Al and Zn co-doped sodium ion battery layered positive electrode material and preparation method thereof
By co-doping NaNi1/3Fe1/3Mn1/3O2 materials with Al and Zn, the problems of complex phase change and slow sodium ion transport kinetics of O3-type layered positive electrode materials were solved, the structural stability and high energy density of the materials at high voltage were achieved, and the cycle and rate performance of the battery were improved.
Patent Information
- Application Number
- CN202411926408.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2044-12-25
AI Technical Summary
O3-type NaNi1/3Fe1/3Mn1/3O2 layered positive electrode materials have problems of complex phase transition and slow sodium ion transport kinetics under high voltage conditions, resulting in battery capacity attenuation and reduced rate performance.
Adopting the co-doping strategy of Al and Zn, the NaNi1/3Fe1/3Mn1/3O2 material was co-doped with double metal cations to prepare Na(Ni1/3Fe1/3Mn1/3)1-2xAlxZnxO2. The structural strength and stability of the material were improved by the appropriate amount of Al element, and the ion diffusion performance was improved by the Zn element.
The material's cycle performance and rate performance have been significantly improved. After 200 cycles at 1C, the capacity retention rate is greater than or equal to 73%, and the material's structural stability and ion diffusion performance have been improved.
Smart Images
Figure CN119650659B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of sodium ion battery positive electrode materials, and particularly relates to an Al and Zn co-doped sodium ion battery layered positive electrode material and a preparation method thereof. Background Art
[0002] The development of green, renewable energy has become a top priority. Lithium-ion batteries, currently the dominant electrochemical energy storage system, have been widely used in portable electronics, electric vehicles, and energy storage grids. However, with the increasing cost of lithium and the depletion of lithium reserves, researchers are committed to finding alternative energy sources that can replace or partially replace lithium-ion batteries (LIBs). Sodium-ion batteries, due to their widespread availability and low cost, are becoming the preferred choice for next-generation energy storage systems.
[0003] In sodium-ion batteries, the cathode material is a key factor in determining battery capacity, operating voltage, and cost. Common cathode materials include layered oxides, polyanionic compounds, Prussian blue analogs, and organic materials. Layered oxide cathode materials have been extensively studied due to their high theoretical capacity, low cost, and ease of synthesis. Layered oxide cathode materials are typically classified into P2 and O3 phases, depending on the relative orientation and stacking sequence of adjacent metal oxide layers. O3-type layered oxides exhibit high specific capacity and energy density, and have excellent potential for large-scale commercial applications.
[0004] Among the many O3-type cathode materials, NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O2 layered materials (NFMs) are considered one of the best choices for SIBs cathode materials due to their low cost, eco-friendliness, and relatively stable structure. However, the practical application prospects of NFMs are limited by two key defects. Under high voltage conditions, the electrochemical cycle curve of the NFM charge and discharge process will show a long voltage platform, and the cathode material will undergo transition metal layer slip and Na + The ordered rearrangement of vacancies leads to complex phase transition problems, and its phase structure undergoes a complex evolution of O3-P3-O3′-P3′-O3 during the charge and discharge process. The complex phase transition of the material will cause damage to the crystal structure and huge volume changes, resulting in obstruction of the diffusion channel of sodium ions and the generation of mechanical cracks in the material, causing the capacity attenuation and cycle performance of the battery to decrease. In addition, NFM also faces the problem of slow sodium ion transport kinetics inherent in O3-type materials. For O3-type materials, due to the short distance between sodium layers, Na + The activation energy of diffusion is high, when Na + Migration from one octahedral site to another requires passing through a tetrahedral shared edge site with a high energy barrier, resulting in slow kinetics and reduced rate performance. Summary of the Invention
[0005] The present invention aims at the slow Na + Diffusion kinetics and complex phase transition problems, a sodium ion battery layered cathode material and its preparation method are provided, by O3 type NaNi 1 / 3 Fe 1 / 3Mn 1 / 3 The O2 layered sodium ion battery positive electrode is co-doped with double metal cations to achieve improved material rate performance and cycle performance.
[0006] The technical solution adopted by the present invention is:
[0007] The present invention discloses a sodium ion battery layered positive electrode material co-doped with Al and Zn, the chemical formula of which is Na(Ni 1 / 3 Fe 1 / 3Mn 1 / 3 ) 1-2x Al x Zn x O2, where 0.01≤x≤0.06.
[0008] As a preferred embodiment, the present invention provides a layered positive electrode material for sodium ion batteries co-doped with Al and Zn, the chemical formula of which is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 1-2x Al x Zn x O2, wherein 0.01≤x≤0.04, more preferably 0.015≤x≤0.03, and even more preferably 0.015≤x≤0.025.
[0009] In this invention, the appropriate Al doping strategy improves the mechanical properties of the sodium layered oxide, enhancing its structural strength and stability while mitigating lattice distortion during phase transitions. The appropriate Zn doping strategy also enhances the material's ion diffusion properties, resulting in high voltage and energy density. The synergistic effect of the equal and appropriate Al and Zn additions enables the battery to maintain a capacity of greater than 73% after 200 cycles at 1C.
[0010] The present invention also provides a method for preparing the above-mentioned Al and Zn co-doped sodium ion battery layered positive electrode material, comprising the following steps:
[0011] (1) Grind the sodium source, nickel-iron-manganese-based precursor, aluminum source, and zinc source in a mortar according to a set molar ratio;
[0012] (2) ball milling the crushed materials in a planetary mixer to obtain a mixed powder;
[0013] (3) Under an oxidizing atmosphere, the mixed powder is first kept at 450~600 ℃ for 3~8 h, and then kept at 850~1000 ℃ for 720~1200 min to obtain the O3-type layered sodium ion battery positive electrode material.
[0014] Preferably, in step (1), the sodium source is sodium carbonate; the nickel-iron-manganese-based precursor is Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 (OH)2; the aluminum source is aluminum oxide; the zinc source is zinc oxide.
[0015] Preferably, in step (1), the particle size of sodium carbonate is less than or equal to 150 μm, preferably 100-150 μm; the nickel-iron-manganese-based precursor is Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 The particle size of (OH)2 is less than or equal to 20 μm, preferably 1-10 μm; the particle size of aluminum oxide is less than or equal to 200 nm, preferably 100-200 nm; the particle size of zinc oxide is less than or equal to 10 μm, preferably 0.1-10 μm.
[0016] Preferably, in step (2), the stirring and mixing time is 5 to 10 minutes.
[0017] Preferably, in step (3), the oxidizing atmosphere is an air atmosphere or an oxygen atmosphere.
[0018] Preferably, in step (3), the mixed powder is first heated from room temperature to 450-600°C at a heating rate of 1-2°C / min and kept at that temperature for 3-8 h, and then heated to 750-950°C at a heating rate of 3-8°C / min and kept at that temperature for 15-30 h.
[0019] Preferably, in step (3), the obtained product is crushed to a particle size of 1-15 μm, preferably 1-5 μm, before being assembled into a battery.
[0020] The prepared cathode active material powder, carbon black, and polyvinylidene fluoride (PVDF) were added to N-methylpyrrolidone (NMP) at a mass ratio of 8:1:1 (NMP was three times the mass of the cathode active material powder). This slurry was centrifugally milled into a uniform slurry and evenly coated onto aluminum foil. The aluminum foil was then transferred to a forced-air dryer and dried at 80°C for 4 hours. The slurry was then cut into 12 mm diameter electrodes using a punching machine. After roller pressing, the electrodes were vacuum-dried at 110°C for 12 hours. CR2016 coin cells were assembled in an argon-filled glove box using sodium metal foil as the negative electrode, glass fiber GF / D as the separator, and a 1M NaPF6 / PC / FEC solution (95:5 by volume) as the electrolyte. The assembled cells were subjected to charge-discharge cycle testing on a Newway battery testing system with a test voltage range of 2 to 4.2 V, 200 cycles at a 1C rate, and a test temperature of 25°C. The resulting battery has a capacity retention rate greater than or equal to 73% after 200 cycles at 1C.
[0021] The beneficial effects of the present invention are as follows:
[0022] (1) The raw materials of the present invention are cheap, the preparation method provided is simple, and the conditions are easy to control, which has certain commercial prospects.
[0023] (2) After element doping, the prepared material is still a pure O3 phase with good crystallinity and will not change the structural characteristics of the original material.
[0024] (3) By regulating the content ratio of ion doping, the structural strength and stability of the main material can be improved, its structural degradation can be inhibited, and the phase change path can be changed. The interlayer structure and interlayer force of the layered material can be regulated, thereby improving the comprehensive electrochemical performance of the layered positive electrode material. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG1 is a graph showing the cycle performance of the positive electrode materials of Example 1 and Comparative Example 1 at 1C;
[0026] FIG2 is a graph showing the rate performance of the positive electrode materials of Example 1 and Comparative Example 1;
[0027] FIG3 is a graph showing the cycle performance of the positive electrode materials of Example 2 and Comparative Example 1 at 1C;
[0028] FIG4 is a graph showing the rate performance of the positive electrode materials of Example 2 and Comparative Example 1;
[0029] FIG5 is a graph showing the cycle performance of the positive electrode materials of Example 3 and Comparative Example 1 at 1C;
[0030] FIG6 is a graph showing the rate performance of the positive electrode materials of Example 3 and Comparative Example 1;
[0031] FIG7 is a graph showing the cycle performance of the positive electrode material of Comparative Example 2 at 1C;
[0032] FIG8 is a graph showing the rate performance of the positive electrode material of Comparative Example 2;
[0033] FIG9 is a graph showing the cycle performance of the positive electrode material of Example 3 at 1C;
[0034] FIG10 is a graph showing the rate performance of the positive electrode material of Comparative Example 3;
[0035] FIG11 is an X-ray diffraction pattern of Examples 1, 2, 3 and Comparative Examples 1, 2, 3;
[0036] FIG12 is a scanning electron microscope image of the positive electrode materials of Example 1 and Comparative Example 1.
[0037] In the accompanying drawings, NFM represents a battery assembled from the product obtained in Comparative Example 1, AZ1 represents a battery assembled from the product obtained in Comparative Example 2, AZ2 represents a battery assembled from the product obtained in Example 1, AZ3 represents a battery assembled from the product obtained in Example 2, AZ4 represents a battery assembled from the product obtained in Example 3, and AZ5 represents a battery assembled from the product obtained in Comparative Example 3. DETAILED DESCRIPTION
[0038] Example 1
[0039] Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 0.96 Al 0.02 Zn 0.02 Preparation of O2 (x=0.02): Steps:
[0040] (I) 1.12 g sodium carbonate (particle size less than 150 μm), 1.75 g Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 (OH)2 precursor (particle size less than 20 μm), 0.02 g of aluminum oxide (particle size 100-200 nm), and 0.33 g of zinc oxide (particle size 0.1-10 μm) were ground in a mortar for 10 min;
[0041] (II) The ground powder from step (I) was mixed in a planetary mixer at 300 rpm for 6 min.
[0042] (III) Place the mixed powder from step (II) in a muffle furnace and heat it at 1 °C min under air atmosphere. -1 The temperature was heated to 450 °C and kept at this temperature for 300 min, and then the temperature was heated at 5 °C min -1The temperature was raised to 900 °C at a rate of 1000 °C, kept at this temperature for 1200 min, and then cooled to room temperature to obtain Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 0.96 Al 0.02 Zn 0.02 After grinding, the particle size of the O2 positive electrode material is controlled to be between 1-5 μm.
[0043] Electrochemical performance determination:
[0044] The prepared cathode active material powder (particle size 1-5 μm), carbon black (particle size 8-500 nm), and polyvinylidene fluoride (PVDF) were added to N-methylpyrrolidone (NMP) at a mass ratio of 8:1:1 (NMP was three times the mass of the cathode active material powder). This mixture was centrifugally ball-milled to form a uniform slurry, which was then evenly coated onto aluminum foil. The foil was then transferred to a forced-air dryer and dried at 80°C for 4 hours. The resulting slurry was then cut into 12 mm diameter electrodes using a punching machine. These electrodes were rolled and vacuum-dried at 110°C for 12 hours. CR2016 coin cells were assembled in an argon-filled glove box using sodium metal foil as the anode, glass fiber GF / D as the separator, and a 1M NaPF6 / PC / FEC solution (95:5 by volume) as the electrolyte. The assembled batteries were subjected to charge and discharge cycle tests on the Xinwei battery testing system. The test voltage range was 2 to 4.2 V, the test conditions were 200 cycles at a 1C rate, and the test temperature was 25°C.
[0045] Comparative Example 1
[0046] Same as Example 1, except that the material obtained is O3 type NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 O2 layered cathode material.
[0047] Figure 1 shows the cycle performance test results of Example 1 and Comparative Example 1. The capacity retention rate of Comparative Example 1 after 200 cycles at 1C is only 50.88%, while the capacity retention rate of the battery of Example 1 is increased to 73.98% after 200 cycles at 1C, and the cycle performance is significantly improved.
[0048] FIG2 shows the rate performance test results of Example 1 and Comparative Example 1. The rate performance of Example 1 is better than that of Comparative Example 1.
[0049] Example 2
[0050] Same as Example 1, except that the Al / Zn doping amounts of the positive electrode material prepared in step I are 3% respectively, and the positive electrode material prepared is Na(Ni1 / 3 Fe 1 / 3 Mn 1 / 3 ) 0.94 Al 0.03 Zn 0.03 O2.
[0051] FIG3 shows the cycle performance test results of Example 2 and Comparative Example 1. The capacity retention rate of the battery of Example 2 is increased to 73.46% after 200 cycles at 1C, and the cycle performance is significantly improved.
[0052] FIG4 shows the rate performance test results of Example 1 and Comparative Example 1. The rate performance of Example 2 is also better than that of Comparative Example 1.
[0053] Example 3
[0054] Same as Example 1, except that the Al / Zn doping amounts of the positive electrode material prepared in step I are 4% respectively, and the prepared positive electrode material is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 0.92 Al 0.04 Zn 0.04 O2.
[0055] FIG5 shows the cycle performance test results of Example 3 and Comparative Example 1. The capacity retention rate of the battery of Example 3 is increased to 67.46% after 200 cycles at 1C, and the cycle performance is significantly improved.
[0056] FIG6 shows the rate performance test results of Example 3 and Comparative Example 1. The rate performance of Example 3 is also better than that of Comparative Example 1.
[0057] Comparative Example 2
[0058] Same as Example 1, except that the Al / Zn doping amounts of the positive electrode material prepared in step I are 3% respectively, and the positive electrode material prepared is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 0.98 Al 0.01 Zn 0.01 O2.
[0059] Figure 7 shows the cycle performance test results of Comparative Example 2. The capacity of the battery in Comparative Example 2 is 67.51% after 200 cycles at 1C, which is a relative decrease compared to the capacity retention rate of 73.98% after 200 cycles in Example 1. When the Al / Zn co-doping content is low, its effect on enhancing the stability of the positive electrode material will be lost.
[0060] FIG8 shows the rate performance test results of Comparative Example 2. The capacity of Comparative Example 2 with trace amounts of Al / Zn doping is improved compared to that of undoped Comparative Example 1 under different rate test conditions.
[0061] Comparative Example 3
[0062] Same as Example 1, except that the Al / Zn doping amounts of the positive electrode material prepared in step I are 6% respectively, and the positive electrode material prepared is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 0.88 Al 0.06 Zn 0.06 O2.
[0063] Figure 9 shows the cycle performance test results of Comparative Example 3. The capacity of the battery in Comparative Example 3 is 64.21% after 200 cycles at 1C, which is a relatively low capacity retention rate of 73.98% after 200 cycles compared to Example 1. When the Al / Zn co-doping content is high, it is not conducive to the stability of the positive electrode material.
[0064] FIG10 shows the rate performance test results of Comparative Example 3. The rate performance is lost due to a high Al / Zn co-doping content.
[0065] FIG11 shows the X-ray diffraction patterns of Example 1, Example 2, Example 3, and Comparative Example 1, Comparative Example 2, Comparative Example 3. It can be seen from the figure that Al / Zn co-doping does not change the material NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3 The O2 layered material has the original O3 phase structural characteristics, and each positive electrode material maintains good crystallinity.
[0066] Scanning electron microscope images were taken for Comparative Example 1 and Example 1. As can be seen from Figure 12, Example 1 and Comparative Example 1 maintain the secondary particle structure composed of lamellar primary particles, indicating that Al / Zn co-doping does not change the material morphology.
Claims
1. An Al and Zn co-doped layered cathode material for sodium ion batteries, characterized in that: The chemical formula of the positive electrode material is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 1-2x Al x Zn x O2, of which 0.01 <x<0.06。 2. The Al and Zn co-doped sodium ion battery layered positive electrode material according to claim 1, characterized in that: The chemical formula of the positive electrode material is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 1-2x Al x Zn x O2, where 0.015≤x≤0.
03.
3. The Al and Zn co-doped sodium ion battery layered cathode material according to claim 1, characterized in that: The chemical formula of the positive electrode material is Na(Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 ) 1-2x Al x Zn x O2, where 0.015≤x≤0.
025.
4. The method for preparing an Al and Zn co-doped sodium ion battery layered cathode material according to any one of claims 1 to 3, wherein: The following steps are involved: (1) Grind the sodium source, nickel-iron-manganese-based precursor, aluminum source, and zinc source in a mortar according to a set molar ratio; (2) Mixing the crushed materials in a planetary mixer to obtain a mixed powder; (3) The mixed powder is heat-treated to obtain an O3-type layered sodium ion battery positive electrode material.
5. The method for preparing an Al and Zn co-doped sodium ion battery layered cathode material according to claim 4, wherein: In the step (1), the sodium source is sodium carbonate; the nickel-iron-manganese-based precursor is Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 (OH)2; the aluminum source is aluminum oxide; the zinc source is zinc oxide.
6. The method for preparing an Al and Zn co-doped sodium ion battery layered cathode material according to claim 4, wherein: In step (1), the particle size of sodium carbonate is less than or equal to 150 μm; the nickel-iron-manganese-based precursor is Ni 1 / 3 Fe 1 / 3 Mn 1 / 3 The particle size of (OH)2 is less than or equal to 20 μm; the particle size of aluminum oxide is less than or equal to 200 nm; and the particle size of zinc oxide is less than or equal to 10 μm.
7. The method for preparing an Al and Zn co-doped sodium ion battery layered cathode material according to claim 4, wherein: The powders in step (2) are mixed by ball milling.
8. The method for preparing an Al and Zn co-doped sodium ion battery layered cathode material according to claim 4, wherein: The heat treatment conditions in step (3) are to keep the temperature at 450-600°C for 3-8 h in an oxidizing atmosphere, and then keep the temperature at 850-1000°C for 720-1200 min, and cool the furnace after sintering.
9. The method for preparing an Al and Zn co-doped layered cathode material for sodium ion batteries according to claim 8, wherein: The obtained product is crushed to a particle size of 1-15 μm before being assembled into batteries.
10. The method for preparing an Al and Zn co-doped sodium ion battery layered cathode material according to claim 4, wherein: The prepared cathode active material powder, carbon black, and polyvinylidene fluoride were added to N-methylpyrrolidone in a mass ratio of 8:1:1, with the N-methylpyrrolidone content being three times the mass of the cathode active material powder. The mixture was centrifugally milled into a uniform slurry and evenly coated on aluminum foil. The aluminum foil was then transferred to a forced air dryer and dried at 80°C for 4 hours. The slurry was then cut into 12 mm diameter electrodes using a punching machine, rolled, and vacuum-dried at 110°C for 12 hours. CR2016 button cells were assembled in an argon-filled glove box using sodium metal foil as the anode, glass fiber GF / D as the separator, and a 1 M NaPF6 PC / FEC solution as the electrolyte. The assembled cells were subjected to charge and discharge cycle testing in a Newway battery testing system with a test voltage range of 2-4.2 V, 200 cycles at a 1C rate, and a test temperature of 25°C. The resulting cells exhibited a capacity retention rate of greater than or equal to 73% after 200 cycles at 1C.