Double-doped modified O3 type sodium-ion battery positive electrode material as well as preparation method and application thereof

Abstract

The invention belongs to the field of sodium ion batteries, and particularly relates to a bimetallic element doped and modified O3 type sodium ion battery positive electrode material which is modified by double doping. The chemical formula of the sodium ion battery positive electrode material is NaNi < 0.5-x > A < x > Mn < 0.5-y > B < y > O < 2 >, A represents one of Nb, Ta, Mo and W, B represents one of Ti and Zr, x ranges from 0.01 to 0.05, and y ranges from 0.01 to 0.30. By doping and introducing double-position metal elements, the layered spacing can be enlarged, the local electronic structure can be regulated and controlled, the material stability and air stability in the circulation process can be further enhanced, and the electrochemical performance of the material system can be improved. The preparation method adopts a simple high-temperature solid-phase method and comprises the following steps: weighing raw materials according to a stoichiometric ratio, grinding, tabletting and calcining in air. The preparation method is simple in steps, low in cost and convenient for industrial large-scale production, and has better rate capability, cycle performance and air stability when being applied to the sodium-ion battery positive electrode material.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium-ion battery materials, and particularly relates to a dual-site doped and modified O3-type sodium-ion battery cathode material, a preparation method thereof, and an application thereof. Background Art

[0002] Large-scale electrical energy storage (EES) is a key issue for the development of sustainable new energy technologies, such as electric vehicles (EVs) and renewable power generation stations (UPS). High-energy-density lithium-ion batteries (LIBs) have been widely used in the energy storage field, but the problems of limited lithium resources and high future development costs have attracted people's attention. Sodium-ion batteries (SIBs), as an emerging energy storage technology, have received extensive attention in recent years. Compared with traditional lithium-ion batteries (LIBs), sodium-ion batteries have significant advantages such as rich resources, low cost, excellent low-temperature performance, and environmental protection, and are considered to be one of the most promising technologies in the field of large-scale energy storage.

[0003] Layered oxides have received extensive attention as cathode materials for sodium-ion batteries due to their easy synthesis and high capacity. Among them, compared with the P2 type, the O3 type has a higher reversible capacity and good rate performance. However, some major problems have hindered the development of its commercial application: (1) Phase transition problem: The O3-type layered oxide cathode material will undergo multiple phase transitions during cycling. For example, severe phase transitions are likely to occur in the deeply charged state, resulting in the destruction of structural stability and then causing a decline in electrochemical performance. (2) Side reaction: The material is prone to side reactions with the electrolyte, which will consume active substances and reduce the performance and life of the battery. (3) High surface alkalinity: The high surface alkalinity will affect the air stability of the material, making it easy to absorb moisture and carbon dioxide in the air and deteriorate, and it will also have an adverse impact on the interfacial performance of the battery. Summary of the Invention

[0004] In order to solve the above problems existing in the O3-type layered oxide cathode material, the applicant has previously explored various modification strategies, such as ion doping, structural design, surface coating, and process optimization. Among them, dual-site doping is an effective modification method. By selecting two suitable metal elements for doping at different metal positions, the characteristics of different elements can be utilized to optimize the O3-type material in multiple aspects. For example, some metal ions can change the lattice parameters and expand the layer spacing, providing a more favorable channel for sodium-ion transmission; at the same time, the doping ions can also enhance the structural stability and air stability of the material, inhibit the occurrence of harmful phase transitions, and improve the structural integrity of the material during cycling; in addition, by adjusting the electronic structure of the transition metal layer, the redox performance of the material can be optimized, and the specific capacity and rate performance of the battery can be improved, etc.

[0005] In view of the deficiencies of the existing technology, the present invention proposes a dual-site doped modified O3-type sodium-ion battery cathode material to improve the problems of poor rate performance and fast capacity decay of the cathode material.

[0006] To solve the above technical problems, according to one aspect of the present invention, the present invention belongs to the field of sodium-ion batteries and specifically relates to a dual-site doped modified O3-type sodium-ion battery cathode material. Doped and modified by dual metal elements. The chemical formula of the sodium-ion battery cathode material is NaNi 0.5-x A x Mn 0.5-y B y O2, where A represents one of Nb, Ta, Mo, and W, B represents one of Ti and Zr, x is from 0.01 to 0.05, and y is from 0.01 to 0.30.

[0007] The introduction of doping with metal elements can expand the layer spacing, regulate the local electronic structure, and further enhance the material stability and air stability during cycling, thereby improving the electrochemical performance of this material system.

[0008] Preferably, the metal elements are a combination of Nb and Ti.

[0009] According to the second aspect of the present invention, a preparation method of the dual-site doped modified O3-type layered sodium-ion battery cathode material is provided, including:

[0010] Step 1: Weigh sodium salt, nickel oxide, manganese oxide, and metal oxide respectively according to the molar ratio of each element in the chemical formula, and grind for 20 - 60 minutes;

[0011] Step 2: Press the above-mentioned fully mixed powder into a tablet under a pressure of 5 - 20 MPa, then heat it at a heating rate of 5 °C / min to 450 °C and hold for 5 hours, and then heat it to 900 °C and calcine for 15 hours in an air atmosphere, and cool to room temperature to obtain the dual-metal element doped modified O3-type layered sodium-ion battery cathode material.

[0012] Further, in Step 1, the sodium salt is anhydrous sodium carbonate;

[0013] The manganese oxide is one of manganese dioxide and manganese sesquioxide, and the nickel oxide is nickel monoxide. Further, the manganese oxide is manganese sesquioxide;

[0014] Preferably, in step 1), any one of niobium pentoxide, tantalum pentoxide, molybdenum trioxide or tungsten trioxide is used as the metal oxide, and any one of titanium dioxide or zirconium dioxide is added as the metal oxide; part of Ni is replaced by Nb, Ta, Mo or W, and Mn is replaced by Ti or Zr ions to form double-metal site doping; further, the metal oxide is niobium pentoxide / titanium dioxide.

[0015] According to the third aspect of the present invention, the present invention provides an application of the O3-type sodium ion battery cathode material described in the first aspect in a sodium ion battery.

[0016] In certain embodiments of the present invention, a bimetallic element-doped modified O3-type layered sodium ion battery cathode material is used as the active material, acetylene black is used as the conductive agent, and polyvinylidene fluoride is used as the binder. They are mixed evenly according to a mass ratio of 8:1:1 - 7:2:1, and N-methylpyrrolidone is used as the solvent. It is coated on an aluminum foil, vacuum dried and cut into electrode sheets. A sodium metal sheet is used as the counter electrode, Whatman GF / D is used as the separator, and 1M sodium perchlorate dissolved in propylene carbonate and fluoroethylene carbonate is used as the electrolyte. The battery is assembled in a glove box filled with argon, and the voltage window is 2.0 - 4.2V. The beneficial effect of the technical solution provided by the present invention is that bimetallic elements, such as Nb and Ti, are used to modify the O3-type layered sodium ion battery cathode material. The bimetallic elements can greatly improve the structural stability and electronic conductivity of the electrode material. The preparation method of the present invention has simple steps, mild conditions, and is convenient for large-scale industrial production.

[0017] Compared with the prior art, the significant advantages of the present invention are:

[0018] (1) The doping elements used are niobium / titanium. In the form of high-valent metal Nb 5+ ions, it can effectively adjust the electronic structure of the O3-type layered material, improve the conductivity and layer spacing; Ti 4+ ions can stabilize the layered structure and inhibit phase transformation;

[0019] (2) The doping elements used are niobium / titanium, which will form compounds with the sodium source during high-temperature calcination, enhancing its structural stability;

[0020] (3) The doping elements used are niobium / titanium, which have the advantages of low cost, environmental friendliness, simple process and good reproducibility. Description of the Drawings

[0021] Figure 1 It is the scanning electron microscope image of the material in Example 5.

[0022] Figure 2 It is the X-ray diffraction pattern of the materials in Example 5 and the comparative example.

[0023] Figure 3 Graph for comparing the rate performance of the materials in Example 5 and the comparative example.

[0024] Figure 4 Graph for comparing the cycling performance of the materials in Example 5 and the comparative example.

[0025] Figure 5 Charge-discharge curve of the materials in Example 5 and the comparative example after being exposed to air for 7 days. Detailed implementation manners

[0026] Example 1:

[0027] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.394 g of manganese sesquioxide, and 0.043 g of molybdenum trioxide, and ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0028] Example 2:

[0029] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.394 g of manganese sesquioxide, and 0.040 g of niobium pentoxide, and ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0030] Example 3:

[0031] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.394 g of manganese sesquioxide, and 0.066 g of tantalum pentoxide, and ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0032] Example 4:

[0033] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.252 g of manganese sesquioxide, and 0.158 g of titanium dioxide, and ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0034] Example 5:

[0035] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.252 g of manganese(III) oxide, 0.158 g of titanium dioxide, and 0.055 g of niobium pentoxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby. The SEM test results are as Figure 1 show that the microstructure of the obtained material is microspheres composed of nanosheet-like particles, with a size of about 20 μm. The XRD test results are as Figure 2 , where the abscissa is the 2θ angle and the ordinate is the intensity (a.u.). The XRD pattern reflects the characteristics of the crystal structure in the sample by measuring the diffraction intensity of X-rays at different angles. Comparing with the comparative example, it is found that the local enlarged view on the right focuses on the diffraction peak near the (003) crystal plane, which more clearly shows the shape and position differences of the diffraction peaks of Example 5 and the comparative example on this crystal plane, indicating that Ti and Nb are successfully incorporated into the crystal structure, and the left shift of the peak position indicates an increase in the interlayer spacing after doping.

[0036] Example 6

[0037] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.252 g of manganese(III) oxide, 0.158 g of titanium dioxide, and 0.033 g of tantalum pentoxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0038] Example 7

[0039] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.252 g of manganese(III) oxide, 0.158 g of titanium dioxide, and 0.045 g of molybdenum trioxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0040] Example 8

[0041] Take 0.556 g of sodium carbonate, 0.351 g of nickel oxide, 0.252 g of manganese(III) oxide, 0.158 g of titanium dioxide, and 0.033 g of tungsten trioxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0042] Example 9

[0043] Take 0.556 g of sodium carbonate, 0.358 g of nickel oxide, 0.315 g of manganese(III) oxide, 0.123 g of zirconium dioxide, and 0.0213 g of niobium pentoxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0044] Example 10

[0045] Take 0.556 g of sodium carbonate, 0.358 g of nickel oxide, 0.355 g of manganese(III) oxide, 0.039 g of titanium dioxide, and 0.0213 g of niobium pentoxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0046] Example 11

[0047] Take 0.556 g of sodium carbonate, 0.358 g of nickel oxide, 0.355 g of manganese(III) oxide, 0.039 g of titanium dioxide, and 0.044 g of tantalum pentoxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0048] Example 12

[0049] Take 0.556 g of sodium carbonate, 0.358 g of nickel oxide, 0.355 g of manganese(III) oxide, 0.039 g of titanium dioxide, and 0.029 g of molybdenum trioxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 950 °C at a rate of 5 °C / min and hold for 12 hours. After cooling, collect the black powder for standby.

[0050] Comparative Example

[0051] Take 0.556 g of sodium carbonate, 0.374 g of nickel oxide, 0.394 g of manganese(III) oxide, ball-mill and mix them for 30 minutes; then take out the powder and place it in a quartz boat. In an air atmosphere, heat it to 450 °C at a rate of 5 °C / min and hold for 5 hours, then heat it to 900 °C and hold for 12 hours. After cooling, collect the black powder for standby.

[0052] The above examples were tested as follows:

[0053] The black powder samples (active materials), acetylene black (conductive agent), and PVDF (binder) synthesized in Examples 1-9 and the comparative example were mixed evenly in N-methylpyrrolidone (NMP) according to a mass ratio of 8:1:1, then coated on aluminum foil, and dried in a vacuum drying oven at 110 °C for 10 hours. After taking out, it was cut into electrode discs with a diameter of 12 mm. Taking this as the positive electrode sheet, a sodium metal sheet was used as the counter electrode, Whatman GF / D glass fiber filter paper was used as the separator, and the electrolyte was 1 M NaClO4 dissolved in PC+FEC (volume ratio 95:5). A CR2032 type button battery was assembled in a glove box filled with argon for protection. It was tested using a LAND CT2001A type (Wuhan Blue Electric) multi-channel battery test system, with the voltage range between 2.0 - 4.2 V and the temperature at room temperature.

[0054] The rate performance graphs obtained from the electrodes prepared from the products of Example 5 and the comparative example are as Figure 3 shown, and the cycling performance graphs are as Figure 4 , and the charge-discharge curve graphs are as Figure 5 shown. Figure 3 The results in Figure 4 show that after double-site element doping of the O3-type sodium ion battery cathode material, the rate performance is greatly improved, effectively improving the conductivity of the material; Figure 5 The results in

[0055] show that after cycling 200 times under 1C conditions, the cycling capacity retention rate of Example 5 is 77% higher than 35% of the comparative example.

[0056] Example Cycling performance Rate performance Example 1 <![CDATA[30mAh g -1 at 1C (200 cycles)]]> <![CDATA[32mAh g -1 at 10C]]> Example 2 <![CDATA[50mAh g -1 at 1C (200 cycles)]]> <![CDATA[46mAh g -1 at 10C]]> Example 3 <![CDATA[52mAh g -1 at 1C (200 cycles)]]> <![CDATA[43mAh g -1 at 10C]]> Example 4 <![CDATA[50mAh g -1 at 1C (200 cycles)]]> <![CDATA[24mAh g -1 at 10C]]> Example 5 <![CDATA[69mAh g -1 at 1C (200 cycles)]]> <![CDATA[54mAh g -1 at 10C <!-- 4 -->]]> Example 6 <![CDATA[53mAh g -1 at 1C (200 cycles)]]> <![CDATA[48mAh g -1 at 10C]]> Example 7 <![CDATA[41mAh g -1 at 1C (200 cycles)]]> <![CDATA[46mAh g -1 at 10C]]> Example 8 <![CDATA[38mAh g -1 at 1C (200 cycles)]]> <![CDATA[33mAh g -1 at 10C]]> Example 9 <![CDATA[36mAh g -1 at 1C (200 cycles)]]> <![CDATA[24mAh g -1 at 10C]]> Example 10 <![CDATA[60mAh g -1 at 1C (200 cycles)]]> <![CDATA[50mAh g -1 at 10C]]> Example 11 <![CDATA[54mAh g -1 at 1C (200 cycles)]]> <![CDATA[53mAh g -1 at 10C]]> Example 12 <![CDATA[42mAh g -1 at 1C (200 cycles)]]> <![CDATA[46mAh g -1 at 10C]]> Comparative example <![CDATA[25mAh g -1 at 1C (200 cycles)]]> <![CDATA[2.1mAh g -1 at 10C]]>

[0057] Based on the above examples and comparative examples, it can be seen that after appropriate double-site metal element doping in the examples, the electronic and ionic conductivities and structural stability of the material are improved. Compared with the comparative example, NaNi 0.5-x A x Mn 0.5-y B y O2 exhibits excellent rate performance and cycling stability. From the comparison of the data in the table, it can be seen that after 200 cycles, the reversible specific capacity of the cathode material in Example 5 is 69 mAh g -1 , much higher than 25 mAh g -1 of the comparative example. From the comparison of the rate performance, under 10C conditions (1C = 200 mAg -1), the cathode material of Example 5 exhibits 54 mAh g -1 , while that of the comparative example is only 2.1 mAh g -1 .

[0058] The above embodiments are the preferred embodiments of the present invention. However, the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A double-site doped modified O3-type layered sodium ion battery positive electrode material, the chemical formula of the sodium ion battery positive electrode material is NaNi 0.5-x A x Mn 0.5-y B y O2, A represents one of Nb, Ta, Mo, and W, B represents one of Ti and Zr, x is 0.01 to 0.05, and y is 0.01 to 0.

30.

2. The sodium ion battery positive electrode material according to claim 1, characterized in that: A and B are selected from any of the following combinations: 1) A is Nb and B is Ti; 2) A is Ta, B is Ti; 3) A is Mo and B is Ti; 4) A is W, B is Ti; 5) A is Nb and B is Zr.

3. A method for preparing the dual-site doped modified O3-type layered sodium ion battery positive electrode material according to claim 1, comprising the following steps: Step 1) according to the molar ratio of each element in the chemical formula, weigh the sodium salt, nickel oxide, manganese oxide and metal oxide respectively, and ball mill for 20-60 minutes; Step 2) The above powders are fully mixed, and the mixture is pressed into a tablet at a pressure of 5-20 MPa, and then the temperature is increased to 450°C at a heating rate of 5°C / min, and then the temperature is increased to 850°C-1000°C for calcination for 15 hours, calcined in an air atmosphere, and cooled to room temperature to obtain the binary element doped modified O3 type layered sodium ion battery positive electrode material.

4. The method according to claim 3, characterized in that: The sodium salt in step 1) is anhydrous sodium carbonate.

5. The method according to claim 3, characterized in that: The manganese oxide is one of manganese dioxide and manganese trioxide, and the nickel oxide is nickel monoxide.

6. The method according to claim 3, characterized in that: In step 1), any one of niobium pentoxide, tantalum pentoxide, molybdenum trioxide or tungsten trioxide is used as the metal oxide, and any one of titanium dioxide or zirconium dioxide is added as the metal oxide; Nb, Ta, Mo or W is used to replace part of Ni, and Ti or Zr ions are used to replace Mn to form dual metal doping.

7. The method according to claim 6, characterized in that: Sodium carbonate, nickel oxide, manganese trioxide, niobium pentoxide and titanium dioxide are ground and mixed; then taken out and calcined in air atmosphere, and collected after cooling to obtain the product.

8. Use of the dual-site doped modified O3-type layered sodium ion battery positive electrode material according to claim 1 for preparing button batteries.

9. The use according to claim 8, wherein the preparation of the button battery comprises the following steps: The invention discloses an O3-type layered sodium ion battery cathode material modified by doping with bimetallic elements as active material, acetylene black as conductive agent, polyvinylidene fluoride as binder, which are uniformly mixed in a mass ratio of 8:1:1-7:2:1, and coated on aluminum foil with dimethyl pyrrolidone as solvent, and cut into electrode sheets after vacuum drying, wherein a metal sodium sheet is used as counter electrode, Whatman GF / D is used as diaphragm, 1M sodium perchlorate dissolved in propylene carbonate and fluoroethylene carbonate is used as electrolyte, and the battery is assembled in an argon-filled glove box, and the voltage window is 2.0-4.2V.

10. The use according to claim 9, wherein A is Nb and B is Ti in the dual-site doped modified O3-type layered sodium ion battery positive electrode material.

Images