Manganese-based sodium-ion battery positive electrode material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a manganese-based sodium ion battery positive electrode material and a preparation method and application thereof. According to the manganese-based sodium-ion battery positive electrode material provided by the invention, the chemical general formula of the manganese-based sodium-ion battery positive electrode material is NaaNibMncTidCueMezO2, a is more than or equal to 0.65 and less than or equal to 0.85, b is more than or equal to 0.01 and less than or equal to 0.05, c is more than or equal to 0.74 and less than or equal to 0.93, d is more than or equal to 0.04 and less than or equal to 0.15, e is more than or equal to 0.01 and less than or equal to 0.05, z is more than or equal to 0 and less than or equal to 0.03, b + c + d + e + z is equal to 1.0, and Me is an added metal element. The manganese-based sodium-ion battery positive electrode material has good specific capacity, cycling stability, thermal stability and rate capability, has a remarkable cost advantage compared with a conventional sodium-ion battery material, and has a good commercialization prospect.

Description

Technical Field

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

[0002] The energy issue has always been a key issue related to the development of human society. In recent years, people's attention to renewable energy such as wind energy and solar energy has been increasing day by day, and the efficient storage and distribution of renewable energy require a large amount of investment and innovation in the construction of energy infrastructure. New energy batteries are particularly crucial. Among them, sodium-ion battery cathode materials have gradually become advantageous battery materials due to the wide availability of sodium resources, low raw material prices, and low production costs. However, compared with lithium-ion batteries, the technology of existing sodium-ion battery cathode materials is still immature, and their specific capacity, cycle stability, thermal stability, and rate performance still need to be improved, which greatly limits their commercial applications. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the specific capacity, cycle stability, thermal stability, and rate performance of existing sodium-ion battery cathode materials still need to be improved, and thus provide a manganese-based sodium-ion battery cathode material, a preparation method thereof, and an application thereof.

[0004] The present invention provides a manganese-based sodium-ion battery cathode material, and the chemical general formula of the manganese-based sodium-ion battery cathode material is Na a Ni b Mn c Ti d Cu e Me z O2, where 0.65 ≤ a ≤ 0.85, 0.01 ≤ b ≤ 0.05, 0.74 ≤ c ≤ 0.93, 0.04 ≤ d ≤ 0.15, 0.01 ≤ e ≤ 0.05, 0 ≤ z ≤ 0.03 and b + c + d + e + z = 1.0, and Me is a metal element added.

[0005] Optionally, the chemical general formula of the manganese-based sodium-ion battery cathode material is Na a Ni b Mn c Ti d Cu e Me z O2, where 0.65 ≤ a ≤ 0.85, 0.01 ≤ b ≤ 0.05, 0.74 ≤ c ≤ 0.93, 0.04 ≤ d ≤ 0.15, 0.01 ≤ e ≤ 0.05, 0.0001 ≤ z ≤ 0.03 and b + c + d + e + z = 1.0, and Me is a metal element added.

[0006] Preferably, Me is selected from at least one of Mg, Fe, W, Zn, Sb, Sn, and Al.

[0007] The present invention provides a method for preparing a cathode material for a sodium-ion battery based on manganese, comprising the following steps:

[0008] 1) Mixing a sodium source, a nickel source, a manganese source, a titanium source, a copper source, a metal addition source, and water to form a suspension, followed by grinding and spray drying to obtain a spray material;

[0009] 2) Sintering the spray material obtained in step 1) to obtain a sintered material;

[0010] 3) Depositing a carbon source on the sintered material obtained in step 2) to obtain the cathode material for the sodium-ion battery based on manganese.

[0011] Preferably, in step 1), the sodium source is selected from at least one of sodium carbonate, sodium acetate, and sodium bicarbonate;

[0012] and / or, the nickel source is selected from at least one of nickel oxide and nickel hydroxide;

[0013] and / or, the manganese source is selected from at least one of manganese dioxide, manganese tetroxide, manganese sesquioxide, and manganese carbonate.

[0014] Preferably, the titanium source is selected from at least one of titanium dioxide, titanium hydroxide, and titanium sesquioxide;

[0015] and / or, the copper source is selected from at least one of copper oxide, copper hydroxide, cuprous oxide, and basic copper carbonate;

[0016] and / or, the metal addition source is selected from at least one of magnesium oxide, magnesium hydroxide, and magnesium carbonate.

[0017] Preferably, in step 1), the solid content of the suspension is 25-45 wt%;

[0018] and / or, in step 1), the rotation speed of the grinding is 1000-2500 rpm, and the sanding time is 1-4 h.

[0019] The solid content of the suspension in the present invention refers to the mass ratio of the total mass of the sodium source, nickel source, manganese source, titanium source, copper source, and metal addition source in the suspension to the mass of the suspension.

[0020] Preferably, in step 1), the inlet temperature of the spray drying is 150-210 °C, and the feeding rate is 3-5 L / h.

[0021] Optionally, the atomizer frequency of the spray drying is 200-450 Hz.

[0022] Preferably, the sintering temperature in step 2) is 600-1000 °C, and the sintering time is 4-24 h;

[0023] and / or, the sintering is carried out in an air atmosphere.

[0024] Optionally, the intake flow rate of compressed air during the sintering process is 0.5-10 m 3 / min.

[0025] Preferably, the carbon source in step 3) is selected from at least one of acetylene black, graphene, carbon nanotubes, and glucose;

[0026] and / or, in step 3), the carbon source is deposited on the sintered material by chemical vapor deposition.

[0027] Optionally, before the step of depositing the carbon source in step 3), there is also a step of crushing and sieving the sintered material.

[0028] The present invention provides an application of the above-mentioned manganese-based sodium-ion battery cathode material in a sodium-ion battery.

[0029] The technical solution of the present invention has the following advantages:

[0030] 1. The manganese-based sodium-ion battery cathode material provided by the present invention has a chemical general formula of Na a Ni b Mn c Ti d Cu e Me zO2, where 0.65 ≤ a ≤ 0.85, 0.01 ≤ b ≤ 0.05, 0.74 ≤ c ≤ 0.93, 0.04 ≤ d ≤ 0.15, 0.01 ≤ e ≤ 0.05, 0 ≤ z ≤ 0.03 and b + c + d + e + z = 1.0, and Me is a doped metal element. In the cathode material for sodium-ion batteries of the present invention, a large amount of manganese resources are used as raw materials, greatly reducing nickel resources, significantly reducing the material cost, and increasing the thermal stability of the material; the co-doping of Ni and Cu can form a continuous electron conduction network, reducing polarization; at the same time, Ti strengthens the framework, which can indirectly reduce electron localization by stabilizing the crystal lattice, improving electron / ion conductivity, Ni inhibits distortion, jointly reducing cracks and phase changes during cycling, Cu relieves volume strain, Ti fixes oxygen vacancies, inhibits Mn migration and irreversible phase changes (such as P2→O2 phase change), Ni / Cu expands the layer spacing, Ti optimizes the Na+ occupancy, and synergistically accelerates Na+ diffusion (for example, improving rate performance) to provide reversible capacity (redox activity). Ti acts as an inactive support to balance capacity and stability. The cathode material for sodium-ion batteries provided by the present invention has good specific capacity, cycle stability, thermal stability, and rate performance in terms of electrochemical performance through the synergistic cooperation of Ni, Mn, Ti, and Cu elements, and has a significant cost advantage compared with conventional sodium battery materials, showing good commercial prospects.

[0031] 2. The preparation method of the cathode material for sodium-ion batteries provided by the present invention includes the following steps: 1) A sodium source, a nickel source, a manganese source, a titanium source, a copper source, a doped metal source, and water are mixed to form a suspension, which is ground and spray-dried to obtain a spray material; 2) The spray material obtained in step 1) is sintered to obtain a sintered material; 3) A carbon source is deposited on the sintered material obtained in step 2) to obtain the cathode material for sodium-ion batteries. The present invention also uses spray drying to prepare the cathode material for sodium-ion batteries, which can improve the morphology and further enhance the specific capacity, cycle stability, thermal stability, and rate performance of the material. Brief Description of the Drawings

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 SEM image of the cathode material for sodium-ion batteries prepared in Example 1 of the present invention;

[0034] Figure 2 SEM image of the cathode material for sodium-ion batteries prepared in Example 7 of the present invention. Detailed implementation mode

[0035] The following embodiments are provided to better further understand the present invention. It is not limited to the described optimal implementation mode, and does not limit the content and protection scope of the present invention. Any product that is the same as or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with those of other existing technologies falls within the protection scope of the present invention.

[0036] For those embodiments in which specific experimental steps or conditions are not indicated, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments whose manufacturers are not indicated, they are all conventional reagent products that can be obtained through commercial purchase.

[0037] Mn used in the embodiments of the present invention 0.92 Fe 0.03 Cu 0.05 (OH)2 precursor is prepared as follows: Manganese nitrate, iron nitrate, and copper nitrate are prepared into a manganese-iron-copper metal salt solution A with a total metal ion concentration of 3 mol / L according to the molar ratio of manganese element, iron element, and copper element of 0.92:0.03:0.05. An ammonia water solution with a concentration of 2 mol / L is prepared; OH - A sodium hydroxide solution with a concentration of 2 mol / L is prepared. Then, the prepared solution A, ammonia water solution, and sodium hydroxide solution are added to the reaction kettle in a co-current manner. The flow rate of solution A is 10 L / h, the flow rate of the sodium hydroxide solution is 4 L / h, and the flow rate of the ammonia complexing agent solution is 0.03 L / h. The reaction is carried out at 70 °C for 30 h, and the reaction pH of the system is controlled at 9 to obtain Mn 0.92 Fe 0.03 Cu 0.05 (OH)2 precursor.

[0038] Example 1

[0039] This example provides a preparation method for a cathode material of a manganese-based sodium-ion battery, including the following steps:

[0040] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, copper oxide, and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element, and magnesium element of 0.80:0.05:0.79:0.10:0.05:0.01, and then mix them with water to obtain a suspension with a solid content of 30 wt%. Grind it at 2000 rpm for 3 h, and then spray dry. The inlet temperature of the spray dryer is 180 °C, the feed rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0041] 2) Load the spray material obtained in step 1) into a sagger, place it in a box furnace for sintering. The sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain the sintered material;

[0042] 3) Crush the sintered material obtained in step 2) and then screen it. Then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.79 Ti 0.10 Cu 0.05 Mg 0.01 O2 (the SEM image scanned by scanning electron microscope is as shown in Figure 1 )

[0043] Example 2

[0044] This example provides a method for preparing a positive electrode material for a manganese-based sodium-ion battery, including the following steps:

[0045] 1) Weigh sodium acetate, nickel oxide, manganese dioxide, titanium dioxide, copper hydroxide, and magnesium carbonate according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element, and magnesium element of 0.80:0.05:0.74:0.15:0.05:0.01. Then mix them with water to obtain a suspension with a solid content of 45 wt%. Grind it at 2500 rpm for 1 h, and then spray dry it. The inlet temperature of the spray dryer is 200 °C, the feed rate is 5 L / h, and the atomizer frequency of the spray dryer is 450 Hz. After spray drying, the spray material is obtained;

[0046] 2) Load the spray material obtained in step 1) into a sagger, place it in a box furnace for sintering. The sintering temperature is 600 °C, the sintering time is 24 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 10 m 3 / min to obtain the sintered material;

[0047] 3) Crush the sintered material obtained in step 2) and then screen it. Then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.74 Ti 0.15 Cu 0.05 Mg 0.01 O2

[0048] Example 3

[0049] This example provides a method for preparing a positive electrode material for a manganese-based sodium-ion battery, including the following steps:

[0050] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, copper oxide and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element and magnesium element being 0.80:0.05:0.79:0.10:0.05:0.01, then mix with water to obtain a suspension with a solid content of 25 wt%, grind at 1000 rpm for 4 h, then spray dry. The inlet temperature of the spray dryer is 150 °C, the feed rate is 3 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0051] 2) Load the spray material obtained in step 1) into a sagger, put it into a box furnace for sintering. The sintering temperature is 1000 °C, the sintering time is 5 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0052] 3) Crush the sintered material obtained in step 2) and then screen it, and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.79 Ti 0.10 Cu 0.05 Mg 0.01 O2 of the sodium-ion manganese-based battery.

[0053] Example 4

[0054] This example provides a preparation method of a positive electrode material for a sodium-ion manganese-based battery, including the following steps:

[0055] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, copper oxide and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element and magnesium element being 0.80:0.05:0.79:0.10:0.05:0.01, then mix with water to obtain a suspension with a solid content of 30 wt%, grind at 2000 rpm for 3 h, then spray dry. The inlet temperature of the spray dryer is 180 °C, the feed rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0056] 2) Load the spray material obtained in step 1) into a sagger, put it into a box furnace for sintering. The sintering temperature is 1000 °C, the sintering time is 10 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0057] 3) Crush the sintered material obtained in step 2) and then screen it, and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na of the sodium-ion manganese-based battery0.80 Ni 0.05 Mn 0.79 Ti 0.10 Cu 0.05 Mg 0.01 O2。

[0058] Example 5

[0059] This example provides a method for preparing a cathode material for a manganese-based sodium-ion battery, comprising the following steps:

[0060] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, copper oxide and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element and magnesium element of 0.85:0.05:0.79:0.10:0.05:0.01, then mix with water to obtain a suspension with a solid content of 30 wt%, grind at 2000 rpm for 3 h, and then spray dry. The inlet temperature of the spray dryer is 180 °C, the feed rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0061] 2) Load the spray material obtained in step 1) into a crucible and place it in a box furnace for sintering. The sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is an air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0062] 3) Crush the sintered material obtained in step 2), sieve it, and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the cathode material Na 0.85 Ni 0.05 Mn 0.79 Ti 0.10 Cu 0.05 Mg 0.01 O2。

[0063] Example 6

[0064] This example provides a method for preparing a cathode material for a manganese-based sodium-ion battery, comprising the following steps:

[0065] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, copper oxide and ferric oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element and iron element of 0.80:0.05:0.79:0.10:0.05:0.01, then mix with water to obtain a suspension with a solid content of 30 wt%, grind at 2000 rpm for 3 h, and then spray dry. The inlet temperature of the spray dryer is 180 °C, the feed rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0066] 2) Load the spray material obtained in step 1) into a crucible and place it in a box furnace for sintering. The sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0067] 3) Crush and sieve the sintered material obtained in step 2), and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.79 Ti 0.10 Cu 0.05 Fe 0.01 O2 of the sodium-ion battery based on manganese.

[0068] Example 7

[0069] This example provides a method for preparing a positive electrode material for a sodium-ion battery based on manganese, including the following steps:

[0070] 1) Weigh sodium carbonate, nickel oxide, titanium dioxide, and the precursor Mn 0.92 Fe 0.03 Cu 0.05 (OH)2 according to the molar ratio of sodium element, nickel element, titanium element, and manganese element of 0.80:0.05:0.10:0.85, and mix and grind at 2000 rpm for 3 h to obtain a mixed material;

[0071] 2) Load the mixed material obtained in step 1) into a crucible and place it in a box furnace for sintering. The sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0072] 3) Crush and sieve the sintered material obtained in step 2), and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.782 Ti 0.10 Cu 0.0425 Fe 0.0255 O2 (the SEM image scanned by scanning electron microscope is as shown in Figure 2 ).

[0073] Example 8

[0074] This example provides a method for preparing a positive electrode material for a sodium-ion battery based on manganese, including the following steps:

[0075] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, copper oxide and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, copper element and magnesium element being 0.80:0.05:0.79:0.10:0.05:0.01, mix them and grind at 2000 rpm for 3 h to obtain a mixed material;

[0076] 2) Put the mixed material obtained in step 1) into a sagger, place it in a box furnace for sintering, the sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0077] 3) Crush the sintered material obtained in step 2), sieve it, and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.79 Ti 0.10 Cu 0.05 Mg 0.01 O2 of the sodium-ion battery based on manganese.

[0078] Comparative Example 1

[0079] This comparative example provides a preparation method of a positive electrode material for a sodium-ion battery based on manganese, including the following steps:

[0080] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, copper oxide and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, copper element and magnesium element being 0.80:0.05:0.89:0.05:0.01, then mix with water to obtain a suspension with a solid content of 30 wt%, grind at 2000 rpm for 3 h, and then spray dry. The inlet temperature of the spray dryer is 180 °C, the feed rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0081] 2) Put the spray material obtained in step 1) into a sagger, place it in a box furnace for sintering, the sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0082] 3) Crush the sintered material obtained in step 2), sieve it, and then deposit a carbon source on the sintered material powder by chemical vapor deposition to obtain the positive electrode material Na 0.80 Ni 0.05 Mn 0.89 Cu 0.05 Mg 0.01 O2 of the sodium-ion battery based on manganese.

[0083] Comparative Example 2

[0084] This comparative example provides a method for preparing a cathode material for a sodium-ion battery based on manganese, including the following steps:

[0085] 1) Weigh sodium carbonate, nickel oxide, manganese dioxide, titanium dioxide, and magnesium oxide according to the molar ratio of sodium element, nickel element, manganese element, titanium element, and magnesium element being 0.80:0.05:0.84:0.10:0.01. Then mix them with water to obtain a suspension with a solid content of 30 wt%. Grind it at 2000 rpm for 3 h, and then perform spray drying. The inlet temperature of the spray dryer is 180 °C, the feeding rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0086] 2) Put the spray material obtained in step 1) into a crucible and place it in a box furnace for sintering. The sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is an air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0087] 3) Crush the sintered material obtained in step 2) and then sieve it. Then deposit a carbon source on the sintered powder through chemical vapor deposition to obtain the cathode material Na 0.80 Ni 0.05 Mn 0.84 Ti 0.10 Mg 0.01 O2 for the sodium-ion battery based on manganese.

[0088] Comparative Example 3

[0089] This example provides a method for preparing a cathode material for a sodium-ion battery based on manganese, including the following steps:

[0090] 1) Weigh sodium carbonate, manganese dioxide, titanium dioxide, copper oxide, and magnesium oxide according to the molar ratio of sodium element, manganese element, titanium element, copper element, and magnesium element being 0.80:0.84:0.10:0.05:0.01. Then mix them with water to obtain a suspension with a solid content of 30 wt%. Grind it at 2000 rpm for 3 h, and then perform spray drying. The inlet temperature of the spray dryer is 180 °C, the feeding rate is 4 L / h, and the atomizer frequency of the spray dryer is 350 Hz. After spray drying, a spray material is obtained;

[0091] 2) Put the spray material obtained in step 1) into a crucible and place it in a box furnace for sintering. The sintering temperature is 900 °C, the sintering time is 10 h, the sintering atmosphere is an air atmosphere, and the inlet flow rate of compressed air during the process is 2 m 3 / min to obtain a sintered material;

[0092] 3) Pulverize the sintered material obtained in step 2), sieve it, and then deposit a carbon source on the powdered sintered material by chemical vapor deposition to obtain the positive electrode material of the manganese-based sodium-ion battery, Na 0.80 Mn 0.84 Ti 0.10 Cu 0.05 Mg 0.01 O2.

[0093] Test Example

[0094] Take the positive electrode materials of the manganese-based sodium-ion batteries obtained in Examples 1-8 and Comparative Examples 1-3 as the main materials respectively, and make electrode sheets by homogenizing and coating according to the ratio of 95 g (main material): 2.5 g (PVDF): 2.5 g (SP). Use metallic sodium as the counter electrode, glass fiber as the separator, and a solution of 1 mol / L NaPF6 in ethylene carbonate (EC) / dimethyl carbonate (DMC) (volume ratio of EC and DMC is 1:1) as the electrolyte to assemble a CR2032 coin cell.

[0095] Put the assembled battery into a BlueTEC test system for electrical performance testing. The electrical performance test parameters are set as follows: voltage range 2.0 V - 4.0 V, charge at 0.1C in the first cycle, then discharge at 0.1C, charge and discharge at 0.2C in the second cycle, charge fully at 0.5C in the third cycle, charge and discharge at 1C in the fourth cycle, and then continue to charge and discharge at 1C for 50 cycles. Record the initial charge specific capacity, rate performance (discharge specific capacity at 1C in the fourth cycle / charge specific capacity at 0.1C in the first cycle * 100%), and discharge cycle capacity retention rate from the fifth cycle to the 54th cycle. The test results are shown in Table 1.

[0096] Use differential scanning calorimetry (DSC) to test the thermal stability of the material, with a heating rate of 10 °C / min and a temperature range of 150 °C - 300 °C; charge a newly assembled battery to 4.1V at a current of 0.1C, then discharge to 2.0V at 0.1C, then charge to 4.1V at 0.1C again, and then let it stand for 10 h. Disassemble the positive electrode sheet in a glove box, scrape off the electrode material, place it in an Al2O3 crucible, and conduct DSC testing under N2 gas. Record the temperature corresponding to the first peak in the DSC test. The higher the temperature corresponding to the first peak, the better the thermal stability of the material. The test results are shown in Table 1.

[0097] Table 1

[0098]

[0099] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to exhaustively list all implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A manganese-based sodium ion battery positive electrode material, characterized in that: The chemical formula of the manganese-based sodium ion battery positive electrode material is Na a Ni b Mn c Ti d Cu e Me z O2, wherein 0.65≤a≤0.85, 0.01≤b≤0.05, 0.74≤c≤0.93, 0.04≤d≤0.15, 0.01≤e≤0.05, 0≤z≤0.03 and b+c+d+e+z=1.0, Me is an added metal element.

2. The manganese-based sodium ion battery positive electrode material according to claim 1, characterized in that The Me is selected from at least one of Mg, Fe, W, Zn, Sb, Sn, and Al.

3. A method for preparing a manganese-based sodium ion battery positive electrode material according to claim 1 or 2, characterized in that: The following steps are involved: 1) mixing a sodium source, a nickel source, a manganese source, a titanium source, a copper source, an added metal source and water to form a suspension, grinding and spray drying to obtain a spray material; 2) sintering the sprayed material obtained in step 1) to obtain a sintered material; 3) depositing a carbon source on the sintered material obtained in step 2) to obtain the manganese-based sodium ion battery positive electrode material.

4. The method for preparing the positive electrode material of manganese-based sodium ion battery according to claim 3, characterized in that: The sodium source in step 1) is selected from at least one of sodium carbonate, sodium acetate and sodium bicarbonate; And / or, the nickel source is selected from at least one of nickel oxide and nickel hydroxide; And / or, the manganese source is selected from at least one of manganese dioxide, trimanganese tetroxide, dimanganese trioxide and manganese carbonate.

5. The method for preparing the manganese-based sodium ion battery positive electrode material according to claim 3 or 4, characterized in that: The titanium source is selected from at least one of titanium dioxide, titanium hydroxide, and titanium pentoxide; And / or, the copper source is selected from at least one of copper oxide, copper hydroxide, cuprous oxide, and basic copper carbonate; And / or, the metal additive source is selected from at least one of magnesium oxide, magnesium hydroxide and magnesium carbonate.

6. The method for preparing the manganese-based sodium ion battery positive electrode material according to any one of claims 3 to 5, characterized in that: The solid content of the suspension in step 1) is 25-45wt%; And / or, the grinding speed in step 1) is 1000-2500 rpm, and the sanding time is 1-4 h.

7. The method for preparing the manganese-based sodium ion battery positive electrode material according to any one of claims 3 to 6, characterized in that: The air inlet temperature of the spray drying in step 1) is 150-210° C. and the feed rate is 3-5 L / h.

8. The method for preparing the manganese-based sodium ion battery positive electrode material according to any one of claims 3 to 7, characterized in that: The sintering temperature in step 2) is 600-1000°C and the sintering time is 4-24h; And / or, the sintering is performed in an air atmosphere.

9. The method for preparing the manganese-based sodium ion battery positive electrode material according to any one of claims 3 to 8, characterized in that: The carbon source in step 3) is selected from at least one of acetylene black, graphene, carbon nanotubes, and glucose; and / or, in step 3), a carbon source is deposited on the sintered material by vapor deposition; Optionally, before the step of depositing the carbon source in step 3), the step of crushing and sieving the sintered material is also included.

10. Use of the manganese-based sodium ion battery positive electrode material according to claim 9 in sodium ion batteries.

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