alloy; Lithium titanate material dedoped with lithium ions; carbon material capable of doping and dedoping lithium ions; transition metal oxide materials capable of doping and dedoping lithium ions such as tin oxide, antimony oxide, vanadium oxide, oxidation Titanium; or a silicon material that can be doped and dedoped with lithium ions.
  • the present invention preferably employs a carbon material which can be doped and dedoped with lithium ions.
  • Such a carbon material may be graphite or amorphous carbon such as activated carbon, carbon fiber, carbon black, natural graphite or the like.
  • the positive electrode slurry in the embodiment of the present invention may be composed of the fluorophosphate, the positive electrode active material, the conductive agent, the binder, and the like, and the negative electrode slurry may be composed of the fluorophosphate, the negative electrode active material, the conductive agent, A binder or the like is mixed.
  • carbon black and acetylene black can be used as a conductive agent (or a conductive material).
  • the binder (or binder) may be selected from the group consisting of vinylidene fluoride/hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene, and mixtures thereof. Or a styrene butadiene rubber (SBR) based polymer.
  • the components such as the conductive agent and the binder in the positive electrode and the negative electrode may be the same or different.
  • the fluorophosphate, the active material, the conductive agent, the binder, and the like may be composed of a slurry in an amount generally used in a lithium ion battery.
  • the slurry preferably comprises: 0.1 to 15% of a fluorophosphate, 55 to 99% of an active material, 0.1 to 15% of a conductive agent, and 0.1 to 15% of a binder, by mass fraction.
  • the content of the fluorophosphate is more preferably 0.1 to 10% by weight, still more preferably 0.2 to 8%, most preferably 1 to 6%.
  • the mass percentage of the active material is more preferably 60 to 97%, and most preferably 75 to 95%.
  • the mass percentage of the conductive agent is more preferably from 0.5 to 10%, and most preferably from 1 to 8%.
  • the mass percentage of the binder is more preferably from 0.5 to 10%, and most preferably from 1 to 7%.
  • the lithium ion battery electrode includes a current collector, and the present invention is not particularly limited, and may be commonly used in the art, such as copper foil, aluminum foil, or the like.
  • the present invention provides a method of preparing a lithium ion battery electrode, comprising the steps of:
  • the additive is a fluorophosphate represented by Formula I;
  • M is an alkali metal element, 0 ⁇ a ⁇ 3, x and y are integers, 1 ⁇ x, y ⁇ 4, and x + y ⁇ 5.
  • the embodiment of the present invention first provides a slurry including an additive, which is a fluorophosphate represented by Formula I, the contents of which are as described above, and will not be further described herein.
  • the slurry comprises an active material, a conductive agent and a binder, the contents of which are also as described above.
  • the slurry further includes a solvent such as an organic solvent or water to disperse or dissolve the above components.
  • the solvent is preferably N-methylpyrrolidone (NMP), acetone or water, and the amount thereof to be used in the invention is not particularly limited.
  • the mass ratio of the fluorophosphate, the active material, the conductive agent and the binder in the slurry is preferably 0.1 to 15% of the fluorophosphate, 55 to 99% of the active material,
  • the conductive agent is 0.1 to 15%
  • the binder is 0.1 to 15%
  • the slurry has a solid content of 10 to 90%.
  • the fluorophosphate is 0.1 to 10%
  • the active material is 60 to 97%
  • the conductive agent is 0.5 to 10%
  • the binder is 0.5 to 10%
  • the slurry solid content is 30 to 85%. More preferably, it is 0.2 to 8% of fluorophosphate, 75 to 95% of active material, 1 to 8% of conductive agent, and 1 to 7% of binder; and the solid content of the slurry is 40 to 70%.
  • the preparation method of the slurry is not particularly limited.
  • the fluorophosphate may be added to the solvent, stirred and dissolved to prepare a fluorophosphate solution; then the positive electrode active material, the conductive agent and The binder is added to the above solution and stirred to form a uniform slurry.
  • the solids content (i.e., solid content) of the slurry is preferably from 10 to 90%, more preferably from 30 to 85%, most preferably from 40 to 70%.
  • the lithium ion battery electrode includes a current collector, and the present invention is not particularly limited, and it is generally used in the art.
  • the lithium ion battery electrode includes an electrode material supported on a current collector, the electrode material being formed by coating and drying the slurry.
  • the drying may be carried out by drying, and the temperature is preferably from 80 to 200 ° C, more preferably from 100 to 150 ° C, so that the above-mentioned fluorophosphate can be kept stable.
  • the drying time may be from 1 minute to 50 minutes; the roll pressing is a technical means well known to those skilled in the art, and the invention is not particularly limited.
  • the present invention can prepare a positive electrode of a lithium ion battery, and can also prepare a negative electrode.
  • the preparation process of the lithium ion battery electrode in the invention is simple and easy, and the manufacturing cost is low, and is suitable for the lithium ion secondary battery.
  • the lithium ion battery electrode of the present invention is made into a battery, the battery rate performance is remarkably improved, the cycle life is significantly prolonged, and the battery safety performance is improved.
  • the present invention also provides a lithium ion battery comprising the above-described electrode, which has excellent rate performance and safety performance, and is low in cost.
  • the structure of the lithium ion battery may be a structure conventional in the art, and may include a casing, an electrolyte, a separator, a positive electrode sheet, and a negative electrode sheet.
  • the positive electrode sheet and/or the negative electrode sheet may be the electrodes described above, and details are not described herein again.
  • the separator may be selected from various separator layers used in lithium ion batteries known to those skilled in the art, such as polyolefin microporous membranes (PP microporous membranes), polyethylene felts (PE felts). ), glass fiber mat, ultra-fine glass fiber paper or PP/PE/PP composite film.
  • the separator is a PP/PE/PP composite membrane.
  • the electrolyte is a non-aqueous electrolyte containing a lithium salt and a non-aqueous solvent.
  • the lithium salt may be lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium trifluoromethanesulfonate, lithium perfluorobutyl sulfonate, lithium aluminate, One or more of lithium chloroaluminate, lithium fluorosulfonimide, lithium fluorophosphate, lithium chloride and lithium iodide, preferably LiPF 6 .
  • the nonaqueous solvent may be ⁇ -butyrolactone, ethyl methyl carbonate (EMC), methyl propyl carbonate, dipropyl carbonate, acid anhydride, N-methylpyrrolidone, N-methylformamide, N-methyl
  • EMC ethyl methyl carbonate
  • methyl propyl carbonate dipropyl carbonate
  • acid anhydride N-methylpyrrolidone
  • N-methylformamide N-methyl
  • N-methyl N-methyl
  • acetamide, acetonitrile, N,N-dimethylformamide, sulfolane, dimethyl sulfoxide, dimethyl sulfite, and other cyclic organic esters containing fluorine, sulfur or unsaturated bonds Preferably, one or more of ethylene carbonate (EC), diethyl carbonate (DEC) and EMC are preferred.
  • the non-aqueous solvent is a mixed solvent of EC/EMC/DEC, and the volume ratio of the three may be 1:1:1.
  • the concentration of the lithium salt in the electrolytic solution may be from 0.3 to 4 mol/liter, preferably from 0.5 to 2 mol/liter.
  • the present invention can prepare a lithium ion battery according to a method known to those skilled in the art.
  • the method comprises: sequentially winding a positive electrode, a negative electrode and a separator between the positive electrode and the negative electrode to form a pole core, the pole The core is placed in the battery case, the electrolyte is added, and then sealed and formed into a lithium ion battery.
  • the positive electrode comprises a current collector and a positive electrode material supported on the current collector, the negative electrode comprising a current collector and a negative electrode material supported on the current collector; at least one of the two is an electrode described above, and the other may It is a conventional electrode in the art.
  • the housing may be conventionally used in the art, such as a battery aluminum case.
  • the methods of winding, sealing, and forming are all known in the art; the amount of the electrolyte is also a conventional amount.
  • the lithium ion battery of the present invention may have a cylindrical shape, a coin shape, a square shape, or any other shape; the shape of the battery is independent of the basic structure, and design changes may be made according to the purpose.
  • the invention performs performance tests on the lithium ion battery, including a normal temperature cycle performance test, a 45 ° C cycle performance test, and a 5 C rate performance test. The results show that after the fluorophosphate-containing pole piece provided by the invention is assembled into a battery, the battery has better normal temperature cycle performance, high temperature cycle stability, and the rate performance is also obviously improved.
  • the lithium ion battery electrode provided by the invention has low manufacturing cost and is beneficial to practical industrialization.
  • the fluorophosphate used was purchased from Shenzhen Jinghua New Material Co., Ltd.
  • Preparation of positive electrode a total of 3% of sodium difluorophosphate was added to a solvent of N-methylpyrrolidone (NMP) to dissolve and dissolve, and 88% of lithium cobaltate (LiCoO 2 ) as a positive electrode active material was added. 4% of acetylene black as conductive material and 5% of polyvinylidene fluoride (PVDF) were added to the solution and stirred to form a uniform slurry. The solid content of the slurry was 55%, and the obtained slurry was coated on the slurry. The aluminum foil having a thickness of 12 ⁇ m was coated on both sides and dried at 120 ° C, and then rolled and cut to obtain a positive electrode.
  • NMP N-methylpyrrolidone
  • PVDF polyvinylidene fluoride
  • the production of the negative electrode the total negative solids mass fraction of 95% of artificial graphite (Shansong Technology, SS1-P10), 2% of the binder styrene-butadiene rubber latex (SBR), 1% binder carboxymethyl Cellulose (CMC), 2% of conductive material SP and water were added to a disperser for mixing to prepare a slurry having a slurry solid content of 35%.
  • the obtained slurry was applied to both surfaces of a copper foil having a thickness of 10 ⁇ m, dried, and then rolled and cut to obtain a negative electrode.
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 1, except that the fluorophosphate in the positive electrode material was lithium difluorophosphate.
  • the positive electrode, the negative electrode and the battery were prepared by the same method and procedure as in Example 1, except that the fluorophosphate in the positive electrode material was lithium difluorophosphate, the positive electrode active material was lithium iron phosphate, and the ratio of each component was difluorophosphoric acid. Lithium 5%, lithium iron phosphate 89%, acetylene black 3%, binder polyvinylidene fluoride 3%, and the slurry solid content is 60%.
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 1, except that the fluorophosphate in the positive electrode material was lithium difluorophosphate, and the positive electrode active material was lithium nickel manganese cobalt oxide (LiNi 1/3 Mn 1). /3 Co 1/3 O 2 ).
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 1, except that the fluorophosphate in the positive electrode material was potassium difluorophosphate and the positive electrode active material was lithium nickel manganese cobalt oxide (Li 1.2 Ni 1/6). Mn 1/6 Co 4/6 O 2 ).
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 1, except that the fluorophosphate in the positive electrode material was lithium difluorophosphate, and the positive electrode active material was lithium nickel manganese cobalt oxide (LiNi 1/3 Mn 1). /3 Co 1/3 O 2 ), the ratio of each component is 1% of lithium difluorophosphate, 90% of lithium nickel manganese cobalt oxide, 5% of acetylene black, 4% of binder polyvinylidene fluoride, and the solid content of the slurry is 58%.
  • PVDF adhesive polyvinylidene fluoride
  • the production of the negative electrode in deionized water, add 3% of the total negative solids, sodium difluorophosphate, stir and dissolve, then 92% of artificial graphite, 2% of binder styrene butadiene rubber latex (SBR), 1%
  • SBR binder styrene butadiene rubber latex
  • the binder carboxymethyl cellulose (CMC) and 2% of the conductive material SP were added to a disperser for mixing to prepare a slurry having a slurry solid content of 35%.
  • the obtained slurry was applied to both surfaces of a copper foil having a thickness of 10 ⁇ m, dried, and then rolled and cut to obtain a negative electrode.
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 7, except that the fluorophosphate in the negative electrode material was lithium difluorophosphate.
  • the positive electrode, the negative electrode and the battery were prepared by the same method and procedure as in Example 1, except that the fluorophosphate in the negative electrode material was lithium difluorophosphate, and the negative electrode active material was natural graphite (Shansang Technology, DMGS), each group.
  • the ratio is 5% of lithium difluorophosphate, 89% of natural graphite, SP 3%, SBR 2%, CMC 1%, and the solid content of the slurry is 45%.
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 7, except that the fluorophosphate in the negative electrode material was lithium difluorophosphate, and the negative electrode active material was a silicon carbon negative electrode (Shansong Technology, Si-CS- 3).
  • the positive electrode, the negative electrode and the battery were prepared by the same method and procedure as in Example 7, except that the fluorophosphate in the negative electrode material was potassium difluorophosphate, and the ratio of each component was 2% potassium difluorophosphate and 92% artificial graphite. , SP 3%, SBR 2%, CMC 1%, the slurry solid content is 45%.
  • Preparation of positive electrode Adding 3% of lithium difluorophosphate with a total positive electrode solid mass fraction in N-methylpyrrolidone (NMP) solvent, and dissolving 88% of lithium cobaltate (LiCoO 2 ) as a positive electrode active material, 4% of acetylene black as a conductive material, 5% of a binder polyvinylidene fluoride (PVDF) was added to the solution to form a uniform slurry, the solid content of the slurry was 55%, and the obtained slurry was coated on the thickness.
  • NMP N-methylpyrrolidone
  • PVDF binder polyvinylidene fluoride
  • the production of the negative electrode in deionized water, adding 3% of the total negative solids mass fraction of lithium difluorophosphate stirred and dissolved, and then 92% of artificial graphite, 2% of binder styrene butadiene rubber latex (SBR), 1% The binder carboxymethyl cellulose (CMC), 2% of the conductive material SP was added to the disperser for mixing to prepare a slurry having a slurry solid content of 35%. The obtained slurry was applied to both surfaces of a copper foil having a thickness of 10 ⁇ m, dried, and then rolled and cut to obtain a negative electrode.
  • SBR binder styrene butadiene rubber latex
  • CMC carboxymethyl cellulose
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 7, except that the fluorophosphate in the negative electrode material was Li 2 PO 3 F, and the ratio of each component was Li 2 PO 3 F 2%, artificial graphite. 92%, SP 3%, SBR 2%, CMC 1%, and the slurry solid content was 45%.
  • the positive electrode, the negative electrode and the battery were prepared by the same method and procedure as in Example 1, except that the fluorophosphate in the negative electrode material was lithium difluorophosphate, and the negative electrode active material was natural graphite (Shansang Technology, DMGS), each group.
  • the ratio is 15% lithium difluorophosphate, 79% natural graphite, SP 3%, SBR 2%, CMC 1%, and the solid content of the slurry is 45%.
  • the positive electrode, the negative electrode and the battery were prepared by the same method and procedure as in Example 1, except that the fluorophosphate in the negative electrode material was lithium difluorophosphate, and the negative electrode active material was natural graphite (Shansang Technology, DMGS), each group.
  • the ratio is 0.2% lithium difluorophosphate, 93.8% natural graphite, SP 3%, SBR 2%, CMC 1%, the slurry solid content is 45%.
  • the positive electrode, the negative electrode and the battery were prepared in the same manner and in the same manner as in Example 1, except that the drying temperature was 180 °C.
  • PVDF adhesive polyvinylidene fluoride
  • the production of the negative electrode the total negative solids mass fraction of 95% artificial graphite, 2% binder styrene butadiene rubber latex (SBR), 1% binder carboxymethyl cellulose (CMC), 2%
  • SBR styrene butadiene rubber latex
  • CMC binder carboxymethyl cellulose
  • the conductive material SP and water were added to a disperser for mixing to prepare a slurry having a solid content of 35%.
  • the obtained slurry was applied to both surfaces of a copper foil having a thickness of 10 ⁇ m, dried, and then rolled and cut to obtain a negative electrode.
  • the finished batteries obtained in Examples 1 to 16 and Comparative Example 1 were tested in the following manners: at room temperature, firstly charged at a constant current of 1 C to 4.2 V, and then charged at a constant voltage until the current dropped to 0.05 C. Finally, the current was discharged at a constant current of 1 C to 3.0 V. The cycle was cycled for 300 weeks, and the discharge capacity at the first week and the discharge capacity at the 500th week were recorded, and then the capacity retention rate of the battery at normal temperature cycle was calculated according to the following formula. The calculation results are shown in Table 1 below, and Table 1 is an example and Performance test results of lithium ion batteries in the comparative example;
  • Capacity retention ratio discharge capacity at the 300th week / discharge capacity at the first week ⁇ 100%.
  • the finished batteries obtained in Examples 1 to 16 and Comparative Example 1 were tested in the following manners: at 45 ° C, firstly charged at a constant current of 1 C to 4.2 V, and then charged at a constant voltage until the current dropped to 0.05. C, then discharged at a constant current of 1 C to 3.0 V. So cycle for 300 weeks, record the first week of the release The capacity and the discharge capacity at the 300th week, and then calculate the capacity retention rate of the battery at 45 ° C cycle according to the following formula, the calculation results are shown in Table 1 below;
  • Capacity retention ratio discharge capacity at the 300th week / discharge capacity at the first week ⁇ 100%.
  • the finished batteries obtained in Examples 1 to 16 and Comparative Example 1 were tested in the following manners: under normal temperature conditions, the current was firstly charged to 4.2 V with a current of 1 C, and then the constant voltage was charged until the current dropped to 0.05 C. Then, it was discharged at a constant current of 5 C to 3.0 V. So cycled for 50 weeks, recording the 1C discharge capacity of the first week and the 5C discharge capacity of the 50th week, and then calculating the capacity retention rate of the normal temperature ratio of the battery according to the following formula, and the calculation results are shown in Table 1 below;
  • Capacity retention ratio discharge capacity at the 50th week / 1C discharge capacity at the first week ⁇ 100%.
  • Example 1 82 80 71 Example 2 90 87 75 Example 3 87 84 76 Example 4 89 82 79 Example 5 86 82 69 Example 6 83 79 72 Example 7 85 79 70 Example 8 79 76 68 Example 9 91 85 80 Example 10 85 80 72 Example 11 87 81 74 Example 12 92 87 78 Example 13 89 86 75 Example 14 82 86 73
  • Example 15 86 79 83
  • Example 16 82 74 68 Comparative example 1 75 69 58
  • the fluorophosphate-containing pole piece provided by the invention is assembled into a battery, the battery has good normal temperature circulation performance, high temperature cycle stability is good, and the rate performance is also obviously improved, indicating that the fluorophosphoric acid is improved.
  • the addition of salt improves the internal polarization of the battery and the stability of the SEI film, while improving the internal resistance of the battery due to the good conductivity of the fluorophosphate.

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Abstract

本发明提供了一种氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用，所述锂离子电池电极包括集流体和负载在其上的电极材料，所述电极材料由包括添加剂的浆料制成，所述添加剂为MaPOxFy的氟代磷酸盐；其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。本发明采用式I所示的氟代磷酸盐制备锂离子电池电极，能有效改善极片的极化情况，提高SEI膜稳定性，改善极片表面析锂状况。本发明提供的锂离子电池电极制造成本低，组装成电池后，电池倍率性能明显提高，析锂状况明显改善、循环稳定性也有明显提高，电池安全性能得到提高。

Description

一种氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用 技术领域
本发明涉及锂离子二次电池技术领域，尤其涉及一种氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用。
背景技术
锂离子电池因具有工作电压高、能量密度大、自放电率低、无记忆效应、循环寿命长和无污染等优点，广泛应用于日常生活的各个领域，包括各种便携式电子设备和电动汽车等。但随着科技的快速发展，便携式电子设备的微型化、长待机、长寿命的发展，以及电动汽车等大功率、高能量设备的启用，都对作为储能电源的锂离子二次电池的能量密度、循环寿命、环境适应能力等性能提出了越来越高的要求。
在实际的电池设计中，通过对正负极材料掺杂、包覆改性，或在电解液中加入功能性添加剂等方式来改善电池的循环寿命等性能，这些是目前行业内的主流方法。通过提高活性物质的质量百分含量或增加极片的厚度，也是提升电池能量密度的有效方法之一。然而，现有的方法存在如下缺陷：①在首次循环过程中，锂离子电池体系中电解液和电极材料会在固液相间层面上发生反应，形成一层SEI膜，该过程将消耗电极材料活性物质中的锂，从而导致锂离子电池初始容量偏低；②在充放电过程中，一定厚度的极片导致电池形成较大的浓差极化，进而引起电池容量无法正常发挥、倍率性能差、低温析锂、循环容量衰减等一系列问题。
为了改善上述问题，在现有的技术中，申请号为201210415398.6的中国专利文献通过将锂源包覆到聚合物内形成核壳包覆结构后，添加到电极材料中，以改善电池因首次充放电成膜而导致的容量损失。采用此方法可以弥补因形成SEI膜所造成的锂损失，但是其实际工业化成本较高，同时，该方法也很难保证锂单质能被完全包覆且在高温制极片工艺中能稳定存在，不利于在锂离子电池中的应用。
发明内容
有鉴于此，本申请提供一种氟代磷酸盐在制备锂离子电池电极中的应用、 锂离子电池电极、其制备方法和应用，采用本发明提供的锂离子电池电极，能获得倍率性能和安全性能等性能优异的电池，且成本低。
本发明提供氟代磷酸盐在制备锂离子电池电极中的应用，所述氟代磷酸盐具有式I通式：
MaPOxFy式I；
其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
本发明提供一种锂离子电池电极，包括集流体和负载在所述集流体上的电极材料；所述电极材料由包括添加剂的浆料制成，所述添加剂为式I所示的氟代磷酸盐；
MaPOxFy式I；
其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
优选地，所述M选自Li、Na、K或Rb，y≤3，x+y≤4。
优选地，所述氟代磷酸盐在锂离子电池电极材料中占的质量百分含量为0.1～15％。
优选地，所述锂离子电池电极材料由包括氟代磷酸盐、活性物质、导电剂和粘结剂的浆料制成；以质量分数计，所述浆料包括：0.1～15％的氟代磷酸盐、55～99％的活性物质、0.1～15％的导电剂和0.1～15％的粘结剂。
优选地，所述锂离子电池电极为正极，所述正极中活性物质选自过渡金属氧化物或过渡金属硫化物。
优选地，所述锂离子电池电极为负极，所述负极中活性物质选自含锂金属、钛酸锂材料、碳材料、过渡金属氧化物材料或硅材料。
本发明提供一种锂离子电池电极的制备方法，包括以下步骤：
将包括添加剂的浆料涂布在集流体上，干燥并辊压，得到锂离子电池电极；所述添加剂为式I所示的氟代磷酸盐；
MaPOxFy式I；
其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
优选地，所述干燥的温度为80～200℃。
本发明还提供一种锂离子电池，其包括上文所述的电极。
与现有技术相比，本发明采用式I所示的氟代磷酸盐制备锂离子电池电极，能有效改善极片的极化情况，提高SEI膜稳定性，改善极片表面析锂状况。本发明提供的锂离子电池电极制造成本低，制成电池后，电池倍率性能明显提高， 循环寿命明显延长，电池安全性能得到提高。
附图说明
图1为氟代磷酸盐添加在极片和电解液中的对比示意图。
具体实施方式
下面对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
本发明提供了氟代磷酸盐在制备锂离子电池电极中的应用，所述氟代磷酸盐具有式I通式：
MaPOxFy式I；
其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
本发明将式I所示的氟代磷酸盐作为锂离子电池电极添加剂，用于制备锂离子电池电极，能够有效改善极片的导电能力，并能够在极片表面成膜，可以改善极片极化、析锂和SEI膜的稳定性，能够充分改善电池的性能，还能够降低成本，使之适合应用于锂离子二次电池。
在本发明中，所述氟代磷酸盐具有式I通式。其中，M为碱金属元素，优选为锂(Li)、钠(Na)、钾(K)或铷(Rb)，更优选为Li或Na。式I中，0＜a≤3，优选为1或2。x和y均为整数，1≤x，y≤4，x+y≤5。作为优选，1≤x，y≤3，x+y≤4。在本发明的优选实施例中，x＝y＝2。具体的，所述氟代磷酸盐可为LiPO2F2、NaPO2F2、KPO2F2和Li2PO3F等。在本发明中，式I所示的氟代磷酸盐可以为市售产品，也可以通过制备得到。
在本发明中，所述氟代磷酸盐在锂离子电池电极材料中占的质量百分含量优选为0.1～15％，更优选为0.1～10％，进一步优选为0.2～8％，最优选为1～6％。在本发明的实施例中，含有所述氟代磷酸盐的电极极片的结构如图1中(b)所示，图1为氟代磷酸盐添加在极片和电解液中的对比示意图。图1中，(a)为氟代磷酸盐添加在电解液中，(b)为氟代磷酸盐添加在极片中；1为氟代磷酸盐为主要成分的SEI膜，2为活性物质，3为氟代磷酸盐，4为集流体。由图1可知，本发明含有所述氟代磷酸盐的电极极片中，氟代磷酸盐可包覆在活性物质颗粒上，使电极性能显著提高。
本发明提供了一种锂离子电池电极，包括集流体和负载在所述集流体上的电极材料；所述电极材料由包括添加剂的浆料制成，所述添加剂为式I所示的氟代磷酸盐；
MaPOxFy式I；
其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
采用本发明提供的锂离子电池电极，能获得倍率性能和安全性能等性能优异的电池，且降低成本，适于工业化推广应用。
本发明实施例采用式I所示的氟代磷酸盐为锂离子电池电极添加剂，制成锂离子电池电极。其中，所述氟代磷酸盐具有式I通式，M为碱金属元素，优选为锂(Li)、钠(Na)、钾(K)或铷(Rb)，更优选为Li或Na。式I中，0＜a≤3，优选为1或2。x和y均为整数，1≤x，y≤4，x+y≤5。作为优选，1≤x，y≤3，x+y≤4。在本发明的优选实施例中，x＝y＝2。具体的，所述氟代磷酸盐可为LiPO2F2、NaPO2F2、KPO2F2和Li2PO3F等。在本发明中，式I所示的氟代磷酸盐可以为市售产品，也可以通过制备得到。
在本发明中，所述氟代磷酸盐在锂离子电池电极材料中占的质量百分含量优选为0.1～15％，更优选为0.1～10％，进一步优选为0.2～8％，最优选为1～6％。本发明可以通过调节氟代磷酸盐在电极中的添加量，获得性能更加优异的电池。在本发明的实施例中，含有所述氟代磷酸盐的电极极片的结构如图1中(b)所示。
在本发明的实施例中，所述锂离子电池电极材料由包括氟代磷酸盐、活性物质、导电剂和粘结剂的浆料制成。所述锂离子电池电极为极片，可以为正极片，也可以为负极片。所述锂离子电池电极可以为正极，所述正极中活性物质(或活性材料、活性组分)可以为本领域中通常使用的任何过渡金属氧化物或过渡金属硫化物。例如，钴酸锂(LiCoO2)、LiMntO2t(t＝1或2)、LiNi1-tMntO2(0≤t＜1)、LiNitCo1-tO2(0＜t＜1)、镍锰钴酸锂(LiNi1/3Mn1/3Co1/3O2、Li1.2Ni1/6Mn1/6Co4/6O2)、磷酸铁锂(LiFePO4)等各种含锂的过渡金属复合氧化物，又如MoS2、SnS2、MoO3、V2O5等各种不含锂的过渡金属氧化物或过渡金属硫化物，优选为含锂的过渡金属复合氧化物。以上这些正极活性材料可以从市场上购买得到，也可以通过制备得到。
在本发明中，所述锂离子电池电极也可以为负极，所述负极中活性材料可以为现有技术中能商购的任何负极活性物质，包括金属锂或锂合金；可掺杂和 脱掺杂锂离子的钛酸锂材料；可掺杂和脱掺杂锂离子的碳材料；可掺杂和脱掺杂锂离子的过渡金属氧化物材料如氧化锡、氧化铌、氧化钒、氧化钛；或可掺杂和脱掺杂锂离子的硅材料。本发明优选采用可掺杂和脱掺杂锂离子的碳材料，这样的碳材料可以是石墨，也可以为非晶碳，例如活性炭、碳纤维、炭黑、天然石墨等。
本发明实施例中的正极浆料可由所述氟代磷酸盐、正极活性材料、导电剂、粘合剂等混合组成，负极浆料则可由所述氟代磷酸盐、负极活性材料、导电剂、粘合剂等混合组成。其中，炭黑、乙炔黑可以用作导电剂(或导电材料)。粘合剂(或粘结剂)可以选自偏二氟乙烯/六氟丙烯共聚物、聚偏二氟乙烯(PVDF)、聚丙烯腈、聚甲基丙烯酸甲酯、聚四氟乙烯及其混合物、或基于丁苯橡胶(SBR)的聚合物。在本发明中，正极和负极中的导电剂、粘结剂等组分可以相同，也可以不同。
在本发明的实施例中，所述氟代磷酸盐、活性物质、导电剂和粘结剂等可按照锂离子电池中通常使用的用量组成浆料。以质量分数计，所述浆料优选包括：0.1～15％的氟代磷酸盐、55～99％的活性物质、0.1～15％的导电剂和0.1～15％的粘结剂。其中，所述氟代磷酸盐的质量百分含量更优选为0.1～10％，进一步优选为0.2～8％，最优选为1～6％。所述活性物质的质量百分含量更优选为60～97％，最优选为75～95％。所述导电剂的质量百分含量更优选为0.5～10％，最优选为1～8％。所述粘结剂的质量百分含量更优选为0.5～10％，最优选为1～7％。
所述锂离子电池电极包括集流体，本发明对其没有特殊限制，采用本领域常用的即可，如铜箔、铝箔等。
相应地，本发明提供了一种锂离子电池电极的制备方法，包括以下步骤：
将包括添加剂的浆料涂布在集流体上，干燥并辊压，得到锂离子电池电极；所述添加剂为式I所示的氟代磷酸盐；
MaPOxFy式I；
其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
本发明实施例首先提供包括添加剂的浆料，所述添加剂为式I所示的氟代磷酸盐，其内容如前文所述，在此不再一一赘述。在本发明的实施例中，所述浆料包括活性物质、导电剂和粘结剂，这些组分的内容也如前文所述。所述浆料还包括溶剂，如有机溶剂或水，用以分散或溶解上述组分。所述溶剂优选为N-甲基吡咯烷酮(NMP)、丙酮或水，本发明对其用量没有特殊限制。
在本发明的实施例中，所述浆料中氟代磷酸盐、活性物质、导电剂和粘结剂的质量配比优选为：氟代磷酸盐0.1～15％、活性物质55～99％、导电剂0.1～15％、粘结剂0.1～15％；浆料固含量为10～90％。并进一步优选为：氟代磷酸盐0.1～10％、活性物质60～97％、导电剂0.5～10％、粘结剂0.5～10％；浆料固含量为30～85％。更优选为：氟代磷酸盐0.2～8％、活性物质75～95％、导电剂1～8％、粘结剂1～7％；浆料固含量为40～70％。
本发明对所述浆料的制备方法没有特殊限制，比如制作正极时，可在溶剂中加入氟代磷酸盐，搅拌溶解，配制成含氟代磷酸盐溶液；然后将正极活性物质、导电剂和粘结剂加入上述溶液中，搅拌混合成均匀的浆料。所述浆料的固体质量含量(即固含量)优选为10～90％，更优选为30～85％，最优选为40～70％。
得到浆料后，本发明实施例将其均匀涂布在集流体上，并干燥，再经辊压、裁切，得到锂离子电池电极。所述锂离子电池电极包括集流体，本发明对其没有特殊限制，采用本领域常用的即可。
在本发明中，所述锂离子电池电极包括负载在集流体上的电极材料，所述电极材料由浆料经涂布、干燥制成。所述干燥可以采用烘干的方式，温度优选为80～200℃，更优选为100～150℃，可使上述氟代磷酸盐保持稳定。所述干燥的时间可为1分钟～50分钟；所述辊压为本领域技术人员熟知的技术手段，本发明没有特殊限制。
本发明可以制备得到锂离子电池正极，也可以制备得到负极。本发明中锂离子电池电极的制备工艺简单易行，制造成本低，适合应用于锂离子二次电池。将本发明的锂离子电池电极制成电池后，电池倍率性能明显提高，循环寿命明显延长，电池安全性能得到提高。
本发明还提供了一种锂离子电池，其包括上文所述的电极，具有优异的倍率性能和安全性能，且成本低。
在本发明的实施例中，所述锂离子电池的结构采用本领域常规的结构即可，可包括壳体、电解液、隔膜、正极片和负极片。其中，所述正极片和/或负极片可以为上文所述的电极，在此不再赘述。
在本发明的实施例中，所述隔膜可以选自本领域技术人员公知的锂离子电池中所用的各种隔膜层，例如聚烯烃微多孔膜(PP微多孔膜)、聚乙烯毡(PE毡)、玻璃纤维毡、超细玻璃纤维纸或PP/PE/PP复合膜。作为一种优选的实施方式，所述隔膜为PP/PE/PP复合膜。
在本发明的实施例中，所述电解液为非水电解液，含有锂盐和非水溶剂。其中，所述锂盐可以为六氟磷酸锂(LiPF6)、四氟硼酸锂、六氟砷酸锂、高氯酸锂、三氟甲基磺酸锂、全氟丁基磺酸锂、铝酸锂、氯铝酸锂、氟代磺酰亚胺锂、氟代磷酸锂、氯化锂和碘化锂中的一种或几种，优选为LiPF6。所述非水溶剂可以为γ-丁内酯、碳酸甲乙酯(EMC)、碳酸甲丙酯、碳酸二丙酯、酸酐、N-甲基吡咯烷酮、N-甲基甲酰胺、N-甲基乙酰胺、乙腈、N,N-二甲基甲酰胺、环丁砜、二甲亚砜、亚硫酸二甲酯以及其它含氟、含硫或含不饱和键的环状有机酯中的一种或几种，优选为碳酸乙烯酯(EC)、碳酸二乙酯(DEC)和EMC中的一种或多种。在本发明的优选实施例中，所述非水溶剂为EC/EMC/DEC的混合溶剂，三者的体积比可为1:1:1。所述锂盐在电解液中的浓度可以为0.3～4摩尔/升，优选为0.5～2摩尔/升。
本发明可以按照本领域技术人员所公知的方法制备锂离子电池，一般来说，该方法包括：将正极、负极和位于正极与负极之间的隔膜依次卷绕，形成极芯，将所述极芯置入电池壳体中，加入电解液，然后密封，化成，制成锂离子电池。其中，所述正极包括集流体和负载在集流体上的正极材料，所述负极包括集流体和负载在集流体上的负极材料；两者中至少一个为上文所述的电极，另一个可以为本领域常规电极。所述壳体采用本领域常用的即可，如电池铝壳。所述卷绕、密封和化成的方法均为本领域人员所公知的技术手段；所述电解液的用量也为常规用量。
本发明的锂离子电池可为圆筒形、硬币型、方形及其它任意的形状；电池的形状与基本结构无关，可根据目的而实施设计变更。本发明对所述锂离子电池进行性能测试，包括常温循环性能测试、45℃循环性能测试、5C倍率性能测试。结果表明，本发明提供的含有氟代磷酸盐的极片组装成电池后，电池具有较好的常温循环性能，高温循环稳定性良好，倍率性能也有较为明显的提高。此外，本发明提供的锂离子电池电极制造成本低，利于实际工业化推广。
为了进一步理解本申请，下面结合实施例对本申请提供的氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用进行具体地描述。
以下实施例中，所用的氟代磷酸盐购自深圳市景华新材料有限公司。
实施例1
1、正极的制作：在N-甲基吡咯烷酮(NMP)溶剂中加入总正极固体质量 分数3％的二氟磷酸钠搅拌溶解，将88％的作为正极活性物质的钴酸锂(LiCoO2)、4％的作为导电材料的乙炔黑、5％的粘合剂聚偏氟乙烯(PVDF)加入溶液中，搅拌制成均匀浆料，浆料固含量为55％，将得到的浆料涂布在厚度为12μm的铝箔两面，并在120℃干燥，再经辊压、裁切，得到正极。
2、负极的制作：将总负极固体质量分数95％的人造石墨(杉杉科技，SS1-P10)、2％的粘结剂丁苯橡胶乳(SBR)，1％的粘结剂羧甲基纤维素(CMC)、2％的导电材料SP及水加入到分散器进行混合，制成浆料，浆料固含量为35％。将得到的浆料涂布在厚度为10μm的铜箔两面，并干燥，再经辊压、裁切，得到负极。
3、二次电池的组装：分别将上述正极、负极与聚丙烯膜(PP/PE/PP)卷绕成一个方型锂离子电池的极芯，随后将LiPF6按1摩尔/升的浓度溶解在混合溶剂(EC：EMC：DEC＝1:1:1体积比)中，形成非水电解液，将该电解液以3.7g/Ah的量注入电池铝壳中，密封，0.1C常温化成，制成锂离子电池。
实施例2
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是正极材料中的氟代磷酸盐为二氟磷酸锂。
实施例3
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是正极材料中的氟代磷酸盐为二氟磷酸锂，正极活性材料为磷酸铁锂，各组分比例为二氟磷酸锂5％、磷酸铁锂89％、乙炔黑3％、粘结剂聚偏氟乙烯3％，浆料固含量为60％。
实施例4
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是正极材料中的氟代磷酸盐为二氟磷酸锂，正极活性材料为镍锰钴酸锂(LiNi1/3Mn1/3Co1/3O2)。
实施例5
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是正极材料中的氟代磷酸盐为二氟磷酸钾，正极活性材料为镍锰钴酸锂(Li1.2Ni1/6Mn1/6Co4/6O2)。
实施例6
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是正极 材料中的氟代磷酸盐为二氟磷酸锂，正极活性材料为镍锰钴酸锂(LiNi1/3Mn1/3Co1/3O2)，各组分比例为二氟磷酸锂1％、镍锰钴酸锂90％、乙炔黑5％、粘结剂聚偏氟乙烯4％，浆料固含量为58％。
实施例7
1、正极的制作：在N-甲基吡咯烷酮(NMP)溶剂中加入总正极固体质量分数92％的作为正极活性物质的钴酸锂(LiCoO2)、3％的作为导电材料的乙炔黑、5％的粘合剂聚偏氟乙烯(PVDF)加入溶液中，搅拌制成均匀浆料，浆料固含量为55％，将得到的浆料涂布在厚度为12μm的铝箔两面，并在120℃干燥，再经辊压、裁切，得到正极。
2、负极的制作：在去离子水中加入总负极固体质量分数3％的二氟磷酸钠搅拌溶解，再将92％的人造石墨、2％的粘结剂丁苯橡胶乳(SBR)，1％的粘结剂羧甲基纤维素(CMC)、2％的导电材料SP加入分散器进行混合，制成浆料，浆料固含量为35％。将得到的浆料涂布在厚度为10μm的铜箔两面，并干燥，再经辊压、裁切，得到负极。
3、二次电池的组装：分别将上述正极、负极与聚丙烯膜卷绕成一个方型锂离子电池的极芯，随后将LiPF6按1摩尔/升的浓度溶解在混合溶剂(EC：EMC：DEC＝1:1:1体积比)中，形成非水电解液，将该电解液以3.7g/Ah的量注入电池铝壳中，密封，化成，制成锂离子电池。
实施例8
采用与实施例7相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为二氟磷酸锂。
实施例9
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为二氟磷酸锂，负极活性材料为天然石墨(杉杉科技，DMGS)，各组分比例为二氟磷酸锂5％、天然石墨89％、SP 3％、SBR 2％、CMC 1％，浆料固含量为45％。
实施例10
采用与实施例7相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为二氟磷酸锂，负极活性材料为硅碳负极(杉杉科技，Si-C-S-3)。
实施例11
采用与实施例7相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为二氟磷酸钾，各组分比例为二氟磷酸钾2％、人造石墨92％、SP 3％、SBR 2％、CMC 1％，浆料固含量为45％。
实施例12
1、正极的制作：在N-甲基吡咯烷酮(NMP)溶剂中加入总正极固体质量分数3％的二氟磷酸锂搅拌溶解，将88％的作为正极活性物质的钴酸锂(LiCoO2)、4％的作为导电材料的乙炔黑、5％的粘合剂聚偏氟乙烯(PVDF)加入溶液中搅拌制成均匀浆料，浆料固含量为55％，将得到的浆料涂布在厚度为12μm的铝箔两面，并在120℃干燥，再经辊压、裁切，得到正极。
2、负极的制作：在去离子水中加入总负极固体质量分数3％的二氟磷酸锂搅拌溶解，再将92％的人造石墨、2％的粘结剂丁苯橡胶乳(SBR)，1％的粘结剂羧甲基纤维素(CMC)、2％的导电材料SP加入在分散器进行混合，制成浆料，浆料固含量为35％。将得到的浆料涂布在厚度为10μm的铜箔两面，并干燥，再经辊压、裁切，得到负极。
3、二次电池的组装：分别将上述正极、负极与聚丙烯膜卷绕成一个方型锂离子电池的极芯，随后将LiPF6按1摩尔/升的浓度溶解在混合溶剂(EC：EMC：DEC＝1:1:1)中，形成非水电解液，将该电解液以3.7g/Ah的量注入电池铝壳中，密封，化成，制成锂离子电池。
实施例13
采用与实施例7相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为Li2PO3F，各组分比例为Li2PO3F 2％、人造石墨92％、SP 3％、SBR 2％、CMC 1％，浆料固含量为45％。
实施例14
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为二氟磷酸锂，负极活性材料为天然石墨(杉杉科技，DMGS)，各组分比例为二氟磷酸锂15％、天然石墨79％、SP 3％、SBR 2％、CMC 1％，浆料固含量为45％。
实施例15
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是负极材料中的氟代磷酸盐为二氟磷酸锂，负极活性材料为天然石墨(杉杉科技，DMGS)，各组分比例为二氟磷酸锂0.2％、天然石墨93.8％、SP 3％、SBR 2％、 CMC 1％，浆料固含量为45％。
实施例16
采用与实施例1相同的方法和步骤制备正极、负极和电池，不同的是烘干温度为180℃。
对比例1
1、正极的制作：在N-甲基吡咯烷酮(NMP)溶剂中加入总正极固体质量分数92％的作为正极活性物质的钴酸锂(LiCoO2)、3％的作为导电材料的乙炔黑、5％的粘合剂聚偏氟乙烯(PVDF)加入溶液中，搅拌制成均匀浆料，浆料固含量为55％，将得到的浆料涂布在厚度为12μm的铝箔两面，并在120℃干燥，再经辊压、裁切，得到正极。
2、负极的制作：将总负极固体质量分数95％的人造石墨、2％的粘结剂丁苯橡胶乳(SBR)，1％的粘结剂羧甲基纤维素(CMC)、2％的导电材料SP及水加入到分散器进行混合，制成浆料，浆料固含量为35％。将得到的浆料涂布在厚度为10μm的铜箔两面，并干燥，再经辊压、裁切，得到负极。
3、二次电池的组装：分别将上述正极、负极与聚丙烯膜卷绕成一个方型锂离子电池的极芯，随后将LiPF6按1摩尔/升的浓度溶解在混合溶剂(EC：EMC：DEC＝1:1:1体积比)中，形成非水电解液，将该电解液以3.7g/Ah的量注入电池铝壳中，密封，化成，制成锂离子电池。
实施例12电池性能测试
1、电池的常温循环性能测试
将实施例1～16和对比例1中得到的成品电池，分别按照以下方式进行测试：在室温下，先以1C的电流恒流充电至4.2V，再恒压充电至电流下降为0.05C，最后以1C的电流恒流放电至3.0V。如此循环300周，记录第1周的放电容量和第500周的放电容量，然后根据以下公式，计算出电池的常温循环的容量保持率，计算结果示于下表1，表1为实施例和对比例中锂离子电池的性能测试结果；
容量保持率＝第300周的放电容量/第1周的放电容量×100％。
2、电池的45℃循环性能测试
将实施例1～16和对比例1中得到的成品电池，分别按照以下方式进行测试：在45℃条件下，先以1C的电流恒流充电至4.2V，再恒压充电至电流下降为0.05C，然后以1C的电流恒流放电至3.0V。如此循环300周，记录第1周的放 电容量和第300周的放电容量，然后根据以下公式：计算出电池的45℃循环的容量保持率，计算结果示于下表1；
容量保持率＝第300周的放电容量/第1周的放电容量×100％。
3、电池的5C倍率性能测试
将实施例1～16和对比例1中得到的成品电池，分别按照以下方式进行测试：在常温条件下，先以1C的电流恒流充电至4.2V，再恒压充电至电流下降为0.05C，然后以5C的电流恒流放电至3.0V。如此循环50周，记录第1周的1C放电容量和第50周的5C放电容量，然后根据以下公式，计算出电池的常温倍率的容量保持率，计算结果示于下表1；
容量保持率＝第50周的放电容量/第1周的1C放电容量×100％。
表1实施例和对比例中锂离子电池的性能测试结果
  常温循环容量保持率％ 45℃循环容量保持率％ 倍率循环容量保持率％
实施例1 82 80 71
实施例2 90 87 75
实施例3 87 84 76
实施例4 89 82 79
实施例5 86 82 69
实施例6 83 79 72
实施例7 85 79 70
实施例8 79 76 68
实施例9 91 85 80
实施例10 85 80 72
实施例11 87 81 74
实施例12 92 87 78
实施例13 89 86 75
实施例14 82 86 73
实施例15 86 79 83
实施例16 82 74 68
对比例1 75 69 58
由表1数据可知：本发明提供的含有氟代磷酸盐的极片组装成电池后，电池具有较好的常温循环性能，高温循环稳定性良好，倍率性能也有较为明显的提高，说明氟代磷酸盐的添加，改善了电池内部极化和SEI膜的稳定性，同时由于氟代磷酸盐的良好电导率，改善了电池内阻。
以上所述仅是本发明的优选实施方式，应当指出，对于使本技术领域的专业技术人员，在不脱离本发明技术原理的前提下，是能够实现对这些实施例的多种修改的，而这些修改也应视为本发明应该保护的范围。

Claims (10)

  1. 氟代磷酸盐在制备锂离子电池电极中的应用，所述氟代磷酸盐具有式I通式：
    MaPOxFy 式I；
    其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
  2. 一种锂离子电池电极，包括集流体和负载在所述集流体上的电极材料；所述电极材料由包括添加剂的浆料制成，所述添加剂为式I所示的氟代磷酸盐；
    MaPOxFy 式I；
    其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
  3. 根据权利要求2所述的锂离子电池电极，其特征在于，所述M选自Li、Na、K或Rb，y≤3，x+y≤4。
  4. 根据权利要求2所述的锂离子电池电极，其特征在于，所述氟代磷酸盐在锂离子电池电极材料中占的质量百分含量为0.1～15％。
  5. 根据权利要求2所述的锂离子电池电极，其特征在于，所述锂离子电池电极材料由包括氟代磷酸盐、活性物质、导电剂和粘结剂的浆料制成；以质量分数计，所述浆料包括：0.1～15％的氟代磷酸盐、55～99％的活性物质、0.1～15％的导电剂和0.1～15％的粘结剂。
  6. 根据权利要求5所述的锂离子电池电极，其特征在于，所述锂离子电池电极为正极，所述正极中活性物质选自过渡金属氧化物或过渡金属硫化物。
  7. 根据权利要求5所述的锂离子电池电极，其特征在于，所述锂离子电池电极为负极，所述负极中活性物质选自含锂金属、钛酸锂材料、碳材料、过渡金属氧化物材料或硅材料。
  8. 一种锂离子电池电极的制备方法，包括以下步骤：
    将包括添加剂的浆料涂布在集流体上，干燥并辊压，得到锂离子电池电极；所述添加剂为式I所示的氟代磷酸盐；
    MaPOxFy 式I；
    其中，M为碱金属元素，0＜a≤3，x和y均为整数，1≤x，y≤4，x+y≤5。
  9. 根据权利要求8所述的制备方法，其特征在于，所述干燥的温度为80～200℃。
  10. 一种锂离子电池，其特征在于，包括权利要求2～7任一项所述的电极或权利要求8～9任一项所述的制备方法制得的电极。
PCT/CN2017/090557 2016-06-30 2017-06-28 一种氟代磷酸盐在制备锂离子电池电极中的应用、锂离子电池电极、其制备方法和应用 WO2018001274A1 (zh)

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