O3-type nickel-iron-manganese-based sodium ion layered oxide material and preparation method and application thereof

Abstract

The invention provides an O3 type nickel manganese iron-based sodium ion layered oxide material and a preparation method and application thereof, the chemical structural formula of the oxide material is Na < 1-z > M < 1-x-y > Ti < x > Cu < y > Li < z > O2, x is more than 0 and less than or equal to 0.2, y is more than 0 and less than 0.1, z is more than 0 and less than 0.2, and M is at least one of Ni, Cu, Zn, Co, Mn, Fe, Cr and V. The material is obtained through a solid-phase synthesis method, and the obtained material has a layered structure; according to the invention, through transition metal substitution, the harmful phase change under Na < + > / vacancy order and high voltage is obviously inhibited, so that the charging and discharging curves of the material at 2.0-4.0 V and 2.0-4.2 V are smoother; when the material is used as an electrode active material, the capacity of the electrochemical energy storage device can be maintained, and meanwhile, the cycling stability and the rate capability of the electrochemical energy storage device can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of electrode material preparation technology, and more specifically, to a layered oxide material, its preparation method, and its application. Background Technology

[0002] The core demand driving the advancement of sodium-ion battery technology lies in developing cathode materials that combine high performance, long cycle life, and low cost. Among various candidate cathode materials, layered oxides are considered one of the most promising materials due to their low molecular weight, excellent specific capacity, good electrochemical activity, and simple preparation process. Among the reported layered oxide cathode material systems, classic ternary materials have shown undeniable advantages: their theoretical initial capacity is expected to exceed 230 mAh / g, and their actual reversible specific capacity can exceed 130 mAh / g within a voltage range of 2.0-4.1V. They also possess a relatively high operating voltage above 3.1V, and their raw materials are widely distributed and their costs are controllable, making them potential for large-scale application. However, although these ternary materials exhibit impressive initial reversible specific capacity, their cycle stability is insufficient to meet practical application requirements. Furthermore, they suffer from strong hygroscopicity and are prone to structural changes in air, which severely restricts their industrialization process. Research has revealed two main reasons for the capacity decay of these materials: First, during charge-discharge cycles, the materials undergo complex phase transitions, which can lead to internal stress accumulation, crystal structure distortion, and even microscopic cracks, thus affecting the sodium ion transport efficiency and reversible insertion / extraction capability. Second, under high-voltage conditions, side reactions easily occur between the electrode material surface and the electrolyte, causing the dissolution of transition metal elements such as Ni and Mn, gradual deterioration of the material structure, and potentially inducing safety hazards such as dendrite growth in the negative electrode. It is noteworthy that these problems are more pronounced in high-capacity layered materials with high nickel content, becoming a core technological bottleneck hindering sodium-ion batteries from achieving high energy density.

[0003] Existing research reports that bulk doping with metal elements can improve the cycling stability of electrode materials to some extent, but this method usually requires sacrificing some electrode capacity. Meanwhile, surface coating technology is a common method to suppress side reactions on the electrode material surface and the dissolution of transition metal elements. However, this technology has a key problem: a significant phase interface forms between the coating layer and the bulk material. During sodium ion insertion / extraction, the uneven stress changes within the material can further lead to cracking and separation of the coating layer from the bulk phase. Summary of the Invention

[0004] The purpose of this invention is to provide a structural design and performance regulation technology for O3-type sodium-ion battery nickel-manganese layered oxide materials. While ensuring the high reversible capacity of the cathode material, it greatly enhances the stability of the metal cation redox reaction of the material. The preparation method of this layered oxide cathode material is simple, the synthesized material has good consistency, and it has high specific capacity and excellent cycle performance. It is easy to scale up industrial production and is conducive to the development of long-life sodium-ion batteries.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In view of the above-mentioned technical problems existing in the prior art, one of the objectives of the present invention is to provide a layered oxide material, wherein the chemical structural formula of the oxide material is: Na 1-z M 1-x-y Ti x Cu y Li z O2, wherein M is at least one of Ni, Cu, Zn, Co, Mn, Fe, Cr, and V, and the material has an O3-type layered structure, wherein M and Ti form octahedrons with their six nearest oxygen atoms, and the octahedrons are connected by sharing edges to form a layered distribution, and Na is located in the interstitial position of the oxygen octahedrons between the layers; wherein 0 < x ≤ 0.2, 0 < y < 0.1, and 0 < z < 0.2.

[0007] Li, Ti, and Cu doping elements can stabilize layered cathode materials at the microscopic and atomic levels. Na is non-fully occupied in the range of 0.8≤x<1, which reduces the electrostatic adsorption of oxygen by sodium ions in the sodium layer, thereby widening the interlayer spacing of sodium layers and increasing the diffusion rate of sodium ions.

[0008] A second objective of this invention is to provide a method for preparing the layered oxide material according to any of the above embodiments, the method comprising the following steps:

[0009] A layered oxide of NaMO2 with an O3 phase structure is mixed uniformly with lithium, titanium, and copper sources, and then calcined at a temperature of 800-1000℃ to obtain the layered oxide material; wherein M is at least one of Ni, Cu, Zn, Co, Mn, Fe, Cr, and V.

[0010] In some embodiments, the TiO2 particles have a particle size of 20-50 nm.

[0011] In some implementations, the calcination atmosphere is an air atmosphere or an oxygen atmosphere.

[0012] In some implementations, the calcination time is 1-24 hours.

[0013] In some implementations, the method includes the following steps:

[0014] The NaMO2 layered oxide is mixed with lithium, titanium, and copper sources, an organic solvent is added, and the mixture is stirred evenly to form a slurry. The slurry is then dried and calcined at a temperature of 700-1000°C to obtain the layered oxide material. The organic solvent is at least one of ethanol, isopropanol, and N-methylpyrrolidone.

[0015] In some embodiments, the NaMO2 layered oxide is mixed with lithium, titanium and copper sources, and then the organic solvent is added. The mixture is magnetically stirred for 5-10 hours and then evaporated to dryness at 80-120°C to obtain precursor powder. The organic solvent is ethanol.

[0016] In some embodiments, the NaMO2 layered oxide can be commercially available or prepared by solid-state sintering; the solid-state sintering method includes the following steps:

[0017] The raw materials are weighed according to the stoichiometric ratio, mixed, and ball-milled for 4-12 hours using ethanol or acetone as the ball milling medium to prepare a mixed slurry. The slurry is then dried at 60-80℃ to obtain the precursor powder. The powder is then placed in an alumina crucible and heated to 800-1000℃ in a muffle furnace. The temperature is held for 6-15 hours. After sintering, the powder is allowed to cool naturally to obtain the final product.

[0018] The raw material is a mixture of M source and sodium source, wherein the M source is at least one of oxide, hydroxide, carbonate, acetate, sulfate and nitrate of M; and the sodium source is at least one of oxide, hydroxide, carbonate, acetate, sulfate and nitrate of sodium; wherein the sodium source is in excess by 5-10%.

[0019] A third objective of this invention is to provide a positive electrode active material, which includes the layered oxide material of any of the above embodiments and / or the layered oxide material obtained by the preparation method of any of the above embodiments.

[0020] The fourth objective of this invention is to provide a positive electrode material, which includes the above-mentioned positive electrode active material.

[0021] The fifth objective of this invention is to provide a positive electrode, which includes the aforementioned positive electrode material.

[0022] The sixth objective of this invention is to provide an electrochemical energy storage device, which includes the aforementioned positive electrode.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) The sodium-ion cathode material provided by this invention has a long cycle life and high rate performance. Within a voltage window of 2.0–4.0 V, it achieves a cycle life of 0.1 A·g⁻¹.-1 Electrochemical performance was tested by charge-discharge at a current density of 0.2 A·g⁻¹, and the initial discharge specific capacity was 141 mAh / g. Capacity retention was 93% after 100 charge-discharge cycles at a current density of 0.2 A·g⁻¹. This performance was also demonstrated within a voltage window of 2.0–4.2 V and a current density of 0.1 A·g⁻¹. -1 0.2 A·g -1 0.5 A·g -1 1 A·g -1 2 A·g -1 5 A·g -1 The test characterization under charge and discharge rate showed that it still had a reversible specific capacity of 70mAh / g.

[0025] (2) The preparation method of the nickel-manganese-iron-based composite material provided by the present invention is a solid-state synthesis method. The introduction of Ti introduces strong Ti-O bonds into the structure; Li occupying Na sites + It can anchor the layered structure with O2; the introduction of Cu can reduce side reactions on the material surface. The synergistic effect of these three elements gives the material excellent stability, cycling performance, and rate performance. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0027] Figure 1 This is a SEM image of the sodium-ion battery cathode material particles prepared in Example 8 of the present invention;

[0028] Figure 2 XRD patterns of multiple layered oxide materials with different elemental molar percentages provided in the comparative examples and embodiments of this invention;

[0029] Figure 3 This is a comparison chart of the cycling performance of multiple layered oxide materials with different elemental molar percentages provided in Comparative Examples 2, 5 and 8 of this invention;

[0030] Figure 4 This is a comparison chart of the rate performance of multiple layered oxide materials with different elemental molar percentages provided in Comparative Examples 2, 5 and 8 of this invention; Detailed Implementation

[0031] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0033] Example 1

[0034] This embodiment provides an O3-NaNi 0.4 Fe 0.2 Mn 0.3 Ti 0.1 The method for preparing O2 specifically includes the following steps:

[0035] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, and TiO₂ as raw materials, the mixture was prepared in a molar ratio of 1:0.8:0.2:0.6:0.2, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80°C to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450°C in a tube furnace, held at that temperature in air for 6 hours, then heated to 900°C and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown.

[0036] Comparative Example

[0037] This comparative example is used to illustrate the preparation process of the electrode active material of the present invention:

[0038] This comparative example uses NaNi 0.4 Fe 0.2 Mn 0.4 The method for preparing O2 includes the following steps:

[0039] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, and TiO₂ as raw materials, the mixture was prepared in a molar ratio of 1:0.8:0.2:0.8, with Na₂CO₃ in 5% excess. An appropriate amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80°C to obtain the precursor powder. This powder was placed in an alumina crucible and heated in a tube furnace to 450°C, held in air for 6 hours, then heated to 900°C and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. The XRD pattern is shown below. Figure 2 As shown. Constant current charge / discharge mode was used at 0.1 A·g. -1The current density of the above-mentioned sodium-ion battery material was tested within a voltage window of 2.0–4.0 V. The initial discharge specific capacity was 117 mAh / g, followed by a discharge at 0.2 A·g. -1 Long-cycle performance testing was conducted at a current density of [value missing]. After 100 cycles, the capacity retention rate was 71%. Figure 3 As shown. The window voltage is 2.0–4.2 V, at 2 A·g -1 At current density, the discharge specific capacity is 25 mAh / g, such as Figure 4 As shown.

[0040] Example 2

[0041] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0042] This embodiment provides an O3-NaNi 0.4 Fe 0.2 Mn 0.25 Ti 0.15 The method for preparing O2 specifically includes the following steps:

[0043] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, and TiO₂ as raw materials, the mixture was prepared in a molar ratio of 1:0.8:0.2:0.5:0.3, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80℃ to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450℃ in a tube furnace, held at that temperature in air for 6 hours, then heated to 900℃ and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown. Constant current charge / discharge mode was used at 0.1 A·g. -1 The current density of the above-mentioned sodium-ion battery material was tested within a voltage window of 2.0–4.0 V, and the initial discharge specific capacity was 139 mAh / g. For example, initially at 0.1 A·g... -1 Three activation cycles were performed at a current density, followed by activation at 0.2 A·g. -1 Long-cycle performance testing was conducted at a current density of [value missing]. After 100 cycles, the capacity retention rate was 89%. Figure 3 As shown. The window voltage is 2.0–4.2 V, at 2 A·g -1 At current density, the discharge specific capacity is 59 mAh / g, such as Figure 4 As shown.

[0044] Example 3

[0045] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0046] This embodiment provides an O3-NaNi0.4 Fe 0.2 Mn 0.2 Ti 0.2 The method for preparing O2 specifically includes the following steps:

[0047] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, and TiO₂ as raw materials, the mixture was prepared in a molar ratio of 1:0.8:0.2:0.4:0.4, with Na₂CO₃ in 5% excess. Ethanol was used as the ball milling medium, and the mixture was ball-milled for 6 hours to form a slurry. This slurry was then dried at 80°C to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450°C in a tube furnace, held at that temperature in air for 6 hours, then heated to 900°C and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown.

[0048] Example 4

[0049] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0050] This embodiment provides an O3-Na 0.9 Ni 0.4 Fe 0.2 Mn 0.25 Ti 0.15 Li 0.1 The method for preparing O2 specifically includes the following steps:

[0051] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, TiO₂, and Li₂O₃ as raw materials, the materials were prepared in a molar ratio of 0.9:0.8:0.2:0.5:0.3:0.1, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80°C to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450°C in a tube furnace, held at that temperature in air for 6 hours, then heated to 900°C and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown.

[0052] Example 5

[0053] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0054] This embodiment provides an O3-Na 0.85 Ni 0.4 Fe 0.2 Mn 0.25 Ti 0.15 Li 0.15 The method for preparing O2 specifically includes the following steps:

[0055] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, TiO₂, and Li₂O₃ as raw materials, the mixture was prepared in a molar ratio of 0.85:0.8:0.2:0.5:0.3:0.15, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80°C to obtain precursor powder. The precursor powder was then pressed into thin sheets at 20 MPa and placed in an alumina crucible. The furnace was first heated to 450°C and held in air for 6 hours; then heated to 900°C and held in air for 12 hours, followed by natural cooling to obtain the final product. The XRD pattern is shown below. Figure 2 As shown. Constant current charge / discharge mode was used at 0.1 A·g. -1 The current density of the above-mentioned sodium-ion battery material was tested within a voltage window of 2.0–4.0 V, and the initial discharge specific capacity was 140 mAh / g. For example, initially at 0.1 A·g... -1 Three activation cycles were performed at a current density, followed by activation at 0.2 A·g. -1 Long-cycle performance testing was conducted at a current density of [value missing]. After 100 cycles, the capacity retention rate was 89%. Figure 3 As shown. The window voltage is 2.0–4.2 V, at 5 A·g -1 At current density, the discharge specific capacity is 48 mAh / g, such as Figure 4 As shown.

[0056] Example 6

[0057] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0058] This embodiment provides an O3-Na 0.8 Ni 0.4 Fe 0.2 Mn 0.25 Ti 0.15 Li 0.2 The method for preparing O2 specifically includes the following steps:

[0059] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, TiO₂, and Li₂O₃ as raw materials, the materials were prepared in a molar ratio of 0.85:0.8:0.2:0.5:0.3:0.15, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80℃ to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450℃ in a tube furnace, held at that temperature in air for 6 hours, then heated to 900℃ and held in air for 12 hours. The mixture was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown.

[0060] Example 7

[0061] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0062] This embodiment provides an O3-Na 0.85 Ni 0.38 Fe 0.2 Mn 0.2 Ti 0.15 Li 0.15 Cu 0.02 The method for preparing O2 specifically includes the following steps:

[0063] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, TiO₂, Li₂O₃, and CuO as raw materials, the mixture was prepared in a molar ratio of 0.85:0.76:0.2:0.5:0.3:0.15:0.04, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80℃ to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450℃ in a tube furnace, held at that temperature in air for 6 hours, then heated to 900℃ and held in air for 12 hours. The mixture was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown.

[0064] Example 8

[0065] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0066] This embodiment provides an O3-Na 0.85 Ni 0.35 Fe 0.2 Mn 0.2 Ti 0.15 Li 0.15 Cu 0.05 The method for preparing O2 specifically includes the following steps:

[0067] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, TiO₂, Li₂O₃, and CuO as raw materials, the materials were prepared in a molar ratio of 0.85:0.7:0.2:0.5:0.3:0.15:0.1, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80℃ to obtain the precursor powder. This powder was placed in an alumina crucible and heated to 450℃ in a tube furnace, held at that temperature in air for 6 hours, then heated to 900℃ and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. SEM images of the obtained material are shown below. Figure 1 As shown, the XRD pattern is as follows Figure 2 As shown. Constant current charge / discharge mode was used at 0.1 A·g. -1The current density of the above-mentioned sodium-ion battery material was tested within a voltage window of 2.0–4.0 V, and the initial discharge specific capacity was 140 mAh / g. For example, initially at 0.1 A·g... -1 Three activation cycles were performed at a current density, followed by activation at 0.2 A·g. -1 Long-cycle performance testing was conducted at a current density of [value missing]. After 100 cycles, the capacity retention was 92.54%. Figure 3 As shown. The window voltage is 2.0–4.2 V, at 5 A·g -1 At current density, the discharge specific capacity is 70 mAh / g, such as Figure 4 As shown.

[0068] Example 9

[0069] This embodiment illustrates the preparation process of the electrode active material of the present invention:

[0070] This embodiment provides an O3-Na 0.85 Ni 0.32 Fe 0.2 Mn 0.2 Ti 0.15 Li 0.15 Cu 0.08 The method for preparing O2 specifically includes the following steps:

[0071] Using Na₂CO₃, NiO, Fe₂O₃, MnO₂, TiO₂, Li₂O₃, and CuO as raw materials, the mixture was prepared in a molar ratio of 0.85:0.64:0.2:0.5:0.3:0.15:0.16, with Na₂CO₃ in 5% excess. A suitable amount of ethanol was used as the ball milling medium. The mixture was ball-milled for 6 hours to form a slurry, which was then dried at 80℃ to obtain the precursor powder. The powder was placed in an alumina crucible and heated to 450℃ in a tube furnace, held at that temperature in air for 6 hours, then heated to 900℃ and held in air for 12 hours. The powder was then allowed to cool naturally to obtain the final product. The XRD pattern of the obtained material is shown below. Figure 2 As shown.

[0072] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing an O3-type layered oxide material, characterized in that, The chemical structural formula of the oxide material is: Na 0.85 Ni 0.35 Fe 0.2 Mn 0.25 Ti 0.15 Li 0.15 Cu 0.05 O2, wherein the material has an O3-type layered structure, wherein Ni is +2 valence, Fe is +3 valence, Mn is +4 valence, and Li, Ti, and Cu doping elements can stabilize the layered cathode material at the microscopic and atomic levels. The preparation of the layered oxide material includes the following steps: NaNi having an O3 phase structure... 0.4 Fe 0.2 Mn 0.4 O2 layered oxide and titanium, lithium and copper sources are ball-milled and mixed evenly at a molar ratio of 0.85:0.15, then dried and calcined at 800℃-1000℃ for 8-15 hours in air or oxygen atmosphere; after calcination, the mixture is allowed to cool naturally to obtain the layered oxide material.

2. The method for preparing the layered oxide material according to claim 1, characterized in that, Includes the following steps: [The NaNi is then...] 0.4 Fe 0.2 Mn 0.4 O2 layered oxide and titanium source are mixed, an organic solvent is added, and the mixture is ball-milled to form a slurry. The slurry is then dried and calcined at 800-1000°C to obtain the layered oxide material. The organic solvent is at least one of ethanol, isopropanol, and N-methylpyrrolidone.

3. A layered oxide material, characterized in that, It is obtained by the preparation method according to any one of claims 1-2.

4. A positive electrode active material, characterized in that, Includes the layered oxide material as described in claim 3.

5. A positive electrode material, characterized in that, Includes the positive electrode active material as described in claim 4.

6. A positive electrode, characterized in that it comprises the positive electrode material as described in claim 5.

7. An electrochemical energy storage device, characterized in that, Includes the positive electrode as described in claim 6.

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