A high-transmission wide-temperature-range sodium-ion battery anode based on a two-phase layered oxide and a preparation method and application thereof

Abstract

The application discloses a high-transmission wide-temperature-range sodium ion battery anode based on a two-phase layered oxide and a preparation method and application thereof, and belongs to the technical field of sodium ion batteries. The sodium ion battery anode comprises an anode active material, a conductive agent and a binder, wherein the anode active material comprises a layered oxide component and a complex component; the layered oxide component comprises O3-phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and P2-phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, the complex component comprises Na2MnPO4F, Na2FePO4F and Na2FeSiO4, the conductive agent is a mixture of super conductive carbon black (SP) and carbon nanotubes (CNT), and the binder is polyvinylidene fluoride (PVDF). The O3 / P2 two-phase layered oxide provides high capacity and structural stability, the polyanion compound material guarantees ion transmission and thermal stability, and the conductive agent optimizes electron transmission. The prepared sodium ion battery has the effects of breaking through the low-temperature performance limitation, significantly improving the sodium ion transmission efficiency, cycle stability and excellent safety and stability.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery technology, specifically, it relates to a high-transport wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide, its preparation method, and its application. Background Technology

[0002] Sodium-ion batteries are a highly promising rechargeable battery system to replace lithium batteries. However, existing sodium-ion battery cathode materials still have the following drawbacks: First, sodium ion transport kinetics are limited, especially at low temperatures where the ion migration rate drops sharply, leading to severe capacity decay; second, single-phase cathode materials cannot balance capacity and stability. For example, P2-type layered oxides have excellent cycle stability but low capacity, while O3-type layered oxides have high capacity but are prone to phase transitions; third, thermal runaway is likely to occur under high temperatures or mechanical shocks, and the problem of sodium precipitation at low temperatures exacerbates safety risks.

[0003] In existing technologies, composite cathodes mostly employ simple physical mixing methods, failing to form a synergistic conduction network, resulting in sodium ion diffusion coefficients generally below 10. -11 cm 2 With a capacity retention rate of less than 60% at -40℃ and a thermal runaway temperature below 250℃, sodium-ion batteries cannot meet the requirements for applications in extremely cold regions and scenarios with high safety requirements. Therefore, developing composite cathode materials that combine high ion transport, excellent low-temperature performance, and high safety has become a key breakthrough direction for the development of sodium-ion batteries. Summary of the Invention

[0004] The purpose of this invention is to provide a high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide, its preparation method, and its application. Through the synergistic design of multiple components, rapid sodium-ion transport is achieved, improving capacity retention and cycle stability at low temperatures, while simultaneously increasing the thermal runaway threshold and enhancing safety performance.

[0005] To achieve the above objectives, according to one aspect of the present invention, a high-transport wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide is provided, comprising a cathode active material, a conductive agent, and a binder;

[0006] The positive electrode active material comprises 50-70 parts by weight of layered oxide component and 30-45 parts by weight of compound component;

[0007] The layered oxide component includes O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3O2, the mass ratio of the two is 1:1 - 4:1;

[0008] The compound components include Na2MnPO4F, Na2FePO4F, and Na2FeSiO4, with a mass ratio of 1:1:2.

[0009] In a preferred embodiment, the conductive agent is a mixture of superconducting carbon black (SP) and carbon nanotubes (CNTs) in a mass ratio of 1:1 to 5:1.

[0010] In a preferred embodiment, the adhesive is polyvinylidene fluoride (PVDF).

[0011] According to another aspect of the present invention, a method for preparing a high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide as described above is provided, comprising:

[0012] Step 1, remove the O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, Na2MnPO4F, Na2FePO4F, and Na2FeSiO4 are mixed evenly to form a positive electrode active material mixture; and the positive electrode active material mixture is then mixed evenly with superconducting carbon black (SP) and carbon nanotubes (CNT) to form a positive electrode material mixture.

[0013] Step 2: Add the positive electrode material mixture to the PVDF adhesive to form a slurry;

[0014] Step 3: The slurry is coated onto aluminum foil, dried, and sliced ​​to form the positive electrode.

[0015] In a preferred embodiment, in step two, the PVDF adhesive is formed by mixing polyvinylidene fluoride (PVDF) and N-methylpyrrolidone.

[0016] In a preferred embodiment, in step three, the thickness of the aluminum foil is 10μm~12μm.

[0017] According to another aspect of the present invention, the application of the above-described high-transport wide-temperature-range sodium-ion battery cathode based on biphase layered oxide in the preparation of sodium-ion batteries is provided.

[0018] According to another aspect of the present invention, a sodium-ion battery is provided, comprising a positive electrode, a negative electrode, a liquid electrolyte, and a separator, wherein the positive electrode is the high-transport wide-temperature-range sodium-ion battery positive electrode based on biphase layered oxides described above.

[0019] As a preferred embodiment, the negative electrode is prepared by mixing hard carbon, conductive agent, sodium carboxymethyl cellulose and styrene-butadiene rubber to form a slurry, then coating the slurry onto aluminum foil, and then rolling, drying and slicing to form the negative electrode.

[0020] In a preferred embodiment, the mass ratio of hard carbon, conductive agent, sodium carboxymethyl cellulose, and styrene-butadiene rubber is 95.5:1.1:1.8:1.6.

[0021] The positive electrode of the sodium-ion battery provided by this invention is prepared by compounding several positive electrode materials, with the positive electrode active material being NaNi in the O3 phase. 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 The electrode system is mainly composed of O2, with other materials including polyanionic compounds Na2MnPO4F and Na2FePO4F, silicate phase Na2FeSiO4, and superconducting carbon black (SP) and carbon nanotubes (CNT).

[0022] The biphase ion channel design enables the O3 and P2 phases to form an interpenetrating structure. The O3 phase provides a high-capacity foundation, while the P2 phase stabilizes the structure and suppresses phase transitions. The interface between the two phases forms a rapid sodium ion transport channel, significantly improving ion transport efficiency. Polyanionic compound phases (Na2MnPO4F, Na2FePO4F) enhance structural stability, while the silicate phase (Na2FeSiO4) reduces interfacial impedance. The complementary functions of the multiple active phases synergistically optimize low-temperature ion conduction efficiency. SP and CNT construct a three-dimensional conductive network, enhancing network transmission. Combined with the effect of PVDF adhesive, this reduces the aggregation of active materials, ensuring rapid conduction of both electrons and ions.

[0023] The sodium-ion battery prepared according to the present invention has the effects of overcoming the limitations of low temperature performance, significantly improving sodium ion transport efficiency, and excellent cycle stability and safety stability. It is especially suitable for energy storage devices, electric vehicles and other scenarios in low temperature environments. Attached Figure Description

[0024] Figure 1 This is a comparison of the capacity data of sodium-ion batteries prepared in Example 1 of the present invention and Comparative Examples 1-3;

[0025] Figure 2 This is a comparison of the capacity retention data of sodium-ion batteries prepared in Example 2 and Comparative Examples 4-6 at 60°C.

[0026] Figure 3 This is a comparison of the discharge performance data of the lithium-ion batteries prepared in Example 3 and Comparative Examples 7-9 of the present invention at -40°C. Detailed Implementation

[0027] The basic concept of this invention is to use O3 / P2 two-phase layered oxide to provide high capacity and structural stability, polyanionic compound materials to ensure ion transport and thermal stability, and conductive agents to optimize electron transport, thereby achieving synergistic optimization of performance such as capacity, transport, wide temperature range, and safety.

[0028] A typical embodiment of the present invention provides a high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide, comprising a cathode active material, a conductive agent, and a binder.

[0029] The positive electrode active material comprises 50-70 parts by weight of layered oxide component and 30-45 parts by weight of compound component.

[0030] For example, the mass fractions of the layered oxide component and the compound component can be: 50 parts layered oxide component and 30 parts compound component, 50 parts layered oxide component and 45 parts compound component, 50 parts layered oxide component and 40 parts compound component, 60 parts layered oxide component and 40 parts compound component, 60 parts layered oxide component and 36 parts compound component, 64 parts layered oxide component and 32 parts compound component, or 70 parts layered oxide component and 30 parts compound component.

[0031] The layered oxide component includes O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, the mass ratio of the two is 1:1 -4:1.

[0032] For example, O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3The mass ratio of O2 can be 1:1, 1.5:1, 2:1, 2.6:1, 3:1, 3.2:1, or 4:1.

[0033] The compound components include Na2MnPO4F, Na2FePO4F, and Na2FeSiO4, with a mass ratio of 1:1:2.

[0034] Based on this, in a preferred embodiment, the conductive agent is a compound conductive agent, which is a mixture of superconducting carbon black (SP) and carbon nanotubes (CNT).

[0035] The mass ratio of superconducting carbon black (SP) to carbon nanotubes (CNT) is 1:1 to 5:1, for example: 1:1, 2:1, 3:1, 4:1, 5:1.

[0036] The adhesive is polyvinylidene fluoride (PVDF). PVDF adhesive solution can be prepared by mixing polyvinylidene fluoride (PVDF) powder with N-methylpyrrolidone.

[0037] This invention uses NaNi with a specific composition 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 A multi-component mixture of O2, Na2MnPO4F, Na2FePO4F, Na2FeSiO4, SP, CNT and FVDF significantly improves ion transport efficiency, wide temperature range performance and safety performance.

[0038] The complementary lattice of the two-phase layered oxide (O3 / P2) broadens the ion transport channels, the polyanionic material forms a three-dimensional ion conduction network, and SP and CNT construct a continuous conductive network, which significantly improves the diffusion coefficient of sodium ions, reduces the interfacial impedance, and maintains the 5C discharge capacity by ≥93%.

[0039] The O3 / P2 dual-phase synergy suppresses low-temperature phase transitions, and the complementary functions of the multiple active phases enhance the structural stability of the polyanionic compound phases (Na2MnPO4F, Na2FePO4F), while the silicate phase (Na2FeSiO4) reduces interfacial impedance. The three phases work together to optimize low-temperature ion conduction efficiency, resulting in a capacity retention rate of 92% at -40℃ / 0.5C and an 89% capacity retention rate after 500 cycles at 60℃, enabling wide-temperature-range applications.

[0040] Polyanionic compound materials can suppress oxygen release from layered oxides. Na2MnPO4F and Na2FePO4F enhance structural stability and can form a double protection with ceramic diaphragms. The needle penetration test (3mm diameter) showed no fire or explosion, and there was no leakage when overcharged to 5V. The thermal runaway temperature was increased to 290℃, meeting stringent safety requirements and comprehensively enhancing safety performance.

[0041] Another typical embodiment of the present invention provides a method for preparing the high-transport wide-temperature-range sodium-ion battery cathode based on biphase layered oxides, which includes the following steps.

[0042] Step 1, remove the O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, Na2MnPO4F, Na2FePO4F, and Na2FeSiO4 are mixed evenly to form a positive electrode active material mixture; and the positive electrode active material mixture is then mixed evenly with superconducting carbon black (SP) and carbon nanotubes (CNT) to form a positive electrode material mixture.

[0043] Step two involves adding the positive electrode material mixture to the PVDF adhesive solution to form a slurry. The PVDF adhesive solution is formed by mixing polyvinylidene fluoride (PVDF) and N-methylpyrrolidone.

[0044] Step 3: The slurry is coated onto aluminum foil, dried, and sliced ​​to form the positive electrode. The aluminum foil thickness is preferably 10μm~12μm.

[0045] Based on the high-transport wide-temperature-range sodium-ion battery cathode based on biphase layered oxide provided by the present invention, another typical embodiment of the present invention is to provide a sodium-ion battery, which includes a positive electrode, a negative electrode, a liquid electrolyte and a separator.

[0046] The positive electrode is prepared according to the preparation method provided by the present invention. The negative electrode is prepared by mixing hard carbon, a conductive agent, sodium carboxymethyl cellulose, and styrene-butadiene rubber in a mass ratio of 95.5:1.1:1.8:1.6 to form a negative electrode slurry. The slurry is then coated onto an aluminum foil with a thickness of 10-15 μm, and the coating is rolled, dried, and sliced ​​to form a negative electrode sheet. The conductive agent is a mixture of superconducting carbon black (SP) and carbon nanotubes (CNTs), and the separator is preferably a composite ceramic separator.

[0047] The positive electrode, separator, and negative electrode are stacked in an alternating sequence of positive electrode, separator, negative electrode, and positive electrode, or the stacked separator, positive electrode, separator, and negative electrode are wound to form a battery cell. Then, the battery cell is subjected to tab welding and aluminum-plastic film encapsulation.

[0048] The battery cells are baked to remove excess internal moisture. After baking, a certain amount of electrolyte is injected, followed by a period of settling. The cells then undergo pre-formation charging activation, aging, OCV testing, and room temperature aging to obtain improved battery samples.

[0049] The technical solutions claimed in this invention will be further described below through some embodiments. However, the embodiments and comparative examples are for explaining the implementation schemes of this invention and do not exceed the scope of the subject matter of this invention. The scope of protection of this invention is not limited by the embodiments. Unless otherwise specified, the materials and reagents used in this invention can be obtained from commercially available products in the art.

[0050] Example 1

[0051] NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, Na2MnPO4F, Na2FePO4F, and Na2FeSiO4 are mixed uniformly to form a positive electrode active material mixture; the positive electrode active material mixture is then mixed uniformly with SP and CNT to form a positive electrode material mixture; PVDF and N-methylpyrrolidone are mixed to form a PVDF solution; the positive electrode material mixture is then added to the PVDF solution to prepare a positive electrode slurry; NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 The mass ratio of O2, Na2MnPO4F, Na2FePO4F, Na2FeSiO4, SP, CNT, and PVDF is 25:25:10:10:20:3:3:4, and the solid content of the positive electrode slurry is 55%.

[0052] The positive electrode slurry was coated on 11 μm aluminum foil with a double-sided areal density of 36.2 ± 0.6 mg / cm². 2 Positive electrode sheets of specified specifications; the dried positive electrode sheets are manufactured according to a standard of 3.2 g / cm³. 3The process involves rolling, followed by slitting, punching, and baking.

[0053] Hard carbon, conductive agent, sodium carboxymethyl cellulose, and styrene-butadiene rubber were mixed in a mass ratio of 95.5:1.1:1.8:1.6 to prepare a uniformly mixed negative electrode slurry. The negative electrode slurry was then coated, rolled, dried, and sliced ​​on a 12μm aluminum foil to form a negative electrode sheet.

[0054] A secondary sodium-ion battery cell is manufactured using a stacking method. The cell is then subjected to tab welding and encapsulation, with the encapsulation shell being an aluminum-plastic film shell. The cell is baked to remove water, then injected with electrolyte, and subsequently allowed to stand.

[0055] By performing pre-formation, high-temperature aging, OCV testing, and room-temperature aging on the battery cell, an improved battery sample can be obtained, denoted as 1-a.

[0056] Comparative Example 1

[0057] The only difference from Example 1 is that Na2MnPO4F is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 1-b.

[0058] Comparative Example 2

[0059] The only difference from Example 1 is that Na2FePO4F is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 1-c.

[0060] Comparative Example 3

[0061] The only difference from Example 1 is that Na2FeSiO4 is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is recorded as 1-d.

[0062] Four battery samples obtained from Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were fully charged within the range of 1.5-4.2V at charging currents of 0.01C, 0.02C, 0.05C, and 0.1C, respectively. They were then discharged at a 0.1C discharge current, and the 0.1C discharge capacity was recorded. After being charged to 3.7V at a 0.1C current, the batteries were placed at room temperature. Comparative data are shown in the attached figure. Figure 1 As shown, the results indicate that the battery sample provided in Example 1 has a higher capacity.

[0063] Example 2

[0064] NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, Na 0.67 Ni0.33 Mn 0.37 Ti 0.3 O2, Na2MnPO4F, Na2FePO4F, and Na2FeSiO4 are mixed uniformly to form a positive electrode active material mixture; the positive electrode active material mixture is then mixed uniformly with SP and CNT to form a positive electrode material mixture; PVDF and N-methylpyrrolidone are mixed to form a PVDF solution; the positive electrode material mixture is then added to the PVDF solution to prepare a positive electrode slurry; NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 The mass ratio of O2, Na2MnPO4F, Na2FePO4F, Na2FeSiO4, SP, CNT, and PVDF is 32:32:8:8:16:2:0.8:1.2, and the solid content of the positive electrode slurry is 55%.

[0065] The positive electrode slurry was coated on a 10μm aluminum foil with a double-sided areal density of 36.0±0.6mg / cm². 2 Positive electrode sheets of specified specifications; the dried positive electrode sheets are manufactured according to a standard of 3.2 g / cm³. 3 The process involves rolling, followed by slitting, punching, and baking.

[0066] Hard carbon, conductive agent, sodium carboxymethyl cellulose, and styrene-butadiene rubber are mixed in a mass ratio of 95.5:1.1:1.8:1.6 to prepare a uniformly mixed negative electrode slurry. The negative electrode slurry is then coated, rolled, dried, and sliced ​​on a 15μm aluminum foil to form a negative electrode sheet.

[0067] The secondary sodium-ion battery cell is manufactured using a winding method. The cell is then fitted with tabs and encapsulated in an aluminum-plastic film shell. The cell is baked to remove moisture, then injected with electrolyte, and finally allowed to stand.

[0068] By performing pre-formation, high-temperature aging, OCV testing, and room-temperature aging on the battery cells, an improved battery sample can be obtained, denoted as 2-a.

[0069] Comparative Example 4

[0070] The only difference from Example 1 is that Na2MnPO4F is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 2-b.

[0071] Comparative Example 5

[0072] The only difference from Example 1 is that Na2FePO4F is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 2-c.

[0073] Comparative Example 6

[0074] The only difference from Example 1 is that Na2FeSiO4 is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 2-d.

[0075] The four battery samples obtained in Example 2, Comparative Example 4, Comparative Example 5, and Comparative Example 6 were subjected to cyclic testing within the range of 1.5-4.2V at a charge-discharge current of 1C. The comparative data are shown in the attached figure. Figure 2 As shown, the results indicate that the battery sample provided in Example 2 has better cycle stability, with ≥89% after 500 cycles at 1C at 60°C.

[0076] Example 3

[0077] NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, Na2MnPO4F, Na2FePO4F, and Na2FeSiO4 are mixed uniformly to form a positive electrode active material mixture; the positive electrode active material mixture is then mixed uniformly with SP and CNT to form a positive electrode material mixture; PVDF and N-methylpyrrolidone are mixed to form a PVDF solution; the positive electrode material mixture is then added to the PVDF solution to prepare a positive electrode slurry; NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 The mass ratio of O2, Na2MnPO4F, Na2FePO4F, Na2FeSiO4, SP, CNT, and PVDF is 48:12:9:9:18:2.5:0.5:1, and the solid content of the positive electrode slurry is 55%.

[0078] The positive electrode slurry was coated on a 12μm aluminum foil with a double-sided areal density of 35.2±0.6 mg / cm². 2 Positive electrode sheets of specified specifications; the dried positive electrode sheets are manufactured according to a standard of 3.2 g / cm³. 3The process involves rolling, followed by slitting, punching, and baking.

[0079] Hard carbon, conductive agent, sodium carboxymethyl cellulose, and styrene-butadiene rubber are mixed in a mass ratio of 95.5:1.1:1.8:1.6 to prepare a uniformly mixed negative electrode slurry. The negative electrode slurry is then coated, rolled, dried, and sliced ​​on a 10μm aluminum foil to form a negative electrode sheet.

[0080] A secondary sodium-ion battery cell is manufactured using a stacking method. The cell is then subjected to tab welding and encapsulation, with the encapsulation shell being an aluminum-plastic film shell. The cell is baked to remove water, then injected with electrolyte, and subsequently allowed to stand.

[0081] By performing pre-formation, high-temperature aging, OCV testing, and room-temperature aging on the battery cells, an improved battery sample can be obtained, denoted as 3-a.

[0082] Comparative Example 7

[0083] The only difference from Example 1 is that Na2MnPO4F is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 3-b.

[0084] Comparative Example 8

[0085] The only difference from Example 1 is that Na2FePO4F is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is denoted as 3-c.

[0086] Comparative Example 9

[0087] The only difference from Example 1 is that Na2FeSiO4 is not added to the positive electrode active material mixture; all other steps are the same, and the resulting battery sample is recorded as 3-d.

[0088] The battery samples obtained in Example 3, Comparative Example 7, Comparative Example 8, and Comparative Example 9 were subjected to low-temperature discharge tests within the range of 1.5-4.2V at a charge-discharge current of 0.5C. The comparative data are shown in the attached figure. Figure 3 As shown, the results indicate that the battery sample provided in Example 3 has better low-temperature discharge characteristics, with a 0.5C discharge capacity retention rate of ≥92% at -40℃.

[0089] The scope of protection claimed by this invention is not limited to the specific embodiments described above. For those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide, comprising a cathode active material, a conductive agent, and a binder, characterized in that: The positive electrode active material comprises 50-70 parts by weight of layered oxide component and 30-45 parts by weight of compound component; The layered oxide component includes O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2 and P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, the mass ratio of the two is 1:1 - 4:1; The compound components include Na2MnPO4F, Na2FePO4F, and Na2FeSiO4, with a mass ratio of 1:1:

2.

2. The high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide according to claim 1, characterized in that: The conductive agent is a mixture of superconducting carbon black (SP) and carbon nanotubes (CNTs) in a mass ratio of 1:1 to 5:

1.

3. The high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide according to claim 1, characterized in that: The adhesive is polyvinylidene fluoride (PVDF).

4. The method for preparing a high-transport, wide-temperature-range sodium-ion battery cathode based on a biphase layered oxide according to any one of claims 1-3, characterized in that, include: Step 1, remove the O3 phase NaNi 0.2 Fe 0.2 Co 0.2 Mn 0.2 Ti 0.2 O2, P2 phase Na 0.67 Ni 0.33 Mn 0.37 Ti 0.3 O2, Na2MnPO4F, Na2FePO4F, and Na2FeSiO4 are mixed evenly to form a positive electrode active material mixture; and the positive electrode active material mixture is then mixed evenly with superconducting carbon black (SP) and carbon nanotubes (CNT) to form a positive electrode material mixture. Step 2: Add the positive electrode material mixture to the PVDF adhesive to form a slurry; Step 3: The slurry is coated onto aluminum foil, dried, and sliced ​​to form the positive electrode.

5. The method for preparing a high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide according to claim 4, characterized in that: In step two, the PVDF adhesive is formed by mixing polyvinylidene fluoride (PVDF) and N-methylpyrrolidone.

6. The method for preparing a high-transport, wide-temperature-range sodium-ion battery cathode based on a two-phase layered oxide according to claim 4 or 5, characterized in that: In step three, the thickness of the aluminum foil is 10μm~12μm.

7. The application of the high-transport wide-temperature-range sodium-ion battery cathode based on biphase layered oxide as described in any one of claims 1-3 in the preparation of sodium-ion batteries.

8. A sodium-ion battery, comprising a positive electrode, a negative electrode, a liquid electrolyte, and a separator, characterized in that: The positive electrode is the high-transport wide-temperature-range sodium-ion battery positive electrode based on biphase layered oxide as described in any one of claims 1-3.

9. The sodium-ion battery according to claim 8, characterized in that, The method for preparing the negative electrode is as follows: hard carbon, conductive agent, sodium carboxymethyl cellulose and styrene-butadiene rubber are mixed to form a slurry, and then the slurry is coated on aluminum foil, and then rolled, dried and sliced ​​to form the negative electrode.

10. The sodium-ion battery according to claim 9, characterized in that: The mass ratio of hard carbon, conductive agent, sodium carboxymethyl cellulose, and styrene-butadiene rubber is: 95.5：1.1：1.8：1.6。

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