CN114613947A - Preparation method of positive pole piece, positive pole piece and lithium ion battery - Google Patents

Preparation method of positive pole piece, positive pole piece and lithium ion battery Download PDF

Info

Publication number
CN114613947A
CN114613947A CN202210356881.5A CN202210356881A CN114613947A CN 114613947 A CN114613947 A CN 114613947A CN 202210356881 A CN202210356881 A CN 202210356881A CN 114613947 A CN114613947 A CN 114613947A
Authority
CN
China
Prior art keywords
positive pole
pole piece
preparation
slurry
composite material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210356881.5A
Other languages
Chinese (zh)
Inventor
黄建宇
唐亮
黄俏
李帅
黄全伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xiangtan University
Original Assignee
Xiangtan University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xiangtan University filed Critical Xiangtan University
Priority to CN202210356881.5A priority Critical patent/CN114613947A/en
Publication of CN114613947A publication Critical patent/CN114613947A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—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
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/582—Halogenides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/5835—Comprising fluorine or fluoride salts
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Composite Materials (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention discloses a preparation method of a positive pole piece, the positive pole piece and a lithium ion battery, and the preparation method of the positive pole pieceThe method comprises the following steps: preparation of FeSiF6Precursor solution; for the FeSiF6Drying and annealing the precursor solution to obtain the nanoscale FeF2A powder; subjecting the nanoscale FeF2Mixing the powder and graphite powder in a mass ratio of 8:1 to obtain a mixture; ball-milling the mixture to obtain a ferrous fluoride graphite composite material; and preparing the positive pole piece based on the ferrous fluoride graphite composite material. The preparation method of the positive pole piece can obtain high-purity nanoscale FeF2The powder is formed by using cheap carbon material and ferrous fluoride, and has high circulation capacity retention rate and good conductive effect. The preparation method of the positive pole piece can effectively reduce the preparation cost of the ferrous fluoride positive pole material and the process difficulty while ensuring the conductivity of the positive pole piece.

Description

Preparation method of positive pole piece, positive pole piece and lithium ion battery
Technical Field
The invention relates to the technical field of battery preparation, in particular to a preparation method of a positive pole piece, the positive pole piece and a lithium ion battery.
Background
In the technical field of lithium battery application, transition metal fluoride is widely favored as a battery anode material with higher theoretical specific capacity, however, the lithium battery cycling stability is poorer when the fluoride is used as the anode material due to poorer electronic conductivity of the fluoride and the need of overcoming larger activation energy in the electrochemical reaction process.
In order to solve the above problems, the conventional methods in the prior art include two methods, one is to select a conductive agent with high electronic conductivity, such as carbon nanotube, to compound it with ferrous fluoride and design a unique nanostructure, so as to improve the reaction depth and the electronic conductivity of the material; secondly, a suitable polymer is found and is carbonized after being well compounded with ferrous fluoride, so that the composite anode of the vegetation has better circulation stability.
However, the prior art has the significant defects of high cost, complex process and weak repeatability of the experiment. This is because such schemes require the selection of expensive chemicals and a series of complicated preparation processes to synthesize the desired product. The process is complicated, so the repeatability is not strong.
At present, conductive carbon black such as Super P and acetylene black or polymer carbonized carbon with a 3D structure is commonly adopted in the positive pole piece. High cost and poor conductive effect
Disclosure of Invention
Objects of the invention
The invention aims to provide a preparation method of a positive pole piece, the positive pole piece and a lithium ion battery to solve the problems.
(II) technical scheme
In order to solve the above problems, a first aspect of the present invention provides a method for preparing a positive electrode sheet, including: preparation of FeSiF6Precursor solution; for the FeSiF6Drying and annealing the precursor solution to obtain the nanoscale FeF2Powder; the nanoscale FeF is treated2Mixing the powder and graphite powder in a mass ratio of 8:1 to obtain a mixture; ball-milling the mixture to obtain a ferrous fluoride graphite composite material; and preparing the positive pole piece based on the ferrous fluoride graphite composite material.
Further, the ball milling of the mixture to obtain the ferrous fluoride graphite composite material comprises: adding an isopropanol solution to the mixture; ball milling is carried out by adopting a ball mill, and drying treatment is carried out to obtain the ferrous fluoride graphite composite material.
Furthermore, the rotating speed of the ball mill is 250r/min-550r/min, and the ball milling time is 22h-26 h.
Further, the preparation of the positive electrode plate based on the ferrous fluoride graphite composite material comprises the following steps: mixing a ferrous fluoride graphite composite material with polyvinylidene fluoride to form positive electrode slurry; and drying and shaping the positive electrode slurry to obtain the positive electrode plate.
Further, mixing the ferrous fluoride graphite composite material with polyvinylidene fluoride to form positive electrode slurry comprises: dissolving polyvinylidene fluoride by adopting N-methyl pyrrolidone; adding a ferrous fluoride graphite composite material into the dissolved polyvinylidene fluoride to obtain a base slurry; and adding N-methyl pyrrolidone into the basic slurry, and stirring to obtain the anode slurry.
Further, drying and sizing the anode slurry to obtain the anode piece comprises: coating the positive electrode slurry on a carbon-coated aluminum foil; drying the positive pole slurry to obtain a pretreated pole piece; and machining the pretreated pole piece to obtain the positive pole piece.
Further, drying the positive electrode slurry to obtain a pretreated pole piece includes: drying the positive slurry for 20-30h in a constant temperature environment; wherein the temperature of the constant temperature environment is 90-120 ℃.
Further, the preparation of FeSiF6The precursor solution comprises: slowly pouring iron powder into a silicic acid solution for multiple times; taking supernatant after standing, centrifuging the supernatant, and removing excessive iron powder to obtain FeSiF6And (3) precursor solution.
According to another aspect of the invention, a positive pole piece is provided, which is prepared by adopting the preparation method of any one of the above technical schemes.
According to yet another aspect of the present invention, there is provided a lithium ion battery including: the positive pole piece is prepared by the preparation method of any one of the technical schemes.
(III) advantageous effects
The technical scheme of the invention has the following beneficial technical effects:
the preparation method of the positive pole piece can obtain high-purity nanoscale FeF2The powder is formed by using cheap carbon material and ferrous fluoride, and has high circulation capacity retention rate and good conductive effect. The preparation method of the positive pole piece can effectively reduce the preparation cost of the ferrous fluoride positive pole material and the process difficulty while ensuring the conductivity of the positive pole piece.
Drawings
Fig. 1 is a flowchart of a method for manufacturing a positive electrode sheet according to an embodiment of the present invention.
FIG. 2 shows FeF provided by an embodiment of the present invention2XRD characterization of the powder is schematic.
Fig. 3 is a schematic diagram of XRD characterization of the ferrous fluoride graphite composite material provided by an embodiment of the present invention.
FIG. 4 is a schematic SEM topography analysis of graphite.
Fig. 5 is a schematic diagram of SEM morphology analysis of the positive electrode sheet according to an embodiment of the present invention.
Fig. 6 is a schematic diagram of a constant current charge-discharge cycle test performed on a positive electrode plate according to an embodiment of the present invention.
Fig. 7 is a schematic diagram of the electrochemical impedance change of the positive electrode sheet in the liquid electrolyte according to an embodiment of the present invention.
Fig. 8 is a schematic view of a cyclic voltammetry scan test of a positive electrode tab according to an embodiment of the present invention.
Fig. 9 is a schematic diagram of a constant current charge-discharge cycle test performed on a positive electrode plate in the prior art.
In fig. 2 and 3:
2-Theta denotes a 2-fold angle of diffraction in degrees;
intensity (A.u.) indicates the diffraction Intensity, unitless.
PDF # represents a standard PDF card of this material, with very pure specifications corresponding to XRD results.
(002) The (110), (101), (111), (211) and (220) represent crystal planes of substances corresponding to diffraction peaks appearing at this diffraction angle.
In fig. 4:
2 μm indicates a scale bar.
In fig. 5:
10 μm indicates a scale bar.
In fig. 6:
3M represents that the concentration of lithium salt in the electrolyte was 3 mol/L.
Cycle number indicates the number of cycles of charging and discharging the battery, and one Cycle of charging once by discharging.
Discharge capacity(mAhg-1) The specific capacity of the battery discharge is expressed in milliamp-hours/gram.
Coulombic efficiency (%) represents the Coulombic efficiency of the battery, which is the ratio of the charged capacity to the discharged capacity of the battery.
Mossloading represents the areal density of the positive pole piece.
In fig. 7:
-Z "(Ω) represents the inverse of the imaginary part of the electrochemical impedance.
Z' (Ω) represents the real part of the electrochemical impedance.
In fig. 8:
current represents Current in μ A.
Voltage(V vs.Li+and/Li) denotes the electrode potential for lithium.
■, first cyclic voltammetric sweep test;
● denotes the second cycle of cyclic voltammetric sweep testing;
a tangle-solidup represents the third cycle voltammetric sweep test;
≧ represents the fourth cycle of cyclic voltammetry scan test.
In fig. 9:
FeF2@ KB denotes a composite positive electrode of ferrous fluoride and conductive ketjen black;
FeF2@ SP represents the composite positive electrode of ferrous fluoride and conductive Super P;
FeF2@ AB denotes a composite positive electrode of ferrous fluoride and conductive acetylene black.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be understood that the description is intended to be exemplary only, and is not intended to limit the scope of the present invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
In the drawings a schematic view of a layer structure according to an embodiment of the invention is shown. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.
It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Furthermore, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
The noun interpretation:
N-methyl-N-propyl pyrrole bis (trifluoromethyl sulfonyl) imide, namely PYR14TFSI。
The polyethylene oxide is PEO.
The sodium bis (trifluoromethyl) sulfonyl imide is NATFSI.
In an embodiment of the present invention, a method for preparing a positive electrode plate is provided, which may include: preparation of FeSiF6Precursor solution; for the FeSiF6Drying and annealing the precursor solution to obtain the nanoscale FeF2A powder; the nanoscale FeF is treated2Mixing the powder and graphite powder in a mass ratio of 8:1 to obtain a mixture; ball-milling the mixture to obtain a ferrous fluoride graphite composite material; and preparing the positive pole piece based on the ferrous fluoride graphite composite material.
The preparation method of the positive pole piece can obtain high-purity nanoscale FeF2The powder is formed by using cheap carbon material and ferrous fluoride, and has high circulation capacity retention rate and good conductive effect. The preparation method of the positive pole piece can effectively reduce the preparation cost of the ferrous fluoride positive pole material and the process difficulty while ensuring the conductivity of the positive pole piece.
As shown in fig. 1, in an embodiment of the present invention, a method for preparing a positive electrode plate is provided, which includes the following steps:
s100, preparation of FeSiF6And (3) precursor solution.
S101, slowly pouring high-purity iron powder into a silicic acid solution for multiple times; standing, taking supernatant, centrifuging to remove excessive iron powder, and obtaining light green clear FeSiF6And (3) precursor solution.
S200, for the FeSiF6Drying and annealing the precursor solution to obtain the nanoscale FeF2And (3) powder.
S201, the FeSiF6And (5) standing the precursor solution and then drying.
S202, drying the FeSiF6And carrying out annealing treatment on the precursor solution.
S203, after the annealing treatment is finished, cooling to room temperature to obtain light yellow nano FeF2And (3) powder.
XRD characterization of the powder was performed in comparison with standard PDF card, and the results showed that the synthesized FeF2Does not contain any impurity phase and is high-purity nano powder.
S300, subjecting the nanoscale FeF2The powder and graphite powder are mixed in a mass ratio of 8:1 to obtain a mixture.
S400, ball-milling the mixture to obtain the ferrous fluoride graphite composite material.
S401, pouring the mixture into a stainless steel ball milling tank, adding large, medium and small stainless steel balls, adding an isopropanol solution until the isopropanol solution is over the steel balls, performing ball milling for 24 hours at 400r/min by using a double-tank high-speed ball mill, taking out, and drying in a forced air drying oven to evaporate the isopropanol solution to obtain the ferrous fluoride graphite composite material.
S500, preparing the positive pole piece based on the ferrous fluoride graphite composite material.
S501, dissolving PVDF (polyvinylidene fluoride) in NMP (N-methyl pyrrolidone), stirring, and introducing into the mixture to form positive electrode slurry.
And S502, continuously adding NMP into the positive electrode slurry, and stirring for 24 hours at room temperature.
S503, coating the stirred anode slurry on a carbon-coated aluminum foil, drying the carbon-coated aluminum foil, and then pressing and forming to obtain the anode piece.
In an optional embodiment, the positive electrode plate is a positive electrode plate of a lithium iron fluoride battery.
In an alternative embodiment, the nanoscale FeF2The mass ratio of powder to the PVDF was 8: 1.
In an alternative embodiment, the ball milling the mixture to obtain the graphite iron fluoride composite material may include: adding an isopropanol solution to the mixture; ball milling is carried out by adopting a ball mill, and drying treatment is carried out to obtain the ferrous fluoride graphite composite material.
In an alternative embodiment, the rotation speed of the ball mill is 250r/min-550 r/min.
In an alternative embodiment, the ball milling time is 22h to 26 h.
In an alternative embodiment, the preparing the positive electrode plate based on the ferrous fluoride graphite composite material may include: mixing a ferrous fluoride graphite composite material with polyvinylidene fluoride to form positive electrode slurry; and drying and shaping the positive electrode slurry to obtain the positive electrode piece.
In an alternative embodiment, the mixing the ferrocyanide graphite composite material with polyvinylidene fluoride to form the positive electrode slurry may include: dissolving polyvinylidene fluoride by adopting N-methyl pyrrolidone; adding a ferrous fluoride graphite composite material into the dissolved polyvinylidene fluoride to obtain a base slurry; and adding N-methyl pyrrolidone into the basic slurry, and stirring to obtain the anode slurry.
In an optional embodiment, the drying and shaping the positive electrode slurry to obtain the positive electrode sheet may include: coating the positive electrode slurry on a carbon-coated aluminum foil; drying the positive pole slurry to obtain a pretreated pole piece; and machining the pretreated pole piece to obtain the positive pole piece.
In an optional embodiment, the drying the positive electrode slurry to obtain the pre-processed pole piece may include: and drying the positive electrode slurry for 20-30h in a constant temperature environment.
In an alternative embodiment, the temperature of the thermostatic environment is 90-120 ℃.
In an alternative embodiment, the preparation of FeSiF6The precursor solution may include: slowly pouring iron powder into a silicic acid solution for multiple times; taking supernatant after standing, centrifuging the supernatant, and removing excessive iron powder to obtain FeSiF6And (3) precursor solution.
The synthesis process of ferrous fluoride comprises the following steps: 1.3g (excessive) of high-purity iron powder is slowly poured into 10gH for multiple times2SiO4In the solution (the concentration is about 30 percent), a large amount of bubbles are generated by reaction, after standing for 24 hours, supernatant fluid is taken and centrifuged twice to ensure that excessive iron powder is removed, and light green clear FeSiF is obtained6And (3) precursor solution. Spreading the solution in a plastic box, standing for 24h, naturally drying, annealing at 250 deg.C for 4h in a tube furnace, cooling to room temperature, and taking out to obtain light yellow nanoscale FeF2And (3) powder. XRD characterization of the powder was performed in comparison with standard PDF card, and the results showed that the synthesized FeF2Does not contain any impurity phase and is high-purity nano powder.
Compounding ferrous fluoride and graphite: taking 0.8g of ferrous fluoride and 0.1g of graphite powder, pouring the ferrous fluoride and the graphite powder into a stainless steel ball milling tank, adding a plurality of large, medium and small stainless steel balls, and adding an isopropanol solution until the steel balls are covered. After ball milling for 24 hours at 400r/min using a two-pot high-speed ball mill, the mixture was taken out and dried in an air-blown drying oven to evaporate off the isopropanol solution. Obtaining the gray black ferrous fluoride graphite composite material.
Preparing a positive pole piece: the composite material obtained above is FeF 2: graphite 8: weighing a proper amount of composite powder and a proper amount of PVDF (polyvinylidene fluoride), wherein the mass ratio of the ferrous fluoride to the graphite to the PVDF is (8): 1: 1. PVDF is dissolved in a proper amount of NMP (N-methyl pyrrolidone), stirred on a magnetic stirrer at the rotating speed of 300r/min, and then poured into the ball-milled ferrous fluoride and graphite composite powder to form anode slurry. NMP was added continuously to moderate the viscosity of the slurry and stirred at room temperature for 24 h. The slurry was then coated on a carbon-coated aluminum foil, which was coated to 50um using a coating blade, and was dried in a constant-temperature drying oven at 100 ℃ for 24 hours. And (3) stamping the dried pole piece into a circular pole piece with the diameter of 12mm by using a stamping machine, thus obtaining the lithium iron fluoride battery positive pole piece.
The starting point of the invention is to explore whether the cheap carbon material and the ferrous fluoride can form good conductive effect. The results show that the ferrous fluoride and the graphite material are mechanically ball-milled to form the composite anode. The long-cycle capacity retention rate of the battery can be obviously improved. In another embodiment of the present invention, a positive electrode sheet is provided, which is prepared by using the preparation method according to any one of the above technical solutions.
In yet another embodiment of the present invention, there is provided a lithium ion battery, which may include: the positive pole piece is prepared by the preparation method of any one of the technical schemes. The present invention uses PVDF to bond two materials together to improve the electronic conductance of ferrous fluoride. Experiments show that even Ketjen black, which is much more expensive than graphite, has much lower battery cycle performance than graphite. The invention has the greatest advantage that the graphite and ferrous fluoride ball-milling composite anode with low cost is explored and has high cycle capacity retention rate.
FIG. 2 shows FeF provided by an embodiment of the present invention2XRD characterization of the powder is schematic.
The result is shown in fig. 2, and the analysis is performed by comparing with a standard PDF card, and the result shows that the nano-sized FeF synthesized by the preparation method provided by the embodiment of the invention2The powder does not contain any impurity phase, and is high-purity nanopowder.
Fig. 3 is a schematic diagram of XRD characterization of the ferrous fluoride graphite composite material provided by an embodiment of the present invention.
As shown in fig. 3, fig. 3 is a schematic diagram of XRD characterization of the ferrous fluoride graphite composite material by ball milling. The nanoscale FeF is treated2Mixing the powder and graphite powder in a mass ratio of 8:1
And ball-milling the mixture to obtain the ferrous fluoride graphite composite material without other impurity phases.
FIG. 4 is a schematic SEM topography analysis of graphite.
As shown in fig. 4, inexpensive graphite has a two-dimensional lamellar structure.
Fig. 5 is a schematic diagram of SEM morphology analysis of the positive electrode sheet according to an embodiment of the present invention.
As shown in FIG. 5, FeF is present in the ball-milled FeOOH graphite composite material2Uniformly dispersed on the surface layer of the graphite.
Fig. 6 is a schematic diagram of a constant current charge-discharge cycle test performed on a positive electrode plate according to an embodiment of the present invention.
FIG. 6 shows the electrochemical properties of the iron (II) fluoride graphite composite material in DME (ethylene glycol dimethyl ether) electrolyte containing 3mol/L LiFSI (lithium trifluorosulfonimide).
As shown in fig. 6, 1C 571mA g-10.2C means 114.2mA g -15C means 2855mA g-1. At 600 cycles of 0.2C in FIG. 6, the battery discharge capacity was maintained at 300mAhg -11800 cycles at 5C, discharge capacity of 100mAhg-1The above. The coulombic efficiency of the ferrous fluoride graphite composite material is stable, so that the electrochemical performance of a reaction battery made of the positive pole piece is stable and excellent.
Fig. 7 is a schematic diagram of the electrochemical impedance change of the positive electrode sheet in the liquid electrolyte according to an embodiment of the present invention.
As shown in fig. 7, according to the principle of electrochemical impedance, the first semi-circle of the curve in fig. 7 is drawn to intersect with the X-axis, the real number of the intersection point represents the internal resistance of the battery, and the value of the X-axis at the beginning of the curve is subtracted from the real number to obtain the charge transfer resistance of the positive electrode surface.
The impedance of the lithium ion battery made of the anode plate is reduced in the first 20 charge-discharge cycles, which shows that an interface beneficial to lithium ion transmission is generated.
Fig. 8 is a schematic view of a cyclic voltammetry scan test of a positive electrode piece according to an embodiment of the present invention.
As shown in fig. 8, the battery is discharged from an open circuit voltage of about 3V to 1V, and then charged to 4V, which is one cycle.
In each cycle: the first oxidation process (i.e., OX1 stage) corresponds to the conversion of Fe in the positive electrode to Fe2+(ii) a The second oxidation process (i.e., OX2 stage) corresponds to Fe2+Further oxidized to Fe3+(ii) a I.e. the first reduction process (i.e. stage RE 1) corresponds to Fe2+Reducing the iron into Fe; the second reduction (i.e. RE2 stage) corresponds to Fe3+Reduction to Fe2+. The current of the battery under a specific voltage can be analyzed by performing cyclic voltammetry scanning test on the battery, so that the electrochemical reaction of the battery can be judged. The battery made of the positive pole piece has higher stability in the electrochemical reaction process, so that the capacity retention rate of the battery is improved.
Comparative experiment:
fig. 9 is a schematic diagram of a constant current charge-discharge cycle test performed on a positive electrode plate in the prior art.
As shown in fig. 9, all three conductive agents belong to conductive carbon black, and have small difference in conductivity due to different preparation modes, so that ketjen black is the most expensive in cost, and acetylene black is the least expensive. FeF in FIG. 62@ Graphite represents a composite positive electrode of ferrous fluoride and Graphite, and Graphite has a two-dimensional lamellar structure, has a highly crystallized property, and is cheaper than ketjen black in cost.
The invention aims to protect a preparation method of a positive pole piece, the positive pole piece and a lithium ion battery, wherein the preparation method of the positive pole piece can comprise the following steps: preparation of FeSiF6Precursor solution; for the FeSiF6Drying and annealing the precursor solution to obtain the nanoscale FeF2Powder; the nanoscale FeF is treated2Mixing the powder and graphite powder in a mass ratio of 8:1 to obtain a mixture; ball-milling the mixture to obtain a ferrous fluoride graphite composite material; and preparing the positive pole piece based on the ferrous fluoride graphite composite material. The preparation method of the positive pole piece can obtain high-purity nanoscale FeF2The powder is formed by using cheap carbon material and ferrous fluoride, and has high circulation capacity retention rate and good conductive effect. The positive electrode of the present inventionThe preparation method of the pole piece can effectively reduce the preparation cost of the ferrous fluoride anode material and the process difficulty while ensuring the conductivity of the pole piece.
It is to be understood that the above-described embodiments of the present invention are merely illustrative of or explaining the principles of the invention and are not to be construed as limiting the invention. Therefore, any modification, equivalent replacement, improvement and the like made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. Further, it is intended that the appended claims cover all such variations and modifications as fall within the scope and boundaries of the appended claims or the equivalents of such scope and boundaries.

Claims (10)

1. A preparation method of a positive pole piece is characterized by comprising the following steps:
preparation of FeSiF6Precursor solution;
for the FeSiF6Drying and annealing the precursor solution to obtain the nanoscale FeF2Powder;
the nanoscale FeF is treated2Mixing the powder and graphite powder in a mass ratio of 8:1 to obtain a mixture;
ball-milling the mixture to obtain a ferrous fluoride graphite composite material;
and preparing the positive pole piece based on the ferrous fluoride graphite composite material.
2. The method for preparing the positive pole piece according to claim 1, wherein the ball milling the mixture to obtain the iron fluoridated graphite composite material comprises:
adding an isopropanol solution to the mixture;
ball milling is carried out by adopting a ball mill, and drying treatment is carried out to obtain the ferrous fluoride graphite composite material.
3. The method for producing a positive electrode sheet according to claim 2,
the rotating speed of the ball mill is 250r/min-550r/min, and the ball milling time is 22h-26 h.
4. The preparation method of the positive pole piece according to claim 1, wherein the preparation of the positive pole piece based on the ferrous fluoride graphite composite material comprises the following steps:
mixing a ferrous fluoride graphite composite material with polyvinylidene fluoride to form positive electrode slurry;
and drying and shaping the positive electrode slurry to obtain the positive electrode plate.
5. The preparation method of the positive pole piece according to claim 4, wherein the mixing of the ferrous fluoride graphite composite material and the polyvinylidene fluoride to form the positive pole slurry comprises:
dissolving polyvinylidene fluoride by adopting N-methyl pyrrolidone;
adding a ferrous fluoride graphite composite material into the dissolved polyvinylidene fluoride to obtain a base slurry;
and adding N-methyl pyrrolidone into the basic slurry, and stirring to obtain the anode slurry.
6. The preparation method of the positive pole piece according to claim 4, wherein the drying and shaping of the positive pole slurry to obtain the positive pole piece comprises:
coating the positive electrode slurry on a carbon-coated aluminum foil;
drying the positive pole slurry to obtain a pretreated pole piece;
and machining the pretreated pole piece to obtain the positive pole piece.
7. The preparation method of the positive pole piece according to claim 6, wherein the step of drying the positive pole slurry to obtain the pre-treated pole piece comprises the following steps:
drying the positive slurry for 20-30h in a constant temperature environment;
wherein the temperature of the constant temperature environment is 90-120 ℃.
8. The method for preparing the positive pole piece according to claim 1, wherein the FeSiF is prepared6The precursor solution comprises:
slowly pouring iron powder into a silicic acid solution for multiple times;
taking supernatant after standing, centrifuging the supernatant, and removing excessive iron powder to obtain FeSiF6And (3) precursor solution.
9. A positive electrode plate, characterized by being prepared by the preparation method of any one of claims 1 to 8.
10. A lithium ion battery, comprising: the positive electrode plate prepared by the preparation method of any one of claims 1 to 8.
CN202210356881.5A 2022-04-01 2022-04-01 Preparation method of positive pole piece, positive pole piece and lithium ion battery Pending CN114613947A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210356881.5A CN114613947A (en) 2022-04-01 2022-04-01 Preparation method of positive pole piece, positive pole piece and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210356881.5A CN114613947A (en) 2022-04-01 2022-04-01 Preparation method of positive pole piece, positive pole piece and lithium ion battery

Publications (1)

Publication Number Publication Date
CN114613947A true CN114613947A (en) 2022-06-10

Family

ID=81869424

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210356881.5A Pending CN114613947A (en) 2022-04-01 2022-04-01 Preparation method of positive pole piece, positive pole piece and lithium ion battery

Country Status (1)

Country Link
CN (1) CN114613947A (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040062994A1 (en) * 2002-10-01 2004-04-01 Amatucci Glenn G. Transition metal fluoride: carbon nanoamalgam rechargeable battery cell electrode material
JP2013182662A (en) * 2012-02-29 2013-09-12 Mitsubishi Heavy Ind Ltd Positive electrode active material for lithium secondary battery and lithium secondary battery
CN104091949A (en) * 2014-07-16 2014-10-08 北京化工大学常州先进材料研究院 Charcoal-coated metal fluoride nano material with core-shell structure, preparation method and application of nano material as lithium battery positive electrode material
CN106207116A (en) * 2016-07-22 2016-12-07 昆明理工大学 A kind of method of one-step synthesis method ferrous fluoride/C positive electrode material
CN110352524A (en) * 2017-01-30 2019-10-18 纳米技术仪器公司 The metal fluoride and metal chloride active material of cathode that expanded graphite worm for lithium battery is protected

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040062994A1 (en) * 2002-10-01 2004-04-01 Amatucci Glenn G. Transition metal fluoride: carbon nanoamalgam rechargeable battery cell electrode material
JP2013182662A (en) * 2012-02-29 2013-09-12 Mitsubishi Heavy Ind Ltd Positive electrode active material for lithium secondary battery and lithium secondary battery
CN104091949A (en) * 2014-07-16 2014-10-08 北京化工大学常州先进材料研究院 Charcoal-coated metal fluoride nano material with core-shell structure, preparation method and application of nano material as lithium battery positive electrode material
CN106207116A (en) * 2016-07-22 2016-12-07 昆明理工大学 A kind of method of one-step synthesis method ferrous fluoride/C positive electrode material
CN110352524A (en) * 2017-01-30 2019-10-18 纳米技术仪器公司 The metal fluoride and metal chloride active material of cathode that expanded graphite worm for lithium battery is protected

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
M. SINA等: ""Investigation of SEI Layer Formation in Conversion Iron Fluoride Cathodes by Combined STEM/EELS and XPS"", 《J. PHYS. CHEM. C》 *
WENTIAN GU等: ""Metal Fluorides Nanoconfined in Carbon Nanopores as Reversible High Capacity Cathodes for Li and Li-Ion Rechargeable Batteries: FeF2 as an Example"", 《ADV. ENERGY MATER.》 *

Similar Documents

Publication Publication Date Title
Zhao et al. Novel in-situ redox synthesis of Fe3O4/rGO composites with superior electrochemical performance for lithium-ion batteries
Tan et al. Iron fluoride with excellent cycle performance synthesized by solvothermal method as cathodes for lithium ion batteries
CN104094457A (en) Graphene oxide as a sulfur immobilizer in high performance lithium/sulfur cells
CN102668199B (en) The aluminium foil of spread loads carbonaceous particles
Li et al. Macroporous nanostructured Nb2O5 with surface Nb4+ for enhanced lithium ion storage properties
Fang et al. Synthesis of hollow peanut-like hierarchical mesoporous LiNi1/3Co1/3Mn1/3O2 cathode materials with exceptional cycle performance for lithium-ion batteries by a simple self-template solid-state method
Wu et al. Alleviating structural degradation of nickel-rich cathode material by eliminating the surface Fm3¯ m phase
Ling et al. Double-shelled hollow Na 2 FePO 4 F/C spheres cathode for high-performance sodium-ion batteries
CN104868112A (en) Carbon-coated titanium dioxide nanosheet array and graphene composite electrode material and preparation method thereof
CN103682343B (en) Tin cobalt/polyaniline composite material and its preparation method and application
Qiao et al. One-step in situ encapsulation of Ge nanoparticles into porous carbon network with enhanced electron/ion conductivity for lithium storage
CN114551832A (en) Preparation method of nano composite material and lithium ion electrode negative electrode material thereof
Fu et al. Synthesis and Investigation of CuGeO 3 Nanowires as Anode Materials for Advanced Sodium-Ion Batteries
CN111193022B (en) Preparation and application of modified ammonium trifluorooxotitanate for lithium ion battery
CN102169980A (en) Preparation method of anode active material
Zhang et al. Well-designed hollow and porous Co 3 O 4 microspheres used as an anode for Li-ion battery
Zhang et al. A 10‐μm Ultrathin Lithium Metal Composite Anodes with Superior Electrochemical Kinetics and Cycling Stability
CN105810918B (en) A kind of fabricated in situ TiO2The method and its application of mesomorphic carbon graphite alkene nano composite material
Wang et al. Sustainable synthesis of Ni, Mn co-doped FePO4@ C cathode material for Na-ion batteries
Zhang et al. Enhancing the electrochemical performance of Li4Ti5O12 anode materials by codoping with Na and Br
Zhou et al. Ruthenium doped LiMn1. 5Ni0. 5O4 microspheres with enhanced electrochemical performance as lithium-ion battery cathode
Zhao et al. Synthesis and enhanced electrochemical properties of LiNi0. 6Co0. 2Mn0. 2O2 cathode materials via SDBS-assisted hydrothermal method
CN109103432B (en) Pyrovanadate/nitrogen-doped graphene composite material and preparation method and application thereof
Zeng et al. Synthesis of Hollow Three-Dimensional Channels LiNi 0.5 Mn 1.5 O 4 Microsphere by PEO Soft Template Assisted with Solvothermal Method
Zhang et al. PEG-assisted hydrothermal synthesis of porous Li 3 V 2 (PO 4) 3 frameworks for lithium-ion batteries

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination