Preparation method of low-cost high-performance sodium-ion battery cell

Abstract

The invention relates to a preparation method of a low-cost high-performance sodium-ion battery cell. The low-cost high-performance sodium-ion battery cell comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte, the preparation method comprises the following steps: adding sodium carbonate, ferrous oxalate, manganese acetate, ammonium dihydrogen phosphate, a mercaptoethyl guanidine dihydrobromide complexing agent, glucose and ethanol into a ball milling tank for ball milling, and performing vacuum drying to obtain a precursor; placing the precursor in a tubular furnace, and performing high-temperature calcination in an argon atmosphere to obtain an active material; uniformly stirring and mixing an active material, a carbon nanotube, a binder and dimethyl sulfoxide, coating a titanium sheet with the mixture, and drying to obtain a positive electrode; the mercaptoethyl guanidine dihydrobromide complexing agent is prepared from mercaptoethyl guanidine (MEG) dihydrobromide, ethylene oxide and allyl trimethyl ammonium bromide; the prepared battery cell of the ion battery has excellent rate capability and capacity retention ratio, shows excellent structural stability and electrochemical performance, and has a relatively good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium-ion battery cells, and in particular to a preparation method of a low-cost and high-performance sodium-ion battery cell. Background Art

[0002] With the continuous advancement of the national energy transformation strategy, the proportion of clean energy consumption represented by wind energy and solar energy has gradually increased, promoting the development of various electrical energy storage systems. Sodium-ion batteries, which have a similar composition and electrochemical working principle to lithium-ion batteries, benefit from the earth abundance of their raw materials, can reduce the manufacturing cost of batteries, reduce the upfront investment in energy storage power stations, and effectively supplement the market share of lithium-ion batteries in the field of electrochemical energy storage.

[0003] Chinese Patent CN118791056B: A Ni-MOFs-based O3-type sodium-ion battery cathode material, its preparation method and application are proposed, belonging to the technical field of chemical power sources. This sodium-ion battery cathode material uses Ni-MOFs as a precursor, and a manganese source and a sodium source are added, and it is synthesized by a high-temperature solid-phase method.

[0004] Chinese Patent CN119100467A: A sodium-ion battery cathode material, its preparation method and a sodium-ion battery are disclosed. The preparation method includes the following steps: After mixing a nickel-manganese precursor with a sodium salt and a scandium source, it is sintered at a high temperature to obtain a sodium-ion battery cathode material.

[0005] Chinese Patent CN119118090A: A sodium-ion battery cathode material precursor, its preparation method and application are disclosed, belonging to the technical field of sodium batteries. The chemical composition of the precursor is HxMyLz(PO4)4, where M is Fe and / or Mn, L is one or more of V, Ti, Mg, Cr, Zr, 2 < x < 5, 2.6 ≤ y ≤ 3, 0 ≤ z ≤ 0.4. Add the M source, L source and phosphorus source to water and mix evenly, adjust the pH value to 0.5 - 2 with acid, then heat to 80 - 250 °C and react for 4 - 48 h, collect the precipitate and dry it to obtain the cathode material precursor. By pre-realizing the uniform mixing of M and P at the elemental atomic level through a liquid-phase reaction, a standardized precursor raw material is formed, and then a sodium source and a carbon source are mixed, and further sintered to prepare a polyanionic sodium-ion battery cathode material Na4MyLz(PO4)2PzP2O7 / C.

[0006] The sodium-ion battery cells prepared by the above patents and the prior art have high production costs and their electrochemical performance needs to be further improved. Summary of the Invention

[0007] In order to solve the above problems, the present invention provides a preparation method of a low-cost and high-performance sodium-ion battery cell, which includes: a positive electrode, a negative electrode, a separator, and an electrolyte; the preparation method of the positive electrode is as follows:

[0008] S1: Add 12-18 parts of sodium carbonate, 34-42 parts of ferrous oxalate, 1-5 parts of manganese acetate, 47-54 parts of ammonium dihydrogen phosphate, 1-6 parts of mercaptoethylguanidine dihydrobromide complexing agent, 1-6 parts of glucose, and 2-7 parts of ethanol to a ball mill, mill for 16-24 hours, remove from the mill, and vacuum dry to obtain a precursor;

[0009] S2: The precursor is placed in a tube furnace and calcined at high temperature under an argon atmosphere to obtain the active material;

[0010] S3: 60-80 parts of active material, 5-10 parts of carbon nanotubes, 5-10 parts of binder, and 1-5 parts of dimethyl sulfoxide are stirred and mixed evenly, and then coated on a titanium sheet and dried to obtain a positive electrode.

[0011] The high-temperature calcination temperature of S2 is 500-600°C and the time is 8-12 hours.

[0012] The binder is one of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polytetrafluoroethylene, polyvinyl alcohol, acrylonitrile multipolymer, styrene-butadiene rubber and carboxymethyl cellulose.

[0013] The negative electrode is hard carbon.

[0014] The diaphragm is glass fiber.

[0015] The electrolyte is prepared by dissolving sodium perchlorate with a concentration of 1 mol / L in ethylene carbonate and polycarbonate with a volume ratio of 1:1, and adding fluoroethylene carbonate with a mass concentration of 5%.

[0016] The preparation method of the mercaptoethylguanidine dihydrobromide complexing agent is:

[0017] H1 ring-opening addition: Mix 20-34 parts of mercaptoethylguanidine (MEG) dihydrobromide with 10-30 parts of ethylene oxide in 100-200 parts of DMF and react at 80-90°C for 3-6 hours to generate N-(2-hydroxyethyl)-N'-(2-mercaptoethyl)guanidine intermediate;

[0018] H2 quaternization addition: add 30-50 parts of allyltrimethylammonium bromide to the above reaction system and react at 60-70°C for 2-4 hours to generate mercaptoethylguanidine dihydrobromide complexing agent.

[0019] Reaction mechanism

[0020] The thiol (-SH) and amine groups in mercaptoethylguanidine dihydrobromide can form complexes with metal ions on the surface of electrode materials, inhibiting their dissolution and migration and improving the stability of the electrode materials. Furthermore, its quaternized structure helps improve the ionic conductivity of the electrolyte and enhances the transport efficiency of sodium ions in the battery, thereby enhancing the battery's charge-discharge performance and cycle life.

[0021] Technical Effects

[0022] The present invention provides a method for preparing a low-cost, high-performance sodium ion battery cell. Compared with the prior art, the present invention has the following significant effects:

[0023] 1. Mercaptoethylguanidine dihydrobromide complexing agent contains functional groups such as thiol and amine, which can complex with a variety of metal ions with good complexing performance and can improve the performance of sodium ion batteries.

[0024] 2. The sodium-ion battery cathode prepared by the present invention has an open three-dimensional framework structure, has extremely high thermal stability and can meet the rapid transport of sodium ions. In addition, due to the abundant reserves of iron in the earth's crust, it is low-cost and environmentally friendly.

[0025] 3. The present invention in situ coats the carbon coating and Mn on the surface of the material 2+ Doping is used to improve the material's electrical conductivity and broaden the sodium ion migration channels. Electrochemical performance tests show that the ion battery cell prepared by the present invention has excellent rate performance and capacity retention, demonstrating its excellent structural stability and electrochemical performance, and has good application prospects. DETAILED DESCRIPTION

[0026] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention object, the following is a detailed description in conjunction with examples and comparative examples:

[0027] Electrochemical Performance Testing: Constant current charge and discharge tests were conducted using a Xinwei battery testing system with a voltage range of 1.7-4.3V and a temperature of 25°C. Cyclic voltammetry (CV, voltage window 1.7-4.3V) and electrochemical impedance spectroscopy (EIS) were performed using an electrochemical workstation. The first-cycle discharge capacity was measured at a 0.5C rate, and the capacity retention was measured after 1000 cycles at a 5C rate.

[0028] Example 1

[0029] A method for preparing a low-cost, high-performance sodium ion battery cell, comprising: a positive electrode, a negative electrode, a separator, and an electrolyte; the method for preparing the positive electrode is:

[0030] S1: 12 g of sodium carbonate, 34 g of ferrous oxalate, 1 g of manganese acetate, 47 g of ammonium dihydrogen phosphate, 1 g of mercaptoethylguanidine dihydrobromide complexing agent, 1 g of glucose, and 2 g of ethanol were added to a ball mill, ball milled for 16 h, and then vacuum dried to obtain a precursor;

[0031] S2: The precursor is placed in a tube furnace and calcined at high temperature under an argon atmosphere to obtain the active material;

[0032] S3: 60 g of active material, 5 g of carbon nanotubes, 5 g of binder, and 1 g of dimethyl sulfoxide were stirred and mixed evenly, coated on a titanium sheet, and dried to obtain a positive electrode.

[0033] The high-temperature calcination temperature of S2 is 500° C. and the time is 8 hours.

[0034] The binder is polyvinylidene fluoride.

[0035] The negative electrode is hard carbon.

[0036] The diaphragm is glass fiber.

[0037] The electrolyte is prepared by dissolving sodium perchlorate with a concentration of 1 mol / L in ethylene carbonate and polycarbonate with a volume ratio of 1:1, and adding fluoroethylene carbonate with a mass concentration of 5%.

[0038] The preparation method of the mercaptoethylguanidine dihydrobromide complexing agent is:

[0039] H1 ring-opening addition: 20 g of mercaptoethylguanidine (MEG) dihydrobromide and 10 g of ethylene oxide were mixed in 100 g of DMF and reacted at 80 °C for 3 h to generate N-(2-hydroxyethyl)-N'-(2-mercaptoethyl)guanidine intermediate;

[0040] H2 quaternization addition: add 30 g of allyltrimethylammonium bromide to the above reaction system and react at 60°C for 2 h to generate mercaptoethylguanidine dihydrobromide complexing agent.

[0041] Example 2

[0042] A method for preparing a low-cost, high-performance sodium ion battery cell, comprising: a positive electrode, a negative electrode, a separator, and an electrolyte; the method for preparing the positive electrode is:

[0043] S1: 14 g sodium carbonate, 36 g ferrous oxalate, 2 g manganese acetate, 49 g ammonium dihydrogen phosphate, 2 g mercaptoethylguanidine dihydrobromide complexing agent, 2 g glucose, and 3 g ethanol were added to a ball mill, ball milled for 18 h, and vacuum dried to obtain a precursor;

[0044] S2: The precursor is placed in a tube furnace and calcined at high temperature under an argon atmosphere to obtain the active material;

[0045] S3: 65 g of active material, 6 g of carbon nanotubes, 6 g of binder, and 2 g of dimethyl sulfoxide were stirred and mixed evenly, coated on a titanium sheet, and dried to obtain a positive electrode.

[0046] The high-temperature calcination temperature of S2 is 540°C and the time is 9 hours.

[0047] The binder is polyvinylidene fluoride.

[0048] The negative electrode is hard carbon.

[0049] The diaphragm is glass fiber.

[0050] The electrolyte is prepared by dissolving sodium perchlorate with a concentration of 1 mol / L in ethylene carbonate and polycarbonate with a volume ratio of 1:1, and adding fluoroethylene carbonate with a mass concentration of 5%.

[0051] The preparation method of the mercaptoethylguanidine dihydrobromide complexing agent is:

[0052] H1 ring-opening addition: 24 g of mercaptoethylguanidine (MEG) dihydrobromide and 15 g of ethylene oxide were mixed in 140 g of DMF and reacted at 85 °C for 4 h to generate N-(2-hydroxyethyl)-N'-(2-mercaptoethyl)guanidine intermediate;

[0053] H2 quaternization addition: add 35 g of allyltrimethylammonium bromide to the above reaction system and react at 65°C for 3 h to generate mercaptoethylguanidine dihydrobromide complexing agent.

[0054] Example 3

[0055] A method for preparing a low-cost, high-performance sodium ion battery cell, comprising: a positive electrode, a negative electrode, a separator, and an electrolyte; the method for preparing the positive electrode is:

[0056] S1: 16 g sodium carbonate, 40 g ferrous oxalate, 4 g manganese acetate, 52 g ammonium dihydrogen phosphate, 5 g mercaptoethylguanidine dihydrobromide complexing agent, 5 g glucose, and 6 g ethanol were added to a ball mill, ball milled for 22 h, and vacuum dried to obtain a precursor;

[0057] S2: The precursor is placed in a tube furnace and calcined at high temperature under an argon atmosphere to obtain the active material;

[0058] S3: 75 g of active material, 9 g of carbon nanotubes, 9 g of binder, and 4 g of dimethyl sulfoxide were stirred and mixed evenly, coated on a titanium sheet, and dried to obtain a positive electrode.

[0059] The high-temperature calcination temperature of S2 is 580°C and the time is 11 hours.

[0060] The binder is polytetrafluoroethylene.

[0061] The negative electrode is hard carbon.

[0062] The diaphragm is glass fiber.

[0063] The electrolyte is prepared by dissolving sodium perchlorate with a concentration of 1 mol / L in ethylene carbonate and polycarbonate with a volume ratio of 1:1, and adding fluoroethylene carbonate with a mass concentration of 5%.

[0064] The preparation method of the mercaptoethylguanidine dihydrobromide complexing agent is:

[0065] H1 ring-opening addition: 30 g of mercaptoethylguanidine (MEG) dihydrobromide and 25 g of ethylene oxide were mixed in 180 g of DMF and reacted at 85 °C for 5 h to generate N-(2-hydroxyethyl)-N'-(2-mercaptoethyl)guanidine intermediate;

[0066] H2 quaternization addition: add 45 g of allyltrimethylammonium bromide to the above reaction system and react at 65°C for 3 hours to generate mercaptoethylguanidine dihydrobromide complexing agent.

[0067] Example 4

[0068] A method for preparing a low-cost, high-performance sodium ion battery cell, comprising: a positive electrode, a negative electrode, a separator, and an electrolyte; the method for preparing the positive electrode is:

[0069] S1: 18 g of sodium carbonate, 42 g of ferrous oxalate, 5 g of manganese acetate, 54 g of ammonium dihydrogen phosphate, 6 g of mercaptoethylguanidine dihydrobromide complexing agent, 6 g of glucose, and 7 g of ethanol were added to a ball mill, ball milled for 24 h, and then vacuum dried to obtain a precursor;

[0070] S2: The precursor is placed in a tube furnace and calcined at high temperature under an argon atmosphere to obtain the active material;

[0071] S3: 80 g of active material, 10 g of carbon nanotubes, 10 g of binder, and 5 g of dimethyl sulfoxide were stirred and mixed evenly, and then coated on a titanium sheet and dried to obtain a positive electrode.

[0072] The high-temperature calcination temperature of S2 is 600° C. and the time is 12 hours.

[0073] The binder is polytetrafluoroethylene.

[0074] The negative electrode is hard carbon.

[0075] The diaphragm is glass fiber.

[0076] The electrolyte is prepared by dissolving sodium perchlorate with a concentration of 1 mol / L in ethylene carbonate and polycarbonate with a volume ratio of 1:1, and adding fluoroethylene carbonate with a mass concentration of 5%.

[0077] The preparation method of the mercaptoethylguanidine dihydrobromide complexing agent is:

[0078] H1 ring-opening addition: 34 g of mercaptoethylguanidine (MEG) dihydrobromide and 30 g of ethylene oxide were mixed in 200 g of DMF and reacted at 90 °C for 6 h to generate N-(2-hydroxyethyl)-N'-(2-mercaptoethyl)guanidine intermediate;

[0079] H2 quaternization addition: add 50g of allyltrimethylammonium bromide to the above reaction system and react at 70℃ for 4h to generate mercaptoethylguanidine dihydrobromide complexing agent.

[0080] Comparative Example 1

[0081] The other steps were the same as in Example 1 except that the mercaptoethylguanidine dihydrobromide complexing agent was not added.

[0082] Comparative Example 2

[0083] No ethylene oxide was added, and the other procedures were the same as in Example 1.

[0084] Comparative Example 3

[0085] Allyltrimethylammonium bromide was not added, and the other procedures were the same as in Example 1.

[0086] First cycle discharge specific capacity / mA·h / g Specific capacity retention rate / % Example 1 95.9 93.6 Example 2 96.5 93.9 Example 3 98.1 94.5 Example 4 98.7 94.8 Comparative Example 1 72.3 70.3 Comparative Example 2 89.1 88.4 Comparative Example 3 90.0 89.2

[0087] Through the data analysis of the above examples and comparative examples, the low-cost, high-performance sodium ion battery cell prepared by the present invention has excellent electrochemical properties.

[0088] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a low-cost, high-performance sodium ion battery cell, comprising: Positive electrode, negative electrode, diaphragm, electrolyte; the preparation method of the positive electrode is: S1: Add 12-18 parts of sodium carbonate, 34-42 parts of ferrous oxalate, 1-5 parts of manganese acetate, 47-54 parts of ammonium dihydrogen phosphate, 1-6 parts of mercaptoethylguanidine dihydrobromide complexing agent, 1-6 parts of glucose, and 2-7 parts of ethanol to a ball mill, mill for 16-24 hours, remove from the mill, and vacuum dry to obtain a precursor; S2: The precursor is placed in a tube furnace and calcined at high temperature under an argon atmosphere to obtain the active material; S3: 60-80 parts of active material, 5-10 parts of carbon nanotubes, 5-10 parts of binder, and 1-5 parts of dimethyl sulfoxide are stirred and mixed evenly, and then coated on a titanium sheet and dried to obtain a positive electrode.

2. The method for preparing a low-cost, high-performance sodium ion battery cell according to claim 1, wherein: The high-temperature calcination temperature of S2 is 500-600°C and the time is 8-12 hours.

3. The method for preparing a low-cost, high-performance sodium ion battery cell according to claim 1, characterized in that: The binder is one of polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polytetrafluoroethylene, polyvinyl alcohol, acrylonitrile multipolymer, styrene-butadiene rubber and carboxymethyl cellulose.

4. The method for preparing a low-cost, high-performance sodium ion battery cell according to claim 1, wherein: The negative electrode is hard carbon.

5. The method for preparing a low-cost, high-performance sodium ion battery cell according to claim 1, characterized in that: The diaphragm is glass fiber.

6. The method for preparing a low-cost, high-performance sodium ion battery cell according to claim 1, characterized in that: The electrolyte is prepared by dissolving sodium perchlorate with a concentration of 1 mol / L in ethylene carbonate and polycarbonate with a volume ratio of 1:1, and adding fluoroethylene carbonate with a mass concentration of 5%.

7. The method for preparing a low-cost, high-performance sodium ion battery cell according to claim 1, characterized in that: The preparation method of the mercaptoethylguanidine dihydrobromide complexing agent is: H1 ring-opening addition: Mix 20-34 parts of mercaptoethylguanidine (MEG) dihydrobromide with 10-30 parts of ethylene oxide in 100-200 parts of DMF and react at 80-90°C for 3-6 hours to generate N-(2-hydroxyethyl)-N'-(2-mercaptoethyl)guanidine intermediate; H2 quaternization addition: add 30-50 parts of allyltrimethylammonium bromide to the above reaction system and react at 60-70°C for 2-4 hours to generate mercaptoethylguanidine dihydrobromide complexing agent.