Organic positive electrode material of lithium ion battery, preparation method of organic positive electrode material and lithium ion battery

Abstract

The invention provides a lithium ion battery organic positive electrode material and a preparation method thereof, and a lithium ion battery, and belongs to the technical field of lithium ion battery positive electrode materials. The preparation method of the lithium ion battery organic positive electrode material comprises the following steps: step 1, stirring phenazine, sodium hydrosulfite, sodium carbonate, tributyl methyl ammonium chloride and 2-bromoethanol for reaction to obtain 5, 10-bis (2-ethoxyl) phenazine; and step 2, adding N, N '-carbonyldiimidazole into the 5, 10-bis (2-hydroxyethyl) phenazine to obtain poly (5, 10-phenazine diethanol carbonate) which is used as the organic positive electrode material of the lithium ion battery. The lithium ion battery organic positive electrode material has a dihydrophenazine unit structure, and has relatively good stability and relatively high working potential. In the lithium ion battery prepared from the organic positive electrode material of the lithium ion battery, the positive electrode material shows excellent cycling stability, relatively high working potential and relatively high specific capacity and energy density.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion battery positive electrode materials, and in particular to an organic positive electrode material for a lithium ion battery and a preparation method thereof, and a lithium ion battery. Background Art

[0002] With the continuous development of society, electronic devices have been widely used, and lithium-ion batteries are widely used in portable electronic devices such as mobile phones and watches, electric vehicles, aerospace, etc. due to their advantages such as higher energy density and long service life. Currently, lithium-ion batteries mostly use lithium-containing transition metal oxides and phosphide inorganic materials (such as LiFePO4, LiCoO2) as positive electrodes, which have disadvantages such as high cost and harm to the environment.

[0003] Organic materials are developed as electrode materials because they have unique redox active centers that can store high charges. They also have the advantages of strong structural design, wide sources, and low costs, making them promising candidates to replace inorganic materials. Phenazine, one of the main byproducts in the industrial 4-aminodiphenylamine synthesis process, is an azo compound with two nitrogen-containing active centers that can be used as an organic electrode material. According to research reports, p-type dihydrophenazine has a high redox potential (>3V, relative to Li / Li + ), which is suitable as a positive electrode material for lithium-ion batteries. Therefore, how to use industrial waste such as phenazine to synthesize new organic positive electrode materials has become a research hotspot in this field. Summary of the invention

[0004] The present invention is made to solve the above problems, and its purpose is to provide an organic positive electrode material for lithium ion batteries and a preparation method thereof, and a lithium ion battery.

[0005] The present invention provides an organic positive electrode material for a lithium ion battery, which has the following characteristics: the organic positive electrode material for the lithium ion battery is a dihydrophenazine polymer, and the structural formula of the dihydrophenazine polymer is:

[0006]

[0007] The present invention also provides a method for preparing the above-mentioned organic positive electrode material for lithium ion batteries, which has the following characteristics and comprises the following steps: step 1, stirring phenazine, sodium dithionite, sodium carbonate, tributyl methyl ammonium chloride and 2-bromoethanol to react to obtain 5,10-bis(2-hydroxyethyl)phenazine; step 2, adding N,N'-carbonyldiimidazole to 5,10-bis(2-hydroxyethyl)phenazine to obtain poly(5,10-phenazine diethanol carbonate) as the organic positive electrode material for lithium ion batteries.

[0008] The method for preparing the organic positive electrode material for lithium ion batteries provided by the present invention may also have the following characteristics: wherein step 1 comprises the following sub-steps: step 1.1, under a nitrogen atmosphere, adding phenazine, sodium dithionite, sodium carbonate, tributylmethylammonium chloride, solvent acetonitrile and water, and finally adding 2-bromoethanol into a reaction container, stirring at 100° C. for 24 to 48 hours to obtain a first mixture; step 1.2, monitoring the first mixture by TLC method until the reaction of the reactants in the first mixture is terminated, dripping water into the first mixture, collecting the filter cake by suction filtration, and obtaining the product 5,10-bis(2-hydroxyethyl)phenazine, wherein in step 1.1, the molar mass ratio of phenazine, sodium dithionite, sodium carbonate, tributylmethylammonium chloride, and 2-bromoethanol is 1:1.5:2:0.4:6.

[0009] The method for preparing the organic positive electrode material for lithium ion batteries provided by the present invention may also have the following characteristics: wherein, in step 2, the molar ratio of 5,10-bis(2-hydroxyethyl)phenazine to N,N'-carbonyldiimidazole is 1:(3.0-3.6).

[0010] The method for preparing the organic positive electrode material for lithium ion batteries provided by the present invention may also have the following characteristics: wherein step 2 comprises the following sub-steps: step 2.1, under a nitrogen atmosphere, adding N,N'-carbonyldiimidazole to 5,10-bis(2-hydroxyethyl)phenazine, the molar ratio of 5,10-bis(2-hydroxyethyl)phenazine to N,N'-carbonyldiimidazole being 1:(1.0-1.2), acetonitrile being a solvent, and stirring at 90° C. for 12-24 hours to obtain a second mixture; step 2.2, adding N,N'-carbonyldiimidazole to the second mixture, and stirring at 90° C. for 24-48 hours to obtain a polymer mixture; step 2.3, washing, centrifuging, and drying the polymer mixture to obtain poly(5,10-phenazine diethanol carbonate), wherein the molar mass of the N,N'-carbonyldiimidazole added in step 2.2 is twice the molar mass of the N,N'-carbonyldiimidazole added in step 2.1.

[0011] The method for preparing the organic positive electrode material for lithium ion batteries provided by the present invention may also have the following characteristics: wherein, in step 2.3, the washing reagents used for washing are methanol, DMSO, and acetone, respectively, and the washing times are three times each.

[0012] The present invention also provides a lithium ion battery having such characteristics, comprising: the above-mentioned organic positive electrode material for lithium ion battery.

[0013] The lithium-ion battery provided by the present invention may also have the following characteristics: wherein the preparation process of the lithium-ion battery is as follows: the organic positive electrode material, the conductive additive, and the binder of the lithium-ion battery are mixed and ground in a mass ratio of 5:4:4 to obtain a slurry; the slurry is coated on an aluminum foil, and the positive electrode sheet is obtained after drying and slicing; the positive electrode sheet, the negative electrode sheet, the separator and the electrolyte are combined to make a lithium-ion battery.

[0014] The lithium-ion battery provided by the present invention may also have the following characteristics: wherein the negative electrode sheet is lithium foil and the electrolyte is LiPF6-EC / DEC.

[0015] Beneficial effects of the present invention:

[0016] The present invention utilizes industrial byproduct phenazine to synthesize a lithium-ion battery organic positive electrode material with a dihydrophenazine unit structure, provides a new organic polymer positive electrode material with dihydrophenazine as a redox center for lithium-ion batteries, and realizes the conversion and utilization of waste resources.

[0017] The synthesis method of the organic positive electrode material for lithium-ion batteries of the present invention is relatively simple, the preparation process is green and environmentally friendly, the cost is low, and the performance is excellent.

[0018] The organic positive electrode material for lithium ion batteries of the present invention exhibits higher specific capacity and energy density, higher working potential and excellent cycle stability in lithium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The synthetic route of the organic positive electrode material for lithium-ion batteries in the embodiment of the present invention is shown in FIG.

[0020] Figure 2 5 is a charge and discharge curve of a lithium-ion battery in an embodiment of the present invention. In the figure, the number of charge and discharge times is represented by 5th, 50th, 100th and 200th, respectively. 5th, 50th, 100th and 200th represent charge and discharge 5 times, 50 times, 100 times, and 200 times, respectively.

[0021] Figure 3 It is a performance diagram of the charge and discharge test of the lithium-ion battery in the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments and the accompanying drawings specifically describe the organic positive electrode material for lithium ion batteries and the preparation method thereof, as well as the lithium ion battery of the present invention.

[0023] Example

[0024] This embodiment provides an organic positive electrode material for a lithium-ion battery.

[0025] The organic positive electrode material of the lithium-ion battery is a dihydrophenazine polymer, and the structural formula of the dihydrophenazine polymer is:

[0026]

[0027] This embodiment also provides a method for preparing the above organic positive electrode material for lithium-ion batteries.

[0028] Figure 1 The synthetic route of the organic positive electrode material for lithium-ion batteries in the embodiment of the present invention is shown in FIG.

[0029] like Figure 1 As shown, the preparation method of the organic positive electrode material for lithium-ion batteries comprises the following steps:

[0030] Step 1, stirring phenazine, sodium dithionite, sodium carbonate, tributylmethylammonium chloride and 2-bromoethanol to react to obtain 5,10-bis(2-hydroxyethyl)phenazine.

[0031] Step 1 specifically includes the following sub-steps:

[0032] Step 1.1, under nitrogen atmosphere, add 20 mmol phenazine, 30 mmol sodium dithionite, 40 mmol sodium carbonate, 8 mmol tributylmethylammonium chloride, 40 mL acetonitrile and 10 mL water as solvent into a 500 mL two-necked round-bottom flask, and finally add 120 mmol 2-bromoethanol, stir at 100°C for 48 h to obtain a first mixture.

[0033] Step 1.2, the first mixture is monitored by TLC method, the developing solvent is dichloromethane, after the monitoring reaction is terminated, water is added dropwise to the first mixture until no precipitate is produced, the mixture is filtered, and green crystals are collected to obtain 5,10-bis(2-hydroxyethyl)phenazine.

[0034] Step 2: adding N,N'-carbonyldiimidazole to 5,10-bis(2-hydroxyethyl)phenazine to obtain poly(5,10-phenazine diethanol carbonate).

[0035] Step 2 specifically includes the following sub-steps:

[0036] Step 2.1, under nitrogen atmosphere, add 0.370 mmol 5,10-bis(2-hydroxyethyl)phenazine and 0.444 mmol N,N'-carbonyldiimidazole and 0.5 mL acetonitrile as solvent into a 10 mL Shrek bottle, and stir at 90° C. for 24 h to obtain a second mixture.

[0037] Step 2.2, add 0.888 mmol N,N'-carbonyldiimidazole to the second mixture, stir at 90°C for 48 hours to obtain a polymer mixture.

[0038] Step 2.3, washing the polymer mixture three times with methanol, DMSO and acetone solvents respectively, centrifuging and drying to obtain poly(5,10-phenazine diethanol carbonate), which is used as an organic positive electrode material for lithium-ion batteries.

[0039] This embodiment also provides a lithium ion battery, which is a button battery assembled from the above-mentioned lithium ion battery organic positive electrode material, and its specific preparation method is as follows:

[0040] (1) Preparation of working electrode:

[0041] The organic positive electrode material of the lithium-ion battery (poly (5,10-phenazine diethanol carbonate)), the conductive agent multi-walled carbon nanotubes and the binder (PVDF) were mixed in a mass ratio of 5:4:1, and after ball milling for 2 hours, the slurry was evenly coated on the aluminum foil current collector with a coater at a thickness of 200 μm, dried at 80°C under vacuum for 12 hours, and sliced ​​to obtain a positive electrode sheet (working electrode) for use.

[0042] (2) Battery assembly:

[0043] Using 1M LiPF6-EC / DEC as the electrolyte and Celgard2400 membrane as the separator, the battery was packaged into a CR-2016 button battery using a sealing machine in the order of positive electrode shell, positive electrode sheet (working electrode), separator, negative electrode sheet (lithium foil), nickel foam, and negative electrode shell.

[0044] The charge and discharge performance of the lithium-ion battery was tested, and the results are as follows:

[0045] Figure 2 5 is a charge and discharge curve of a lithium-ion battery in an embodiment of the present invention. In the figure, the number of charge and discharge times is represented by 5th, 50th, 100th and 200th, respectively. 5th, 50th, 100th and 200th represent charge and discharge 5 times, 50 times, 100 times, and 200 times, respectively.

[0046] from Figure 2 It can be seen that the organic positive electrode material of the lithium-ion battery of this embodiment has two stable voltage platforms, and the voltage of the charge and discharge platforms is relatively high at about 3.1V and 3.9V.

[0047] Figure 3 It is a performance diagram of the charge and discharge test of the lithium-ion battery in the present invention.

[0048] from Figure 3 As can be seen from the figure, the organic positive electrode material of the lithium ion battery in this embodiment is 0.2Ag -1 At a current density of 186 mA hg -1 Specific capacity and 625Wh Kg-1 The discharge specific energy of the material is 181 mAh g -1 After 200 cycles, the capacity is still 146mA hg -1 , which is 81% of the theoretical capacity, showing good cycle stability.

[0049] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An organic positive electrode material for a lithium-ion battery, characterized in that: The organic positive electrode material of the lithium-ion battery is a dihydrophenazine polymer, and the structural formula of the dihydrophenazine polymer is:

2. A method for preparing an organic positive electrode material for a lithium-ion battery as claimed in claim 1, characterized in that: The following steps are involved: Step 1, stirring phenazine, sodium dithionite, sodium carbonate, tributylmethylammonium chloride and 2-bromoethanol to react to obtain 5,10-bis(2-hydroxyethyl)phenazine; Step 2: Add N,N'-carbonyldiimidazole to the 5,10-bis(2-hydroxyethyl)phenazine to obtain poly(5,10-phenazine diethanol carbonate) as the organic positive electrode material for the lithium ion battery.

3. The method for preparing an organic positive electrode material for a lithium-ion battery according to claim 2, characterized in that: in, Step 1 includes the following sub-steps: Step 1.1, under a nitrogen atmosphere, add the phenazine, the sodium dithionite, the sodium carbonate, the tributyl methyl ammonium chloride, the solvent acetonitrile and water, and finally add 2-bromoethanol into a reaction container, and stir at 100° C. for 24 to 48 hours to obtain a first mixture; Step 1.2, monitoring the first mixture by TLC method until the reaction of the reactants in the first mixture is terminated, adding water dropwise to the first mixture, and collecting the filter cake by suction filtration to obtain the product 5,10-bis(2-hydroxyethyl)phenazine, Wherein, in step 1.1, the molar mass ratio of phenazine, sodium dithionite, sodium carbonate, tributylmethylammonium chloride and 2-bromoethanol is 1:1.5:2:0.4:

6.

4. The method for preparing an organic positive electrode material for a lithium-ion battery according to claim 2, characterized in that: in, In step 2, the molar ratio of the 5,10-bis(2-hydroxyethyl)phenazine to the N,N'-carbonyldiimidazole is 1:(3.0-3.6).

5. The method for preparing an organic positive electrode material for a lithium-ion battery according to claim 2, characterized in that: in, Step 2 includes the following sub-steps: Step 2.1, under a nitrogen atmosphere, adding N,N'-carbonyldiimidazole to the 5,10-bis(2-hydroxyethyl)phenazine, wherein the molar ratio of the 5,10-bis(2-hydroxyethyl)phenazine to the N,N'-carbonyldiimidazole is 1:(1.0-1.2), and the solvent is acetonitrile, and stirring is performed at 90° C. for 12-24 hours to obtain a second mixture; Step 2.2, adding N,N'-carbonyldiimidazole to the second mixture, stirring at 90° C. for 24-48 hours to obtain a polymer mixture; Step 2.3, washing, centrifuging and drying the polymer mixture to obtain the poly(5,10-phenazine diethanol carbonate), The molar mass of the N,N'-carbonyldiimidazole added in step 2.2 is twice the molar mass of the N,N'-carbonyldiimidazole added in step 2.

1.

6. The method for preparing an organic positive electrode material for a lithium-ion battery according to claim 5, characterized in that: in, In step 2.3, the washing reagents used for washing are methanol, DMSO, and acetone, and the washing times are three times each.

7. A lithium ion battery, characterized in that: include: The organic positive electrode material for a lithium-ion battery according to claim 1.

8. The lithium ion battery according to claim 7, Features: in, The preparation process of the lithium ion battery is as follows: The organic positive electrode material for lithium-ion batteries, the conductive additive, and the binder are mixed and ground in a mass ratio of 5:4:4 to obtain a slurry; The slurry is coated on aluminum foil, and after drying and slicing, a positive electrode sheet is obtained; The positive electrode sheet, the negative electrode sheet, a separator and an electrolyte are combined to form the lithium ion battery.

9. The lithium-ion battery according to claim 8, characterized in that: in, The negative electrode sheet is lithium foil, and the electrolyte is LiPF6-EC / DEC.

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