Positive electrode material preparation method therefor, and use thereof

Abstract

Disclosed in the present invention are a positive electrode material, a preparation method therefor, and a use thereof. A sodium-ion battery positive electrode material provided by the present invention comprises the following composition: O3-type positive electrode material and P2-type positive electrode material; the O3-type positive electrode material is Sn and Zn in-situ co-doped Na nNi xZn yFe 1 / 3Mn 1 / 3O 2, where 0.95≤n≤1.02, 0＜x≤0.33, and x+y=0.33. The P2-type positive electrode material is Na mNi pMn qMg zTi 1-p-q-zO 2, where 0.67≤m≤0.8, 0＜p≤0.25, 0.33＜q≤0.6, and 0.01＜z≤0.05. The high-voltage P2 / O3 mixed-phase sodium-ion battery positive electrode material provided by the present invention can effectively shorten the high-voltage platform that produces irreversible phase transitions, and while ensuring high capacity at 4.2V, it also improves the average voltage, thereby enhancing the electrochemical performance stability and high-rate performance of the positive electrode material.

Description

A cathode material, its preparation method and application Technical Field

[0001] This invention belongs to the field of cathode material technology, specifically relating to a mixed-phase high-voltage sodium-ion battery cathode material with a P2 / O3 mixed-phase structure, its preparation method, and its application. Background Technology

[0002] O3-type layered Na x TMO2 cathode materials suffer from drawbacks such as irreversible phase transitions, poor storage stability, and interfacial instability. To improve the structure and storage stability of layered cathodes through cation substitution techniques, researchers have made numerous attempts, such as using Zn... 2+ Fe 3+ Cr 3+ Ti 4+ V 5+ The main element is replaced by doping, which is one of the differences from lithium-ion battery cathode materials. Multiple elements exhibit electrochemical activity and reversibility. The substitution of cations in the transition metal layer can effectively suppress irreversible phase transitions, thereby improving the structural stability, air stability and electrochemical performance of the cathode material.

[0003] However, the Na currently under study x The charging cutoff voltage of TMO2 is generally ≤4.0V, which is a significant disadvantage compared to lithium-ion batteries in terms of energy density. Its substitution mechanism under high voltage is not yet fully understood. Therefore, designing and developing an O3-type layered material with good high-voltage storage stability and high-voltage cycling performance is of great importance.

[0004] The relatively low standard electrochemical potential of sodium-ion electrode materials dictates that they must operate at higher voltages to achieve energy densities equivalent to lithium materials; however, under high voltage, complex phase transitions and severe interfacial reactions inevitably reduce their lifespan. This inherent contradiction makes the development of sodium-containing layered oxide materials with both high energy density and long cycle life extremely difficult. P2-type layered materials not only possess strong resistance to hygroscopic degradation but also maintain their original structure over a wider voltage range, exhibiting high cycle performance. However, due to insufficient sodium content and electrochemical dissolution during discharge, they suffer from low energy density. Efforts have been focused on modifying the structure to overcome the shortcomings of each material. The strategy is to develop low-strain materials with smooth charge-discharge curves and uniform sodium ion distribution. Smooth charge-discharge curves indicate stable solid solution reactions. Stabilizing and suppressing this high-voltage phase transition and extending the solid solution region are crucial for further improving the structural stability of layered sodium oxide materials at high charge cutoff voltages. Therefore, efforts are being made to design biphase O3 and P2-type material structures to compensate for the shortcomings of both pure phases.

[0005] CN114678523A discloses a novel dual-phase layered sodium-ion battery cathode material with a general formula of NaxM1-y-zMnyTizO2. In this general formula, M includes at least one of iron, zinc, nickel, magnesium, lithium, cobalt, chromium, vanadium, titanium, and aluminum, and 0.5 ≤ x ≤ 1.0, 0 < y ≤ 1.0, 0 < z ≤ 1.0. Appropriate Ti doping promotes the generation of the O3 phase, and the two-phase ratio of P2 and O3 phases can be further adjusted by regulating the doping ratio of Ti. Under the synergistic effect of the P2 / O3 dual phase, the P2→O2 phase transition at a high voltage of 4.3V can be effectively inhibited, and the volume change can be effectively alleviated, thus maintaining a stable P2 / O3 phase structure and ensuring the stability of Na + embedding and extraction, thereby achieving higher cycle stability. The cathode material prepared by the present invention has a high energy density, rate performance, and good cycle performance. However, the molar proportion of Ni in the raw materials of this material is 0.35 - 0.4, which is inclined to the nickel-enhancing route in the development of oxide cathodes (0 < Ni ≤ 0.33). One of the reasons for its high capacity and excellent cycle performance on the surface may be the contribution of high nickel and high titanium (the molar proportion of Ti in Example 2 is 0.2), and at the same time, there will be extra NiO impurity peaks in the characterization; secondly, the manganese source used is carbonate, which will generate more CO2 in the sintering process compared with the manganese oxide source, and even more gas will be produced inevitably during the later battery cycle, so there is a lack of subsequent tail gas treatment measures; thirdly, this document does not mention the shortening of the phase transition platform during the charging process of this material. Summary of the Invention

[0006] The purpose of the present invention is to provide a mixed-phase high-voltage sodium-ion battery layered cathode material, its preparation method and application. This cathode material has both a high energy density, a short high-voltage phase transition region, high cycle performance, and structural stability.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a sodium-ion battery cathode material, including the following components: O3-type cathode material and P2-type cathode material;

[0009] The O3-type cathode material is Na n Ni x Zn y Fe 1 / 3 Mn 1 / 3 O2, where 0.95 ≤ n ≤ 1.02, 0 < x ≤ 0.33, x + y = 0.33;

[0010] The P2-type cathode material is Na m Ni p Mn q Mg z Ti1-p-q-z O2, where 0.67≤m≤0.8, 0<p≤0.25, 0.33<q≤0.6, 0.01<z≤0.05;

[0011] The mass ratio of the O3 type cathode material to the P2 type cathode material is 1:(0.3-3).

[0012] This invention combines an O3-type cathode material and a P2-type cathode material, both doped with two active elements (Zn and Sn) in situ, to form a P2 / O3 mixed-phase single-crystal cathode material. This improves the stability of the electrochemical performance and high-rate performance of the cathode material, and solves the problem of maintaining the structural stability of the single-crystal material while addressing the capacity and voltage plateau and shortening the high-voltage phase transition region in existing sodium-ion battery cathode materials.

[0013] According to a specific embodiment of the present invention, the mass ratio of the O3 type cathode material to the P2 type cathode material is 3:1.

[0014] According to a specific embodiment of the present invention, the O3-type cathode material is NaNi with in-situ double doping of Sn and Zn. 0.33 Fe 0.33 Mn 0.33 O2.

[0015] According to a specific embodiment of the present invention, the P2 type cathode material is Na. 0.67 Ni 0.25 Mn 0.6 Mg 0.033 Ti 0.117 O2.

[0016] Secondly, the present invention provides a method for preparing the above-mentioned sodium-ion battery cathode material, comprising the following steps:

[0017] S1. Sodium source, nickel source, iron source, manganese source, zinc source and tin source are mixed and calcined to obtain O3 type cathode material;

[0018] S2. Sodium source, nickel source, manganese source, magnesium source and titanium source are mixed and calcined to obtain P2 type cathode material;

[0019] S3. Mix the O3 type cathode material with the P2 type cathode material to obtain a mixed-phase P2 / O3 type cathode material.

[0020] In the above preparation method, in step S1, the mixing is carried out according to any of the following conditions:

[0021] 1) Mix sodium, nickel, iron, and manganese sources, and then dope with zinc and tin sources;

[0022] 2) Mix sodium, nickel, iron, manganese and tin sources, and then dope with zinc source.

[0023] In the above preparation method, in step S1, the sodium source is selected from anhydrous sodium carbonate.

[0024] In the above preparation method, in step S1, the nickel source is selected from nickel oxide.

[0025] In the above preparation method, in step S1, the iron source is selected from ferric oxide.

[0026] In the above preparation method, in step S1, the manganese source is selected from one or more of manganese tetroxide, manganese dioxide, and manganese oxide.

[0027] In the above preparation method, in step S1, the zinc source is selected from zinc oxide.

[0028] In the above preparation method, in step S1, the tin source is selected from tin dioxide.

[0029] In the above preparation method, the calcination conditions in step S1 are: a temperature of 900-1000℃, preferably 950℃, and a time of 10-20h.

[0030] In the above preparation method, in step S1, the calcination is carried out according to the following operation: first, the temperature is raised to 450-550℃ (preferably 500℃), and held for 3-7h (preferably 5h); then the temperature is raised to 900-1000℃ (preferably 950℃), and held for 12-18h (preferably 15h), with a heating rate of 2℃ / min; then the temperature is lowered to 600-700℃ (preferably 650℃), and held for 0.5-3.5h (preferably 2h), with a cooling rate of 2℃ / min.

[0031] In the above preparation method, in step S2, the sodium source is selected from anhydrous sodium carbonate.

[0032] In the above preparation method, in step S2, the nickel source is selected from nickel oxide.

[0033] In the above preparation method, in step S2, the manganese source is selected from one or more of manganese tetroxide, manganese dioxide, and manganese oxide.

[0034] In the above preparation method, in step S2, the magnesium source is selected from magnesium oxide.

[0035] In the above preparation method, in step S2, the titanium source is selected from titanium dioxide.

[0036] In the above preparation method, the calcination conditions in step S2 are: a temperature of 850-950℃, preferably 900℃, and a time of 12-18h;

[0037] In the above preparation method, in step S2, the calcination is carried out as follows: first, the temperature is raised to 450-550℃ (preferably 500℃), and held for 3-7h (preferably 5h); then the temperature is raised to 850-950℃ (preferably 900℃), and held for 12-18h (preferably 15h), with a heating rate of 2℃ / min; then the temperature is lowered to 600-700℃ (preferably 650℃), and held for 0.5-3.5h (preferably 2h), with a cooling rate of 2℃ / min.

[0038] Thirdly, the present invention provides a sodium-ion battery, comprising a positive electrode and a negative electrode; the material of the positive electrode comprises the aforementioned positive electrode material. Attached Figure Description

[0039] Figure 1 shows the change curves of the 2-4.2V high voltage plateau in the first charging curves of the embodiment and the comparative example.

[0040] Figure 2 shows the XRD characterization diagrams of different proportions of O3 and P2 phase materials in the embodiments.

[0041] Figure 3 is a scanning electron microscope image of the mixed-phase cathode material synthesized in Example 1. Embodiments of the present invention

[0042] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0043] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0044] Unless otherwise specified, all reagents, materials, instruments, etc. used in the following examples are commercially available.

[0045] Example 1: In-situ dual-doped O3-type and P2-type mixed cathode material with Sn and Zn.

[0046] (1) Preparation of O3-type cathode material:

[0047] The mass of sodium carbonate is calculated based on a total material concentration of 2 mol and a sodium content of 1 mol. The mass of nickel oxide, ferric oxide, and manganese oxide is calculated based on a molar ratio of 1:1:1. The auxiliary materials of 5000 ppm zinc oxide and 2000 ppm tin dioxide are weighed according to the total material. After weighing all the raw materials, they are transferred to a ball mill jar and put into a 3D mixer for 3 hours of mixing.

[0048] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-950℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 950-650℃ at a rate of 2℃ / min, holding for 2 hours. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain O3-type NaNi with in-situ double doping of Sn and Zn. 0.33 Fe 0.33 Mn 0.33 O2.

[0049] (2) Preparation of P2 type cathode material:

[0050] The total material concentration is 2 mol, the sodium content is 0.67 mol with an excess of 5%, and the mass of sodium carbonate is calculated. The nickel source, manganese source, magnesium source, and titanium source are calculated according to the molar ratio of 0.25:0.6:0.033:0.117, respectively. After weighing each raw material, it is transferred to a ball mill jar and put into a 3D mixer for 3 hours of mixing.

[0051] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-900℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 900-650℃ at a rate of 2℃ / min, holding for 2 hours; and then calcining in air. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain the P2 type cathode material Na. 0.67 Ni 0.25 Mn 0.6 Mg 0.033 Ti 0.117 O2.

[0052] (3) Mixing:

[0053] The O3 type cathode material obtained in step (1) and the P2 type cathode material obtained in step (2) are weighed in a molar ratio of 3:1 and placed in a sealed container. The mixture is then transferred to a 3D mixer for 3 hours to obtain a mixed-phase cathode material.

[0054] Example 2: In-situ dual-doped O3-type and P2-type mixed cathode material with Sn and Zn.

[0055] (1) Preparation of O3-type cathode material:

[0056] The mass of sodium carbonate was calculated based on a total material concentration of 2 mol and a sodium content of 1 mol. The masses of nickel oxide, ferric oxide, manganese oxide, and tin oxide were calculated based on a molar ratio of 0.33:0.33:0.3:0.03. The masses of auxiliary material 5000 ppm zinc oxide were also calculated based on the total material. After weighing all the raw materials, they were transferred to a ball mill jar and placed in a 3D mixer for 3 hours of mixing.

[0057] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-950℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 950-650℃ at a rate of 2℃ / min, holding for 2 hours; and then calcining in air. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain O3-type NaNi with in-situ double doping of Sn and Zn. 0.33 Fe 0.33 Mn 0.33 O2.

[0058] (2) Preparation of P2 type cathode material:

[0059] The total material concentration is 2 mol, the sodium content is 0.67 mol with an excess of 5%, and the mass of sodium carbonate is calculated. The nickel source, manganese source, magnesium source, and titanium source are calculated according to the molar ratio of 0.25:0.6:0.033:0.117, respectively. After weighing each raw material, it is transferred to a ball mill jar and put into a 3D mixer for 3 hours of mixing.

[0060] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-900℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 900-650℃ at a rate of 2℃ / min, holding for 2 hours; and then calcining in air. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain the P2 type cathode material Na. 0.67 Ni 0.25 Mn 0.6 Mg 0.033 Ti 0.117 O2.

[0061] (3) Mixing:

[0062] The above-mentioned O3 type cathode material and P2 type cathode material were weighed in a molar ratio of 3:1 and placed in a sealed container. The mixture was then transferred to a 3D mixer and mixed for 3 hours to obtain a mixed-phase cathode material.

[0063] Comparative Example 1: O3-type cathode material with in-situ dual doping of Sn and Zn

[0064] The mass of sodium carbonate was calculated based on a total material concentration of 2 mol and a sodium content of 1 mol. The mass of nickel oxide, ferric oxide, and manganese oxide was calculated based on a molar ratio of 1:1:1. The auxiliary materials of 5000 ppm zinc oxide and 2000 ppm tin dioxide were weighed according to the total material. After weighing all the raw materials, they were transferred to a ball mill jar and put into a 3D mixer for 3 hours of mixing.

[0065] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-950℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 950-650℃ at a rate of 2℃ / min, holding for 2 hours; and then calcining in air. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain O3-type NaNi with in-situ double doping of Sn and Zn. 0.33 Fe 0.33 Mn 0.33 O2.

[0066] Comparative Example 2, P2 type cathode material

[0067] The total material concentration is 2 mol, the sodium content is 0.67 mol with an excess of 5%, and the mass of sodium carbonate is calculated. The nickel source, manganese source, magnesium source, and titanium source are calculated according to the molar ratio of 0.25:0.6:0.033:0.117, respectively. After weighing each raw material, it is transferred to a ball mill jar and put into a 3D mixer for 3 hours of mixing.

[0068] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-900℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 900-650℃ at a rate of 2℃ / min, holding for 2 hours; and then calcining in air. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain the P2 type cathode material Na. 0.67 Ni 0.25 Mn 0.6 Mg 0.033 Ti 0.117 O2.

[0069] Comparative Example 3: In-situ dual-doped O3-type cathode material with Sn and Zn [O3 type, Zn-doped, Sn partially replaces Mn]

[0070] The mass of sodium carbonate was calculated based on a total material concentration of 2 mol and a sodium content of 1 mol. The masses of nickel oxide, ferric oxide, manganese oxide, and tin oxide were calculated based on a molar ratio of 0.33:0.33:0.3:0.03. The masses of auxiliary material 5000 ppm zinc oxide were also calculated based on the total material. After weighing all the raw materials, they were transferred to a ball mill jar and placed in a 3D mixer for 3 hours of mixing.

[0071] The uniformly mixed material was then transferred to a muffle furnace. The set temperature program was as follows: heating from 0-500℃ at a rate of 2℃ / min, holding for 5 hours; heating from 500-950℃ at a rate of 2℃ / min, holding for 15 hours; cooling from 950-650℃ at a rate of 2℃ / min, holding for 2 hours; and then calcining in air. After cooling to room temperature, the sintered material was removed, crushed, and sieved through a 250-mesh sieve to obtain O3-type NaNi with in-situ double doping of Sn and Zn. 0.33 Fe 0.33 Mn 0.33 O2.

[0072] Test case

[0073] The cathode materials obtained in Examples 1, 2, 1, 2, and 3 were used to fabricate button cells. The specific steps are as follows:

[0074] The positive electrode materials obtained in Examples 1, 2, 1, 2, and 3 were mixed with conductive agent sp and binder PVDF in a mass ratio of 9:0.5:0.5 to prepare slurries.

[0075] Mixing steps: ① Take 4g of PVDF adhesive into a clean and dry mixing tank, add 0.2g of SP, and put it into the mixing machine for the first mixing; ② After the first mixing, weigh 3.6g of active material and 2.5g of NMP and add them to the mixing tank for the second mixing;

[0076] The slurry was then coated onto an aluminum foil current collector to a thickness of 400 μm. After drying, it was rolled and vacuum dried at 80°C for 12 hours to obtain the positive electrode sheet for a sodium-ion battery. The compaction density of the electrode sheet was controlled to be approximately 2.5 g / cm³. 3 , and received a deduction.

[0077] The prepared button cell was set to 2.0-4.2V for capacity and voltage platform testing.

[0078] The results are as follows.

[0079] 1. Electrochemical performance

[0080]

[0081] As can be seen from Table 1, the cathode materials obtained in Examples 1 and 2 have a 4.2V capacity of about 150mAh / g and an initial efficiency of over 93.7%, which is slightly lower than the pure O3 type cathode materials in Comparative Examples 1 and 3, but the average voltage is higher than that in Comparative Examples 1 and 3, which is 0.034V higher. The pure P2 type cathode material in Comparative Example 2 has a higher initial efficiency, but the 4.2V capacity is too low, only 95.7mAh / g. The cathode material in Comparative Example 3 has a lower capacity and rate performance than that in Example 1.

[0082] 2. High-voltage phase transition zone

[0083] As can be clearly seen from Figure 1, the high-voltage phase transition region of the mixed-phase cathode materials obtained in Examples 1 and 2 is significantly shortened. This indicates that whether Sn or Zn is used as a doping element or as a main element to replace part of the manganese source, both can shorten the phase transition region and increase the solid solution region.

[0084] The charging curve of the pure O3 type cathode material obtained in Comparative Example 1 has a very obvious high-voltage phase transition region; the charging and discharging curve of the pure P2 type cathode material obtained in Comparative Example 2 is very smooth, indicating that its solid solution region is very stable; the charging curves of Comparative Example 3 and Comparative Example 1 have the same trend in the high-voltage range, but the capacity is lower.

[0085] 3. Microstructure

[0086] The O3-type cathode material and the P2-type cathode material from Example 1 were mixed at ratios of 1:1 and 1:3, respectively, to obtain mixed-phase cathode materials with different mixing ratios. Their structures were characterized by XRD.

[0087] The results are shown in Figure 2. As can be seen from Figure 2, the mixed-phase cathode materials obtained with different mixing ratios still maintain strong O3-type characteristic peaks, indicating that their structure has not been altered by the doping of P2-type cathode materials.

[0088] As can be seen from Figure 3, the microstructure of the mixed-phase cathode material obtained in Example 1 is a distinct single-crystal particle.

[0089] The test results above show that the present invention, through Sn and Zn dual doping, can effectively shorten the high-voltage plateau that leads to irreversible phase transition, and improve the average voltage while maintaining high capacity at a high voltage of 4.2V, thereby enhancing the stability of the electrochemical performance and high-rate performance of the cathode material. The resulting high-voltage P2 / O3 mixed-phase sodium-ion battery cathode material possesses high energy density, a short high-voltage phase transition region, high cycle performance, and structural stability.

[0090] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

[0091] Cross-referencing of related applications:

[0092] This application claims priority to Chinese patent application No. 202411616346.4, filed on November 13, 2024, the entire contents of which are incorporated herein by reference. Industrial applicability

[0093] This invention has the following technical advantages:

[0094] The high-voltage P2 / O3 mixed-phase sodium-ion battery cathode material provided by this invention can effectively shorten the high-voltage plateau that generates irreversible phase transitions, and improve the average voltage while ensuring high capacity at a high voltage of 4.2V, thereby improving the stability of the electrochemical performance and high-rate performance of the cathode material.

Claims

1. A sodium-ion battery cathode material, comprising: an O3-type cathode material and a P2-type cathode material; The O3-type positive electrode material is Sn and Zn in-situ double-doped Na n Ni x Zn y Fe 1 / 3 Mn 1 / 3 O2, wherein 0.95≤n≤1.02, 0 The P2-type positive electrode material is Na m Ni p Mn q Mg z Ti 1-p-q-z O2, wherein 0.67≤m≤0.8, 0 0.33 0.01 The mass ratio of the O3 type cathode material to the P2 type cathode material is 1:(0.3-3).

2. The sodium-ion battery cathode material of claim 1, wherein, The mass ratio of the O3 type cathode material to the P2 type cathode material is 3:

1.

3. The sodium-ion battery cathode material of claim 1 or 2, wherein, The O3-type positive electrode material is Sn and Zn in-situ double-doped NaNi 0.33 Fe 0.33 Mn 0.33 O2; The P2-type positive electrode material is Na 0.67 Ni 0.25 Mn 0.6 Mg 0.033 Ti 0.117 O2.

4. A method for preparing the sodium-ion battery cathode material according to any one of claims 1-3, comprising the following steps: S1. Sodium source, nickel source, iron source, manganese source, zinc source and tin source are mixed and calcined to obtain O3 type cathode material; S2. Sodium source, nickel source, manganese source, magnesium source and titanium source are mixed and calcined to obtain P2 type cathode material; S3. Mix the O3 type cathode material with the P2 type cathode material to obtain a mixed-phase P2 / O3 type cathode material.

5. The production method according to claim 4, characterized by, In step S1, the mixing is performed according to any of the following conditions: 1) Mix sodium, nickel, iron, and manganese sources, and then dope with zinc and tin sources; 2) Mix sodium, nickel, iron, manganese and tin sources, and then dope with zinc source.

6. The production method according to claim 4 or 5, characterized by, In step S1, the sodium source is selected from anhydrous sodium carbonate; The nickel source is selected from nickel oxide; The iron source is selected from ferric oxide; The manganese source is selected from one or more of manganese tetroxide, manganese dioxide, and manganese oxide; The zinc source is selected from zinc oxide; The tin source is selected from tin dioxide.

7. The production method according to any one of claims 4 to 6, characterized by, In step S1, the calcination conditions are: temperature 900-1000℃, time 15h; The calcination is carried out as follows: first, the temperature is raised to 450-550℃ and held for 3-7 hours; then the temperature is raised to 900-1000℃ and held for 12-18 hours, with a heating rate of 2℃ / min; then the temperature is lowered to 600-700℃ and held for 0.5-3.5 hours, with a cooling rate of 2℃ / min.

8. The production method according to any one of claims 4 to 7, characterized by, In step S2, the sodium source is selected from anhydrous sodium carbonate; The nickel source is selected from nickel oxide; The manganese source is selected from one or more of manganese tetroxide, manganese dioxide, and manganese oxide; The magnesium source is selected from magnesium oxide; The titanium source is selected from titanium dioxide.

9. The production method according to any one of claims 4 to 8, characterized by, In step S2, the calcination conditions are: temperature 850-950℃, time 15h; The calcination is carried out according to the following operation: first, the temperature is raised to 450-550℃ and held for 3-7 hours, then the temperature is raised to 850-950℃ and held for 12-18 hours, with a heating rate of 2℃ / min; then the temperature is lowered to 600-700℃ and held for 0.5-3.5 hours, with a cooling rate of 2℃ / min.

10. A sodium-ion battery, comprising a positive electrode and a negative electrode; wherein the material of the positive electrode comprises the positive electrode material according to any one of claims 1-3.

Images