A double-modified sodium ion battery layered oxide positive electrode material and preparation method

Abstract

The present invention belongs to the technical field of sodium ion battery positive electrode material preparation, and specifically discloses a double-modified sodium ion battery layered oxide positive electrode material and a preparation method, comprising the following steps: S1, synthesizing a P2-type sodium ion battery nickel-manganese-based layered oxide by a high-temperature solid-phase method; S2, uniformly mixing two or more of lithium fluoride, sodium fluoride, calcium fluoride or magnesium fluoride in proportion to prepare a multi-element fluoride coating material; S3, uniformly mixing the P2-type sodium ion battery nickel-manganese-based layered oxide and the multi-element fluoride coating material in proportion, and then performing a high-temperature quenching treatment to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping. The present invention adopts the above-mentioned double-modified sodium ion battery layered oxide positive electrode material and preparation method, synergistically utilizing surface fluoride coating and near-bulk phase doping to improve the high-voltage cycle performance of the sodium ion battery layered oxide positive electrode material.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium ion battery positive electrode material preparation, and in particular to a double-modified sodium ion battery layered oxide positive electrode material and a preparation method thereof. Background Art

[0002] Due to the abundance and low cost of sodium resources, sodium-ion batteries are expected to replace lithium-ion batteries in large-scale energy storage and low-speed electric vehicles. However, the low energy density of sodium-ion batteries limits their practical application. The positive electrode material is the key to improving the energy density of sodium-ion batteries. Among the many sodium-ion battery positive electrode materials, layered oxides (Na x TMO2 (TM stands for transition metal) has the advantages of diverse composition, simple preparation process, relatively excellent performance and environmental friendliness, and is the most promising type of positive electrode material for rapid industrialization. P2-type layered oxides have unique triangular prism sodium ion sites that reduce the diffusion energy barrier during sodium ion migration, making P2-type layered oxides have better rate performance. 2 / 3 Ni 1 / 3 Mn 2 / 3 As a typical P2-type sodium ion battery layered oxide cathode material, O2 also has the advantages of high theoretical specific capacity (≈173mAh / g), high operating voltage (>3.6V) and low cost, becoming one of the most practical cathode materials. 2 / 3 Ni 1 / 3 Mn 2 / 3 The poor high-voltage cycling performance of O2 cathode materials limits their practical applications.

[0003] In the existing technology, both coating strategy and doping strategy can improve P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 The high voltage cycling performance of O2 cathode materials. However, the coating strategy lacks a direct effect on the bulk phase, and the doping strategy has a very limited effect on the surface interface. The simultaneous construction of the surface coating layer and bulk ion doping can synergistically utilize the advantages of surface coating and bulk doping, while building a stable and efficient electrode-electrolyte interface to achieve a stable crystal structure and reversible lattice oxygen redox, thereby improving the P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 The cycling performance of O2 cathode materials. Fluorides are very stable due to their low Gibbs free energy of formation. Furthermore, fluorides are more resistant to moisture in the surrounding air than oxides, which is beneficial for improving the air stability of layered oxides. Summary of the Invention

[0004] The purpose of the present invention is to provide a double-modified sodium ion battery layered oxide positive electrode material and a preparation method, which synergistically utilizes surface fluoride coating and near-bulk phase doping to improve the high voltage cycle performance of the sodium ion battery layered oxide positive electrode material.

[0005] To achieve the above object, the present invention provides a method for preparing a double-modified sodium ion battery layered oxide positive electrode material, comprising the following steps:

[0006] S1. Synthesis of P2-type sodium ion battery nickel-manganese-based layered oxide using a high-temperature solid-phase method;

[0007] S2. Mix two or more of lithium fluoride, sodium fluoride, calcium fluoride or magnesium fluoride in proportion to prepare a multi-element fluoride coating material;

[0008] S3. The P2 type sodium ion battery nickel-manganese based layered oxide obtained in S1 and the multi-element fluoride coating material obtained in S2 are mixed evenly in proportion, and then subjected to high temperature quenching treatment to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping.

[0009] Preferably, S1 is specifically:

[0010] Sodium carbonate, nickel oxide, and manganese oxide were mixed uniformly by ball milling according to the proportion to obtain precursor powder, which was tableted and calcined to obtain a product with the chemical formula of Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2's P2-type sodium-ion battery uses nickel-manganese-based layered oxide.

[0011] Preferably, the mass ratio of the sodium carbonate, the nickel oxide and the manganese oxide is 2.226:1.471:3.174.

[0012] Preferably, the calcination temperature is 900° C. and the calcination time is 12 hours.

[0013] Preferably, in S2, the multi-component fluoride coating material is specifically one of a binary fluoride coating material of lithium fluoride and calcium fluoride with a molar ratio of 1:4, a binary fluoride coating material of sodium fluoride and calcium fluoride with a molar ratio of 1:2, and a ternary fluoride coating material of lithium fluoride, calcium fluoride and magnesium fluoride with a molar ratio of 0.59:0.279:0.131.

[0014] Preferably, S3 is specifically:

[0015] The P2 type sodium ion battery nickel manganese-based layered oxide obtained in S1 is evenly mixed with the lithium fluoride and calcium fluoride binary fluoride coating material, and then calcined at 800-900°C for 15-120 minutes and then rapidly cooled in air to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping.

[0016] Preferably, S3 is specifically:

[0017] The P2 type sodium ion battery nickel manganese-based layered oxide obtained in S1 is evenly mixed with the sodium fluoride and calcium fluoride binary fluoride coating material, and then calcined at 850-900°C for 15-120 minutes and then rapidly cooled in air to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping.

[0018] Preferably, S3 is specifically:

[0019] The P2 type sodium ion battery nickel manganese-based layered oxide obtained in S1 is evenly mixed with the lithium fluoride, calcium fluoride and magnesium fluoride ternary fluoride coating material, and then calcined at 700-900 ° C for 15-120 minutes and then rapidly cooled in air to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping.

[0020] Preferably, in S3, the mass ratio of the P2 type sodium ion battery nickel manganese based layered oxide to the multi-element fluoride coating material is 100:0~3.

[0021] The present invention also provides a double-modified sodium ion battery layered oxide positive electrode material.

[0022] Therefore, the present invention adopts the above-mentioned double-modified sodium ion battery layered oxide positive electrode material and preparation method, and the beneficial effects are as follows:

[0023] (1) The present invention utilizes the advantages of high stability of fluoride and its ability to resist moisture erosion in the surrounding air, and simultaneously realizes surface fluoride coating and near-bulk phase multi-element doping of P2 type sodium ion battery nickel-manganese based layered oxide positive electrode material through high temperature quenching treatment. The advantages of surface coating and near-bulk phase doping are synergistically utilized to achieve a stable crystal structure and reversible lattice oxygen redox while constructing a stable and efficient electrode-electrolyte interface. Specifically, surface fluoride can inhibit interfacial side reactions on the one hand, and inhibit oxygen release on the other hand; the near-bulk phase co-doped with multiple elements can inhibit structural degradation on the one hand, and has excellent Na + diffusion kinetics, thereby improving the high-voltage cycling performance of the battery.

[0024] (2) The preparation process adopted by the present invention is simple, has low energy consumption, low production cost, flexible and variable processing capacity, and has broad industrial application prospects.

[0025] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic flow diagram of an embodiment of a double-modified sodium ion battery layered oxide positive electrode material and a preparation method of the present invention;

[0027] Figure 2 The XRD patterns of Examples 1-4 of a double-modified sodium ion battery layered oxide positive electrode material and a preparation method thereof according to the present invention are as follows;

[0028] Figure 3 The XRD patterns of Examples 5-8 of a double-modified sodium ion battery layered oxide positive electrode material and a preparation method thereof according to the present invention are as follows;

[0029] Figure 4 The XRD patterns of Examples 9-11 of a double-modified sodium ion battery layered oxide positive electrode material and a preparation method thereof according to the present invention are as follows;

[0030] Figure 5 HRTEM images of a double-modified sodium ion battery layered oxide positive electrode material and a preparation method according to the present invention, wherein (a) is Example 1 and (b) is Example 3;

[0031] Figure 6 This is a comparison chart of the cycle performance of Examples 1-4 of a double-modified sodium ion battery layered oxide positive electrode material and a preparation method thereof of the present invention;

[0032] Figure 7 This is a comparison chart of the cycle performance of Examples 5-8 of a double-modified sodium ion battery layered oxide positive electrode material and preparation method of the present invention;

[0033] Figure 8 This is a comparison chart of the cycle performance of Examples 9-11 of a double-modified sodium ion battery layered oxide positive electrode material and preparation method of the present invention. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0035] Unless otherwise defined, technical or scientific terms used in the present invention should have the same general meaning as those commonly understood by persons skilled in the art in the art to which the present invention belongs. Unless otherwise specified, the materials used in the examples were prepared according to existing methods or purchased directly from the market.

[0036] The preparation process of the double-modified sodium ion battery layered oxide positive electrode material obtained in the embodiment is shown in FIG. Figure 1shown.

[0037] Example 1

[0038] A double-modified sodium ion battery layered oxide positive electrode material, the preparation method of which is as follows:

[0039] S1. Sodium carbonate, nickel oxide and manganese oxide powders with a mass ratio of 2.226:1.471:3.174 were mixed uniformly by ball milling to obtain precursor powder. The precursor powder was pressed into tablets and calcined in a muffle furnace at 900°C for 12 hours to obtain P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2.

[0040] S2. Evenly mix lithium fluoride and calcium fluoride in a molar ratio of 1:4 by ball milling to obtain a binary fluoride coating material.

[0041] S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and binary fluoride coating material were mixed uniformly in a mass ratio of 100:0, calcined at 800℃ in a muffle furnace for 15 minutes, and then rapidly cooled in air to obtain surface lithium fluoride and calcium fluoride coating and near-bulk phase Li + , Ca 2+ and F - Co-doped dual-modified layered oxide cathode material for sodium-ion batteries, labeled LCF-0.

[0042] Example 2

[0043] The difference from Example 1 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and binary fluoride coating material were mixed evenly in a mass ratio of 100:1 and marked as LCF-1.

[0044] Example 3

[0045] The difference from Example 1 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and binary fluoride coating material were mixed evenly in a mass ratio of 100:2 and marked as LCF-2.

[0046] Example 4

[0047] The difference from Example 1 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3O2 and binary fluoride coating material were mixed evenly in a mass ratio of 100:3 and marked as LCF-3.

[0048] Example 5

[0049] A double-modified sodium ion battery layered oxide positive electrode material, the preparation method of which is as follows:

[0050] S1. Sodium carbonate, nickel oxide and manganese oxide powders with a mass ratio of 2.226:1.471:3.174 were mixed uniformly by ball milling to obtain precursor powder. The precursor powder was pressed into tablets and calcined in a muffle furnace at 900°C for 12 hours to obtain P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2.

[0051] S2. Sodium fluoride and calcium fluoride in a molar ratio of 1:2 are mixed by ball milling to obtain a binary fluoride coating material.

[0052] S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and binary fluoride coating material were mixed uniformly in a mass ratio of 100:0, calcined at 850℃ in a muffle furnace for 15 minutes, and then rapidly cooled in air to obtain surface sodium fluoride and calcium fluoride coating and near-bulk phase Ca 2+ and F - Co-doped dual-modified layered oxide cathode material for sodium-ion batteries, labeled NCF-0.

[0053] Example 6

[0054] The difference from Example 5 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and binary fluoride coating material were mixed uniformly in a mass ratio of 100:1 and marked as NCF-1.

[0055] Example 7

[0056] The difference from Example 5 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and binary fluoride coating material were mixed uniformly in a mass ratio of 100:2 and marked as NCF-2.

[0057] Example 8

[0058] The difference from Example 5 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3O2 and binary fluoride coating material were mixed uniformly in a mass ratio of 100:3 and marked as NCF-3.

[0059] Example 9

[0060] A double-modified sodium ion battery layered oxide positive electrode material, the preparation method of which is as follows:

[0061] S1. Sodium carbonate, nickel oxide and manganese oxide powders with a mass ratio of 2.226:1.471:3.174 were mixed uniformly by ball milling to obtain precursor powder. The precursor powder was pressed into tablets and calcined in a muffle furnace at 900°C for 12 hours to obtain P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2.

[0062] S2. Lithium fluoride, calcium fluoride and magnesium fluoride in a molar ratio of 0.59:0.279:0.131 are uniformly mixed by ball milling to obtain a ternary fluoride coating material.

[0063] S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and ternary fluoride coating material were mixed uniformly in a mass ratio of 100:0, calcined at 700℃ in a muffle furnace for 15 minutes, and then rapidly cooled in air to obtain surface lithium fluoride, calcium fluoride and magnesium fluoride coating and near-bulk phase Li + , Ca 2+ Mg 2+ and F - Co-doped dual-modified layered oxide cathode material for sodium-ion batteries, labeled LCM-0.

[0064] Example 10

[0065] The difference from Example 9 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and ternary fluoride coating material were mixed evenly in a mass ratio of 100:1 and marked as LCM-1.

[0066] Example 11

[0067] The difference from Example 9 is that S3, P2-Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2 and ternary fluoride coating material were mixed evenly in a mass ratio of 100:2 and marked as LCM-2.

[0068] Experimental testing

[0069] The cathode materials prepared in Examples 1-11 were subjected to structural analysis, and the XRD analysis results were as follows: Figure 2-Figure 4 As shown in the HRTEM analysis results, Figure 5 shown.

[0070] Depend on Figure 2 It can be seen that the surface lithium fluoride and calcium fluoride coating and the near-bulk phase Li + , Ca 2+ and F - Co-doped double-modified layered oxide positive electrode materials for sodium ion batteries were successfully prepared.

[0071] Depend on Figure 3 It can be seen that the surface sodium fluoride and calcium fluoride coating and the near-bulk phase Ca 2+ and F - Co-doped double-modified layered oxide positive electrode materials for sodium ion batteries were successfully prepared.

[0072] Depend on Figure 4 It can be seen that the surface lithium fluoride, calcium fluoride and magnesium fluoride coating and the near-bulk phase Li + , Ca 2+ Mg 2+ and F - Co-doped double-modified layered oxide positive electrode materials for sodium ion batteries were successfully prepared.

[0073] Depend on Figure 5 It can be seen that there is no coating layer before modification, but a uniform coating layer exists on the surface of the layered oxide positive electrode material for sodium ion batteries after double modification.

[0074] The positive electrode material prepared in Example 1-11 was used to assemble a button cell. The assembly process of the button cell was as follows:

[0075] The positive electrode material prepared in the example was used as the positive electrode, sodium metal was used as the negative electrode, and glass fiber (Whatman) was used as the separator to complete the assembly of button cells in a glove box.

[0076] The button battery was tested for high voltage cycle performance. The test results are as follows: Figure 6-Figure 8 shown.

[0077] Depend on Figure 6 、 Figure 7 and Figure 8 It can be seen that the double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping exhibits better high-voltage cycling performance than the unmodified sodium ion battery layered oxide positive electrode material, with the best reaching 90.2%.

[0078] Therefore, the present invention adopts the above-mentioned dual-modified sodium ion battery layered oxide positive electrode material and preparation method, and synergistically utilizes surface fluoride coating and near-bulk phase doping to improve the high voltage cycle performance of the sodium ion battery layered oxide positive electrode material.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a double-modified sodium ion battery layered oxide positive electrode material, characterized in that: The following steps are involved: S1. Synthesis of P2-type sodium ion battery nickel-manganese-based layered oxide Na by high temperature solid phase method 2 / 3 Ni 1 / 3 Mn 2 / 3 O2; S2. Mix two or more of lithium fluoride, sodium fluoride, calcium fluoride or magnesium fluoride in proportion to prepare a multi-element fluoride coating material; S3, mixing the P2 type sodium ion battery nickel-manganese-based layered oxide obtained in S1 and the multi-element fluoride coating material obtained in S2 in proportion, and then performing a high-temperature quenching treatment to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping; In S2, the multi-element fluoride coating material is specifically one of a binary fluoride coating material of lithium fluoride and calcium fluoride with a molar ratio of 1:4, a binary fluoride coating material of sodium fluoride and calcium fluoride with a molar ratio of 1:2, and a ternary fluoride coating material of lithium fluoride, calcium fluoride and magnesium fluoride with a molar ratio of 0.59:0.279:0.131; In S3, the mass ratio of the P2 type sodium ion battery nickel manganese based layered oxide to the multi-element fluoride coating material is 100:1-3; S3 specifically: The P2-type sodium ion battery nickel-manganese-based layered oxide obtained in S1 is evenly mixed with the lithium fluoride and calcium fluoride binary fluoride coating material, and then calcined at 800-900° C. for 15 minutes and then rapidly cooled in air to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping; Alternatively, the P2-type sodium ion battery nickel-manganese-based layered oxide obtained in S1 is evenly mixed with the sodium fluoride and calcium fluoride binary fluoride coating material, and then calcined at 850-900° C. for 15 minutes and then rapidly cooled in air to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping; Alternatively, the P2-type sodium ion battery nickel-manganese-based layered oxide obtained in S1 is evenly mixed with the lithium fluoride, calcium fluoride and magnesium fluoride ternary fluoride coating material, and then calcined at 700-900°C for 15 minutes and then rapidly cooled in air to obtain a double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping.

2. The method for preparing a double-modified sodium ion battery layered oxide positive electrode material according to claim 1, characterized in that: S1 is specifically: Sodium carbonate, nickel oxide, and manganese oxide are mixed uniformly by ball milling according to the proportion to obtain precursor powder, which is then tableted and calcined to obtain a product with the chemical formula of Na 2 / 3 Ni 1 / 3 Mn 2 / 3 O2's P2-type sodium-ion battery uses nickel-manganese-based layered oxide.

3. The method for preparing a double-modified sodium ion battery layered oxide positive electrode material according to claim 2, characterized in that: The mass ratio of the sodium carbonate, the nickel oxide, and the manganese oxide is 2.226:1.471:3.

174.

4. The method for preparing a double-modified sodium ion battery layered oxide positive electrode material according to claim 2, characterized in that: The calcination temperature is 900° C. and the calcination time is 12 hours.

5. A double-modified sodium ion battery layered oxide positive electrode material with surface fluoride coating and near-bulk phase doping prepared by the preparation method of the double-modified sodium ion battery layered oxide positive electrode material according to any one of claims 1 to 4.

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