A method for preparing a layered oxide composite material as a positive electrode for sodium ion batteries

Abstract

A method for preparing a layered oxide composite material as a sodium ion battery positive electrode, relating to a sodium ion battery positive electrode material, specifically a method for preparing a layered oxide composite material. The present invention aims to solve the current layered oxide positive electrode material P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 The modification method of O2 has the technical problems of complicated process and high cost. The present invention obtains a layered oxide material with P2 structure by co-precipitation. During the co-precipitation process, iron element is uniformly doped into the manganese position of the material to achieve iron doping modification. On the one hand, the doping of iron ions with larger ionic radius increases the unit cell volume and broadens the sodium ion channel. On the other hand, it can also suppress the Jan-Taylor effect of manganese to a certain extent, thereby improving the electrochemical performance of the material.

Description

Technical Field

[0001] The present invention relates to a positive electrode material for a sodium ion battery, in particular to a method for preparing a layered oxide composite material. Background Art

[0002] In recent years, technologies for converting renewable energy sources such as wind, solar, hydro, and tidal energy into electricity have rapidly developed. However, because the electricity generated is subject to natural constraints and exhibits randomness, intermittency, and volatility, it often leads to energy waste such as curtailment of hydropower, wind power, and solar power. Therefore, the development of efficient, convenient, and safe energy storage technologies has attracted widespread attention from researchers. Among the various energy storage technologies, electrochemical energy storage offers advantages such as ease of use, high energy conversion efficiency, and rapid response, and holds broad application prospects in the energy storage field. Among these technologies, lithium-ion batteries (LIBs) are widely used due to their long cycle life and high energy density. However, with the rapidly increasing demand for batteries in portable electronics and electric vehicles, the limited reserves of lithium resources make it difficult to simultaneously support the development of consumer electronics, electric vehicles, and large-scale energy storage. Compared to limited lithium resources, sodium is abundant on Earth, distributed worldwide, and is cost-effective. Therefore, sodium-ion batteries (NIBs), which primarily rely on sodium resources, are considered a promising alternative to lithium-ion batteries for large-scale deployment. Furthermore, since sodium does not alloy with aluminum, the negative electrode current collector can be replaced with cheaper aluminum instead of copper. Therefore, sodium-ion batteries have received significant attention since 2012.

[0003] P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 has attracted great attention in P2-type materials due to its electrochemical performance and material properties. (1) P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 exhibits high operating voltage (about 3.8 V) and high capacity (about 173 mAh g -1), which in turn gives it a high energy density in layered transition metal oxide cathodes when assembled into full batteries (Clement RJ, Bruce PG, Grey CP. Review—Manganese-Based P2-Type Transition Metal Oxides as Sodium-Ion Battery Cathode Materials. Journal of The Electrochemical Society, 2015, 162(14):A2589.DOI:10.1149 / 2.0201514jes.); (2) Most P2-type oxides are sodium-deficient, while P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 The amount of sodium ions in O2 is sufficient for electrochemical cycling (Lu Z, Dahn J R. In Situ X-Ray Diffraction Study of P2-Na 2 / 3 [Ni 1 / 3 Mn 2 / 3 ]O2.Journal of The Electrochemical Society,2001,148(11):A1225.DOI:10.1149 / 1.1407247), there is no additional component (for example, a sodium-rich sacrificial source is needed during the first charge / discharge process) to compensate for the lack of sodium, and this material has significant advantages in realizing high-energy full batteries; (3) Unlike most layered oxides, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 is stable at room temperature and pressure (Lu Z, Dahn J R. Intercalation of Water in P2, T2 and O2 Structure A z [Co x Ni 1 / 3-x Mn 2 / 3 ]O2.Chemistry of Materials,2001,13(4):1252-1257.DOI:10.1021 / cm000721x), which makes the material easy to handle in actual production; (4) P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3O2 can be generated by natural cooling after conditioned sintering, which is significantly different from other P2-type oxide cathodes. This characteristic is very suitable for large-scale production of materials. Because the P2 phase is unstable during slow cooling, most P2-type oxides must be quenched immediately after sintering at high temperatures (usually 850-950°C) (Pang WK, Kalluri S, Peterson VK, et al. Interplay between Electrochemistry and Phase Evolution of the P2-type Na x (Fe 1 / 2 Mn 1 / 2 )O2 Cathode for Use in Sodium-Ion Batteries. Chemistry of Materials, 2015, 27(8): 3150-3158. DOI: 10.1021 / acs.chemmater.5b00943.). However, this quenching operation is actually dangerous and difficult to handle. Based on the above properties, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 is one of the most promising candidate cathodes for practical applications of high-energy NIBs. However, at a high voltage of 4.2 V, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 will undergo an irreversible P2→O2 phase transition, which will cause changes in the material's structure, leading to poor cycling stability. Researchers have modified the material through strategies such as element doping, surface coating, and micromorphology control to improve the structural stability of the material under high pressure, thereby improving its cycling stability. 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 by Atomic LayerDeposition.ACS Applied Materials&Interfaces, 2017, 9(31):26518-26530.DOI:10.1021 / acsami.7b05326.) Using atomic layer deposition (ALD) technology on P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3The Al2O3 layer is coated on O2. The Al2O3 layer can reduce the decomposition of the electrolyte, avoid the formation of too thick SEI, and improve the electrochemical performance. After 100 cycles, the capacity of the modified sample remains at about 77.4 mAh g -1 , higher than the 52mAhg of the uncoated sample -1 . Liu Y, Shen Q, Zhao X, et al. Hierarchical Engineering of Porous P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3O2Nanofibers Assembled by Nanoparticles Enables Superior Sodium-Ion StorageCathodes.Advanced Functional Materials,2020,30(6):1907837.DOI:10.1002 / adfm.201907837) synthesized P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 nanofibers, the material exhibits excellent rate performance (166.7 mAh g at 0.1C) -1 , 73.4mAh g at 20C -1 ) and significantly improved the material's cyclic stability (capacity retention rate ≈81% after 500 cycles). However, the above scheme still has problems such as complex process, cumbersome technology, and high cost. Therefore, by adopting a simple and efficient modification method, while developing a technical route for large-scale production, combined with the high discharge capacity of the layered oxide material itself, a good foundation is laid for the practical application of sodium-ion battery positive electrode materials, which has a very important research significance for the commercialization and multi-purpose development of sodium-ion batteries. Summary of the Invention

[0004] The present invention aims to solve the problem of the current layered oxide type positive electrode material P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 In order to solve the technical problems of complicated process and high cost of the modification method of O2, a method for preparing a layered oxide composite material as the positive electrode of a sodium ion battery is provided.

[0005] The preparation method of the layered oxide type composite material as the positive electrode of the sodium ion battery of the present invention is carried out according to the following steps:

[0006] 1. Co-precipitation to obtain a precursor: Ammonia water is added dropwise to deionized water to adjust the pH to 10.8-11.2, and then a metal salt solution is added. Alkaline solution is then added dropwise to adjust the pH to 10.6-10.8 for co-precipitation. Stirring is continued for 12-16 hours for aging, followed by filtering, washing, and drying in sequence to obtain a precursor;

[0007] The solute in the metal salt solution is composed of a nickel source, a manganese source and an iron source, and the ratio of the amount of nickel element in the nickel source, the amount of manganese element in the manganese source and the amount of iron element in the iron source is 0.33:0.67-x:x, x≤0.1;

[0008] The sum of the molar concentrations of nickel, manganese and iron in the metal salt solution is 2 mol / L to 2.5 mol / L;

[0009] The volume ratio of the deionized water to the metal salt solution is 1:(2.09-3.01);

[0010] 2. The precursor prepared in step 1 is mixed evenly with the metal salt of the sodium source, and pre-reacted at 450°C to 500°C for 5h to 5.5h, then heated to 850°C to 900°C and kept warm for 16h to 17h, and naturally cooled to room temperature. After being taken out and fully ground, a layered oxide-type positive electrode material is obtained;

[0011] The ratio of the amount of sodium element in the sodium source to the sum of the three metal elements in the precursor is (1.05-1.1):1;

[0012] The reaction atmosphere during the entire reaction process of step 2 is air.

[0013] The present invention uses a co-precipitation method to dissolve a nickel source, a manganese source and an iron source in deionized water in a stoichiometric ratio to form a metal salt solution, and then drop the metal salt solution into the deionized water, and adjust the pH with an alkaline solution composed of sodium hydroxide and ammonia water. After the co-precipitation reaction is completed, stirring is continued for aging, and then filtering, washing and drying are performed to obtain a precursor; then the precursor is evenly mixed with a metal salt of a sodium source in a certain proportion, a high-temperature reaction is carried out, and it is naturally cooled to room temperature to obtain a layered oxide material with a P2 type structure. During the co-precipitation process, iron elements are uniformly doped into the manganese sites of the material to achieve doping modification of the iron element. On the one hand, iron ions with larger ionic radius (larger than +4 valence manganese ions) are doped, which increases the unit cell volume and broadens the sodium ion channel. On the other hand, the Jan-Taylor effect of manganese can be suppressed to a certain extent, thereby improving the electrochemical properties of the material. After the material prepared by the present invention is assembled into a battery as a positive electrode, in terms of cycle performance, at 100mAg -1 After 200 cycles at a current density of 1.54 Å, it still contained 51.18 mAh g -1The discharge capacity and capacity retention rate are 65.21%; in terms of rate performance, at 1000mAg -1 Even at a high current density, there is still 53.37 mAh g -1 Specific capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the SEM image of the layered oxide-type cathode material prepared in Experiment 1;

[0015] Figure 2 is the XRD pattern;

[0016] Figure 3 This is a comparison curve of battery rate performance;

[0017] Figure 4 This is a comparison chart of battery cycle performance;

[0018] Figure 5 This is the cyclic voltammetry curve of the battery. DETAILED DESCRIPTION

[0019] Specific embodiment 1: This embodiment is a method for preparing a layered oxide composite material as a positive electrode of a sodium ion battery, which is specifically carried out according to the following steps:

[0020] 1. Co-precipitation to obtain a precursor: Ammonia water is added dropwise to deionized water to adjust the pH to 10.8-11.2, and then a metal salt solution is added. Alkaline solution is then added dropwise to adjust the pH to 10.6-10.8 for co-precipitation. Stirring is continued for 12-16 hours for aging, followed by filtering, washing, and drying in sequence to obtain a precursor;

[0021] The solute in the metal salt solution is composed of a nickel source, a manganese source and an iron source, and the ratio of the amount of nickel element in the nickel source, the amount of manganese element in the manganese source and the amount of iron element in the iron source is 0.33:0.67-x:x, x≤0.1;

[0022] The sum of the molar concentrations of nickel, manganese and iron in the metal salt solution is 2 mol / L to 2.5 mol / L;

[0023] The volume ratio of the deionized water to the metal salt solution is 1:(2.09-3.01);

[0024] 2. The precursor prepared in step 1 is mixed evenly with the metal salt of the sodium source, and pre-reacted at 450°C to 500°C for 5h to 5.5h, then heated to 850°C to 900°C and kept warm for 16h to 17h, and naturally cooled to room temperature. After being taken out and fully ground, a layered oxide-type positive electrode material is obtained;

[0025] The ratio of the amount of sodium element in the sodium source to the sum of the three metal elements in the precursor is (1.05-1.1):1;

[0026] The reaction atmosphere during the entire reaction process of step 2 is air.

[0027] Specific embodiment 2: This embodiment is different from the specific embodiment 1 in that the alkali solution described in step 1 is 10 molL -1 of sodium hydroxide solution and 0.2 molL -1 The mixture is prepared by mixing the ammonia water with the mixture in a volume ratio of 7:3. Other aspects are the same as those in the first embodiment.

[0028] Specific embodiment 3: This embodiment differs from specific embodiment 1 or 2 in that the washing in step 1 is performed with deionized water. Other aspects are the same as specific embodiment 1 or 2.

[0029] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the drying temperature in step 1 is 100°C and the drying time is 12 hours. Other aspects are the same as specific embodiments 1 to 3.

[0030] Specific embodiment 5: This embodiment differs from specific embodiment 4 in that the nickel source in step 1 is nickel acetate tetrahydrate, nickel nitrate hexahydrate, nickel chloride hexahydrate or nickel sulfate hexahydrate. Other steps are the same as those in specific embodiment 4.

[0031] Specific embodiment 6: This embodiment differs from specific embodiment 5 in that the manganese source in step 1 is manganese acetate tetrahydrate, manganese chloride tetrahydrate or manganese sulfate monohydrate. Other steps are the same as those in specific embodiment 5.

[0032] Specific embodiment 7: This embodiment differs from specific embodiment 6 in that the iron source in step 1 is ferrous oxalate dihydrate or ferrous sulfate heptahydrate. Other steps are the same as those in specific embodiment 6.

[0033] Specific embodiment eight: This embodiment differs from specific embodiment seven in that the sodium source in step two is sodium acetate, sodium citrate, sodium carbonate, sodium bicarbonate or sodium hydroxide. Other aspects are the same as specific embodiment seven.

[0034] Specific embodiment 9: This embodiment differs from specific embodiment 8 in that the ratio of the amount of sodium element in the sodium source in step 2 to the sum of the three metal elements in the precursor is 1.05:1. Other aspects are the same as specific embodiment 8.

[0035] Specific embodiment 10: This embodiment differs from specific embodiment 9 in that, in step 2, a pre-reaction is first performed at 450°C for 5 hours, then the temperature is raised to 850°C and kept for reaction for 16 hours, and then naturally cooled to room temperature. After removal, the material is thoroughly ground to obtain a layered oxide-type positive electrode material. Other aspects are the same as specific embodiment 9.

[0036] The present invention is verified by the following test:

[0037] Experiment 1: This experiment is a method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery, specifically carried out in the following steps:

[0038] 1. Co-precipitation to obtain a precursor: Ammonia water is added dropwise to deionized water to adjust the pH to 11, and then a metal salt solution is added. Alkaline solution is then added dropwise to adjust the pH to 10.7 for co-precipitation. Stirring is continued for 14 hours for aging, followed by filtration, washing, and drying to obtain a precursor;

[0039] The solute in the metal salt solution is composed of a nickel source, a manganese source and an iron source, and the ratio of the amount of nickel element in the nickel source, the amount of manganese element in the manganese source and the amount of iron element in the iron source is 0.33:0.57:0.1;

[0040] The sum of the concentrations of nickel, manganese and iron in the metal salt solution is 2 mol / L -1 ;

[0041] The volume ratio of the deionized water to the metal salt solution is 1:3;

[0042] The alkali solution is 10 molL -1 of sodium hydroxide solution and 0.2 molL -1 Ammonia water is mixed in a volume ratio of 7:3;

[0043] The washing is washing with deionized water;

[0044] The drying temperature is 100°C and the drying time is 12h;

[0045] The nickel source is nickel sulfate hexahydrate;

[0046] The manganese source is manganese sulfate monohydrate;

[0047] The iron source is ferrous sulfate heptahydrate;

[0048] 2. The precursor prepared in step 1 was mixed evenly with the metal salt of the sodium source, and pre-reacted at 450°C for 5 hours, then heated to 850°C and kept for reaction for 16 hours, cooled naturally to room temperature, and then taken out and fully ground to obtain a layered oxide-type positive electrode material;

[0049] The ratio of the amount of sodium element in the sodium source to the sum of the three metal elements in the precursor is 1.05:1;

[0050] The reaction atmosphere during the entire reaction process of step 2 is air;

[0051] The sodium source is sodium carbonate.

[0052] Figure 1 This is the SEM image of the layered oxide positive electrode material prepared in experiment 1. It can be seen from the figure that the material size is uniform, there is no obvious agglomeration, and the dispersion is good, which is conducive to increasing the utilization rate of active materials.

[0053] The layered oxide positive electrode material obtained in Experiment 1 was weighed and mixed with a conductive agent (conductive carbon black) and a binder (PVDF) in a mass ratio of 7:2:1. After the mixture was activated, coated, and punched, it was assembled with a sodium sheet (negative electrode) into a CR2032 button cell, designated as No. 1 cell, and tested. The electrolyte used was 1 mol L -1 NaClO4, the solvent is EC / PC, the volume ratio of the two is 1:1, 5% FEC is used as an additive, and the separator is glass fiber GF / D; finally, the assembled battery is left for more than 12 hours for electrochemical performance testing.

[0054] Comparative test: In this test, no iron source was added during the preparation of the layered oxide positive electrode material. The specific process was different from that of Test 1 in the following aspects:

[0055] The solute in the metal salt solution described in step 1 is composed of a nickel source and a manganese source, and the molar ratio of nickel in the nickel source to manganese in the manganese source is 1:2; the sum of the molar concentrations of nickel and manganese in the metal salt solution is 2 mol / L. Other procedures are the same as those in experiment 1.

[0056] The layered oxide positive electrode material obtained in Experiment 2 was weighed and mixed with a conductive agent (conductive carbon black) and a binder (PVDF) in a mass ratio of 7:2:1. After the mixture was activated, coated, and punched, it was assembled with a sodium sheet (negative electrode) into a CR2032 button cell, designated as No. 2 battery, and tested. The electrolyte used was 1 mol L -1 NaClO4, the solvent is EC / PC, the volume ratio of the two is 1:1, 5% FEC is used as an additive, and the separator is glass fiber GF / D; finally, the assembled battery is left for more than 12 hours for electrochemical performance testing.

[0057] Figure 2The XRD diagram shows that curve 1 corresponds to the product of experiment 1, and curve 2 corresponds to the product of the comparative experiment. It can be observed that there is no obvious difference between the two, but the product of the comparative experiment has an impurity peak, indicating that Fe doping can improve the purity of the material to a certain extent.

[0058] Figure 3 The figure is a comparison curve of the battery rate performance. Curve 1 (black) is for battery No. 1 and curve 2 (red) is for battery No. 2. Table 1 shows the rate performance data of battery No. 1. It can be seen that in terms of rate performance, battery No. 1 retains 53.37 mAh g at a high current density of 1000 mA / g. -1 Specific capacity, 1000mAg -1 The specific capacity is 10mAg -1 The rate performance is improved by 50.04% which is a considerable improvement.

[0059] Table 1

[0060] <![CDATA[Current density / mAg -1 > 10 20 50 100 200 500 1000 <![CDATA[Specific capacity / mAh g -1 > 106.66 94.51 83.38 75.33 68.51 55.07 53.37

[0061] Table 2 is the rate performance data of No. 2 battery. It can be seen that in terms of rate performance, for No. 2 battery composed of positive electrode materials without iron, at 1000mAg -1 At high current density, only 20.55 mAh g was released. -1 The specific capacity of 1000mA / g is only 10mA g -1 The rate performance is 19.15% when compared to the No. 1 battery.

[0062] Table 2

[0063] <![CDATA[Current density / mA g -1 > 10 20 50 100 200 500 1000 <![CDATA[Specific capacity / mAh g -1 > 107.32 90.61 72.48 59.90 47.25 32.79 20.55

[0064] Figure 4 This is a comparison chart of battery cycle performance, with a current density of 100 mA g -1 , Curve 1 is for battery No. 1, and Curve 2 is for battery No. 2. Table 3 shows the cycle performance data of battery No. 1 (100mA g -1 Cycle 200 times), it can be seen that the discharge capacity of battery No. 1 is 100mA g -1 The capacity can reach 86.15mAhg during the cycle -1 , and the capacity retention rate reaches 65.21%, indicating that the battery has excellent cycle performance.

[0065] Table 3

[0066] <![CDATA[Initial discharge capacity / mAhg -1 > <![CDATA[Discharge capacity after cycling / mAh g -1 > Capacity retention rate 86.15 51.18 65.21％

[0067] Table 4 is the cycle performance data of No. 2 battery (100mAg -1Cycle 200 times), it can be seen that the discharge capacity of battery No. 2 is 100mA g -1 The capacity during the cycle is only 74.92mAhg -1 , and the capacity retention rate is only 14.15%, indicating that the cycle performance of battery No. 2 is poor.

[0068] Table 4

[0069] <![CDATA[Initial discharge capacity / mAhg -1 > <![CDATA[Discharge capacity after cycling / mAh g -1 > Capacity retention rate 74.92 10.60 14.15％

[0070] Figure 5 The cyclic voltammetry curves of the batteries are shown in Figure 1, where curve 1 is for battery 1 and curve 2 is for battery 2. It can be observed that the peak intensity of the third pair of redox peaks (representing the P2→O2 phase transition) of battery 1 has decreased significantly, indicating a reduced degree of P2→O2 phase transition. Furthermore, the potential difference between the first two pairs of oxidation and reduction peaks is smaller, indicating less polarization. Furthermore, the peak shape is sharper, indicating a faster reaction rate.

Claims

1. A method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery, characterized in that The preparation method of the layered oxide type composite material as the positive electrode of the sodium ion battery is carried out according to the following steps:

1. Co-precipitation to obtain a precursor: Ammonia water is added dropwise to deionized water to adjust the pH to 10.8-11.2, and then a metal salt solution is added. Alkaline solution is then added dropwise to adjust the pH to 10.6-10.8 for co-precipitation. Stirring is continued for 12-16 hours for aging, followed by filtering, washing, and drying in sequence to obtain a precursor; The solute in the metal salt solution is composed of a nickel source, a manganese source and an iron source, and the ratio of the amount of nickel element in the nickel source, the amount of manganese element in the manganese source and the amount of iron element in the iron source is 0.33:0.67-x:x, x≤0.1; The sum of the molar concentrations of nickel, manganese and iron in the metal salt solution is 2 mol / L to 2.5 mol / L; The volume ratio of the deionized water to the metal salt solution is 1:(2.09-3.01); 2. The precursor prepared in step 1 is mixed evenly with the metal salt of the sodium source, and pre-reacted at 450°C to 500°C for 5h to 5.5h, then heated to 850°C to 900°C and kept warm for 16h to 17h, and naturally cooled to room temperature. After being taken out and fully ground, a layered oxide-type positive electrode material is obtained; The ratio of the amount of sodium element in the sodium source to the sum of the three metal elements in the precursor is (1.05-1.1):1; The reaction atmosphere during the entire reaction process of step 2 is air.

2. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The alkali solution described in step 1 is 10 mol L -1 of sodium hydroxide solution and 0.2 mol L -1 Ammonia water is mixed in a volume ratio of 7:

3.

3. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The washing in step 1 is washing with deionized water.

4. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The drying temperature in step 1 is 100° C. and the drying time is 12 h.

5. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The nickel source described in step 1 is nickel acetate tetrahydrate, nickel nitrate hexahydrate, nickel chloride hexahydrate or nickel sulfate hexahydrate.

6. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The manganese source in step 1 is manganese acetate tetrahydrate, manganese chloride tetrahydrate or manganese sulfate monohydrate.

7. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The iron source described in step 1 is ferrous oxalate dihydrate or ferrous sulfate heptahydrate.

8. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The sodium source in step 2 is sodium acetate, sodium citrate, sodium carbonate, sodium bicarbonate or sodium hydroxide.

9. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that The ratio of the amount of sodium element in the sodium source described in step 2 to the sum of the three metal elements in the precursor is 1.05:

1.

10. The method for preparing a layered oxide composite material as a positive electrode for a sodium ion battery according to claim 1, characterized in that In step 2, the reaction was first carried out at 450° C. for 5 h, then the temperature was raised to 850° C. and kept for reaction for 16 h, and the mixture was naturally cooled to room temperature. After being taken out and fully ground, a layered oxide-type positive electrode material was obtained.

Images