CN115172671A - Composite positive pole piece for sodium ion secondary battery and sodium ion battery - Google Patents

Composite positive pole piece for sodium ion secondary battery and sodium ion battery Download PDF

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CN115172671A
CN115172671A CN202210731443.2A CN202210731443A CN115172671A CN 115172671 A CN115172671 A CN 115172671A CN 202210731443 A CN202210731443 A CN 202210731443A CN 115172671 A CN115172671 A CN 115172671A
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sodium
positive electrode
secondary battery
ion secondary
pole piece
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廖小珍
束潮九
袁思齐
鲍旭
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Shanghai Sudian New Energy Technology Co ltd
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Shanghai Jiaotong University
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • 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
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • 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

Abstract

The invention relates to a composite positive pole piece of a sodium ion secondary battery and the sodium ion secondary battery. The prior positive electrode material of the sodium-ion battery comprises transition metal oxide and/or Prussian blue compounds. The composite positive pole piece comprises three types: 1) Uniformly mixing the anode material of the existing sodium-ion battery and an iron-based polyanion compound to prepare a single-layer coated anode piece; 2) Coating an iron-based polyanion compound, the conventional positive electrode material of the sodium-ion battery and the iron-based polyanion compound layer by layer to form a sandwich type positive electrode piece; 3) The double-coating composite positive pole piece is formed by coating the conventional positive pole material of the sodium-ion battery and the iron-based polyanionic compound layer by layer. The invention comprises a secondary battery adopting the composite positive pole piece. Compared with the prior art, the sodium ion battery containing the composite positive pole piece has excellent cycle stability, and the preparation method is simple and suitable for large-scale production.

Description

Composite positive pole piece for sodium ion secondary battery and sodium ion battery
Technical Field
The invention relates to the technical field of sodium ion secondary batteries and materials, in particular to a composite positive pole piece for a sodium ion secondary battery and the sodium ion secondary battery.
Background
Compared with a lithium ion secondary battery, the sodium ion secondary battery has the remarkable advantages of low price, high safety and the like, has a preparation process and a working principle similar to those of the lithium ion battery, and has a great application prospect in the field of large-scale energy storage. However, the sodium ion secondary battery has a plurality of technical difficulties to be broken through and overcome.
At present, three main types of sodium ion battery positive electrode materials with application prospects mainly comprise layered transition metal oxides, prussian blue materials and polyanion compound materials. The cycling stability of the layered transition metal oxide positive electrode material is generally poor due to the unstable crystal structure characteristic in the charge and discharge process. In order to improve the long-term cycle life of such oxide-type cathode materials, the invention patent (CN 110233252A, CN110838576A, CN111082058 a) discloses a measure to improve the cycle stability of the materials by coating other substances on the surface of the active materials, specifically, the embodiments of the invention patent described above all use the layered transition metal oxide as the core, and respectively implement the electrochemical inert metal carbonate (Na) by means of secondary reaction and calcination 2 CO 3 ) Electrochemically inert oxides (aluminum oxide Al) 2 O 3 ) And phosphates (NaTi) 2 (PO 4 ) 3 ) The anode material is tightly coated on the surface of the layered oxide particles, and the stability of a crystal structure of the anode material in long-term circulation and the cycle service life of a pole piece can be effectively improved by inhibiting the volume strain of active particle crystals and reducing the occurrence of side reactions caused by direct contact of active substances and electrolyte. However, in the above method, since the coating material is not electrochemically active, it is necessary to sacrifice partial capacity at the expense, and increasing the coating amount decreases the charge/discharge capacity per unit mass of the positive electrode side, thereby reducing the charge/discharge capacity per unit mass of the positive electrode sideThe overall energy density of the sodium ion battery is necessarily reduced, and the large-scale production and use are not facilitated.
The Prussian blue type anode material has a large ion diffusion channel and an open crystal framework structure, and is very beneficial to the intercalation and deintercalation of sodium ions. However, the current mainstream material synthesis method mainly based on the coprecipitation process is difficult to avoid the existence of complex water residue and lattice defects in the product. The residual complex water can be removed into the electrolyte in the charging and discharging process to form an aggressive acidic substance with electrolyte salt, so that the structural damage and the transition metal dissolution of the original defect of the Prussian blue material can be aggravated, and the rapid deterioration of the cycle performance can be caused. The performance attenuation of the Prussian blue electrode can be inhibited by compounding a layer of other types of positive electrode materials with nano-scale particle size and good cycle stability on the surface of Prussian blue material particles or an electrode interface.
Disclosure of Invention
The invention aims to overcome the defects of the prior art mentioned above and provide a composite positive pole piece which can not reduce the overall reversible specific capacity of the positive pole side and has obviously improved cycle stability.
The purpose of the invention can be realized by the following technical scheme:
the inventors found that iron-based pyrophosphate/phosphate based polyanion compounds have proven to be effective for sodium battery positive electrode materials due to their open three-dimensional crystal framework and ultra-fast ion diffusion rate, and that the iron-based polyanion compounds have very high crystal structure stability and high sodium storage activity (theoretical specific discharge capacity of 97 to 129mAh g) -1 ) The composite electrode plate is an ideal positive electrode composite synergistic material, and no literature or patent reports exist at present that the iron-based polyanion compound is used for a composite electrode plate preparation process for enhancing the cycle stability of the layered oxide material and the Prussian blue composite material.
On one hand, by means of a 'blending' strategy of mixing nanoscale iron-based pyrophosphate/phosphate polyanion compound particles into a layered transition metal oxide or prussian blue compound material with a larger particle size, the iron-based polyanion compound particles are uniformly filled among the layered transition metal oxide or prussian blue compound material particles, and the composite cathode material is obtained by realizing close combination with a main body cathode material matrix. By combining the excellent sodium storage performance and structural stability of the iron-based polyanionic compound, the direct contact between an active substance and an electrolyte can be effectively separated, and the occurrence of side reactions is reduced; in addition, the volume strain of the main body cathode material in the charging and discharging process can be effectively relieved, the problem of volume expansion of the cathode side is effectively solved, and the cycle stability of the composite cathode material and the cycle life of the sodium-ion battery are improved.
On the other hand, the iron-based polyanion compound coating can be coated on the surface of the layered transition metal oxide or prussian blue compound material coating layer or on both the surface and the bottom surface in a double-layer coating or sandwich coating mode, and the characteristic that the iron-based polyanion compound hardly generates harmful side reaction with the electrolyte is utilized, so that the harmful side reaction between the transition metal oxide and prussian blue compound and the electrolyte is inhibited to the maximum extent, and the long-term circulation stability of the composite positive pole piece is effectively improved.
The specific invention content is as follows:
a composite positive electrode for a sodium ion secondary battery comprises a conventional positive electrode material for the sodium ion battery and an iron-based polyanion compound.
Further, the conventional positive electrode material of the sodium-ion battery comprises a transition metal oxide and/or a Prussian blue compound, and the mass ratio of the iron-based polyanion compound to the conventional positive electrode material of the sodium-ion battery is (0.05-1): 1.
Further, the molecular formula of the transition metal oxide material is Na m M n O p Wherein, M in the molecular formula can selectively contain one or more of Li, mg, al, fe, co, cu, zn, ca, sr, ce, cr, ti, zr, sn, V, nb, sb or Mo on the basis of containing at least one element of Mn and Ni, and M is more than or equal to 0.44, n is more than or equal to 1,p and more than or equal to 2,m, and the values of n and p meet the charge balance of the chemical formula.
Further, the molecular formula of the Prussian blue compound material is A x P[R(CN) 6 ] y P and R are respectively one or more of Mn, fe, ni, co, cu, ce, cr, ti, zn and V; the values of x and y satisfy the charge balance of the chemical formula.
Further, the iron-based polyanion compound is Na 4 Fe x M y (PO 4 ) 2 P 2 O 7 /C，Na 4 Fe x M y PO 4 P 2 O 7 F 3 /C,Na 3 Fe x M y PO 4 F/C and Na 2 Fe x M y P 2 O 7 One or more of the following molecular formulas of/C, wherein M comprises one or more of Ni, mn, co, cu, zn, mg, al, ca, sr, ce, ti, zr, sn, V, nb, sb or Mo, and the values of x and y satisfy the charge balance of the chemical formula.
The positive pole piece for the sodium-ion secondary battery comprises the composite positive pole material, the adhesive and the conductive additive.
Further, the positive pole piece is a sandwich type positive pole piece formed by coating an iron-based polyanion compound, the conventional positive pole material of the sodium-ion battery and the iron-based polyanion compound layer by layer;
or the anode material of the existing sodium-ion battery and the iron-based polyanionic compound are coated layer by layer to form a double-coating composite anode piece;
or the anode pole piece is formed by mixing the anode material of the existing sodium-ion battery and the iron-based polyanion compound and then coating the mixture in a single layer.
Further, the conductive additive is a high-conductivity carbon material, and specifically comprises one or more of graphene, carbon nanotubes, carbon fibers, acetylene black, conductive carbon black or conductive graphite; the mass proportion of the conductive agent in the positive pole piece of the sodium ion secondary battery is 0.5-10wt%;
the binder is a high polymer, and specifically comprises one or more of polyvinyl alcohol (PVA), carboxymethylcellulose sodium (CMC), fluorinated polyolefins (PTFE, PVDF or VGDF), polyurethane, polyolefins (PP or PE) or SBR rubber, and the mass proportion of the binder in the positive pole piece of the sodium-ion secondary battery is 2-10wt%.
Further, the specific preparation method of the positive pole piece comprises the following steps: uniformly dispersing a positive electrode material, a binder and a conductive additive in a solvent, mixing into slurry, coating the slurry on the surface of a current collector, and performing forced air drying, vacuum drying and rolling treatment to obtain a positive electrode plate of the sodium ion secondary battery;
the coating adopts spray coating, extrusion blade coating or screen printing.
A sodium ion secondary battery comprising a positive electrode sheet as described above.
Compared with the prior art, the invention has the beneficial effects that:
(1) On one hand, the invention effectively buffers the volume stress change of an active material component loaded by the positive plate of the sodium ion battery in the charging and discharging process by utilizing the advantage of an ultra-stable crystal structure of the iron-based polyanionic compound in the charging and discharging process, thereby improving the damage problem of the volume expansion of the positive material in the charging and discharging process to the cycle performance of the battery, on the other hand, the iron-based polyanionic compound nano particles cover the surfaces of the layered transition metal oxide and the Prussian blue compound material, and can inhibit the occurrence of harmful side reactions at the electrode/electrolyte interface; therefore, the charge-discharge cycle stability of the composite positive pole piece provided by the invention is obviously improved compared with the prior sodium-ion battery positive pole prepared based on the layered transition metal oxide or the Prussian blue compound.
(2) The invention can not reduce the overall reversible specific capacity of the positive electrode side, is simple and convenient to operate, has low cost and has large-scale production potential. The sodium ion battery comprising the composite positive electrode has excellent cycle life.
Drawings
Fig. 1 is a Scanning Electron Microscope (SEM) image of a composite positive electrode material S1 prepared in example 1 of the present invention;
FIG. 2 Na prepared in example 1 of the invention 0.67 Ni 0.25 Mg 0.08 Mn 0.66 Sn 0.01 O 2 With Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 The composite anode obtained by mixing the raw materials according to 1:1 at 100mA g/C -1 Constant current charge and discharge cycle performance.
FIG. 3 comparative example 1Na of the invention 0.67 Ni 0.25 Mg 0.08 Mn 0.66 Sn 0.01 O 2 Positive electrode at 100mA g -1 Constant current charge-discharge cycle performance.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. It is clear that the scope of protection of the invention is not limited to the examples described below.
Example 1
Forming a layered transition metal oxide Na 0.67 Ni 0.25 Mg 0.08 Mn 0.66 Sn 0.01 O 2 The material and sodium ferric phosphate pyrophosphate material Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 The composite cathode material S1 for the sodium ion secondary battery is prepared by placing/C in a mixing capsule with the volume of 25mL according to the mass ratio of 1:1, and mixing the mixture for 3, 5 and 2 minutes on a THINKY MIXER ARE-310 rotation and revolution stirrer respectively under the conditions of the rotating speeds of 650, 2000 and 650r/min, and is shown in figure 1.
Preparing a positive pole piece: stirring and mixing the composite positive electrode material, the conductive agent and the adhesive according to the mass ratio of 90.
Assembling a sodium ion half cell: in an argon-protected glove box, a 1 mm thick metal Na sheet and Glass Fiber (GFD) were used as a counter electrode and a separator, respectively, and an electrolyte solution using sodium hexafluorophosphate as an electrolyte and a carbonate compound as a solvent was used. In the working voltage range of 2.0-4.3V, the charge-discharge cycle performance test is carried out by using the current density under the multiplying power of 1C, and as shown in figure 2, the capacity retention rate of the prepared battery is 88.9% after the battery is cycled for 200 weeks in the voltage range of 2.0-4.3V.
Comparative example 1
Made in accordance with the invention for comparisonThe excellent cycle performance of the composite positive electrode of the sodium ion secondary battery is prepared by only using a layered transition metal oxide material Na in the embodiment 0.67 Ni 0.25 Mg 0.08 Mn 0.66 Sn 0.01 O 2 As a positive electrode active material, a pole piece D1 was obtained.
The preparation of the pole piece and the assembly and test of the sodium ion half-cell are all carried out by adopting the same process and conditions as the previous embodiment, and the capacity retention rate of the pole piece is 72.1 percent after 200 cycles of the electrode charge-discharge cycle performance test.
Example 2
Adding Na to layered transition metal oxide material 0.71 Ni 0.25 Mg 0.06 Mn 0.64 Zr 0.03 O 2 With sodium iron phosphate pyrophosphate material Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 The composite positive electrode material S2 for the sodium ion secondary battery is prepared by placing the material/C in a small box with a volume of 25mL according to a mass ratio of 10.
The assembly and test of the sodium ion secondary battery were carried out in the same manner as in example 1, and the capacity retention ratio at 200 cycles of the battery was 90.0%.
Comparative example 2
In order to comparatively illustrate the excellent cycle performance of the composite positive electrode material of the sodium-ion secondary battery prepared by the invention, only Na is used in the embodiment 0.7 Ni 0.25 Mg 0.06 Mn 0.64 Zr 0.03 O 2 As a positive electrode active material, a pole piece D2 was obtained.
The preparation of the pole piece and the assembly and test of the sodium ion half-cell are carried out under the same process and conditions as the previous embodiment, and the capacity retention rate of the cell is 86.2 percent within the voltage range of 2.0-4.3V after the charge-discharge cycle performance test for 200 weeks.
Example 3
Manganese-iron-based Prussian blue compound material Na 1.6 Mn[Fe(CN) 6 ] 0.9 With sodium ferric phosphate pyrophosphate material Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 the/C was placed in a 25 mL-volume capsule at a mass ratio of 4:1, and mixed on a THINKY MIXER ARE-310 rotation and revolution stirrer at 650, 2000 and 650r/min for 3, 5 and 2 minutes, respectively, to obtain a composite positive electrode material S3 for a sodium ion secondary battery.
The assembly and test of the sodium ion secondary battery were carried out in the same manner as in example 1, and the capacity retention ratio after 200-week cycles was 85.7% in the voltage range of 2.0 to 4.0V.
Example 4
The layered transition metal oxide material NaNi 0.33 Fe 0.33 Mn 0.33 O 2 With sodium ferric pyrophosphate material Na 2 FeP 2 O 7 Placing the materials into a small box with the volume of 25mL according to the mass ratio of 4:1, and respectively mixing the materials for 3 minutes, 5 minutes and 2 minutes on a THINKY MIXER ARE-310 rotation and revolution stirrer at the rotating speeds of 650r/min, 2000 r/min and 650r/min under the protection of argon gas to prepare the composite cathode material S4 for the sodium-ion secondary battery.
The assembly and test of the sodium ion secondary battery were carried out in the same manner as in example 1, and the capacity retention ratio of the battery was 89.3% after 200 cycles in a voltage range of 2.0 to 4.0V.
Comparative example 3
In order to comparatively illustrate the excellent cycle performance of the composite positive electrode material of the sodium-ion secondary battery prepared by the invention, only NaNi is used in the embodiment 0.33 Fe 0.33 Mn 0.33 O 2 As a positive electrode active material, a pole piece D2 was obtained.
The pole piece preparation and the assembly and test part of the sodium ion half-cell are all carried out by adopting the same process and conditions as the previous embodiment 4, and the capacity retention rate is 78.2% after the charge-discharge cycle performance test for 200 weeks.
Example 5
Adding Na to layered transition metal oxide material 0.67 Ni 0.25 Mg 0.08 Mn 0.66 Sn 0.01 O 2 With sodium iron phosphate pyrophosphate material Na 2 FeP 2 O 7 the/C is placed in a 25mL container according to the mass ratio of 3:1In the small box, the materials ARE respectively mixed for 3 minutes, 5 minutes and 2 minutes on a THINKY MIXER ARE-310 autorotation stirrer and revolution stirrer at the rotating speed of 650r/min, 2000 r/min and 650r/min, and the composite cathode material S5 for the sodium ion secondary battery is prepared.
The assembly and test of the sodium ion secondary battery were carried out in the same manner as in example 1, and the capacity retention ratio at 200 cycles of the battery was 89.5%.
Example 6
Sodium iron phosphate pyrophosphate Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 The material/C, conductive carbon SP and a binder PVDF are uniformly stirred according to the proportion of 8. Drying the pole piece obtained in the first step, and then adding a Prussian blue compound material Na 1.6 Mn[Fe(CN) 6 ] 0.9 The material is uniformly stirred with SP and PVDF according to the proportion of 8. And after the pole piece obtained in the second step is dried, continuously coating a coating of 20um on the surface of the second layer of material, and finally preparing the sandwich type composite electrode S6 after drying and rolling. The assembly and test of the sodium ion secondary battery were carried out in the same manner as in example 1, and the capacity retention rate after 200 cycles of the battery was 87.1%.
Comparative example 4
In order to comparatively illustrate the excellent cycle performance of the composite positive electrode material of the sodium-ion secondary battery prepared by the invention, only Na is used in the embodiment 1.6 Mn[Fe(CN) 6 ] 0.9 As a positive electrode active material, a pole piece D2 was obtained.
The pole piece preparation and the assembly and test part of the sodium ion half-cell are all carried out by adopting the same process and conditions as the previous embodiment 3, and the capacity retention rate of the battery in 200 weeks is 73.2 percent in the charge-discharge cycle performance test.
Example 7
Mixing Na 0.67 Ni 0.25 Mg 0.08 Mn 0.66 Sn 0.01 O 2 Uniformly stirring the mixture with conductive carbon SP and a binder PVDF according to the proportion of 8And spraying a coating with the thickness of 200um on the surface of the aluminum foil. Drying the pole piece obtained in the first step, and adding Na 4 Fe 3 PO 4 P 2 O 7 F 3 Uniformly stirring the material C, SP and PVDF according to the proportion of 8. The assembly and test of the sodium ion secondary battery were carried out in the same manner as in example 1, and the capacity retention ratio of the battery after 200-week cycles was 88.9% in the voltage range of 2.0 to 4.3V.
The results of the capacity retention rate of the electrodes after 200 cycles of 1C rate cycle test are shown in Table 1. The test results herein were based on assembly into a CR2032 button cell.
TABLE 1
Numbering Capacity retention (%)
S1 88.9
S2 90.0
S3 85.7
S4 89.3
S5 89.5
S6 87.1
S7 88.9
D1 72.1
D2 86.2
D3 78.2
D4 73.2
According to the test examples, the capacity retention rate of the sodium ion secondary battery assembled by the composite positive electrode prepared by the blending and secondary coating processes is remarkably improved.
The foregoing is directed to preferred embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention are within the protection scope of the technical solution of the present invention.

Claims (10)

1. The composite positive electrode for the sodium ion secondary battery is characterized by comprising the conventional positive electrode material for the sodium ion battery and an iron-based polyanion compound.
2. The composite positive electrode for the sodium-ion secondary battery according to claim 1, wherein the conventional positive electrode material for the sodium-ion secondary battery comprises a layered transition metal oxide and/or a prussian blue compound, and the mass ratio of the iron-based polyanion compound to the conventional positive electrode material for the sodium-ion secondary battery is (0.05-1): 1.
3. The composite positive electrode according to claim 2, wherein the transition metal oxide material has a formula of Na m M n O p Wherein, M in the molecular formula can selectively contain one or more of Li, mg, al, fe, co, cu, zn, ca, sr, ce, cr, ti, zr, sn, V, nb, sb or Mo on the basis of containing at least one element of Mn and Ni, and M is more than or equal to 0.44, n is more than or equal to 1,p and more than or equal to 2,m, and the values of n and p meet the charge balance of the chemical formula.
4. The composite positive electrode as claimed in claim 2, wherein the Prussian blue compound material has a molecular formula of A x P[R(CN) 6 ] y P and R are respectively one or more of Mn, fe, ni, co, cu, ce, cr, ti, zn and V; the values of x and y satisfy the charge balance of the chemical formula.
5. The composite positive electrode according to claim 1, wherein the iron-based polyanion compound is Na 4 Fe x M y (PO 4 ) 2 P 2 O 7 /C，Na 4 Fe x M y PO 4 P 2 O 7 F 3 /C,Na 3 Fe x M y PO 4 F/C and Na 2 Fe x M y P 2 O 7 One or more of the following molecular formulas of/C, wherein M comprises one or more of Ni, mn, co, cu, zn, mg, al, ca, sr, ce, ti, zr, sn, V, nb, sb or Mo, and the values of x and y satisfy the charge balance of the chemical formula.
6. A composite positive electrode plate for a sodium ion secondary battery, characterized in that the positive electrode plate comprises the composite positive electrode material as claimed in any one of claims 1 to 5, a binder and a conductive additive.
7. The positive pole piece for the sodium-ion secondary battery as claimed in claim 6, wherein the positive pole piece is a sandwich type positive pole piece formed by coating an iron-based polyanion compound, an existing positive pole material of the sodium-ion battery and the iron-based polyanion compound layer by layer;
or the anode material of the existing sodium-ion battery and the iron-based polyanionic compound are coated layer by layer to form a double-coating composite anode piece;
or mixing the anode material of the existing sodium-ion battery and the iron-based polyanion compound and then coating the mixture in a single layer.
8. The positive electrode plate for the sodium-ion secondary battery according to claim 6, wherein the conductive additive is a high-conductivity carbon material, and specifically comprises one or more of graphene, carbon nanotubes, carbon fibers, acetylene black, conductive carbon black or conductive graphite; the mass proportion of the conductive agent in the positive pole piece of the sodium ion secondary battery is 0.5-10wt%;
the binder is a high polymer, and specifically comprises one or more of polyvinyl alcohol (PVA), carboxymethylcellulose sodium (CMC), fluorinated polyolefins (PTFE, PVDF or VGDF), polyurethane, polyolefins (PP or PE) or SBR rubber, and the mass proportion of the binder in the positive pole piece of the sodium-ion secondary battery is 2-10wt%.
9. The positive pole piece for the sodium-ion secondary battery according to claim 6, wherein the specific preparation method of the positive pole piece comprises the following steps: uniformly dispersing a positive electrode material, a binder and a conductive additive in a solvent, mixing into slurry, coating the slurry on the surface of a current collector, and performing forced air drying, vacuum drying and rolling treatment to obtain a positive electrode plate of the sodium ion secondary battery;
the coating adopts spray coating, extrusion blade coating or screen printing.
10. A sodium ion secondary battery, characterized in that the secondary battery comprises a positive electrode sheet according to any one of claims 6 to 9.
CN202210731443.2A 2022-06-24 2022-06-24 Composite positive pole piece for sodium ion secondary battery and sodium ion battery Pending CN115172671A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116344772A (en) * 2023-04-18 2023-06-27 广东广钠新材科技有限公司 Spherical ferric sodium pyrophosphate positive electrode material and preparation method thereof
CN116845236A (en) * 2023-09-01 2023-10-03 北京禾电科技有限责任公司 Polyanionic sodium ion battery positive electrode material, preparation method and application
CN116885197A (en) * 2023-09-07 2023-10-13 四川易纳能新能源科技有限公司 Positive electrode plate, preparation method thereof and sodium ion battery
CN117293302A (en) * 2023-11-24 2023-12-26 山东海化集团有限公司 Composite positive electrode material of sodium ion battery and preparation method thereof

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116344772A (en) * 2023-04-18 2023-06-27 广东广钠新材科技有限公司 Spherical ferric sodium pyrophosphate positive electrode material and preparation method thereof
CN116845236A (en) * 2023-09-01 2023-10-03 北京禾电科技有限责任公司 Polyanionic sodium ion battery positive electrode material, preparation method and application
CN116845236B (en) * 2023-09-01 2024-01-26 北京禾电科技有限责任公司 Polyanionic sodium ion battery positive electrode material, preparation method and application
CN116885197A (en) * 2023-09-07 2023-10-13 四川易纳能新能源科技有限公司 Positive electrode plate, preparation method thereof and sodium ion battery
CN117293302A (en) * 2023-11-24 2023-12-26 山东海化集团有限公司 Composite positive electrode material of sodium ion battery and preparation method thereof

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