O3 phase high-entropy layered oxide positive electrode material and preparation method and application thereof

Abstract

This invention discloses an O3-phase high-entropy layered oxide cathode material, its preparation method, and its application, belonging to the technical field of sodium-ion battery cathode materials. The O3-phase high-entropy layered oxide cathode material has the chemical formula NaNi. 1‑ 8x Ca x Co x Al x Fe x Mn x Si x Ti x Zr x O2, x = 0.05~0.1. Raw materials are weighed according to stoichiometric ratio, mixed, and pulverized to obtain precursor powder. The precursor powder is then sintered in a pure oxygen atmosphere to obtain a first sintered product, which is then pulverized again. The pulverized product is then sintered in a pure oxygen atmosphere for a second step, and after cooling, an O3 phase high-entropy layered oxide cathode material is obtained. Sodium-ion batteries assembled based on this cathode material exhibit excellent high-rate performance and long-cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery cathode material technology, specifically, it relates to an O3 phase high-entropy layered oxide cathode material, its preparation method, and its application. Background Technology

[0002] Layered transition metal oxides (especially O3 type) are among the most promising cathode materials for sodium-ion batteries. However, traditional O3 type cathodes often face complex multiphase transitions, transition metal ion migration, and irreversible oxygen loss during charge and discharge, resulting in poor cycle stability and rapid capacity decay.

[0003] The high-entropy material design strategy involves introducing multiple elements in near-equal molar ratios at a single lattice site to enhance the structural stability and electrochemical reversibility of the material through the high configurational entropy effect.

[0004] Currently, research on sodium-ion high-entropy cathodes is still in the exploratory stage. How to achieve multi-element synergistic stability in the O3-type structure and develop a simple and controllable preparation process are technical problems that urgently need to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a structurally stable, high-entropy layered oxide cathode material with excellent cycle performance, as well as its preparation method and application.

[0006] To achieve the above objectives, according to one aspect of the present invention, a high-entropy layered oxide cathode material with the chemical formula NaNi is provided. 1-8x Ca x Co x Al x Fe x Mn x Si x Ti x Zr x O2, x = 0.05~0.1.

[0007] In a preferred embodiment, x takes the value of 0.0625, 0.05, or 0.1.

[0008] According to another aspect of the present invention, a method for preparing the O3-phase high-entropy layered oxide cathode material described above is provided, comprising: Step 1: Weigh out sodium source, nickel source, calcium source, cobalt source, aluminum source, iron source, manganese source, silicon source, titanium source and zirconium source according to stoichiometric ratio; mix and pulverize the sodium source, nickel source, calcium source, cobalt source, aluminum source, iron source, manganese source, silicon source, titanium source and zirconium source to obtain precursor powder; Step 2: The precursor powder is sintered at 800℃-850℃ in a pure oxygen atmosphere to obtain the first sintered product. The first sintered product is then pulverized again. Step 3: The product pulverized in Step 2 is sintered at 900℃-950℃ in a pure oxygen atmosphere. After cooling, the O3 phase high-entropy layered oxide cathode material is obtained.

[0009] In a preferred embodiment, the zirconium source and silicon source are ZrSiO4, the titanium source and calcium source are CaTiO3, the aluminum source is Al2O3, the iron source is Fe2O3, and the sodium source is Na2CO3.

[0010] In a preferred embodiment, the manganese source is selected from one of MnO, Mn(CH3COO)2, MnCO3, MnC2O4, and Mn(NO3)2.

[0011] In a preferred embodiment, the cobalt source is selected from one of CoO, Co(CH3COO)2, CoCO3, CoC2O4, and Co(NO3)2.

[0012] In a preferred embodiment, the nickel source is selected from one of NiO, Ni(CH3COO)2, NiCO3·2Ni(OH)2·4H2O, NiC2O4, and Ni(NO3)2.

[0013] In a preferred embodiment, in step two, the sintering time for the first step is 5-10 hours; in step three, the sintering time for the second step is 10-20 hours.

[0014] In a preferred embodiment, in steps one and two, the pulverization is carried out in a pulverizer, maintaining a rotation speed of 8000-10000 rpm and a pulverization time of 10-15 minutes.

[0015] According to another aspect of the present invention, the application of the above-described O3 phase high-entropy layered oxide cathode material in the preparation of sodium-ion battery cathodes is provided.

[0016] This invention is based on a high-entropy stabilization strategy. By combining multiple elements, high-entropy layered oxide materials of the O3 phase are prepared by high-temperature solid-state sintering in a pure oxygen atmosphere. The electrochemical performance of the prepared stable O3-type layered oxide cathode material is characterized. The results show that the sodium-ion battery assembled with the cathode material prepared by this method exhibits excellent high-rate performance and long-cycle stability. The cycle retention rate is ≥95% after 500 cycles at 1C, the discharge capacity retention rate is ≥90% at 5C, and the specific capacity is ≥160mAh / g. Attached Figure Description

[0017] Figure 1The image shows a scanning electron microscope image of the O3 phase high-entropy layered oxide cathode material obtained in Example 1. Figure 2 This is a scanning electron microscope image of the O3 phase high-entropy layered oxide cathode material obtained in Example 2; Figure 3 Comparison of cycle data for sodium-ion batteries made from the cathode materials obtained in Example 1 and Comparative Examples 1-4; Figure 4 Comparison of rate data for sodium-ion batteries made from the cathode materials obtained in Example 2 and Comparative Examples 5-8; Figure 5 Comparison of specific capacity performance data for sodium-ion batteries made from the cathode materials obtained in Example 3 and Comparative Examples 9-12. Detailed Implementation

[0018] A typical embodiment of the present invention provides an O3-phase high-entropy layered oxide cathode material composed of multiple elements, with the chemical formula NaNi. 1-8x Ca x Co x Al x Fe x Mn x Si x Ti x Zr x O2, x = 0.05~0.1.

[0019] For example, the value of x can be 0.05, 0.0625, 0.06, 0.07, 0.08 or 0.1.

[0020] The cathode material provided by this invention exhibits a significant high-entropy effect due to the uniform distribution of multiple elements at the transition metal sites, effectively suppressing phase transitions and structural degradation during charging and discharging, and improving cycle stability. (Ca) 2+ and Zr 4+ The large ionic radius acts as a "pillar," widening the sodium interlayer spacing and promoting Na+. + Transmission. Al 3+ Ti 4+ Si 4+ Enhanced MO bond energy stabilizes the crystal structure and suppresses oxygen loss. Co, Fe, Mn, and Ni provide reversible redox reactions, contributing to capacity. This material, when used in sodium-ion batteries, exhibits high reversible capacity (>160 mAh / g, 0.1C), excellent rate performance, and stable cycle life.

[0021] Another typical embodiment of the present invention provides a method for preparing the O3 phase high-entropy layered oxide cathode material described above, which is prepared by high-temperature solid-state sintering and includes the following steps.

[0022] Step 1: Preparation of precursor Weigh out sodium source, nickel source, calcium source, cobalt source, aluminum source, iron source, manganese source, silicon source, titanium source and zirconium source according to stoichiometric ratio; mix and pulverize sodium source, nickel source, calcium source, cobalt source, aluminum source, iron source, manganese source, silicon source, titanium source and zirconium source to obtain precursor powder.

[0023] The zirconium and silicon sources are ZrSiO4, and the titanium and calcium sources are CaTiO3. Using ZrSiO4 and CaTiO3 as composite raw materials simplifies the batching process of the multi-element system.

[0024] The aluminum source is Al2O3, the iron source is Fe2O3, and the sodium source is Na2CO3.

[0025] The manganese source is selected from one of MnO, Mn(CH3COO)2, MnCO3, MnC2O4, and Mn(NO3)2.

[0026] The cobalt source is selected from one of CoO, Co(CH3COO)2, CoCO3, CoC2O4, and Co(NO3)2.

[0027] The nickel source is selected from one of NiO, Ni(CH3COO)2, NiCO3·2Ni(OH)2·4H2O, NiC2O4, and Ni(NO3)2.

[0028] The mixing and pulverization of raw materials are carried out during pulverization, at 8000-10000 rpm for 10-15 minutes.

[0029] Step two, the first step of sintering The precursor powder was sintered in a pure oxygen atmosphere to obtain a first sintered product, which was then pulverized again.

[0030] Sintering is carried out in a box furnace, with the temperature increased to 800℃-850℃ at a set rate, for example, at a rate of 3℃ / min to 800℃, 810℃, 820℃, 830℃, 840℃ or 850℃.

[0031] The sintering time is 5-10 hours, for example, 5 hours, 6 hours, 8 hours, or 10 hours. After sintering, the temperature is allowed to drop naturally.

[0032] After cooling, grind the food in a pulverizer, maintaining a speed of 8000-10000 rpm for 10-15 minutes.

[0033] Step 3, the second sintering step The product pulverized in step two is sintered in a pure oxygen atmosphere in the second step, and after cooling, the O3 phase high-entropy layered oxide cathode material is obtained.

[0034] Sintering is carried out in a box furnace, with the temperature increased to 900°C - 950°C at a set rate, for example, at a rate of 5°C / min to 900°C, 910°C, 920°C, 930°C, 940°C or 950°C.

[0035] The sintering time is 10-20 hours, for example, 10 hours, 12 hours, 15 hours, 18 hours, or 20 hours. After sintering, the furnace is cooled.

[0036] In steps two and three, sintering in a pure oxygen atmosphere ensures that the transition metal is in the designed valence state, forming a single O3 phase. Specific sintering temperatures and times guarantee high crystallinity and low cation mixing in the material.

[0037] 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.

[0038] Example 1 This embodiment prepares the following O3-phase high-entropy layered oxide cathode material: O3-NaNi 0.5 Ca 0.0625 Co 0.0625 Al 0.0625 Fe 0.0625 Mn 0.0625 Si 0.0625 Ti 0.0625 Zr 0.0625 O2 (x=0.0625).

[0039] Weigh out Na₂CO₃, NiO, ZrSiO₄, CaTiO₃, Al₂O₃, Fe₂O₃, MnO, and CoO according to the stoichiometric ratios of the above chemical formulas. Place the raw materials into a pulverizer and mix and pulverize at 8000-10000 rpm for 15 minutes.

[0040] The uniformly mixed raw materials were placed in a sagger and then placed in a box furnace for the first sintering step. The temperature was increased to 850°C at a rate of 3°C / min, and sintered for 8 hours in a pure oxygen atmosphere before naturally cooling down. The first sintered product was then placed back into a pulverizer and pulverized at 8000-10000 rpm for 10 minutes.

[0041] The pulverized sample was spread evenly in a sagger and then placed in a box furnace. The temperature was increased to 950°C at a rate of 5°C / min. After sintering in a pure oxygen atmosphere for 10 hours, the sample was cooled with the furnace to obtain the final sample, which was denoted as sample 1-a.

[0042] Comparative Example 1 Compared to Example 1, the cathode material provided in this comparative example does not contain Si and Zr elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 8 / 7 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.5 Ca 0.0625 Co 0.0625 Al 0.062 5Fe 0.0625 Mn 0.0625 Ti 0.0625 ) 8 / 7 O2, the rest of the steps are the same, and the resulting sample is denoted as 1-b.

[0043] Comparative Example 2 Compared to Example 1, the cathode material provided in this comparative example does not contain Ca or Ti elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 8 / 7 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.5 Co 0.0625 Al 0.0625 Fe 0.062 5Mn 0.0625 Si 0.0625 Zr 0.0625 ) 8 / 7 O2, the rest of the steps are the same, and the resulting sample is denoted as 1-c.

[0044] Comparative Example 3 Compared to Example 1, the cathode material provided in this comparative example does not contain Al and Fe elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by 8 / 7 times to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.5 Ca 0.0625 Co 0.0625 Mn 0.062 5Si 0.0625 Ti 0.0625 Zr 0.0625 ) 8 / 7 O2, the rest of the steps are the same, and the resulting sample is recorded as 1-d.

[0045] Comparative Example 4 Compared to Example 1, the cathode material provided in this comparative example does not contain Mn and Co elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 8 / 7 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.5 Ca 0.0625 Al 0.0625 Fe 0.062 5Si 0.0625 Ti 0.0625 Zr 0.0625 ) 8 / 7 O2, the rest of the steps are the same, and the resulting sample is denoted as 1-e.

[0046] Sodium-ion batteries were fabricated using the five cathode materials obtained in Example 1 and Comparative Examples 1-4. The batteries were charged to 4.1V using a constant current and constant voltage of 1C within the range of 1.8-4.1V, then the current was cut off at 0.05C, and finally discharged to 1.8V using a constant current of 1C. The discharge capacity was recorded, and the cycle retention rate after 500 cycles at 1C was obtained. The results showed that the cathode material used in Example 1 had better cycle characteristics (cycle retention rate ≥95%).

[0047] Example 2 This embodiment prepares the following O3-phase high-entropy layered oxide cathode material: O3-NaNi 0.6 Ca 0.05 Co 0.05 Al 0.05 Fe 0.05 Mn 0.05 Si 0.05 Ti 0.05 Zr 0.05 O2 (x=0.05).

[0048] Weigh out Na2CO3, Ni(CH3COO)2, ZrSiO4, CaTiO3, Al2O3, Fe2O3, Mn(CH3COO)2, and Co(CH3COO)2 according to the stoichiometric ratio of the above chemical formulas. Place the raw materials into a pulverizer and mix and pulverize at 8000-10000 rpm for 15 minutes.

[0049] The uniformly mixed raw materials were placed in a sagger and then placed in a box furnace for the first sintering step. The temperature was increased to 850°C at a rate of 3°C / min, and sintered for 8 hours in a pure oxygen atmosphere before naturally cooling down. The first sintered product was then placed back into a pulverizer and pulverized at 8000-10000 rpm for 10 minutes.

[0050] The pulverized sample was spread evenly in a sagger and then placed in a box furnace. The temperature was increased to 900℃ at a rate of 5℃ / min. After sintering in a pure oxygen atmosphere for 17 hours, the sample was cooled with the furnace to obtain the final sample, which was denoted as sample 2-a.

[0051] Comparative Example 5 Compared to Example 2, the cathode material provided in this comparative example does not contain Si and Zr elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 9 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.6 Ca 0.05 Co 0.05 Al 0.05 Fe 0.05 Mn 0.05 Ti 0.05 ) 10 / 9 O2, the rest of the steps are the same, and the resulting sample is denoted as 2-b.

[0052] Comparative Example 6 Compared to Example 2, the cathode material provided in this comparative example does not contain Ca or Ti elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 9 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.6 Co 0.05 Al 0.05 Fe 0.05 Mn 0.05 Si 0.05 Zr 0.05 ) 10 / 9 O2, the rest of the steps are the same, and the resulting sample is denoted as 2-c.

[0053] Comparative Example 7 Compared to Example 2, the cathode material provided in this comparative example does not contain Al and Fe elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 9 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.6 Ca 0.05 Co 0.05 Mn 0.05 Si 0.05 Ti 0.05 Zr 0.05 ) 10 / 9 O2, the rest of the steps are the same, and the resulting sample is recorded as 2-d.

[0054] Comparative Example 8 Compared to Example 2, the cathode material provided in this comparative example does not contain Mn and Co elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 9 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.6 Ca 0.05 Al 0.05 Fe 0.05 Si 0.05 Ti 0.05 Zr 0.05 ) 10 / 9 O2, the rest of the steps are the same, and the resulting sample is denoted as 2-e.

[0055] Sodium-ion batteries were fabricated using the five cathode materials obtained in Example 2 and Comparative Examples 5-8. The batteries were charged to 4.1V using a constant current and constant voltage of 1C within the range of 1.8-4.1V, and then the current was cut off at 0.05C. The batteries were then discharged to 1.8V using constant currents of 1C, 3C, and 5C, respectively. The 5C discharge capacity retention rate was obtained after recording the different discharge capacities. The results showed that the cathode material used in Example 2 had better rate performance (discharge capacity retention rate ≥90%).

[0056] Example 3 This embodiment prepares the following O3-phase high-entropy layered oxide cathode material: NaNi 0.2 Ca 0.1 Co 0.1 Al 0.1 Fe 0.1 Mn 0.1 Si 0.1 Ti 0.1 Zr 0.1 O2 (x=0.1).

[0057] Weigh out Na₂CO₃, NiC₂O₄, ZrSiO₄, CaTiO₃, Al₂O₃, Fe₂O₃, MnCO₃, and CoCO₃ according to the stoichiometric ratios of the above chemical formulas. Place the raw materials into a pulverizer and mix and pulverize at 8000-10000 rpm for 15 minutes.

[0058] The uniformly mixed raw materials were placed in a sagger and then placed in a box furnace for the first sintering step. The temperature was increased to 850°C at a rate of 3°C / min, and sintered for 8 hours in a pure oxygen atmosphere before naturally cooling down. The first sintered product was then placed back into a pulverizer and pulverized at 8000-10000 rpm for 10 minutes.

[0059] The pulverized sample was spread evenly in a sagger and then placed in a box furnace. The temperature was increased to 930°C at a rate of 5°C / min. After sintering in a pure oxygen atmosphere for 13 hours, the sample was cooled with the furnace to obtain the final sample, which was denoted as sample 3-a.

[0060] Comparative Example 9 Compared to Example 3, the cathode material provided in this comparative example does not contain Si and Zr elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 8 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.2 Ca 0.1 Co 0.1 Al 0.1 Fe 0. 1Mn 0.1 Ti 0.1 ) 10 / 8 O2, the rest of the steps are the same, and the resulting sample is denoted as 3-b.

[0061] Comparative Example 10 Compared to Example 3, the cathode material provided in this comparative example does not contain Ca or Ti elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 8 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.2 Co 0.1 Al 0.1 Fe 0.1 Mn 0. 1Si 0.1 Zr 0.1 ) 10 / 8 O2, the rest of the steps are the same, and the resulting sample is denoted as 3-c.

[0062] Comparative Example 11 Compared to Example 3, the cathode material provided in this comparative example does not contain Al and Fe elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 8 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.2 Ca 0.1 Co 0.1 Mn 0.1 Si 0. 1Ti 0.1 Zr 0.1 ) 10 / 8 O2, the rest of the steps are the same, and the resulting sample is recorded as 3-d.

[0063] Comparative Example 12 Compared to Example 3, the cathode material provided in this comparative example does not contain Mn and Co elements. Simultaneously, to maintain the intact layered structure of the material, the elemental content in the transition metal layer is increased by a factor of 10 / 8 to maintain a 1:1 ratio of Na atoms to transition metal atoms. The resulting material has the chemical formula O3-Na(Ni). 0.2 Ca 0.1 Al 0.1 Fe 0.1 Si 0. 1Ti 0.1 Zr 0.1 ) 10 / 8 O2, the rest of the steps are the same, and the resulting sample is denoted as 3-e.

[0064] Sodium-ion batteries were fabricated using the five cathode materials obtained in Example 3 and Comparative Examples 9-12. The batteries were charged to 4.1V using a constant current and constant voltage of 0.1C within the range of 1.8-4.1V, then the current was cut off at 0.05C, followed by constant current discharge at 0.1C to 1.8V. Different capacities were recorded, and the specific capacity at 0.1C was calculated. The specific capacity of the sodium-ion battery corresponding to sample 3-a was determined. The results showed that the cathode material used in Example 3 had a better specific capacity (specific capacity ≥ 160 mAh / g).

[0065] 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-entropy layered oxide cathode material with O3 phase, characterized in that: Its chemical formula is NaNi 1- 8x Ca x Co x Al x Fe x Mn x Si x Ti x Zr x O2, x = 0.05~0.

1.

2. The O3 phase high-entropy layered oxide cathode material according to claim 1, characterized in that: The value of x is 0.0625, 0.05, or 0.

1.

3. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 1 or 2, characterized in that, include: Step 1: Weigh out sodium source, nickel source, calcium source, cobalt source, aluminum source, iron source, manganese source, silicon source, titanium source and zirconium source according to stoichiometric ratio; mix and pulverize the sodium source, nickel source, calcium source, cobalt source, aluminum source, iron source, manganese source, silicon source, titanium source and zirconium source to obtain precursor powder; Step 2: The precursor powder is sintered at 800℃-850℃ in a pure oxygen atmosphere to obtain the first sintered product. The first sintered product is then pulverized again. Step 3: The product pulverized in Step 2 is sintered at 900℃-950℃ in a pure oxygen atmosphere. After cooling, the O3 phase high-entropy layered oxide cathode material is obtained.

4. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 3, characterized in that: The zirconium and silicon sources are ZrSiO4, the titanium and calcium sources are CaTiO3, the aluminum source is Al2O3, the iron source is Fe2O3, and the sodium source is Na2CO3.

5. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 4, characterized in that: The manganese source is selected from one of MnO, Mn(CH3COO)2, MnCO3, MnC2O4, and Mn(NO3)2.

6. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 5, characterized in that: The cobalt source is selected from one of CoO, Co(CH3COO)2, CoCO3, CoC2O4, and Co(NO3)2.

7. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 6, characterized in that: The nickel source is selected from one of NiO, Ni(CH3COO)2, NiCO3·2Ni(OH)2·4H2O, NiC2O4, and Ni(NO3)2.

8. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 4, 5, 6, or 7, characterized in that: In step two, the sintering time for the first step is 5-10 hours; in step three, the sintering time for the second step is 10-20 hours.

9. The method for preparing the O3 phase high-entropy layered oxide cathode material according to claim 8, characterized in that: In steps one and two, the pulverization is carried out in a pulverizer, maintaining a speed of 8000-10000 rpm and a pulverization time of 10-15 minutes.

10. The application of the O3 phase high-entropy layered oxide cathode material according to claim 1 in the preparation of sodium-ion battery cathodes.

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