WO2024040925A1

WO2024040925A1 - Vacancy-type sodium ion positive electrode material, preparation method therefor, and use thereof

Info

Publication number: WO2024040925A1
Application number: PCT/CN2023/080770
Authority: WO
Inventors: 庄志; 邓城; 吴惠康; 袁远; 郑田瑞; 卢鹏; 刘倩倩; 蔡裕宏; 程跃
Original assignee: 上海恩捷新材料科技有限公司
Priority date: 2022-08-26
Filing date: 2023-03-10
Publication date: 2024-02-29
Also published as: CN115275180A

Abstract

The present invention provides a vacancy-type sodium ion positive electrode material having an O3 phase, an R-3m space group, and a chemical general formula of Na_aNi_bMn_cLi_dM_eO_2+f, wherein M is at least one of Co, Cr, V, Al, Fe, Sn, B, Cu, Ti, Mg, and Zn, 0.9≤a<1, 0<b<0.6, 0<c<0.8, 0<d<0.3, -0.04≤f ≤0.04, b+c+d+e=1, and the material is electrically neutral. In addition, the present invention further provides a preparation method for the vacancy-type sodium ion positive electrode material and a use of the vacancy-type sodium ion positive electrode material in sodium ion batteries.

Description

Vacancy type sodium ion cathode material and its preparation method and application

Technical field

The present invention relates to the technical field related to materials, and particularly relates to a vacancy-type sodium ion positive electrode material and its preparation method and application.

Background technique

With the continued development of clean energy sources such as solar energy, tidal energy, and wind energy, the technological iteration of energy storage batteries is particularly important. Lead-acid batteries are cheap, but their energy density and cycle life limit their development and market share in the energy storage field; lithium-ion batteries have high energy density and long cycle life, but have shortcomings such as high price, poor safety, and high dependence on imported lithium resources. . There is huge demand for lithium-ion batteries in the power, 3C and energy storage fields. Even if all lithium is used to make lithium-ion batteries, there is still a huge gap. Therefore, the development of other forms of electrochemical energy storage solutions is imperative and of great significance. The structures of sodium-ion batteries and lithium-ion batteries are similar, and the processes can be better compatible, which is conducive to the commercialization of sodium-ion batteries. The energy density of sodium-ion batteries is slightly lower than that of lithium-ion batteries, but its price advantage is obvious, and it has better rate performance and safety. It is suitable for use in low-speed two-wheeled vehicles, energy storage, communications and other fields.

At present, sodium ion cathode materials are mainly divided into three categories, namely layered oxides, Prussian blue and polyanionic compounds. Layered oxide has become a key material for the development of major material factories and battery core factories due to its high specific capacity, low price, high discharge voltage equalization, excellent rate performance, wide source of raw materials and environmental friendliness. Layered oxides commonly suffer from air sensitivity and short cycle life. Improving air stability and structural stability is a current research hotspot.

Contents of the invention

The O3-type sodium ion cathode material is a type of layered oxide, but its specific capacity still needs to be further improved, and there are problems such as poor air stability, poor rate performance, and multiple phase changes. High residual alkali on the surface of the material will lead to strong hygroscopicity, which will easily defluorinate the polyvinylidene fluoride PVDF during the coating process, causing the adhesive to fail. In addition, the Na layer of the O3 material has a high Na content, which easily reduces the distance between the material layers under the action of electrostatic shielding, which is not conducive to the extraction and insertion of Na and affects the rate performance. The present invention proposes improvements to address the above defects of O3-type sodium ion cathode materials.

Therefore, the present invention proposes a vacancy-type sodium ion positive electrode material, which is characterized in that the positive electrode material is O3 phase, the space group is R-3m, and the general chemical formula is Na _a Ni _b Mn _c Li _d _Me O _2+f , Where M is at least one of Co, Cr, V, Al, Fe, Sn, B, Cu, Ti, Mg, and Zn, and 0.9≤a<1, 0<b<0.6, 0<c<0.8, 0 <d<0.3, -0.04≤f≤0.04, b+c+d+e=1, and the electrical neutrality of the material is satisfied.

Preferably, 0.9≤a≤0.96, 0.2≤b≤0.43, 0.4≤c≤0.6, 0.02≤d≤0.1, 0≤e≤0.2, and/or f=0.

Preferably, M is at least one of Co, Cr, V, Al, Sn, B, Cu, Ti, Mg, and Zn.

The present invention also proposes a sodium ion battery, which is characterized by including the above-mentioned vacancy type sodium ion positive electrode material.

The present invention also proposes a method for preparing the above-mentioned vacancy type sodium ion cathode material, which is characterized by including: Na element, Ni element and Mn element in the chemical formula Na _a Ni _b Mn _c Li _d M _e O _2+f , Li element, M element atomic number ratio, weigh the appropriate amount containing Na element Compounds, compounds containing Ni element, compounds containing Mn element, compounds containing Li element, and compounds containing M element are ball-milled and mixed to obtain a mixture; and the mixture is calcined to obtain a vacancy-type sodium ion positive electrode material.

Preferably, the compound containing Ni element, the compound containing Mn element, and the compound containing M element are independently at least one of metal oxides, metal nitrates, metal sulfates, metal carbonates, and metal chlorides. .

Preferably, the compound containing Ni element, the compound containing Mn element, and the compound containing M element are metal oxides.

Preferably, the compound containing Na element is at least one of sodium carbonate, sodium hydroxide, and sodium bicarbonate.

Preferably, the compound containing Li element is at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

Preferably, the weighed amount of the compound containing Na element is 100% to 110% of the theoretical amount calculated based on the atomic ratio of Na element, Ni element, Mn element, Li element, and M element.

Preferably, the weighed amount of the compound containing Na element is 102% to 106% of the theoretical amount.

Preferably, the weighed amount of the compound containing Li element is 100% to 110% of the theoretical amount calculated based on the atomic ratio of Na element, Ni element, Mn element, Li element, and M element.

Preferably, the weighed amount of the compound containing Li element is 102% to 106% of the theoretical amount.

Preferably, the ball mill adopts wet ball milling or dry ball milling.

Preferably, the dispersion medium of wet ball milling is at least one of acetone, ethanol, ethylene glycol, and isopropyl alcohol, the ball milling speed is 100 to 1000 rpm, and/or the ball milling time is 1 to 48 hours.

Preferably, the calcination temperature is 700 to 1050°C, the calcination time is 6 to 36 hours, and/or the temperature rise rate of calcination is 1 to 20°C/minute.

The present invention further proposes a method for preparing the above-mentioned vacancy type sodium ion cathode material, which is characterized in that it includes: Na element, Ni element and Mn element according to the general chemical formula Na _a Ni _b Mn _c Li _d M _e O _2+f , Li element, M element atomic ratio. Weigh an appropriate amount of Na element-containing compounds, Ni element-containing compounds, Mn element-containing compounds, Li element-containing compounds, and M element-containing compounds. After ball milling or sand milling, mix A mixture is obtained; and after the mixture is spray-dried, it is calcined to obtain a vacancy-type sodium ion positive electrode material.

Preferably, the weighed amount of the compound containing Na element is 100% of the theoretical amount calculated based on the atomic number ratio of Na element, Ni element, Mn element, Li element, and M element. to 110%.

Preferably, the mixture is ball-milled or sand-milled until the particle size of the mixture is 0.1 to 2 μm.

The present invention further proposes a method for preparing the above-mentioned vacancy-type sodium ion cathode material, which is characterized by including: Ni element and Mn element in the chemical formula ( _Nix _Mny ) CO ₃ or ( _Nix Mn _y ) (OH) ₂ Weigh an appropriate amount of nitrate or sulfate containing Ni element and nitrate or sulfate containing Mn element and dissolve it in water, adjust the pH with precipitant and complexing agent to uniformly precipitate, and dry to obtain the precursor ( _N _{_} _{_} _{_} _{_} _{_} _{_} _{_} _{_} _{_} _{_} Weigh the atomic number ratio of Na element, Ni element, Mn element, Li element and M element in _2+f and take an appropriate amount of compounds containing Na element, compounds containing Li element, compounds containing M element and the precursor (Ni _x Mn _y )CO ₃ or ( _Nix Mn _y )(OH) ₂ is ball-milled and mixed to obtain a mixture; and the mixture is calcined to obtain a vacancy-type sodium ion positive electrode material.

Preferably, the pH value is 7.5 to 13, the complexing agent is ammonia water, the precipitating agent is sodium hydroxide or sodium carbonate, the drying temperature is 80 to 150°C, and/or the drying time is 6 to 48 hours.

Preferably, the compound containing M element is at least one of metal oxide, metal nitrate, metal sulfate, metal carbonate, and metal chloride.

Preferably, the compound containing M element is a metal oxide.

According to the present invention, a vacancy-type sodium ion cathode material is designed to address the above defects of the O3-type sodium ion cathode material. The core is to introduce appropriate Na vacancies into the O3-type material and perform Li doping to solve the problems of high surface residual alkali and poor rate. problem and further improve the material specific capacity. In addition, this cathode material has high specific capacity, good air stability, and multiple rate performance and cycling stability. Moreover, appropriate Na vacancies in the crystal structure can not only effectively improve the chemical stability of layered oxides to ambient air, but also improve the mobility of Na during the extraction/intercalation process without sacrificing capacity. In addition, Na vacancies can also increase the valence state of transition metal ions, thereby enhancing the oxidation resistance of the material and inhibiting unfavorable spontaneous reactions between the material and air. Furthermore, Li has a larger ionic radius and stronger Li-O binding energy. It can also activate lattice oxygen under high voltage and introduce O ^2- /O ^n- pairs to achieve reversible extraction/insertion, thereby improving The specific capacity of the material.

Description of drawings

Figure 1 is a scanning electron microscope (SEM) photo of the sodium ion cathode material of Example 1;

Figure 2 is a scanning electron microscope (SEM) photo of the sodium ion cathode material of Comparative Example 1;

Figure 3 is an X-ray diffraction analysis (XRD) pattern of the sodium ion cathode material of Examples 1 to 3;

Figure 4 is a first cycle capacity diagram of the batteries of Examples 2 and 4 and Comparative Example 2;

Figure 5 is a rate performance diagram of the batteries of Example 4 and Comparative Examples 2 and 3;

Figure 6 is a cycle performance diagram of the batteries of Example 3 and Comparative Examples 3 and 4.

Detailed ways

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

The endpoints of ranges and any values disclosed herein are not limited to that precise range or values, these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges. These values The scope shall be deemed to be specifically disclosed herein.

The first embodiment of the present invention refers to a vacancy-type sodium ion cathode material, which is an O3 phase, has a space group of R-3m, and a general chemical formula of Na _a Ni _b Mn _c Li _d _Me O _2+f , and satisfies The material is electrically neutral. In the general formula, a is defined as the number of atoms of Na element in one cathode material. a satisfies the following conditions: 0.9≤a<1, preferably 0.9≤a≤0.96, and more preferably a is 0.9, 0.91, One of 0.92, 0.93, and 0.96; b is defined as the number of atoms of Ni element in one cathode material, b satisfies the following conditions: 0＜b＜0.6, preferably 0.2≤b≤0.43, more preferably b is one of 0.2, 0.25, 0.3, 0.33, and 0.43; c is defined as the number of atoms of the Mn element in one cathode material, and c satisfies the following conditions: 0＜c＜0.8, preferably 0.4≤c≤0.6 , more preferably c is one of 0.4, 0.5, 0.55, and 0.6; d is defined as the number of atoms of Li element in one cathode material, and d satisfies the following conditions: 0＜d＜0.3, preferably 0.02≤ d≤0.1, more preferably d is one of 0.02, 0.03, 0.05, 0.075, and 0.1; e is defined as the number of atoms of M element in one cathode material, and e satisfies the following conditions: b+c+d+e =1, preferably 0≤e≤0.2, more preferably e is one of 0, 0.05, 0.1, 0.15, 0.17, 0.175, and 0.2; 2+f is defined as the O element in one cathode material Number of atoms, f satisfies the following conditions: -0.04≤f≤0.04, preferably satisfies the following conditions: f=0; M is defined as Co, Cr, V, Al, Fe, Sn, B, Cu, Ti, Mg, Zn At least one element in, preferably at least one element in Co, Cr, V, Al, Sn, B, Cu, Ti, Mg, Zn.

Among the above materials, the advantages of Na vacancies are as follows:

1. After the formation of Na vacancies, the valence state of the M element is higher, which improves the oxidation resistance of the material, thereby improving the air stability of the material;

2. After forming Na vacancies, it can reduce the reaction with water and CO ₂ in humid environment, reduce the amount of residual alkali on the surface, improve air stability, and improve the processing performance of the material (especially the processing performance of pulping and coating);

3. After forming Na vacancies, the migration rate of Na ⁺ can be increased, which helps to improve the rate and cycle stability of the material.

Among the above materials, the advantages of Li doping are as follows:

1. Li has a larger ionic radius than the M element. After doping, it can increase the lattice constant, which is beneficial to improving electrochemical properties, such as reducing Na ⁺ migration energy, improving rate and cycle performance;

2. The Li-O bond has a higher binding energy than the M element and oxygen, and is more stable under high voltage. It can stabilize the lattice oxygen above 4.0V and alleviate the structural damage of the material caused by high voltage;

3. After Li doping, lattice oxygen can be activated under high voltage and the O ^2- /O ^n- redox couple can be introduced to achieve high specific capacity of the material.

However, the introduction of Na vacancies or Li doping alone cannot provide high capacity, long cycle and good processing properties of the material. The comprehensive specific capacity and cycle stability provided by a single modification method are not as good as the synergistic modification effect provided by the two joint modification methods (this embodiment). Therefore, the introduction of Na vacancies or Li doping combined to exert a synergistic effect can jointly optimize the material structure.

A second embodiment of the present invention provides a sodium-ion battery, which includes a vacancy-type sodium ion cathode material, and the vacancy-type sodium ion cathode material is as described above. Preferably, the vacant sodium The ionic cathode material is mixed with a binder to form the battery cathode. Preferably, examples of the binder are at least one of SP and PVDF. Preferably, the mass ratio between the vacancy type sodium ion cathode material and the binder is (70 to 95): (5 to 30), more preferably 90:10.

The third embodiment of the present invention provides a method for preparing a vacancy-type sodium ion cathode material, and the vacancy-type sodium ion cathode material is as described above. The proposed method is a high-temperature solid-phase method, and the specific steps are as follows:

First, according to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element in the general chemical formula Na _a Ni _b Mn _c Li _d M _e O _2+f, weigh an appropriate amount of compounds containing Na element, The Ni element compound, the Mn element-containing compound, the Li element-containing compound, and the M element-containing compound are ball-milled and then mixed to obtain a mixture.

The compound containing Ni element, the compound containing Mn element, and the compound containing M element can be independently but not limited to at least one of metal oxides, metal nitrates, metal sulfates, metal carbonates, and metal chlorides. . Preferably, the compound containing Ni element, the compound containing Mn element, and the compound containing M element are independently metal oxides. For example, the compound containing Ni element is nickel oxide, and the compound containing Mn element is manganese trioxide. The compound containing Na element may be, but is not limited to, at least one of sodium carbonate, sodium hydroxide, and sodium bicarbonate. The compound containing Li element may be, but is not limited to, at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

Ball milling can be, but is not limited to, wet ball milling or dry ball milling. The dispersion medium of wet ball milling can be, but is not limited to, at least one of acetone, ethanol, ethylene glycol, and isopropyl alcohol, the ball milling speed can be, but is not limited to, 100 to 1000 rpm, and the ball milling time can be, but is not limited to, 1 to 48 hours.

Compounds containing Na element, compounds containing Ni element, compounds containing Mn element, The weighing amounts of compounds containing Li element and compounds containing M element can be adjusted according to the theoretical amounts calculated from the atomic number ratio of Na element, Ni element, Mn element, Li element, and M element. The theoretical amounts can be calculated as follows: The formula means:

The theoretical amount of a compound containing Na element = (a) x (molecular weight of a compound containing Na element) x any constant / (number of Na element atoms in a compound containing Na element);

The theoretical amount of a compound containing Ni element = (b) x (molecular weight of a compound containing Ni element) x any constant/(number of Ni element atoms in a compound containing Ni element);

The theoretical amount of a compound containing Mn element = (c) x (molecular weight of a compound containing Mn element) x any constant / (number of Mn element atoms in a compound containing Mn element);

The theoretical amount of a compound containing Li element = (d) x (molecular weight of a compound containing Li element) x any constant/(number of Li element atoms in a compound containing Li element);

The theoretical amount of a compound containing M element = (e) x (molecular weight of a compound containing M element) x any constant/(number of M element atoms in a compound containing M element);

where all arbitrary constants are the same.

The weighed amount of the compound containing Ni element, the compound containing Mn element, and the compound containing M element can be but is not limited to 100 to 110% of its theoretical amount, preferably 100%.

The weighed amount of the compound containing Na element may be, but is not limited to, 100 to 110% of its theoretical amount, preferably 102% to 106%.

The weighed amount of the compound containing Li element may be, but is not limited to, 100 to 110% of its theoretical amount, preferably 102% to 106%.

Next, the mixture is calcined to obtain a vacancy-type sodium ion cathode material. Generally speaking, the calcination temperature can be, but is not limited to, 700 to 1050°C, and the calcination time can be, but is not limited to, 6 to 36 hours, the temperature rise rate of calcination may be, but is not limited to, 1 to 20°C/minute. In addition, after calcination and cooling, crushing, grinding, and sieving can be carried out to make the particle size of the vacancy-type sodium ion cathode material uniform.

The fourth embodiment of the present invention provides a method for preparing a vacancy-type sodium ion cathode material, and the vacancy-type sodium ion cathode material is as described above. The proposed method is spray drying, and the specific steps are as follows:

First, according to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element in the general chemical formula Na _a Ni _b Mn _c Li _d M _e O _2+f, weigh an appropriate amount of compounds containing Na element, Ni element compounds, Mn element-containing compounds, Li element-containing compounds, and M element-containing compounds are ball-milled or sand-milled, and then mixed to obtain a mixture.

The compound containing Ni element, the compound containing Mn element, and the compound containing M element can independently be, but are not limited to, at least one of metal oxides, metal nitrates, metal sulfates, metal carbonates, and metal chlorides. . Preferably, the compound containing Ni element, the compound containing Mn element, and the compound containing M element are independently metal oxides. For example, the compound containing Ni element is nickel oxide, and the compound containing Mn element is manganese trioxide. The compound containing Na element may be, but is not limited to, at least one of sodium carbonate, sodium hydroxide, and sodium bicarbonate. The compound containing Li element may be, but is not limited to, at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

Ball milling or sand milling may be performed until the particle size of the mixture is, but is not limited to, 0.1 to 2 μm.

The weighing amounts of compounds containing Na element, compounds containing Ni element, compounds containing Mn element, compounds containing Li element and compounds containing M element can be measured according to the values of Na element, Ni element, Mn element, Li element and M element. The theory obtained by calculating the atomic number ratio The theoretical quantities can be expressed by the following formulas:

where all arbitrary constants are the same.

Next, the mixture is spray-dried and then calcined to obtain a vacancy-type sodium ion cathode material. Generally speaking, the calcination temperature may be, but is not limited to, 700 to 1050°C, the calcination time may be, but is not limited to, 6 to 36 hours, and the temperature rise rate of calcination may be, but is not limited to, 1 to 20°C/minute. In addition, after calcination and cooling, it can be crushed, ground, and screened to make the vacancy-type sodium ion positive electrode The particle size of the material is uniform.

The fifth embodiment of the present invention provides a method for preparing a vacancy-type sodium ion cathode material, and the vacancy-type sodium ion cathode material is as described above. The proposed method is a co-precipitation method, and the specific steps are as follows:

First, according to the atomic number ratio of Ni element to Mn element in the chemical formula ( _Nix Mn _y ) _CO3 or ( _Nix Mn _y )(OH) ₂ , weigh an appropriate amount of nitrate or sulfate containing Ni element and Mn element The nitrate or sulfate is dissolved in water, the pH is adjusted with a precipitant and a complexing agent to uniformly precipitate, and the precursor ( _Nix Mn _y )CO ₃ or ( _Nix Mn _y ) (OH) ₂ is obtained by drying. In the chemical formula, x and y satisfy the following conditions: x:y=b:c, and x+y=1. Generally speaking, the pH value can be but not limited to 7.5 to 13, the complexing agent can be but is not limited to ammonia water, the precipitating agent can be but is not limited to sodium hydroxide or sodium carbonate, and the drying temperature can be but is not limited to 80 to 150°C. , the drying time can be but is not limited to 6 to 48 hours.

Then, according to the atomic number ratio of the Na element, Ni element, Mn element, Li element, and M element in the general chemical formula Na _a Ni _b Mn _c Li _d _Me O _2+f, weigh an appropriate amount of the compound containing the Na element, and the compound containing the Na element. The compound of Li element, the compound containing M element, and the precursor ( _NixMny ) _CO3 or ( _NixMny ₎ (OH) ₂ are ball _- milled and then mixed to obtain a mixture.

The compound containing M element may be, but is not limited to, at least one of metal oxide, metal nitrate, metal sulfate, metal carbonate, and metal chloride. Preferably, the compound containing M element is a metal oxide. The compound containing Na element may be, but is not limited to, at least one of sodium carbonate, sodium hydroxide, and sodium bicarbonate. The compound containing Li element may be, but is not limited to, at least one of lithium carbonate, lithium hydroxide, and lithium acetate.

The theoretical quantity of precursor ( _Nix Mn _y )CO ₃ or ( _Nix Mn _y ) (OH) ₂ = (b)x (precursor ( _Nix Mn _y )CO ₃ or ( _Nix Mn _y ) (OH) Molecular weight of ₂ ) x any constant/(x) or (c)x (molecular weight of precursor (Ni _x Mn _y ) CO ₃ or (Ni _x Mn _y ) (OH) ₂ ) x any constant/(y);

where all arbitrary constants are the same.

Then, the mixture is calcined to obtain a vacancy-type sodium ion cathode material. Generally speaking, the calcination temperature may be, but is not limited to, 700 to 1050°C, the calcination time may be, but is not limited to, 6 to 36 hours, and the temperature rise rate of calcination may be, but is not limited to, 1 to 20°C/minute.

The invention is illustrated by the following examples:

Example 1

In this embodiment, the cathode material Na _0.9 Mn _0.6 Ni _0.25 Li _0.05 Cu _0.1 O ₂ is prepared. The description is as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, and copper oxide according to the stoichiometric ratio of the chemical formula Na _0.9 Mn _0.6 Ni _0.25 Li _0.05 Cu _0.1 O ₂ , where sodium carbonate and lithium carbonate are the theoretical addition amounts. 104%, put the above raw materials into a ball mill and mechanically ball mill for 6 hours, and the ball milling speed is 350 rpm.

The ball-milled mixture is calcined in a high-temperature furnace at 875°C. The calcining time is 12 hours and the temperature rise rate is 3°C/minute. After cooling, grinding, and passing through a 300-mesh sieve, the cathode material is obtained (as shown in Figure 1). .

The cathode material prepared above was pulped with SP and PVDF at a mass ratio of 90:5:5. After coating, drying, and cutting, it was used as a cathode, and assembled into a button cell to evaluate its electrochemical performance.

Example 2

In this embodiment, the cathode material Na _0.92 Mn _0.5 Ni _0.25 Li _0.075 Cu _0.125 Mg _0.05 O ₂ is prepared. The description is as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, copper oxide, and magnesium oxide according to the stoichiometric ratio of the chemical formula Na _0.92 Mn _0.5 Ni _0.25 Li _0.075 Cu _0.125 Mg _0.05 O ₂ , among which sodium carbonate and lithium carbonate To be 102% of the theoretical addition amount, put the above raw materials into a ball mill and mechanically ball mill for 2 hours, and the ball milling speed is 500 rpm.

The ball-milled mixture is calcined in a high-temperature furnace at 875°C. The calcining time is 12 hours and the temperature rise rate is 3°C/minute. After cooling, grinding, and passing through a 300-mesh sieve, the positive electrode is obtained. Material.

Example 3

In this embodiment, the cathode material Na _0.96 Mn _0.6 Ni _0.2 Li _0.05 Sn _0.1 Ti _0.05 O ₂ is prepared. The description is as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, tin dioxide, and titanium dioxide according to the stoichiometric ratio of the chemical formula Na _0.96 Mn _0.6 Ni _0.2 Li _0.05 Sn _0.1 Ti _0.05 O ₂ , among which sodium carbonate and lithium carbonate It is 106% of the theoretical addition amount. The above raw materials are put into a sand mill and mechanically ground until the particle size is 0.2 μm, and then spray-dried.

The spray-dried mixture was calcined in a high-temperature furnace at 900°C. The calcining time was 10 hours and the heating rate was 5°C/minute. The cathode material was obtained after cooling, grinding, and passing through a 300-mesh sieve.

Example 4

In this embodiment, the cathode material Na _0.93 Mn _0.5 Ni _0.25 Li _0.05 Ti _0.1 Mg _0.1 O ₂ is prepared. The description is as follows:

Weigh appropriate amounts of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, titanium dioxide, and magnesium oxide according to the stoichiometric ratio of the chemical formula Na _0.93 Mn _0.5 Ni _0.25 Li _0.05 Ti _0.1 Mg _0.1 O ₂ , The sodium carbonate and lithium carbonate are 101% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

The ball-milled mixture is calcined in a high-temperature furnace at 950°C. The calcining time is 10 hours and the temperature rise rate is 3°C/minute. The cathode material is obtained after cooling, grinding, and passing through a 300-mesh sieve.

Example 5

In this example, the cathode material Na _0.91 Mn _0.5 Ni _0.25 Li _0.05 Co _0.1 Cr _0.1 O ₂ is prepared. The description is as follows:

According to the atomic number ratio of Ni element and Mn element in the chemical formula (Ni _0.333 Mn _0.667 ) CO ₃ , weigh an appropriate amount of nickel sulfate and manganese sulfate and dissolve it in water. Use sodium carbonate precipitant and ammonia water complexing agent to adjust the pH to make it precipitate evenly. Dry to _obtain _the precursor ₍ Ni _0.333 Mn _0.667 ₎ CO _3. Weigh sodium carbonate, ₍ _Ni _0.333 _{Mn 0.667} ₎ CO ₃ precursor, and Lithium carbonate, cobalt tetroxide and chromium oxide are ball milled to obtain a mixture, and the mixture is calcined to obtain a vacancy-type sodium ion cathode material. The sodium carbonate and lithium carbonate are 103% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

The ball-milled mixture is calcined in a high-temperature furnace at 900°C. The calcining time is 10 hours and the temperature rise rate is 3°C/minute. The cathode material is obtained after cooling, grinding, and passing through a 300-mesh sieve.

Example 6

In this embodiment, the cathode material Na _0.9 Mn _0.55 Ni _0.33 Li _0.02 B _0.05 Zn _0.05 O ₂ is prepared. The description is as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, boron oxide, and zinc oxide according to the stoichiometric ratio of the chemical formula Na _0.9 Mn _0.55 Ni _0.33 Li _0.02 B _0.05 Zn _0.05 O ₂ , among which sodium carbonate and lithium carbonate It is 103% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

Example 7

In this embodiment, the cathode material Na _0.9 Mn _0.55 Ni _0.33 Li _0.02 V _0.05 Zn _0.05 O ₂ is prepared. The description is as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, vanadium pentoxide, and zinc oxide according to the stoichiometric ratio of the chemical formula Na _0.9 Mn _0.55 Ni _0.33 Li _0.02 V _0.05 Zn _0.05 O ₂ , in which sodium carbonate and Lithium carbonate is 103% of the theoretical addition amount. Put the above raw materials into the ball mill. Medium mechanical ball milling for 2 hours, ball milling speed 500rpm.

Example 8

In this embodiment, the cathode material Na _0.93 Mn _0.4 Ni _0.43 Li _0.02 Ti _0.15 O ₂ is prepared. The description is as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate and titanium dioxide according to the stoichiometric ratio of the chemical formula Na _0.93 Mn _0.4 Ni _0.43 Li _0.02 Ti _0.15 O ₂ , where sodium carbonate is 103% of the theoretical addition amount, and The above raw materials are put into a sand mill and mechanically ground to a particle size of 0.2 μm and then spray-dried.

Example 9

In this embodiment, the cathode material Na _0.9 Mn _0.6 Ni _0.3 Li _0.1 O ₂ is prepared. The description is as follows:

According to the chemical formula (Ni _0.333 Mn _0.667 ), the atomic number ratio of Ni element to Mn element in CO ₃ Weigh an appropriate amount of nickel sulfate and manganese sulfate and dissolve it in water, adjust the pH with sodium carbonate precipitant and ammonia complexing agent to precipitate evenly, and dry to obtain the precursor (Ni _0.333 Mn _0.667 )CO ₃ , according to the general chemical formula Na _0.9 Mn The element ratio in _0.6 Ni _0.3 Li _0.1 O ₂ is measured by weighing sodium carbonate, (Ni _0.333 Mn _0.667 ) CO ₃ precursor and lithium carbonate and ball milling to obtain a mixture, and then calcining the mixture to obtain a vacancy-type sodium ion cathode material. The sodium carbonate and lithium carbonate are 103% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

Example 10

In this embodiment, the cathode material Na _0.9 Mn _0.5 Ni _0.3 Al _0.15 Li _0.05 O ₂ is prepared. The description is as follows:

According to the atomic number ratio of Ni element and Mn element in the chemical formula (Ni _0.375 Mn _0.625 ) CO ₃ , weigh an appropriate amount of nickel sulfate and manganese sulfate and dissolve it in water. Use sodium carbonate precipitant and ammonia water complexing agent to adjust the pH to make it precipitate evenly. Dry to obtain the precursor (Ni _0.375 Mn _0.625 )CO _3. According to the general chemical formula Na _0.9 Mn _0.5 Ni _0.3 Al _0.15 Li _0.05 O ₂ , weigh sodium carbonate, (Ni _0.375 Mn _0.625 ) CO ₃ precursor, and lithium carbonate. After ball milling with alumina, a mixture is obtained, and the mixture is calcined to obtain a vacancy-type sodium ion cathode material. The sodium carbonate and lithium carbonate are 103% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

Example 11

According to the atomic number ratio of Ni element and Mn element in the chemical formula (Ni _0.333 Mn _0.667 ) CO ₃ , weigh an appropriate amount of nickel sulfate and manganese sulfate and dissolve it in water. Use sodium carbonate precipitant and ammonia water complexing agent to adjust the pH to make it precipitate evenly. _Dry to _obtain _the precursor (Ni _0.333 Mn _0.667 ₎ CO _3. Weigh sodium carbonate, ₍ _Ni _0.333 _Mn _0.667 )CO ₃ precursor, Lithium carbonate, titanium dioxide and magnesium oxide are ball milled to obtain a mixture, and the mixture is calcined to obtain a vacancy-type sodium ion cathode material. The sodium carbonate and lithium carbonate are 108% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

The cathode material prepared above was pulped with SP and PVDF in a mass ratio of 90:5:5. After coating, drying and cutting, it was used as a cathode and assembled into a button cell to evaluate its electrochemical properties. able.

Example 12

According to the atomic number ratio of Ni element and Mn element in the chemical formula (Ni _0.333 Mn _0.667 ) CO ₃ , weigh an appropriate amount of nickel sulfate and manganese sulfate and dissolve it in water. Use sodium carbonate precipitant and ammonia water complexing agent to adjust the pH to make it precipitate evenly. Dry to _obtain _the precursor ₍ Ni _0.333 Mn _0.667 ₎ CO _3. Weigh sodium carbonate, ₍ _Ni _0.333 _{Mn 0.667} ₎ CO ₃ precursor, Lithium carbonate, titanium dioxide and magnesium oxide are ball milled to obtain a mixture, and the mixture is calcined to obtain a vacancy-type sodium ion cathode material. The sodium carbonate and lithium carbonate are 101% of the theoretical addition amount. The above raw materials are put into a ball mill and mechanically ball milled for 2 hours, and the ball milling speed is 500 rpm.

Comparative example 1

In this comparative example, the cathode material Na _0.9 Mn _0.6 Ni _0.25 Cu _0.15 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, and copper oxide according to the stoichiometric ratio of the chemical formula Na _0.9 Mn _0.6 Ni _0.25 Cu _0.15 O ₂ , where sodium carbonate is the theoretical added amount. 104%, put the above raw materials into a ball mill and mechanically ball mill for 6 hours, and the ball milling speed is 350 rpm.

The ball-milled mixture is calcined in a high-temperature furnace at 875°C. The calcining time is 12 hours and the temperature rise rate is 3°C/minute. After cooling, grinding, and passing through a 300-mesh sieve, the cathode material is obtained (as shown in Figure 2). .

Comparative example 2

In this comparative example, the cathode material NaMn _0.5 Ni _0.25 Li _0.05 Ti _0.1 Mg _0.1 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, titanium dioxide, and magnesium oxide according to the stoichiometric ratio of the chemical formula NaMn _0.5 Ni _0.25 Li _0.05 Ti _0.1 Mg _0.1 O ₂ , of which sodium carbonate and lithium carbonate are theoretical additions 103% of the amount, put the above raw materials into a ball mill and mechanically ball mill for 2 hours, and the ball milling speed is 500 rpm.

Comparative example 3

In this comparative example, the cathode material Na _0.93 Mn _0.5 Ni _0.25 Ti _0.1 Fe _0.05 Mg _0.1 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of nickel sulfate and manganese sulfate and dissolve it in a certain amount of water according to the stoichiometric ratio of the chemical formula Mn _0.667 Ni _0.333 (OH) _2. Use sodium hydroxide and ammonia to adjust the pH to make it precipitate evenly. After drying at 100°C, the precursor is obtained. Mn _0.667 Ni _0.333 (OH) ₂ .

Weigh an appropriate amount of the above precursor, sodium carbonate, ferric oxide, titanium dioxide, and magnesium oxide according to the stoichiometric ratio of the chemical formula Na _0.93 Mn _0.5 Ni _0.25 Ti _0.1 Fe _0.05 Mg _0.1 O ₂ and place them in a mill for mechanical ball milling for 2 hours. Finally, a mixture was obtained. The ball milling speed was 300 rpm, in which sodium carbonate was 103% of the theoretical addition amount.

The ball-milled mixture is calcined in a high-temperature furnace at 850°C. The calcining time is 15 hours and the temperature rise rate is 4°C/minute. The cathode material is obtained after cooling, grinding, and passing through a 300-mesh sieve.

Comparative Example 4

In this comparative example, the cathode material NaMn _0.6 Ni _0.2 Sn _0.1 Mg _0.1 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, tin dioxide, and magnesium oxide according to the stoichiometric ratio of the chemical formula NaMn _0.6 Ni _0.2 Sn _0.1 Mg _0.1 O _2. The sodium carbonate is 103% of the theoretical addition amount. The above raw materials are put into a sand mill and mechanically ground to a particle size of 0.2 μm and then spray-dried.

Comparative example 5

In this comparative example, the cathode material NaMn _0.5 Ni _0.25 Li _0.05 Co _0.1 Cr _0.1 O ₂ is prepared. The instructions are as follows:

Weigh appropriate amounts of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate, cobalt tetroxide and chromium oxide according to the stoichiometric ratio of the chemical formula NaMn _0.5 Ni _0.25 Li _0.05 Co _0.1 Cr _0.1 O ₂ , of which sodium carbonate and lithium carbonate are theoretical additions 103% of the amount, put the above raw materials into a ball mill and add isopropyl alcohol to mechanically ball mill for 2 hours, and the ball milling speed is 500 rpm.

The wet material after ball milling is spray-dried and placed in a high-temperature furnace for calcination at 950°C. The calcination time is 10 hours and the temperature rise rate is 3°C/minute. The cathode material is obtained after cooling, grinding, and passing through a 300-mesh sieve.

Comparative Example 6

In this comparative example, the cathode material NaMn _0.55 Ni _0.33 B _0.07 Zn _0.05 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, boron trioxide and zinc oxide according to the stoichiometric ratio of the chemical formula NaMn _0.55 Ni _0.33 B _0.07 Zn _0.05 O ₂ , where sodium carbonate is 103% of the theoretical addition amount, Put the above raw materials into a ball mill for mechanical ball milling for 2 hours, and the ball milling speed is 500rpm.

The ball-milled mixture is calcined in a high-temperature furnace at 950°C for 10 hours, the heating rate is 3°C/min, and the cathode material is obtained after cooling, grinding, and passing through a 300-mesh sieve.

Comparative Example 7

In this comparative example, the cathode material NaMn _0.55 Ni _0.33 V _0.07 Zn _0.05 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide, vanadium pentoxide and zinc oxide according to the stoichiometric ratio of the chemical formula NaMn _0.55 Ni _0.33 V _0.07 Zn _0.05 O ₂ , where sodium carbonate is 103% of the theoretical addition amount, Put the above raw materials into a ball mill for mechanical ball milling for 2 hours, and the ball milling speed is 500rpm.

Comparative example 8

In this comparative example, the cathode material NaMn _0.6 Ni _0.25 Li _0.05 Cu _0.1 O ₂ is prepared. The instructions are as follows:

Weigh appropriate amounts of sodium carbonate, manganese trioxide, nickel oxide, lithium carbonate and copper oxide according to the stoichiometric ratio of the chemical formula NaMn _0.6 Ni _0.25 Li _0.05 Cu _0.1 O ₂ , where sodium carbonate and lithium carbonate are 104% of the theoretical addition amount , put the above raw materials into a ball mill and grind them mechanically for 6 hours. The ball mill speed is 350rpm.

The ball-milled mixture was calcined in a high-temperature furnace at 875°C. The calcining time was 12 hours and the heating rate was 3°C/minute. The cathode material was obtained after cooling, grinding, and passing through a 300-mesh sieve.

Comparative Example 9

In this comparative example, the cathode material NaMn _0.6 Ni _0.25 Cu _0.15 O ₂ is prepared. The instructions are as follows:

Weigh an appropriate amount of sodium carbonate, manganese trioxide, nickel oxide and copper oxide according to the stoichiometric ratio of the chemical formula NaMn _0.6 Ni _0.25 Cu _0.15 O ₂ , where sodium carbonate is 104% of the theoretical addition amount. Put the above raw materials into a ball mill. Mechanical ball milling for 6 hours, ball milling speed 350rpm.

Comparative Example 10

In this comparative example, the cathode material NaMn _0.6 Ni _0.2 Li _0.03 Sn _0.1 Mg _0.07 O ₂ is prepared. The instructions are as follows:

According to the stoichiometric ratio of the chemical formula Mn _0.75 Ni _0.25 (OH) _2, weigh an appropriate amount of nickel sulfate and Manganese sulfate is dissolved in a certain amount of water, the pH is adjusted with sodium hydroxide and ammonia water to uniformly precipitate, and the precursor Mn _0.75 Ni _0.25 (OH) ₂ is obtained after drying at 100°C.

According to the stoichiometric ratio of the chemical formula NaMn _0.6 Ni _0.2 Li _0.03 Sn _0.1 Mg _0.07 O ₂ , weigh an appropriate amount of the above precursor, sodium carbonate, lithium carbonate, tin dioxide and magnesium oxide and place them in a mill for mechanical ball milling for 8 hours to obtain Mixture, ball milling speed is 200 rpm, in which sodium carbonate and lithium carbonate are 104% of the theoretical addition amount.

Table 1. Electrochemical analysis results

Please refer to Figure 3. The cathode materials of Examples 1 to 3 are all vacancy-type sodium ion cathode materials. The (003) characteristic peak between 16 and 17 degrees of 2θ is obviously shifted to a lower angle than the standard card #54-0087. It shows that the formation of sodium vacancies expands the interlayer spacing and is conducive to the migration of Na ⁺ .

Please refer to Figure 4. Examples 3 and 4 are Li-doped cathode materials combined with sodium vacancies, and Comparative Example 2 is a cathode material doped only with Li. It can be seen from the results that the first cycle capacity of the cathode material doped with Li combined with sodium vacancies (Example 3 and Example 4) is better than that of the cathode material doped only with Li (Comparative Example 2).

Referring to Figure 5, Example 4 is a cathode material doped with Li combined with sodium vacancies, Comparative Example 2 is a cathode material doped only with Li, and Comparative Example 3 is a cathode material with only sodium vacancies. It can be seen from the results that the rate performance of the cathode material doped with Li combined with sodium vacancies (Example 4) is better than that of the cathode material doped only with Li (Comparative Example 2) and the cathode material with only sodium vacancies (Comparative Example 3), especially The difference is more obvious at 5C high magnification.

Please refer to Figure 6. Example 3 is a cathode material doped with Li and combined with sodium vacancies, and a comparative example. 3 is a cathode material with only sodium vacancies, and Comparative Example 4 is a cathode material without Li doping and no sodium vacancies. It can be seen from the results that sodium vacancies alone will not significantly improve the cathode material's cycle performance in the first 100 cycles. Li doping must be used to significantly improve the cathode material's cycle performance in the first 100 cycles.

Please look at Table 1. The preparation processes of Example 1 and Comparative Example 1 are roughly the same, except whether Li is doped or not. It can be seen from the results that Li element doping can significantly increase the specific capacity of the cathode material and have a higher capacity retention rate.

The preparation processes of Example 4 and Comparative Example 2 are roughly the same, except that the Na content is different. It can be seen from the results that although the existence of sodium vacancies will slightly reduce the specific capacity, it can significantly improve the capacity retention rate. The preparation processes of Example 4 and Comparative Example 3 are roughly the same, except that the Li content is different. It can be seen from the results that Li element doping can significantly improve the specific capacity and capacity retention rate of the cathode material.

The preparation processes of Example 5 and Comparative Example 5 are roughly the same, except that the Na content is different. It can be seen from the results that although the presence of sodium vacancies will slightly reduce the specific capacity, it can significantly improve the capacity retention rate.

The preparation processes of Example 6 and Comparative Example 6 are approximately the same, and the preparation processes of Example 7 and Comparative Example 7 are approximately the same, except that the Li content and the Na content are different. It can be seen from the results that Li element doping combined with sodium vacancies can increase the specific capacity and significantly improve the capacity retention rate.

The preparation processes of Example 1, Comparative Example 1, Comparative Example 8 and Comparative Example 9 are approximately the same, except that the Li content is different and the Na content is different. Comparing Comparative Example 8 and Comparative Example 9, it can be seen that the difference between the two lies in whether Li is doped or not; it can be seen from the results that Li doping can increase the specific capacity, but will slightly reduce the capacity retention rate. Comparing Comparative Example 1 and Comparative Example 9, it can be seen that the difference between the two lies in the presence or absence of Na vacancies; it can be seen from the results that Na vacancies can reduce the specific capacity, but will Improve capacity retention. Comparing Example 1 and Comparative Example 9, it can be seen that the difference between the two lies in the presence or absence of Na vacancies and the presence or absence of Li doping. From the results, it can be seen that Li doping with Na vacancies can significantly increase the specific capacity and capacity retention rate, and the specific capacity The increase in capacity retention rate was unexpected from the expected values obtained through Comparative Example 1, Comparative Example 8, and Comparative Example 9.

The above content related to common knowledge will not be described in detail, and those skilled in the art can understand it.

The above are only some specific embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection. The technical scope of the present invention is not limited to the content in the description, and must be determined based on the scope of the claims.

Claims

A vacancy-type sodium ion cathode material, characterized in that the cathode material is O3 phase, the space group is R-3m, and the general chemical formula is Na a Ni b Mn c Li d Me O 2+f , where M is At least one of Co, Cr, V, Al, Fe, Sn, B, Cu, Ti, Mg and Zn, and 0.9≤a<1, 0<b<0.6, 0<c<0.8, 0<d< 0.3, -0.04≤f≤0.04, b+c+d+e=1, and satisfy the electrical neutrality of the material.
The vacancy type sodium ion cathode material according to claim 1, characterized in that, 0.9≤a≤0.96, 0.2≤b≤0.43, 0.4≤c≤0.6, 0.02≤d≤0.1, 0≤e≤0.2, and/ Or f=0.
The vacancy-type sodium ion cathode material according to claim 1, wherein M is at least one of Co, Cr, V, Al, Sn, B, Cu, Ti, Mg, and Zn.
A sodium ion battery, characterized by comprising: the vacancy type sodium ion positive electrode material according to any one of claims 1 to 3.
A method for preparing the vacancy-type sodium ion positive electrode material according to any one of claims 1 to 3, characterized by comprising:

According to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element in the general chemical formula Na a Ni b Mn c Li d M e O 2+f , weigh an appropriate amount of compounds containing Na element and Ni element After ball milling, compounds, compounds containing Mn element, compounds containing Li element, and compounds containing M element are mixed to obtain a mixture; and

The mixture is calcined to obtain the vacancy-type sodium ion cathode material.
The preparation method according to claim 5, characterized in that, containing Ni element The compound, the compound containing the Mn element, and the compound containing the M element are independently at least one of metal oxides, metal nitrates, metal sulfates, metal carbonates, and metal chlorides, and the compound containing the Na element is carbonic acid At least one of sodium, sodium hydroxide, and sodium bicarbonate, and/or the compound containing Li element is at least one of lithium carbonate, lithium hydroxide, and lithium acetate.
The preparation method according to claim 5, characterized in that the weighed amount of the compound containing Na element is the theoretical amount calculated according to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element. 100% to 110%, and/or the weighing amount of the compound containing Li element is 100% to 110% of the theoretical amount calculated based on the atomic ratio of Na element, Ni element, Mn element, Li element, and M element .
The preparation method according to claim 5, characterized in that the ball mill adopts wet ball milling or dry ball milling, the calcining temperature is 700 to 1050°C, the calcining time is 6 to 36 hours, and/or the heating rate of calcining is 1 to 20 ℃/minute.
The preparation method according to claim 8, wherein the dispersion medium of wet ball milling is at least one of acetone, ethanol, ethylene glycol, and isopropyl alcohol, the ball milling speed is 100 to 1000 rpm, and/or the ball milling time is 1 to 48 hours.
A method for preparing the vacancy-type sodium ion positive electrode material according to any one of claims 1 to 3, characterized by comprising:

According to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element in the general chemical formula Na a Ni b Mn c Li d M e O 2+f , weigh an appropriate amount of compounds containing Na element and Ni element Compounds containing Mn elements, compounds containing Li elements, and compounds containing M elements are ball-milled or sand-milled, and then mixed to obtain a mixture; and

After the mixture is spray-dried, it is calcined to obtain the vacancy-type sodium ion cathode material.
The preparation method according to claim 10, characterized in that the Ni element-containing compound, the Mn element-containing compound, and the M element-containing compound are independently metal oxides, metal nitrates, metal sulfates, and metal carbonates. , and at least one of metal chlorides, the compound containing Na element is at least one of sodium carbonate, sodium hydroxide, and sodium bicarbonate, and/or the compound containing Li element is lithium carbonate, lithium hydroxide, acetic acid At least one of lithium.
The preparation method according to claim 10, characterized in that the weighed amount of the compound containing Na element is the theoretical amount calculated according to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element. 100% to 110%, and/or the weighing amount of the compound containing Li element is 100% to 110% of the theoretical amount calculated based on the atomic ratio of Na element, Ni element, Mn element, Li element, M element .
The preparation method according to claim 10, characterized in that ball milling or sand milling until the particle size of the mixture is 0.1 to 2 μm, the calcination temperature is 700 to 1050°C, the calcination time is 6 to 36 hours, and/or the calcined The heating rate is 1 to 20°C/minute.
A method for preparing the vacancy-type sodium ion positive electrode material according to any one of claims 1 to 3, characterized by comprising:

Weigh an appropriate amount of nitrate or sulfate containing Ni element and nitric acid containing Mn element according to the atomic number ratio of Ni element and Mn element in the chemical formula (Ni x Mn y ) CO 3 or (Ni x Mn y ) ( OH ) 2 Dissolve salt or sulfate in water, adjust the pH with precipitant and complexing agent to uniformly precipitate, and dry to obtain the precursor ( Nix Mn y )CO 3 or ( Nix Mn y ) (OH) 2 , where x: y =b:c, And x+y=1;

According to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element in the general chemical formula Na a Ni b Mn c Li d M e O 2+f , weigh an appropriate amount of compounds containing Na element and Li element. The compound, the compound containing M element, and the precursor ( NixMny ) CO3 or ( NixMny ) (OH) 2 are ball milled and mixed to obtain a mixture; and

The mixture is calcined to obtain the vacancy-type sodium ion cathode material.
The preparation method according to claim 14, characterized in that the compound containing M element is at least one of metal oxide, metal nitrate, metal sulfate, metal carbonate and metal chloride, and contains Na element The compound is at least one of sodium carbonate, sodium hydroxide, and sodium bicarbonate, and/or the compound containing Li element is at least one of lithium carbonate, lithium hydroxide, and lithium acetate.
The preparation method according to claim 14, characterized in that the weighed amount of the compound containing Na element is the theoretical amount calculated according to the atomic number ratio of Na element, Ni element, Mn element, Li element and M element. 100% to 110%, and/or the weighing amount of the compound containing Li element is 100% to 110% of the theoretical amount calculated based on the atomic ratio of Na element, Ni element, Mn element, Li element, M element .
The preparation method according to claim 14, characterized in that the pH value is 7.5 to 13, the complexing agent is ammonia water, the precipitating agent is sodium hydroxide or sodium carbonate, the drying temperature is 80 to 150°C, and the drying time is 6 to 48 hours, the calcination temperature is 700 to 1050°C, the calcination time is 6 to 36 hours, and/or the temperature rise rate of calcination is 1 to 20°C/minute.