A method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material

Abstract

This invention relates to the field of battery technology and discloses a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material. The method involves dissolving nickel nitrate, cobalt nitrate, manganese nitrate, and titanium nitrate in deionized water and stirring to obtain a metal salt solution. A complexing agent and sodium 2,5-dihydrofuran-3-carboxylate are added to the metal salt solution, and sodium hydroxide solution is added to adjust the pH to 7.0-8.5. The mixture is stirred to form a uniform complex sol. Sodium carbonate is dissolved in deionized water to obtain a sodium source solution. The sodium source solution is slowly added dropwise to the complex sol, followed by spray drying to obtain a precursor powder. The precursor powder is placed in an alumina crucible and sintered in segments under air atmosphere, then ground and sieved to obtain a high-capacity layered transition metal oxide cathode material. The sodium-ion battery cathode material prepared by this invention exhibits high discharge specific capacity, high capacity retention, and excellent electrochemical performance.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material. Background Technology

[0002] As the global energy structure shifts towards cleaner and lower-carbon energy, large-scale energy storage technology has become crucial for supporting the consumption of renewable energy. Sodium-ion batteries, due to the abundance, wide distribution, and low cost of sodium resources, have shown enormous application potential in the field of large-scale energy storage and have become one of the current research hotspots in the field of energy materials.

[0003] As a core component of sodium-ion batteries, the performance of cathode materials directly determines the battery's energy density, cycle life, and safety. Layered transition metal oxides, due to their high theoretical specific capacity and excellent ion diffusion channels, represent an important research direction for cathode materials in sodium-ion batteries.

[0004] Chinese Patent CN120565664B: Provides an O3-type layered oxide sodium ion cathode material, its preparation method, and its application. The cathode material comprises a sodium nickel-iron-manganese-zinc oxide core and a sodium nickel-iron-manganese-zinc oxide shell; in the sodium nickel-iron-manganese-zinc oxide core, zinc accounts for 7%~10% of the total molar amount of nickel, iron, manganese, and zinc; in the sodium nickel-iron-manganese-zinc oxide shell, zinc accounts for 1%~5% of the total molar amount of nickel, iron, manganese, and zinc; the sodium nickel-iron-manganese-zinc oxide core and the sodium nickel-iron-manganese-zinc oxide shell each independently include a first lattice control element; the sodium nickel-iron-manganese-zinc oxide shell also includes a second lattice control element.

[0005] Chinese Patent CN120914235A discloses a layered oxide sodium-ion cathode material, its preparation method, and its application, relating to the field of sodium-ion battery technology. Specifically, the layered oxide sodium-ion cathode material has a core-shell structure, wherein the core layer comprises an O3-type layered oxide, and the shell layer comprises a sodium-containing phosphate, wherein the sodium-containing phosphate includes NaCaPO4; the surface of the core layer comprises a mixed phase of O3-type layered oxide and calcium; in the mixed phase, the concentration of calcium gradually increases from the inside to the outside.

[0006] Existing layered transition metal oxide cathode materials have the following problems in practical applications: On the one hand, due to the difference in the radius of transition metal ions and uneven dispersion during the preparation process, metal ion segregation is prone to occur, leading to an increase in crystal structure defects and affecting the electrochemical performance of the material; on the other hand, traditional sintering processes are mostly single-temperature sintering, which makes it difficult to achieve the orderly growth of crystal structure. The layered structure of the material is not stable enough, and structural collapse is prone to occur during long-term charge-discharge cycles, resulting in severe capacity decay. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] To address the shortcomings of existing technologies, this invention provides a method for preparing high-capacity layered transition metal oxide sodium-ion battery cathode materials, solving the problems of metal ion segregation and insufficient stability of layered structures that affect the electrical performance of materials in existing technologies.

[0009] (II) Technical Solution

[0010] A method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, the method comprising the following steps:

[0011] S1: By weight, dissolve 7-12 parts nickel nitrate, 1-5 parts cobalt nitrate, 5-10 parts manganese nitrate, and 1-3 parts titanium nitrate in 150-180 parts deionized water and stir until completely dissolved to obtain a metal salt solution; add 20-30 parts complexing agent to the metal salt solution to obtain a complexed sol, then add 0.5-2% sodium 2,5-dihydrofuran-3-carboxylate according to the total mass of the complexed sol, add sodium hydroxide solution to adjust the pH value to 7.0-8.5, stir to react, and form a homogeneous complexed sol;

[0012] In this step, a 10%-20% sodium hydroxide solution is used to adjust the pH to 7.0-8.5 to maintain the optimal environment for the complexation reaction, prevent premature hydrolysis and precipitation of metal ions, and ensure that the sol is uniform, transparent, and stable.

[0013] S2: Dissolve 2-6 parts of sodium carbonate in 10-20 parts of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 30-60 minutes after the addition is complete, and then spray dry to obtain the precursor powder;

[0014] During this process, sodium carbonate solution is slowly added dropwise, allowing Na⁺ to permeate uniformly in the complexed sol. Combined with spray drying, this achieves microscopic uniform mixing of Na⁺ and transition metal ions, with no local sodium enrichment or deficiency, thus realizing uniform doping of the sodium source.

[0015] S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

[0016] Furthermore, the complexing agent is citric acid or ethylenediaminetetraacetic acid.

[0017] Furthermore, the sodium hydroxide solution has a mass percentage of 10-20%.

[0018] Furthermore, in S1, the stirring reaction temperature is 50-70℃ and the time is 60-120 min.

[0019] Furthermore, in S2, the inlet air temperature of the spray dryer is 200-220℃, and the outlet air temperature is 80-100℃.

[0020] Furthermore, in S3, the segmented sintering step is as follows: first, the temperature is raised to 350-450℃ at a heating rate of 2-5℃ / min, and sintered for 2-4 hours; then, the temperature is raised to 750-850℃ at a heating rate of 1-3℃ / min, and sintered for 8-12 hours.

[0021] Furthermore, in step S3, the mesh size of the sieve used for grinding and sieving is 200-300 mesh.

[0022] Further, the method for preparing the sodium 2,5-dihydrofuran-3-carboxylate is as follows:

[0023] By weight, 11-22 parts of 2,5-dihydrofuran-3-carboxylic acid (CAS No.: 1002728-73-5), 4-8 parts of sodium hydroxide, and 300-500 parts of deionized water are mixed and stirred at room temperature until the solution is clear and transparent to obtain an aqueous solution of sodium 2,5-dihydrofuran-3-carboxylate. The water is evaporated and dried to obtain sodium 2,5-dihydrofuran-3-carboxylate.

[0024] The necessity of this step is as follows: (1) Carboxylic acids have poor water solubility and are prone to agglomeration, while sodium salts have high solubility and are evenly dispersed; (2) Carboxylic acids will lower the pH of the system and cause metal ions to hydrolyze and precipitate, while sodium salts do not disturb the pH; (3) Carboxylic acids need to be neutralized in situ to form salts, and coordination is delayed; sodium salts directly participate in efficient coordination, and the ions are more evenly dispersed.

[0025] The steric hindrance and conjugated π-electron effect of the furan ring can block the agglomeration and segregation of metal ions, enabling the four transition metal ions to achieve atomic-level uniform dispersion in the sol, thus avoiding lattice distortion and crystal defects caused by excessively high local concentrations.

[0026] Sodium 2,5-dihydrofuran-3-carboxylate was added to S1. The furan ring of sodium 2,5-dihydrofuran-3-carboxylate forms a coordinating structure with the carboxyl group, and forms a complex complex system with citric acid / ethylenediaminetetraacetic acid. Through the strong coordination ability of the carboxyl group and the conjugated electronic effect of the furan ring, the segregation of transition metal ions is suppressed, the crystal growth orientation is optimized during the segmented sintering process, the orderly growth of layered crystals is promoted, crystal defects are reduced, and the stability of the layered structure is enhanced.

[0027] This application constructs a composite complex system, specifically: using citric acid / ethylenediaminetetraacetic acid as the main complexing agent to provide strong coordination sites with multiple carboxyl groups, and reacting with Ni²⁺, Co²⁺, Mn²⁺, and Ti. 4⁺ Forms a stable chelate; sodium 2,5-dihydrofuran-3-carboxylate is an auxiliary complexing agent. The furan ring provides a conjugated π-electron system, and the carboxyl group provides a coordinating group. The two form a synergistic coordination structure, which, together with the main complexing agent, constructs a double complexing system, achieving a synergistic enhancement of coordination ability, steric hindrance, and electronic effects. Citric acid is an aliphatic polycarboxyl complexing agent without a conjugated structure; sodium 2,5-dihydrofuran-3-carboxylate contains a furan ring π-conjugated system, forming a synergistic coordination, and has strong coordination, steric hindrance, and electronic regulation effects, which cannot be replaced by citric acid.

[0028] (iii) Beneficial technical effects

[0029] 1. The more uniformly dispersed ion complex system completely solves the problem of metal ion segregation, significantly reduces the crystal defect rate, and improves the batch consistency of materials.

[0030] 2. The layered structure is more stable. Segmented sintering promotes orderly crystal growth, making it less prone to interlayer slip and structural collapse during cycling, thus significantly extending the battery cycle life.

[0031] 3. Excellent electrochemical performance: discharge specific capacity reaches 129.5-130.5 mAh / g, and capacity retention rate is 93.9%-94.8% after 500 cycles, which is far higher than that of traditional processes.

[0032] 4. The highly efficient and orderly layered structure of sodium ion transport provides a continuous low-impedance migration channel, significantly improving rate performance and charge / discharge efficiency.

[0033] 5. The process is adapted to industrial sol-gel + spray drying + segmented sintering, with strong process controllability, making it suitable for large-scale production. Detailed Implementation

[0034] To further illustrate the technical means and effects of the present invention in achieving the intended purpose, the following detailed description of the specific implementation methods and effects of the present invention, in conjunction with embodiments, is provided below.

[0035] Electrochemical performance testing:

[0036] The positive electrode material, conductive carbon black, and polyvinylidene fluoride were mixed in a mass ratio of 8:1:1, and N-methylpyrrolidone was added to form a uniform slurry. The slurry was coated onto aluminum foil and vacuum dried at 110°C for 12 hours. The slurry was then cut into electrode sheets with a diameter of 12 mm to serve as the working electrode. A sodium metal sheet was used as the counter electrode and reference electrode, glass fiber was used as the separator, and 1 mol / L NaPF / EC+DMC (volume ratio 1:1) was used as the electrolyte. The cells were assembled into a coin cell in an argon-protected glove box.

[0037] At 25°C, charge and discharge cycles were performed at a 1C rate with a voltage range of 2.0-4.0V to test the discharge specific capacity; at 25°C, charge and discharge cycles were performed at a 1C rate with a voltage range of 2.0-4.0V for 500 cycles to test the capacity retention.

[0038] Example 1

[0039] This embodiment provides a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, including the following steps:

[0040] S1: Dissolve 7g nickel nitrate, 1g cobalt nitrate, 5g manganese nitrate, and 1g titanium nitrate in 150g deionized water and stir until completely dissolved to obtain a metal salt solution; add 20g complexing agent to the metal salt solution to obtain a complexed sol, then add 0.5% sodium 2,5-dihydrofuran-3-carboxylate (by mass of the total complexed sol), adjust the pH to 7.0 with sodium hydroxide solution, stir to react, and form a homogeneous complexed sol;

[0041] S2: Dissolve 2g of sodium carbonate in 10g of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 30min after the addition is complete, and then spray dry to obtain the precursor powder;

[0042] S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

[0043] The complexing agent is citric acid.

[0044] The sodium hydroxide solution has a mass percentage of 10%.

[0045] The stirring reaction temperature of S1 is 50℃ and the time is 60min.

[0046] The inlet air temperature of the S2 spray dryer is 200℃, and the outlet air temperature is 80℃.

[0047] The S3 segmented sintering steps are as follows: first, the temperature is raised to 350℃ at a heating rate of 2℃ / min and sintered for 2 hours; then, the temperature is raised to 750℃ at a heating rate of 1℃ / min and sintered for 8 hours.

[0048] The S3 grinding and sieving process uses a 300-mesh sieve.

[0049] The method for preparing sodium 2,5-dihydrofuran-3-carboxylic acid is as follows: 11g of 2,5-dihydrofuran-3-carboxylic acid (CAS No.: 1002728-73-5), 4g of sodium hydroxide, and 300g of deionized water are mixed and stirred at room temperature until the solution is clear and transparent to obtain an aqueous solution of sodium 2,5-dihydrofuran-3-carboxylic acid. The water is evaporated to remove the water, and the solution is dried to obtain sodium 2,5-dihydrofuran-3-carboxylic acid.

[0050] Example 2

[0051] This embodiment provides a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, including the following steps:

[0052] S1: Dissolve 9g nickel nitrate, 2g cobalt nitrate, 6g manganese nitrate, and 2g titanium nitrate in 160g deionized water and stir until completely dissolved to obtain a metal salt solution; add 23g complexing agent to the metal salt solution to obtain a complexed sol, then add sodium 2,5-dihydrofuran-3-carboxylate (1% of the total mass of the complexed sol), add sodium hydroxide solution to adjust the pH to 7.5, stir to react, and form a homogeneous complexed sol;

[0053] S2: Dissolve 3g of sodium carbonate in 14g of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 40min after the addition is complete, and then spray dry to obtain the precursor powder;

[0054] S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

[0055] The complexing agent is citric acid.

[0056] The sodium hydroxide solution has a mass percentage of 15%.

[0057] The stirring reaction temperature of S1 is 55℃ and the time is 80min.

[0058] The inlet air temperature of the S2 spray dryer is 205°C, and the outlet air temperature is 85°C.

[0059] The S3 segmented sintering steps are as follows: first, the temperature is raised to 380℃ at a heating rate of 3℃ / min and sintered for 3 hours; then, the temperature is raised to 780℃ at a heating rate of 2℃ / min and sintered for 9 hours.

[0060] The S3 grinding and sieving process uses a 300-mesh sieve.

[0061] The method for preparing sodium 2,5-dihydrofuran-3-carboxylic acid is as follows: 16g of 2,5-dihydrofuran-3-carboxylic acid (CAS No.: 1002728-73-5), 6g of sodium hydroxide, and 400g of deionized water are mixed and stirred at room temperature until the solution is clear and transparent to obtain an aqueous solution of sodium 2,5-dihydrofuran-3-carboxylic acid. The water is evaporated and dried to obtain sodium 2,5-dihydrofuran-3-carboxylic acid.

[0062] Example 3

[0063] This embodiment provides a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, including the following steps:

[0064] S1: Dissolve 11g nickel nitrate, 4g cobalt nitrate, 8g manganese nitrate, and 2g titanium nitrate in 170g deionized water and stir until completely dissolved to obtain a metal salt solution; add 28g complexing agent to the metal salt solution to obtain a complexed sol, then add sodium 2,5-dihydrofuran-3-carboxylate (1.5% of the total mass of the complexed sol), add sodium hydroxide solution to adjust the pH to 8, stir to react, and form a homogeneous complexed sol;

[0065] S2: Dissolve 5g of sodium carbonate in 18g of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 50min after the addition is complete, and then spray dry to obtain the precursor powder;

[0066] S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

[0067] The complexing agent is ethylenediaminetetraacetic acid.

[0068] The sodium hydroxide solution has a mass percentage of 15%.

[0069] The stirring reaction temperature of S1 is 65℃ and the time is 100min.

[0070] The inlet air temperature of the S2 spray dryer is 215°C, and the outlet air temperature is 95°C.

[0071] The S3 segmented sintering steps are as follows: first, the temperature is raised to 430℃ at a heating rate of 4℃ / min and sintered for 3 hours; then, the temperature is raised to 830℃ at a heating rate of 2℃ / min and sintered for 11 hours.

[0072] The S3 grinding and sieving process uses a 200-mesh sieve.

[0073] The method for preparing sodium 2,5-dihydrofuran-3-carboxylic acid is as follows: 18g of 2,5-dihydrofuran-3-carboxylic acid (CAS No.: 1002728-73-5), 7g of sodium hydroxide, and 450g of deionized water are mixed and stirred at room temperature until the solution is clear and transparent to obtain an aqueous solution of sodium 2,5-dihydrofuran-3-carboxylic acid. The water is evaporated and dried to obtain sodium 2,5-dihydrofuran-3-carboxylic acid.

[0074] Example 4

[0075] This embodiment provides a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, including the following steps:

[0076] S1: Dissolve 12g nickel nitrate, 5g cobalt nitrate, 10g manganese nitrate, and 3g titanium nitrate in 180g deionized water and stir until completely dissolved to obtain a metal salt solution; add 30g complexing agent to the metal salt solution to obtain a complexed sol, then add sodium 2,5-dihydrofuran-3-carboxylate (2% of the total mass of the complexed sol), add sodium hydroxide solution to adjust the pH to 8.5, stir to react, and form a homogeneous complexed sol;

[0077] S2: Dissolve 6g of sodium carbonate in 20g of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 60min after the addition is complete, and then spray dry to obtain the precursor powder;

[0078] S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

[0079] The complexing agent is ethylenediaminetetraacetic acid.

[0080] The sodium hydroxide solution has a mass percentage of 20%.

[0081] The stirring reaction temperature of S1 is 70℃, and the time is 120min.

[0082] The inlet air temperature of the S2 spray dryer is 220°C, and the outlet air temperature is 100°C.

[0083] The S3 segmented sintering steps are as follows: first, the temperature is raised to 450℃ at a heating rate of 5℃ / min and sintered for 4 hours; then, the temperature is raised to 850℃ at a heating rate of 3℃ / min and sintered for 12 hours.

[0084] The S3 grinding and sieving process uses a 200-mesh sieve.

[0085] The method for preparing sodium 2,5-dihydrofuran-3-carboxylic acid is as follows: 22g of 2,5-dihydrofuran-3-carboxylic acid (CAS No.: 1002728-73-5), 8g of sodium hydroxide, and 500g of deionized water are mixed and stirred at room temperature until the solution is clear and transparent to obtain an aqueous solution of sodium 2,5-dihydrofuran-3-carboxylic acid. The water is evaporated and dried to obtain sodium 2,5-dihydrofuran-3-carboxylic acid.

[0086] Comparative Example 1

[0087] This comparative example provides a method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, comprising the following steps:

[0088] S1: Dissolve 7g nickel nitrate, 1g cobalt nitrate, 5g manganese nitrate, and 1g titanium nitrate in 150g deionized water and stir until completely dissolved to obtain a metal salt solution; add 20g complexing agent to the metal salt solution, add sodium hydroxide solution to adjust the pH to 7.0, stir to react, and form a uniform complexed sol;

[0089] S2: Dissolve 2g of sodium carbonate in 10g of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 30min after the addition is complete, and then spray dry to obtain the precursor powder;

[0090] S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

[0091] The complexing agent is citric acid.

[0092] The sodium hydroxide solution has a mass percentage of 10%.

[0093] The stirring reaction temperature of S1 is 50℃ and the time is 60min.

[0094] The inlet air temperature of the S2 spray dryer is 200℃, and the outlet air temperature is 80℃.

[0095] The S3 segmented sintering steps are as follows: first, the temperature is raised to 350℃ at a heating rate of 2℃ / min and sintered for 2 hours; then, the temperature is raised to 750℃ at a heating rate of 1℃ / min and sintered for 8 hours.

[0096] The S3 grinding and sieving process uses a 300-mesh sieve.

[0097] Comparative Example 2:

[0098] 2,3-Dihydrofuran was used instead of sodium 2,5-dihydrofuran-3-carboxylate, and the rest was the same as in Example 1.

[0099] Comparative Example 3:

[0100] Sodium formate was used instead of sodium 2,5-dihydrofuran-3-carboxylate, and the rest was the same as in Example 1.

[0101] Table 1: Test results of discharge specific capacity and capacity retention of sodium-ion battery cathode materials

[0102] Discharge specific capacity (mAh / g) Capacity retention rate (%) Example 1 129.5 93.9 Example 2 129.7 94.1 Example 3 130.1 94.5 Example 4 130.5 94.8 Comparative Example 1 113.1 83.5 Comparative Example 2 123.7 89.5 Comparative Example 3 125.5 87.8

[0103] As shown in the table, the use of sodium 2,5-dihydrofuran-3-carboxylate as an auxiliary complexing agent in this application can significantly improve the discharge specific capacity and cycle retention rate. Compared with Comparative Example 1 (113.1 mAh / g, 83.5%) without the addition of this substance, Examples 1-4 with the addition of sodium 2,5-dihydrofuran-3-carboxylate achieved a discharge specific capacity of 129.5-130.5 mAh / g and a capacity retention rate of 93.9%-94.8%, with a significant improvement in both capacity and retention rate. This indicates that the substance can form a stable, low-impedance interface film on the electrode surface, reduce electrolyte side reactions, improve the effective sodium / lithium intercalation / deintercalation capacity, and significantly suppress capacity decay during cycling.

[0104] This application uses sodium 2,5-dihydrofuran-3-carboxylate, in which both sodium carboxylate and unsaturated cyclic ether structures are indispensable and exhibit a synergistic effect. Comparative Example 3 uses only sodium formate (125.5 mAh / g, 87.8%): although it is an improvement over the blank Comparative Example 1, due to the lack of unsaturated cyclic ether structures, a dense and stable polymer interface layer cannot be formed, resulting in insufficient interface protection and a significantly lower capacity retention rate than the examples. Comparative Example 2 uses only 2,3-dihydrofuran (123.7 mAh / g, 89.5%). Although it has a cyclic ether structure that can participate in film formation, it lacks the polar adsorption and site guiding effect of sodium carboxylate, leading to insufficient coordination, resulting in metal ion segregation, increased crystal defects, decreased integrity of the layered structure, uneven film formation, and high impedance. Therefore, the discharge specific capacity and cycle stability are still significantly inferior to the examples. Thus, only sodium 2,5-dihydrofuran-3-carboxylate can achieve optimal interface control.

[0105] Examples 1-4 simultaneously possess sodium carboxylate (-COONa) and 2,5-dihydrofuran unsaturated cyclic ether structures. The two work synergistically: sodium carboxylate provides strong adsorption, causing the additive to preferentially accumulate on the electrode surface; the unsaturated cyclic ether polymerizes at the interface, forming a dense, flexible, and stable interfacial film with excellent ionic conductivity. This results in higher discharge specific capacity and higher capacity retention, significantly superior to comparative examples with single components or missing structures, demonstrating the irreplaceable technical advantages of this compound structure.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high-capacity layered transition metal oxide sodium-ion battery cathode material, characterized in that, The preparation method includes the following steps: S1: By weight, dissolve 7-12 parts nickel nitrate, 1-5 parts cobalt nitrate, 5-10 parts manganese nitrate, and 1-3 parts titanium nitrate in 150-180 parts deionized water and stir until completely dissolved to obtain a metal salt solution; add 20-30 parts complexing agent to the metal salt solution to obtain a complexing sol, then add 0.5-2% sodium 2,5-dihydrofuran-3-carboxylate according to the total mass of the complexing sol, add sodium hydroxide solution to adjust the pH value to 7.0-8.5, stir to react, and form a homogeneous complexing sol; S2: Dissolve 2-6 parts of sodium carbonate in 10-20 parts of deionized water to obtain a sodium source solution; slowly add the sodium source solution dropwise to the complexed sol, and continue stirring for 30-60 minutes after the addition is complete, and then spray dry to obtain the precursor powder; S3: The precursor powder is placed in an alumina crucible and sintered in segments under an air atmosphere. After cooling to room temperature in the furnace, it is ground and sieved to obtain a high-capacity layered transition metal oxide cathode material.

2. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, The complexing agent is citric acid or ethylenediaminetetraacetic acid.

3. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, The sodium hydroxide solution has a mass percentage of 10-20%.

4. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, In step S1, the stirring reaction temperature is 50-70℃ and the time is 60-120 min.

5. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, In step S2, the inlet air temperature of the spray dryer is 200-220℃, and the outlet air temperature is 80-100℃.

6. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, In S3, the segmented sintering step is as follows: first, the temperature is raised to 350-450℃ at a heating rate of 2-5℃ / min, and sintered for 2-4 hours; then, the temperature is raised to 750-850℃ at a heating rate of 1-3℃ / min, and sintered for 8-12 hours.

7. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, In step S3, the mesh size of the sieve used for grinding and sieving is 200-300 mesh.

8. The method for preparing the high-capacity layered transition metal oxide sodium-ion battery cathode material according to claim 1, characterized in that, The sodium 2,5-dihydrofuran-3-carboxylate is prepared by reacting 2,5-dihydrofuran-3-carboxylic acid with sodium hydroxide.