Sodium-ion battery positive electrode material, preparation method, pole piece and application
The biphase layered oxide material synthesized by the sol-gel method, with doping to control the P2/O3 phase ratio, solves the problems of cycle stability and rate performance of sodium-ion battery cathode materials, and achieves high specific capacity and excellent cycle performance.
Patent Information
- Application Number
- CN202511141801.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-15
- Publication Date
- 2025-11-11
AI Technical Summary
Existing sodium-ion battery cathode materials have poor cycle stability and rate performance, especially layered oxide materials, where structural phase transitions during charge and discharge cause changes in crystal volume, leading to poor cycle stability.
The biphase layered oxide material NaaNibFecMndMgeMfO2, synthesized by the sol-gel method, can be improved by doping with elements such as K, Zn, and Li to regulate the ratio of P2 and O3 phases, forming favorable grain boundaries, suppressing irreversible phase transitions, and enhancing cycle stability and specific capacity.
It achieves high specific capacity and excellent cycling stability and rate performance, with a reversible specific capacity of 155.6 mAh·g⁻¹ at a current density of 0.01 A·g⁻¹, retaining 90% after 100 cycles at 0.1 A·g⁻¹ and 80% after 300 cycles at 0.5 A·g⁻¹.
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Figure CN120933366A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of sodium-ion batteries, and in particular to sodium-ion battery cathode materials, preparation methods, electrode sheets, and applications. Background Technology
[0002] The tremendous success of lithium-ion batteries in commercial applications demonstrates the vast market demand for energy storage devices. Due to the high price of lithium ore, lithium-ion batteries, while high-performance, are also expensive, making them more suitable for high-value-added products such as mobile phones, laptops, and electric vehicles. Sodium resources are abundant and inexpensive, resulting in lower-priced sodium-ion batteries. For applications with lower energy density requirements or price sensitivity, such as inexpensive low-speed electric vehicles, large-scale energy storage power stations, and home energy storage systems, sodium-ion batteries may be a better choice.
[0003] The main challenge currently facing sodium-ion batteries lies in the cathode material. Among the three main types of cathode materials—layered oxides, polyanionic oxides, and Prussian blue-based oxides—layered oxides have attracted much attention due to their higher specific capacity and simpler synthesis process; however, their cycle stability needs improvement. The general structural formula of layered oxides is Na₂O₃. x TMO2 (TM is a transition metal element) is classified into different configurations, such as P2, P3, O2, and O3, based on the sodium ion coordination configuration and oxygen atom stacking mode. Among them, the P2 and O3 configurations have been extensively studied. The P2 phase exhibits better rate performance and cycle stability due to its lower sodium ion diffusion barrier, while the O3 phase has a higher specific capacity due to its higher initial sodium content. Layered oxide materials typically undergo structural phase transitions during charge and discharge. In P2 phase materials, a P2-O2 transition occurs, while in O3 phase materials, an O3-O'3-P3-P'3 transition occurs. These phase transitions cause significant changes in crystal volume, leading to grain fragmentation and decreased cycle stability. Improving the cycle performance of materials is a key issue in the research field of layered oxides.
[0004] Therefore, it is particularly important to develop a two-phase layered oxide material with high specific capacity and excellent cycle performance and rate performance as a cathode material for sodium-ion batteries, combining the advantages of P2 phase materials and O3 phase materials. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a layered oxide material synthesized by a sol-gel method, which comprises two phases and exhibits high specific capacity, excellent cycle stability, and high rate performance. This material is also used as a cathode material for sodium-ion batteries, along with its preparation method, electrode sheet, and applications.
[0006] The present invention relates to sodium-ion battery cathode materials, preparation methods, electrode sheets, and applications, including a two-phase layered oxide, wherein the chemical formula of the two-phase layered oxide material is Na.a Ni b Fe c Mn d Mg e M f O₂, where b + c + d + e + f = 1, 0.5 ≤ a < 1.1, 0.05 ≤ b ≤ 0.35, 0.05 ≤ c < 0.35, 0.2 < d ≤ 0.8, 0.03 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.3, M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, and the values of a, b, c, d, e, f make the general formula satisfy the valence balance, and there are two phases of P2 and O3 in the XRD diffraction pattern; where the P2 structure provides wide ion channels, reduces the sodium ion diffusion barrier, promotes sodium ion diffusion, the O3 phase increases the overall sodium content, realizes a higher specific capacity, and a favorable grain boundary can be formed between the two phases to inhibit the irreversible phase change during cycling, thereby improving the cycling stability. The means of element doping can effectively regulate the P2 / O3 phase ratio, so that the biphasic layered oxide as the cathode material of the sodium ion battery has both the best specific capacity and cycling stability at the same time; When the layered oxide is used as the cathode material of the sodium ion battery, it has a high initial capacity, shows good cycling stability and rate performance. At a current density of 0.01 A·g -1 a reversible specific capacity of 155.6 mAh·g -1 can be achieved. At a current density of 0.1 A·g -1 after 100 cycles, there is a retention rate of 90%. At a current density of 0.5 A·g -1 after 300 cycles, there is a retention rate of 80%.
[0007] Preferably, the chemical formula of the biphasic layered oxide material is Na a Ni b Fe c Mn d Mg e M fO2, where b + c + d + e + f = 1, 0.5 ≤ a < 1.1, 0.05 ≤ b ≤ 0.35, 0.05 ≤ c < 0.35, 0.2 < d ≤ 0.8, 0.03 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.3, M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, and the values of a, b, c, d, e, and f make the general formula satisfy the valence balance and have one or more phases in the XRD diffraction pattern.
[0008] Preferably, the biphasic layered oxide material is prepared by a co-precipitation method, a sol-gel method, a solid-phase sintering method, or a ball-milling method.
[0009] Preferably, the preparation method of the composite material of the biphasic layered oxide material includes the following steps: S1. Obtain a mixed solution: According to the molar ratio of each metal element in the chemical formula, dissolve a sodium source, a nickel source, a manganese source, an iron source, a magnesium source, and an M source (M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, etc.) in a solvent, and add a complexing agent to the mixed solution, and stir evenly at room temperature to obtain a mixed clear solution; S2. Obtain a dry gel: Heat the above clear solution at 10 - 120 °C to obtain a gel, and heat the gel again to obtain the required dry gel; S3. Place the obtained dry gel at 200 - 1000 °C for heat preservation for 2 - 10 h, then raise the temperature to 700 - 1500 °C for heat preservation for 2 - 16 h, and grind it to finally obtain a layered oxide.
[0010] Preferably, in S2, the solution is heated at 10 - 120 °C for 1 - 36 h, and the obtained gel is heated at 60 - 300 °C for 1 - 36 h to obtain a dry gel.
[0011] Preferably, in S3, the obtained dry gel is placed at 200 - 1000 °C for heat preservation for 2 - 10 h, and then the temperature is raised to 700 - 1500 °C at a heating rate of 1 - 8 °C / min for heat preservation for 2 - 16 h.
[0012] Preferably, the sodium source includes at least one of sodium carbonate, sodium bicarbonate, sodium nitrate, and sodium acetate; The nickel source includes at least one of nickel carbonate, nickel acetate, nickel nitrate, nickel sulfate, nickel oxalate, and nickel chloride; The manganese source includes at least one of manganese carbonate, manganese acetate, manganese nitrate, manganese sulfate, manganese oxalate, and manganese chloride. The iron source includes at least one of ferric acetate, ferric nitrate, ferric sulfate, ferric oxalate, and ferric chloride. The magnesium source includes at least one of magnesium acetate, magnesium nitrate, magnesium sulfate, magnesium oxalate, and magnesium chloride. The M source includes at least one of carbonate M, acetic acid M, nitric acid M, sulfuric acid M, oxalic acid M, and chloride M.
[0013] Preferably, the two-phase layered oxide material, its preparation method, and the electrode are used for energy storage applications.
[0014] Preferably, it includes a current collector and conductive additives, binders, and biphase layered oxide materials or single-phase and multiphase layered oxide materials coated on the current collector.
[0015] Preferably, sodium-ion batteries with positive electrode plates are used for energy storage applications.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: when layered oxide materials are used as cathode materials for sodium-ion batteries, they exhibit high initial capacity, good cycle stability and rate performance, at 0.01 A·g -1 At a current density of 155.6 mAh·g, it can achieve -1 The reversible specific capacity is 0.1 A·g -1 At a current density of 0.5 A·g, it retains 90% of its current after 100 cycles. -1 At the specified current density, it retains 80% of its current after 300 cycles. Attached Figure Description
[0017] Figure 1 SEM image of the two-phase layered oxide material prepared in Example 1; Figure 2 HRTEM image of the biphase layered oxide material prepared in Example 1; Figure 3 The image shows the XRD pattern of the two-phase layered oxide material prepared in Example 1. Figure 4 The two-phase layered oxide material prepared in Example 1 was subjected to a temperature of 0.1 A·g. -1 Cyclic performance at current density; Figure 5 The two-phase layered oxide material prepared in Example 1 was subjected to a temperature of 0.5 A·g. -1 Cyclic performance at current density; Figure 6The rate performance diagram shows the biphase layered oxide material prepared in Example 1. Detailed Implementation
[0018] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
[0019] Example 1 A method for preparing a two-phase layered oxide material specifically includes the following steps: S1. Obtaining a mixed solution: According to the molar ratio of each metal element in the chemical formula, dissolve the sodium source, nickel source, manganese source, iron source, magnesium source and M source (M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, etc.) in a solvent, add a complexing agent to the mixed solution, and stir evenly at room temperature to obtain a mixed clear solution; S2. Obtaining dry gel: Heat the above clear solution at 10~120℃ for 1-36h to obtain gel, and heat the gel at 60-300℃ for 1-36h to obtain the desired dry gel; S3. The obtained dry gel is kept at 200~1000℃ for 2~10h, then heated to 700~1500℃ and kept for 2~16h, and then ground to finally obtain a layered oxide material; In this embodiment, Figure 1 The image shows a SEM image of the two-phase layered oxide material prepared in Example 1. The image shows that the material has a typical microstructure of layered oxide materials. Figure 2 The image shows an HRTEM image of the biphase layered oxide material prepared in Example 1. The image shows that the material has two phases at the microscopic level. Figure 3 The image shows the XRD pattern of the two-phase layered oxide material prepared in Example 1. The image shows that the material has two phases, P2 and O3.
[0020] Example 2 A method for preparing a two-phase layered oxide material specifically includes the following steps: S1. Obtaining a mixed solution: According to the molar ratio of each metal element in the chemical formula (different from Example 1), sodium source, nickel source, manganese source, iron source, magnesium source and M source (M is selected from K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, etc.) are dissolved in a solvent, and a complexing agent is added to the mixed solution. The mixture is stirred evenly at room temperature to obtain a clear mixed solution. S2. Obtaining the dry gel: Heat the above clear solution at 120°C to obtain a gel, and then heat the gel again to obtain the desired dry gel; S3. The obtained dry gel is kept at 800℃ for 2~10h, then heated to 700~1200℃ and kept for 2~16h, and then ground to finally obtain a layered oxide material.
[0021] Example 3 A method for preparing a two-phase layered oxide material specifically includes the following steps: S1. Obtaining a mixed solution: According to the molar ratio of each metal element in the chemical formula (different from Example 1 and Example 2), sodium source, nickel source, manganese source, iron source, magnesium source and M source (M is selected from multiple of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, etc.) are dissolved in a solvent, and a complexing agent is added to the mixed solution. The mixture is stirred evenly at room temperature to obtain a clear mixed solution. S2. Obtaining dry gel: Heat the above clear solution at 10~120℃ to obtain gel, and heat the gel again to obtain the desired dry gel; S3. The obtained dry gel is kept at 900℃ for 2~10h, then heated to 700~1500℃ and kept for 2~16h, and then ground to finally obtain a layered oxide material.
[0022] Example 4 A method for preparing a two-phase layered oxide material specifically includes the following steps: S1. Obtaining a mixed solution: Dissolve sodium source, nickel source, manganese source, iron source and magnesium source in solvent according to the molar ratio of each metal element in the chemical formula, add complexing agent to the mixed solution, and stir evenly at room temperature to obtain a mixed clear solution; S2. Obtaining dry gel: Heat the above clear solution at 10~120℃ for 1-36h to obtain gel, and heat the gel at 60-300℃ for 1-36h to obtain the desired dry gel; S3. The obtained dry gel is kept at 200~1000℃ for 2~10h, then heated to 700~1500℃ and kept for 2~16h, and then ground to finally obtain a layered oxide material.
[0023] Application examples The biphase layered oxide materials prepared in Examples 1-4 were mixed with a conductive agent (acetylene black) and a binder (polyvinylidene fluoride) in a mass ratio of 7:2:1. An appropriate amount of N-methylpyrrolidone was added, and the mixture was thoroughly mixed to form a slurry. The slurry was coated onto aluminum foil and vacuum dried for 12 hours. The slurry was then pressed into an electrode sheet. A button cell (CR2032) was assembled using the prepared electrode sheet as the positive electrode, a sodium metal sheet as the negative electrode, glass fiber as the separator, and NaClO4 as the electrolyte. The electrochemical performance of the button cell was tested using a Blue Battery Testing System. The two-phase layered oxide material of Example 1 at 0.1 A·g -1 Test results at current density are as follows Figure 4 As shown in the figure, it can be seen that at 0.1 A·g -1 At the specified current density, the first-cycle discharge specific capacity of the biphase layered oxide material in Example 1 was 131.8 mAh·g. -1 After 100 cycles, the discharge specific capacity was 118.1 mAh·g. -1 The capacity retention rate was 89.6%. The two-phase layered oxide material of Example 1 at 0.5 A·g... -1 Test results at current density are as follows Figure 5 As shown in the figure, it can be seen that at 0.5 A·g -1 At the specified current density, the first-cycle discharge specific capacity of the biphase layered oxide material in Example 1 was 89.1 mAh·g. -1 After 300 cycles, the discharge specific capacity is 71.3 mAh·g. -1 Capacity retention rate: 80.0%; Figure 6 This is a rate performance image of the two-phase layered oxide material in Example 1. As can be seen from the image, at 0.01 A·g... -1 The current density can reach 155.6 mAh·g -1 The reversible specific capacity at 1 A·g -1 Even at high current density, it still has 74.5 mAh·g -1 The reversible specific capacity, when the current returns to a low current density, the capacity recovers accordingly, indicating that the biphase layered oxide material of the present invention has excellent rate performance. The above test results demonstrate that the biphase layered oxide material prepared in this invention has a high initial specific capacity and exhibits excellent cycle stability and rate performance when used as a cathode material for sodium-ion batteries.
[0024] Table 1 shows the results of Examples 1-4 on the two-phase layered oxide materials at 0.1 A·g. -1 First-cycle discharge specific capacity at current density and capacity retention after 100 cycles; Table 1: Dual-phase layered oxide materials at 0.1 A·g -1 Electrochemical performance at current density As can be seen from the data in Table 1, the biphase layered oxide material prepared in the embodiments of the present invention has high initial capacity and good cycle stability when used as a cathode material for sodium-ion batteries. By using element doping to achieve biphase structure regulation of layered oxides, favorable grain boundaries can be formed, irreversible phase transitions can be suppressed, and cycle stability can be improved. By reasonably adjusting the ratio of the two phases, excellent electrochemical performance with high capacity, high rate performance and high cycle stability can be achieved.
[0025] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A sodium-ion battery cathode material, characterized in that, comprising a biphasic layered oxide material, the chemical formula of the biphasic layered oxide material being Na a Ni b Fe c Mn d Mg e M f O2, where b + c + d + e + f = 1, 0.5 ≤ a < 1.1, 0.05 ≤ b ≤ 0.35, 0.05 ≤ c < 0.35, 0.2 < d ≤ 0.8, 0.03 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.3, M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, and the values of a, b, c, d, e, f satisfy the valence balance of the general formula, and having two phases of P2 and O3 in the XRD diffraction pattern.
2. The sodium-ion battery cathode material as described in claim 1, characterized in that, The chemical formula of the biphasic layered oxide material is Na a Ni b Fe c Mn d Mg e M f O2, where b + c + d + e + f = 1, 0.5 ≤ a < 1.1, 0.05 ≤ b ≤ 0.35, 0.05 ≤ c < 0.35, 0.2 < d ≤ 0.8, 0.03 ≤ e ≤ 0.2, 0 ≤ f ≤ 0.3, M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, and the values of a, b, c, d, e, f make the general formula satisfy the valence balance and have one or more phases in the XRD diffraction pattern.
3. The sodium-ion battery cathode material as described in claim 1, characterized in that, The biphase layered oxide material was prepared by co-precipitation, sol-gel method, solid-state sintering and ball milling.
4. A method for preparing a sodium-ion battery cathode material, characterized in that, The preparation method of the two-phase layered oxide material includes the following steps: S1. Obtaining a mixed solution: According to the molar ratio of each metal element in the chemical formula, dissolve the sodium source, nickel source, manganese source, iron source, magnesium source and M source (M is selected from one or more of K, Zn, Li, Co, Cd, Ti, Ca, Ba, Sr, Cr, Si, Ge, Ga, In, Zr, Sb, Sn, Mo, W, Te, V, La, Ce, Pr, Ru, Nb, Gd, Dy, Er, Yb, B, Ag, Au, Y, Sc, Sb, Bi, Sb, Te, etc.) in a solvent, add a complexing agent to the mixed solution, and stir evenly at room temperature to obtain a mixed clear solution; S2. Obtaining dry gel: Heat the above clear solution at 10~120℃ to obtain gel, and heat the gel again to obtain the desired dry gel; S3. The obtained dry gel is kept at 200~1000℃ for 2~10h, then heated to 700~1500℃ and kept for 2~16h, and then ground to finally obtain a two-phase layered oxide material.
5. The method for preparing sodium-ion battery cathode material as described in claim 4, characterized in that, In step S2, the mixed solution is heated at 10-120°C for 1-36 hours, and the resulting gel is heated at 60-300°C for 1-36 hours to obtain a dry gel.
6. The method for preparing sodium-ion battery cathode material as described in claim 2, characterized in that, In step S3, the obtained dry gel is kept at 200~1000℃ for 2~10h, and then heated to 700~1500℃ at a heating rate of 1~8℃ / min and kept at that temperature for 2~16h.
7. The method for preparing sodium-ion battery cathode material as described in claim 4, characterized in that, The sodium source includes at least one of sodium carbonate, sodium bicarbonate, sodium nitrate, and sodium acetate. The nickel source includes at least one of nickel carbonate, nickel acetate, nickel nitrate, nickel sulfate, nickel oxalate, and nickel chloride; The manganese source includes at least one of manganese carbonate, manganese acetate, manganese nitrate, manganese sulfate, manganese oxalate, and manganese chloride. The iron source includes at least one of ferric acetate, ferric nitrate, ferric sulfate, ferric oxalate, and ferric chloride. The magnesium source includes at least one of magnesium acetate, magnesium nitrate, magnesium sulfate, magnesium oxalate, and magnesium chloride. The M source includes at least one of carbonate M, acetic acid M, nitric acid M, sulfuric acid M, oxalic acid M, and chloride M.
8. A sodium-ion battery cathode material, preparation method, electrode sheet, and application, characterized in that, Two-phase layered oxide materials, preparation methods, and electrode applications for energy storage.
9. A sodium-ion battery positive electrode, characterized in that, It includes a current collector and conductive additives, binders, and biphase layered oxide materials or single-phase and multiphase layered oxide materials coated on the current collector.
10. The sodium-ion battery positive electrode sheet as described in claim 9, characterized in that, Sodium-ion batteries with positive electrode plates are used for energy storage applications.