A composite multi-element sodium ion battery positive electrode material and preparation method thereof

Abstract

The present invention discloses a composite multi-element sodium ion battery positive electrode material and a preparation method thereof, which relates to the technical field of sodium battery positive electrode materials, including a component having the following chemical formula: Na x Mn a Ni b Fe c M d O 2‑z N z , 0.67≤x≤0.9, 0<z≤0.05, a+b+c+d=1, M represents a composite of at least one element among Ti, Mg, Co, and Cu with Ag, Sr, Ga, or a rare earth element; N represents a composite of F, B, and P. The composite multi-element sodium ion battery positive electrode material disclosed in the present invention has excellent storage stability, cycle performance and electrochemical properties, and high charge and discharge specific capacity and efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium-ion battery electrode materials, and particularly to a composite multi-element sodium-ion battery cathode material and a preparation method thereof. Background Art

[0002] Due to its rich sodium content and working principle similar to commercial lithium-ion batteries, sodium-ion batteries have been continuously concerned in large-scale energy storage and are widely regarded as an effective alternative or supplement to lithium-ion batteries. In sodium-ion batteries, the cathode material is an important part of the sodium battery, which plays a decisive role in improving electrochemical performance, enhancing energy density, and reducing the cost of the entire battery. Developing low-cost and high-performance cathode materials is one of the keys to promoting the industrialization of sodium-ion batteries.

[0003] Sodium-ion cathode materials mainly include transition metal oxides, polyanions, and other materials (Prussian blue, organic molecules, polymers, etc.). Due to the excellent properties of transition metal oxides such as high energy density, high discharge voltage, and high reversible cycle performance, they have been widely studied in the academic community. However, the existing transition metal oxide-based cathode materials have a series of problems such as low specific capacity, low cycle efficiency, and poor conductivity due to their own structural characteristics and instability. In addition, the disadvantages of poor storage stability in air and easy occurrence of serious interfacial side reactions in electrolytes for commercially available transition metal oxides result in severe capacity decay during long cycling and high-current charge-discharge processes, that is, the cycle performance and rate performance are difficult to meet the requirements of commercial applications.

[0004] To solve the above problems, the Chinese invention patent with the application publication number CN115692684A discloses a multi-element composite cathode material, a preparation method thereof, and a battery. It is used to solve the problems of poor storage stability and cycle performance of the cathode material of sodium-ion batteries in related technologies. A multi-element composite cathode material, the chemical formula of this multi-element composite cathode material is Na x Ni y Fe z Mn u Bi v Cs w [[ID=,26]]O2; wherein, 0.6 ≤ x ≤ 1.0, 0 < y ≤ 0.8, 0 < z ≤ 0.8, 0 < u ≤ 0.8, 0 ≤ v ≤ 0.2, 0 ≤ w ≤ 0.2, and v and w are not both 0. The capacity and cycle stability of this sodium-ion battery cathode material have both been improved. However, there is still room for further improvement in these performances.

[0005] It can be seen that the development of composite multi-element sodium ion battery positive electrode materials and their preparation methods with good storage stability, good cycle performance and electrochemical properties, high charge and discharge specific capacity and efficiency meet market demand, have high market value and application prospects, and are of great significance to promoting the development of sodium ion battery positive electrode materials. Summary of the Invention

[0006] The main purpose of the present invention is to solve the above technical problems and provide a composite multi-element sodium ion battery positive electrode material and a preparation method thereof with good storage stability, excellent cycle performance and electrochemical performance, high charge and discharge specific capacity and efficiency.

[0007] To achieve the above objectives, the present invention provides a composite multi-element sodium ion battery cathode material, comprising components having the following chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , 0.67≤x≤0.9, 0<z≤0.05, a+b+c+d=1, M represents a combination of at least one element among Ti, Mg, Co, Cu and Ag, Sr, Ga, and rare earth elements; N represents a combination of F, B, and P.

[0008] Preferably, the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of (2-3):(1-2):(0.8-1.2).

[0009] Preferably, x=0.7, and a:b:c=0.6:0.2:(0.12-0.15).

[0010] Another object of the present invention is to provide a method for preparing the composite multi-element sodium ion battery positive electrode material, comprising the following steps:

[0011] Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture;

[0012] Step S2, adding the mixture into a high-speed ball mill and ball milling;

[0013] Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

[0014] Preferably, the iron source in step S1 is at least one of ferroferric oxide, ferrous oxide, and ferric oxide.

[0015] Preferably, the sodium source in step S1 is sodium carbonate.

[0016] Preferably, the manganese source in step S1 is at least one of manganese oxide, manganese dioxide, dimanganese trioxide, and trimanganese tetraoxide.

[0017] Preferably, the nickel source in step S1 is at least one of nickel oxide and nickel hydroxide.

[0018] Preferably, the M source in step S1 is a mixture of at least one of titanium dioxide, magnesium oxide, cobalt oxide, copper oxide, silver oxide, strontium oxide, gallium oxide and rare earth oxide.

[0019] Preferably, the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide.

[0020] Preferably, the mass ratio of the silver oxide, strontium oxide, gallium oxide, rare earth oxide and mixture is (0.1-0.3):0.1:(0.1-0.2):0.15:(3-5).

[0021] Preferably, the nitrogen source is tri-tert-butylphosphine tetrafluoroborate.

[0022] Preferably, the ball milling speed in step S2 is 300 r / min-600 r / min, and the time is 1 h-3 h.

[0023] Preferably, the sintering in step S3 is carried out in air at a temperature of 850-1000° C. and for a time of 9-16 hours.

[0024] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0025] (1) The preparation method of the composite multi-element sodium ion battery positive electrode material disclosed in the present invention can be completed by ball milling and sintering, does not require special equipment, has low requirements on reaction conditions and environment, has high preparation efficiency and yield, is suitable for efficient large-scale industrial production, and has high promotion and application value.

[0026] (2) The composite multi-element sodium ion battery positive electrode material disclosed in the present invention includes components having the following chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z, 0.67≤x≤0.9, 0<z≤0.05, a+b+c+d=1, M represents a combination of at least one of Ti, Mg, Co, and Cu with Ag, Sr, Ga, or a rare earth element; N represents a combination of F, B, and P. The interaction between these elements results in a cathode material with high energy density, excellent storage stability, superior cycling and electrochemical performance, and high charge-discharge capacity and efficiency, effectively meeting the needs of the battery market for logistics vehicles, 3C mobile electronics, and other applications.

[0027] (3) In the composite multi-element sodium ion battery cathode material disclosed in the present invention, the added M represents a composite of at least one element selected from Ti, Mg, Co, and Cu with Ag, Sr, Ga, and rare earth elements; and N represents a composite of F, B, and P. The co-incorporation of these elements can better stabilize the crystal structure of the cathode material and reduce phase transitions; significantly increase the redox potential of the cathode material, thereby increasing capacity; and improve the electrochemical performance of the cathode material, thereby increasing the cycle capacity retention rate and initial charge and discharge efficiency.

[0028] (4) The composite multi-element sodium ion battery positive electrode material disclosed in the present invention has more stable structural performance through the rational selection of raw materials and process parameters, and the cycle stability and high rate performance in the electrochemical sodium storage process are further improved. DETAILED DESCRIPTION

[0029] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations. Example 1

[0030] A composite multi-element sodium ion battery cathode material, comprising components having the following general chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , z=0.01, a+b+c+d=1, M represents a composite of Mg, Cu, Ag, Sr, Ga, and rare earth elements; N represents a composite of F, B, and P; the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of 2:1:0.8; x=0.7, and a:b:c=0.6:0.2:0.12.

[0031] A method for preparing the composite multi-element sodium ion battery positive electrode material comprises the following steps:

[0032] Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture;

[0033] Step S2, adding the mixture into a high-speed ball mill and ball milling;

[0034] Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

[0035] In step S1, the iron source is ferric oxide; the sodium source is sodium carbonate; the manganese source is manganese tetraoxide; and the nickel source is nickel oxide.

[0036] In step S1, the M source is a mixture of magnesium oxide, copper oxide, silver oxide, strontium oxide, gallium oxide and rare earth oxides; the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide; the mass ratio of the silver oxide, strontium oxide, gallium oxide and rare earth oxide mixture is 0.1:0.1:0.1:0.15:3; the molar ratio of magnesium oxide to copper oxide is 5:3; and the N source is tri-tert-butylphosphine tetrafluoroborate.

[0037] The ball milling in step S2 is performed at a speed of 300 r / min for 1 h. The sintering in step S3 is performed at a temperature of 850° C. for 9 h in air. Example 2

[0038] A composite multi-element sodium ion battery cathode material, comprising components having the following general chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , z=0.02, a+b+c+d=1, M represents a composite of Mg, Ag, Sr, Ga, and rare earth elements; N represents a composite of F, B, and P; the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of 2.2:1.2:0.9; x=0.7, and a:b:c=0.6:0.2:0.13.

[0039] A method for preparing the composite multi-element sodium ion battery positive electrode material comprises the following steps:

[0040] Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture;

[0041] Step S2, adding the mixture into a high-speed ball mill and ball milling;

[0042] Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

[0043] In step S1, the iron source is ferric oxide; the sodium source is sodium carbonate; the manganese source is manganese tetraoxide; the nickel source is nickel oxide; the M source is a mixture of magnesium oxide, silver oxide, strontium oxide, gallium oxide and rare earth oxides; the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide; the mass ratio of the silver oxide, strontium oxide, gallium oxide, rare earth oxide and mixture is 0.15:0.1:0.12:0.15:3.5; and the N source is tri-tert-butylphosphine tetrafluoroborate.

[0044] The ball milling in step S2 is performed at a rotation speed of 400 r / min for 1.5 h. The sintering in step S3 is performed at a temperature of 900° C. for 11 h in air. Example 3

[0045] A composite multi-element sodium ion battery cathode material, comprising components having the following general chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , z=0.03, a+b+c+d=1, M represents a composite of Ti, Ag, Sr, Ga, and rare earth elements; N represents a composite of F, B, and P; the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of 2.5:1.5:1; x=0.7, and a:b:c=0.6:0.2:0.13.

[0046] A method for preparing the composite multi-element sodium ion battery positive electrode material comprises the following steps:

[0047] Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture;

[0048] Step S2, adding the mixture into a high-speed ball mill and ball milling;

[0049] Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

[0050] In step S1, the iron source is ferric oxide; the sodium source is sodium carbonate; the manganese source is manganese tetraoxide; the nickel source is nickel oxide; the M source is a mixture of titanium dioxide, silver oxide, strontium oxide, gallium oxide and rare earth oxides; the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide; the mass ratio of the silver oxide, strontium oxide, gallium oxide, rare earth oxide and mixture is 0.2:0.1:0.15:0.15:4; and the N source is tri-tert-butylphosphine tetrafluoroborate.

[0051] The ball milling in step S2 is performed at a rotation speed of 450 r / min for 2 h. The sintering in step S3 is performed at a temperature of 930° C. for 13 h in air. Example 4

[0052] A composite multi-element sodium ion battery cathode material, comprising components having the following general chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , z=0.04, a+b+c+d=1, M represents a composite of Co, Cu, Ag, Sr, Ga, and rare earth elements; N represents a composite of F, B, and P; the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of 2.8:1.8:1.1; x=0.7, and a:b:c=0.6:0.2:0.14.

[0053] A method for preparing the composite multi-element sodium ion battery positive electrode material comprises the following steps:

[0054] Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture;

[0055] Step S2, adding the mixture into a high-speed ball mill and ball milling;

[0056] Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

[0057] In step S1, the iron source is ferric oxide; the sodium source is sodium carbonate; the manganese source is manganese tetraoxide; the nickel source is nickel oxide; the M source is a mixture of cobalt oxide, copper oxide, silver oxide, strontium oxide, gallium oxide and rare earth oxides; the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide; the mass ratio of the silver oxide, strontium oxide, gallium oxide, rare earth oxide and mixture is 0.25:0.1:0.18:0.15:4.5; the molar ratio of the cobalt oxide and copper oxide is 3:5; and the N source is tri-tert-butylphosphine tetrafluoroborate.

[0058] The ball milling in step S2 is performed at a rotation speed of 550 r / min for 2.5 h. The sintering in step S3 is performed at a temperature of 960° C. for 14 h in air. Example 5

[0059] A composite multi-element sodium ion battery cathode material, comprising components having the following general chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , z=0.05, a+b+c+d=1, M represents a composite of Cu, Ag, Sr, Ga, and rare earth elements; N represents a composite of F, B, and P; the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of 3:2:1.2; x=0.7, and a:b:c=0.6:0.2:0.15.

[0060] A method for preparing the composite multi-element sodium ion battery positive electrode material comprises the following steps:

[0061] Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture;

[0062] Step S2, adding the mixture into a high-speed ball mill and ball milling;

[0063] Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

[0064] In step S1, the iron source is ferric oxide; the sodium source is sodium carbonate; the manganese source is manganese tetraoxide; the nickel source is nickel oxide; the M source is a mixture of copper oxide, silver oxide, strontium oxide, gallium oxide and rare earth oxides; the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide; the mass ratio of the silver oxide, strontium oxide, gallium oxide, rare earth oxide and mixture is 0.3:0.1:0.2:0.15:5; and the N source is tri-tert-butylphosphine tetrafluoroborate.

[0065] The ball milling in step S2 is performed at a rotation speed of 600 r / min for 3 h; and the heat preservation sintering in step S3 is performed at a temperature of 1000° C. for 16 h in air.

[0066] Comparative Example 1

[0067] The present invention provides a composite multi-element sodium ion battery positive electrode material, the formula and preparation method of which are similar to those of Example 1, except that strontium oxide, gallium oxide and N source are not added.

[0068] Comparative Example 2

[0069] The present invention provides a composite multi-element sodium ion battery positive electrode material, the formula and preparation method of which are similar to those of Example 1, except that no silver oxide and rare earth oxide are added.

[0070] In order to further illustrate the beneficial technical effects of the composite multi-element sodium ion battery positive electrode material prepared in each embodiment of the present invention, the composite multi-element sodium ion battery positive electrode material prepared in each example was ground and mixed with a conductive agent Super P and a binder PVDF in a mass ratio of 85:5:10. NMP was added to prepare a slurry with a solid-liquid ratio of 30% and magnetically stirred for 1 hour. After the slurry was uniformly mixed, the slurry was drawn onto a 15 μm thick aluminum foil to form a positive electrode sheet. In an argon glove box, a metal sodium sheet was used as the negative electrode, a Celgard 2400 type diaphragm was used as the diaphragm, and 1 mol / L NaPF6 / PC was used as the electrolyte to assemble a CR2032 button cell. At 25°C, room temperature charge and discharge were carried out in a voltage range of 2.0 to 4.4 V and a current density of 0.1C, and the first discharge specific capacity was recorded. At 25°C, charge to 4.4V at 1C constant current, constant voltage until the current drops to 0.05C, let it stand for 5 minutes, then discharge to 3.0V at 1C constant current, let it stand for 5 minutes, and cycle for 200 cycles. The battery capacity retention rate = discharge capacity in the 200th week / discharge capacity in the first week × 100%. At room temperature, charge to 4.4V at 1C constant current, constant voltage to 0.05C, let it stand for 1 hour, measure the internal resistance, and then place it in a 60°C constant temperature box. After standing for 30 days, measure the internal resistance at high temperature, cool to room temperature, charge to 4.4V at 0.2C constant current, then constant voltage to 0.05C, let it stand for 5 minutes, and then discharge to 3.0V at 0.2C, and record the discharge capacity. Capacity retention rate = discharge capacity after storage / discharge capacity before storage × 100%; internal resistance change rate = (internal resistance after storage - internal resistance before storage) / internal resistance before storage × 100%. The test results are shown in Table 1.

[0071] Table 1

[0072]

[0073] As can be seen from Table 1, the sodium ion battery using the composite multi-element sodium ion battery positive electrode material disclosed in the embodiment of the present invention has better electrochemical performance, high temperature storage performance and cycle performance than the comparative example product; the addition of strontium oxide, gallium oxide, N source, silver oxide and rare earth oxide is beneficial to improving the above performance.

[0074] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite multi-element sodium ion battery positive electrode material, characterized in that: It includes components having the following general chemical formula: Na x Mn a Ni b Fe c M d O 2-z N z , 0.67≤x≤0.9, 0<z≤0.05, a+b+c+d=1, M represents a composite of at least one element among Ti, Mg, Co, Cu and Ag, Sr, Ga, and rare earth elements; N represents a composite of F, B, and P; the rare earth elements are a composite of Pr, Nd, and Gd in a molar ratio of (2-3):(1-2):(0.8-1.2).

2. The composite multi-element sodium ion battery positive electrode material according to claim 1, characterized in that The x=0.7, and the a:b:c=0.6:0.2:(0.12-0.15).

3. A method for preparing the composite multi-element sodium ion battery positive electrode material according to any one of claims 1-2, characterized in that: The steps include: Step S1, using an iron source, a sodium source, a manganese source, a nickel source, an M source, and a N source as raw materials, preparing the ingredients according to a set ratio, and mixing them uniformly to obtain a mixture; Step S2, adding the mixture into a high-speed ball mill and ball milling; Step S3: sintering the ball-milled mixture in a muffle furnace at a high temperature, and obtaining a composite multi-element sodium ion battery positive electrode material after cooling.

4. The method for preparing the composite multi-element sodium ion battery positive electrode material according to claim 3, characterized in that: In step S1, the iron source is at least one of ferroferric oxide, ferrous oxide, and ferric oxide; the sodium source is sodium carbonate; the manganese source is at least one of manganese oxide, manganese dioxide, manganese trioxide, and manganese tetraoxide; and the nickel source is at least one of nickel oxide and nickel hydroxide.

5. The method for preparing the composite multi-element sodium ion battery positive electrode material according to claim 3, characterized in that: The M source in step S1 is a mixture of at least one of titanium dioxide, magnesium oxide, cobalt oxide, copper oxide, silver oxide, strontium oxide, gallium oxide and rare earth oxides; the rare earth oxides include praseodymium oxide, neodymium oxide and gadolinium oxide.

6. The method for preparing a composite multi-element sodium ion battery positive electrode material according to claim 5, characterized in that: The mass ratio of the silver oxide, strontium oxide, gallium oxide, rare earth oxide and the mixture is (0.1-0.3):0.1:(0.1-0.2):0.15:(3-5).

7. The method for preparing a composite multi-element sodium ion battery positive electrode material according to claim 3, characterized in that: The nitrogen source is tri-tert-butylphosphine tetrafluoroborate.

8. The method for preparing a composite multi-element sodium ion battery positive electrode material according to claim 3, characterized in that: The ball milling speed in step S2 is 300 rpm to 600 rpm, and the time is 1 h to 3 h.

9. The method for preparing a composite multi-element sodium ion battery positive electrode material according to claim 3, characterized in that: The temperature of the heat preservation sintering in step S3 is 850-1000° C., the time is 9-16 hours, and it is carried out in air.

Images