Oxidative coupling preparation and application of nitrogen / phosphine double-site conjugated polymer organic positive electrode material

Abstract

The invention discloses an oxidative coupling preparation method of a nitrogen / phosphine double-site conjugated polymer organic positive electrode material and application of the nitrogen / phosphine double-site conjugated polymer organic positive electrode material in an alkali metal-based battery. The nitrogen / phosphine double-site conjugated polymer with a permanent porous structure and a hierarchical network is prepared by enabling a triphenylamine derivative monomer and triphenylphosphine to react for 24-48 hours in an organic solvent (such as chloroform and nitromethane) under the protection of inert gas and the action of a catalyst (such as FeCl3 or AlCl3) through a Scholl oxidative coupling reaction and directly copolymerizing the triphenylamine derivative monomer and the triphenylphosphine in the organic solvent (such as chloroform and nitromethane) at the temperature of 0-30 DEG C, and the nitrogen / phosphine double-site conjugated polymer with the permanent porous structure and the hierarchical network is obtained. A typical embodiment of the present invention is named P (PZ2TPA-TPP). The polymer has high-density nitrogen and phosphorus active sites, triphenylamine and triphenylphosphine units are synchronously introduced into the structure, a difunctional site network for synergistically accelerating anion transmission is formed, and the technical bottlenecks of low ion transmission efficiency, poor rate capability, insufficient cycle stability and the like of a traditional organic positive electrode material are effectively improved. The material can be used for preparing a positive plate, and shows high working voltage (about 3.79 V), high specific capacity (-135mAh g <-1 >), excellent cycling stability (the voltage is not obviously attenuated after 200 times of cycling) and excellent rate capability (the voltage is still kept about 100mAh g <-1 > under 10Ag <-1 >) in a lithium dual-ion battery. After the lithium double-ion total battery is further assembled, under a high-load condition (gt; 2 mg cm <-2 >) shows long cycle life (600 times of cycle stability), high energy density and practical application potential, for example, the material can supply power to a smart phone in real time. The preparation process is simple and convenient, the yield is high (up to 88%), and the method is suitable for alkali metal-based batteries of lithium, sodium, potassium and the like, and has important scientific significance and industrial application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery materials, in particular to a preparation and application of an organic positive electrode material, more particularly to a kind of nitrogen / phosphine biste site conjugated polymer organic positive electrode material based on Scholl oxidative coupling method, based on triphenylamine derivative and triphenylphosphine copolymerization is formed, and is applied to high energy density lithium double ion battery and other alkali metal-based battery. BACKGROUND

[0002] Current commercialized lithium ion batteries mainly rely on transition metal oxide inorganic positive electrode materials (such as LiCoO2, LiNi 1-x-y Co x Mn y O2), but this kind of material has the problems of scarce transition metal resources, large pollution in mining and processing, rising cost, etc., which is difficult to meet the long-term sustainable development demand.

[0003] Organic electrode materials have become an important direction to replace inorganic electrodes due to their strong designability, low cost and good environmental compatibility. Among them, organic p-type positive electrode materials need to realize charge compensation through anion (such as PF6-) intercalation / deintercalation during work, and can be matched with commercial graphite negative electrode to build lithium double ion battery. Its working voltage is usually more than 3V, which is significantly better than n-type organic electrode (usually less than 3V vs. Li+ / Li), and is more in line with the demand of the next generation of high-voltage energy storage.

[0004] However, the existing p-type organic positive electrode materials still have the key technical bottlenecks of low ion transmission efficiency, fast voltage decay, poor rate performance, and insufficient cycle stability, which can be attributed to their close-packed irregular bulk structure or micropore-dominated porous structure, which is not conducive to the rapid transmission of large-size anions.

[0005] Here, by directly copolymerizing two p-type units through Scholl oxidative coupling method, the combination of π conjugation extension and permanent porous structure can be realized, which provides the possibility to form an optimized ion transmission framework and solve the above problems. Therefore, it has pioneering value to develop a high-voltage, high-active site exposure, multi-mode synergistic ion transmission and simple preparation of nitrogen / phosphine biste site conjugated polymer p-type positive electrode material, which promotes the practicalization of lithium double ion battery and other alkali metal batteries. SUMMARY

[0006] The present application provides a polymer preparation method based on Scholl oxidative coupling, specifically, triphenylphosphine is directly copolymerized with another p-type monomer, which realizes more efficient ion transmission network compared to porous polymers containing only nitrogen sites, thereby realizing excellent rate performance and cycle stability.

[0007] The present application is realized by the following technical scheme:

[0008] This invention provides a nitrogen / phosphine dual-site conjugated polymer cathode material, one example named P(PZ2TPA-TPP). One of the two comonomers of P(PZ2TPA-TPP) is a triphenylphosphine unit, and the other is a triphenylamine derivative. Since this polymer is not a one-dimensional linear polymer, a repeating unit comprising both monomers is provided, as follows:

[0009]

[0010] R1 is a triphenylamine derivative, and its chemical formula can be:

[0011]

[0012] The present invention also provides a method for preparing the above-mentioned type of polymer, comprising: reacting monomer R1 and triphenylphosphine in an organic solvent at 0°C to 30°C for 24 to 48 hours under an inert gas atmosphere and with the action of a catalyst.

[0013] In one specific embodiment, the specific steps of the above preparation method include: placing triphenylphosphine, monomer R1 and catalyst in an organic solvent and reacting them at 0°C to 30°C to prepare the polymer.

[0014] In one specific embodiment, the catalyst includes FeCl3 or AlCl3, and the organic solvent includes one or both of chloroform and nitromethane.

[0015] The present invention also provides an application of a polymer electrode material, namely, the application of the above-mentioned nitrogen / phosphine dual-site conjugated polymer cathode material, or the nitrogen / phosphine dual-site conjugated polymer cathode material prepared by the above-mentioned method, in alkali metal-based batteries.

[0016] In one specific embodiment, the alkali metal-based battery includes an alkali metal battery and an alkali metal ion battery.

[0017] In one specific embodiment, the alkali metal includes lithium, sodium, and potassium; the alkali metal ion includes lithium ion, sodium ion, or potassium ion.

[0018] The present invention also provides a positive electrode sheet, the positive electrode sheet comprising the above-mentioned nitrogen / phosphine dual-site conjugated polymer positive electrode material, or the nitrogen / phosphine dual-site conjugated polymer positive electrode material prepared by the above-mentioned method for preparing polymer electrode materials.

[0019] The present invention also provides an alkali metal ion battery, wherein the positive electrode material of the battery includes the above-mentioned nitrogen / phosphine dual-site conjugated polymer positive electrode material, or the nitrogen / phosphine dual-site conjugated polymer positive electrode material obtained by the above-mentioned method for preparing nitrogen / phosphine dual-site conjugated polymer positive electrode material; or the electrode sheet of the battery includes the above-mentioned positive electrode sheet.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] 1. The present invention provides an organic polymer electrode material, its preparation method and application. By precisely selecting the reactive monomers and controlling the reaction, an electrode material with an enhanced network structure is obtained. It has high-density N / P dual active sites and hierarchical porous characteristics, which makes the polymer have high capacity, high potential and high stability. It enables the constructed alkali metal-based battery to have excellent energy density, cycle life and cycle stability.

[0022] 2. The present invention provides an organic polymer electrode material, its preparation method and application. By designing the reactive monomers, a class of organophosphine site conjugated polymer cathode materials can be obtained, which have novel network structures and unique electrochemical properties. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0024] Figure 1 The synthetic route of P(PZ2TPA-TPP) in this embodiment of the invention is shown below;

[0025] Figure 2 The Fourier transform infrared spectrum of P(PZ2TPA-TPP) in embodiment P of the present invention;

[0026] Figure 3 This is a low-current charge-discharge curve of P(PZ2TPA-TPP) in a lithium dual-ion battery according to an embodiment of the present invention;

[0027] Figure 4 This is a voltage retention diagram of P(PZ2TPA-TPP) in a lithium dual-ion battery according to an embodiment of the present invention;

[0028] Figure 5 This is a rate performance diagram of P(PZ2TPA-TPP) in a lithium dual-ion battery according to an embodiment of the present invention;

[0029] Figure 6 This is a low-current charge-discharge curve of P(PZ2TPA-TPP) in a lithium-based dual-ion full cell according to an embodiment of the present invention;

[0030] Figure 7 This is a graph showing the long-cycle performance of P(PZ2TPA-TPP) in a lithium-based dual-ion full cell according to an embodiment of the present invention.

[0031] Figure 8 This diagram illustrates the practical application potential of P(PZ2TPA-TPP) in lithium-based dual-ion full batteries according to embodiments of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0033] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0034] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0036] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0037] like Figure 1 As shown in the embodiment of the present invention, a method for preparing a nitrogen / phosphine dual-site conjugated polymer cathode material P (PZ2TPA-TPP) includes: reacting monomer R1 and triphenylphosphine in an organic solvent at 0℃~30℃ for 24~48h under an inert gas atmosphere and in the presence of a catalyst. The inert gas includes nitrogen, argon, or helium, preferably nitrogen. The catalyst can be FeCl3, AlCl3, CuCl2, or FeBr3, preferably FeCl3. The ratio of monomer R1 to triphenylamine is 0.5-2, and can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2. The reaction temperature can be 0℃, 5℃, 10℃, 15℃, 20℃, 25℃, or 30℃. The reaction time can be 24h, 28h, 32h, 34h, 36h, 40h, 44h, 46h, or 48h. The organic solvent includes one or more of chloroform, dichloromethane, dichloroethane, dibromomethane, dibromoethane, or nitromethane, with chloroform being preferred.

[0038] The chemical formula of monomer R1 can be:

[0039]

[0040] To improve the purity of the product, the synthesized product was filtered to collect the precipitate, and then subjected to Soxhlet extraction with methanol to remove residual catalyst and oligomer impurities, followed by freeze drying.

[0041] The application of the aforementioned nitrogen / phosphine dual-site conjugated polymer cathode material, or the nitrogen / phosphine dual-site conjugated polymer cathode material prepared by the aforementioned method, in alkali metal-based batteries. The aforementioned nitrogen / phosphine dual-site conjugated polymer cathode material, or the nitrogen / phosphine dual-site conjugated polymer cathode material prepared by the aforementioned method, is used to prepare cathode sheets.

[0042] Example 1

[0043] like Figure 1 As shown in the embodiment of the present invention, a method for preparing a nitrogen / phosphine dual-site conjugated polymer cathode material P (PZ2TPA-TPP) includes the following steps:

[0044] R1 (1.99 g, 3 mmol), triphenylphosphine (0.79 g, 3 mmol), and chloroform (30 mL) were added to a three-necked flask and magnetically stirred until the solids were completely dissolved. In a separate beaker, ferric chloride (2.43 g, 15 mmol) was dissolved in 20 mL of nitromethane. The reaction system was cooled to 0 °C in an ice-water bath. Half of the ferric chloride solution was slowly added dropwise to the reaction system. After the addition was complete, the temperature was slowly raised to 30 °C and stirred at a constant temperature under a nitrogen atmosphere for 24 h. The remaining half of the ferric chloride solution was then added, and the reaction continued at 30 °C for another 24 h. After the reaction was complete, the reaction solution was slowly poured into 200 mL of methanol to terminate the reaction, and the mixture was allowed to stand overnight to ensure complete sedimentation. The crude product was collected by vacuum filtration and placed in a Soxhlet extractor for continuous extraction with methanol as the extractant for 48 h. The extracted product was then transferred to a vacuum freeze dryer and dried for 12 h to obtain 2.48 g of emerald green P(PZ2TPA-TPA) solid. The average yield of this gram-scale synthesis process is 88%.

[0045] The Fourier transform infrared spectrum of P(PZ2TPA-TPA) was analyzed, and the results are shown in the figure. Figure 2 .

[0046] like Figure 2 As shown, characteristic absorption peaks related to triphenylamine, triphenylphosphine, and dihydrophenazine are clearly observed in P(PZ2TPA-TPA). For example, at 1278 cm⁻¹. -1 The nearby absorption peaks can be clearly attributed to the CN stretching vibration of the tertiary amine. P(PZ₂TPA-TPA) at 820 cm⁻¹ -1 A significant absorption peak was observed at [value missing], corresponding to the out-of-plane bending vibration of the CH group of the 1,4-disubstituted benzene ring, confirming the formation of C-C covalent bonds between aromatic rings. [Value missing] at 1105 cm⁻¹ -1 The presence of a typical aromatic PC bond stretching vibration peak indicates the successful introduction of the triphenylphosphine unit. These characteristics combined demonstrate the formation of a rational chemical structure for the target polymer.

[0047] Example 2

[0048] This invention provides a method for preparing a positive electrode sheet, comprising the following steps: first, mixing P(PZ2TPA-TPP) (80wt%), Ketjen Black (10wt%), and polyacrylonitrile copolymer (10wt%) from Example 1, and then uniformly coating the mixture onto aluminum foil. The loading of P(PZ2TPA-TPP) on the electrode sheet is greater than 2 mg / cm³. -2 It is pressed into a circular aluminum electrode sheet.

[0049] Preparation of the negative electrode graphite sheet: First, graphite (90 wt%) and polyacrylonitrile copolymer (10 wt%) are mixed, and then uniformly coated onto copper foil. The graphite loading mass on the electrode sheet is greater than 5 mg / cm³.-2 It is pressed into a circular copper electrode sheet.

[0050] Example 3

[0051] This invention provides a method for preparing a lithium dual-ion half-cell, comprising the following steps: using a P(PZ2TPA-TPP) electrode sheet as the positive electrode, lithium metal as the negative electrode, and 1M LiPF6+EC / DEC / EMC as the electrolyte. The electrochemical performance of the half-cell is then tested.

[0052] from Figure 3 It can be seen that the median voltage of the battery is around 3.79V, and it can exhibit a capacity of approximately 135mAh g. -1 High capacity.

[0053] from Figure 4 It can be seen that after 200 cycles, the discharge voltage of the battery did not decrease significantly, indicating that the redox process of the P(PZ2TPA-TPA) cathode has excellent reversibility and is suitable for practical applications.

[0054] from Figure 5 It can be seen that up to 10Ag can be achieved. -1 It exhibits high current rate performance and still maintains approximately 100 mAh g at this current density. -1 High reversible capacity.

[0055] Example 4

[0056] This invention provides a method for preparing a lithium-based dual-ion full battery, comprising the following steps: assembling a full battery using a P(PZ2TPA-TPP) electrode sheet as the positive electrode, graphite as the negative electrode, and 1M LiPF6+EC / DEC / EMC as the electrolyte.

[0057] from Figure 6 It can be seen that the dual-ion full cell can be easily activated by the first charge and maintains stable electrochemical characteristics over up to 300 cycles.

[0058] from Figure 7 It can be seen that dual-ion full cells with different degrees of high load exhibit superior stability within 600 cycles, which serves as a proof of concept and confirms the practical application potential of dual-ion battery systems.

[0059] from Figure 8 It can be seen that a high-load single-layer pouch battery can provide real-time power to smartphones.

Claims

1. A nitrogen / phosphine bis-site conjugated polymer organic positive electrode material, characterized in that One of the two co-units is triphenylphosphine and the other is triphenylamine derivative, one of which contains two monomer repeating units as shown below:

2. A method for preparing a nitrogen / phosphine bis-site conjugated polymer organic cathode material, characterized in that, The triphenylphosphine and triphenylamine derivative monomers are subjected to oxidative coupling reaction in an organic solvent to obtain a nitrogen / phosphine biste site-containing conjugated polymer. The triphenylamine derivative monomer can be: named R1.

3. The method for preparing the nitrogen / phosphine dual-site conjugated polymer organic cathode material according to claim 2, characterized in that, The application further relates to a preparation method of the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material. The monomers R1 and triphenylphosphine are subjected to reaction in an organic solvent under the action of a catalyst under an inert gas atmosphere at 0-30 DEG C for 24-48 h.

4. The method for preparing the nitrogen / phosphine dual-site conjugated polymer organic cathode material according to claim 3, characterized in that, The catalyst can be FeCl3, AlCl3, CuCl2 or FeBr3.

5. The method for preparing the nitrogen / phosphine dual-site conjugated polymer organic cathode material according to claim 4, characterized in that, The ratio of the monomers R1 to triphenylphosphine is 0.5-2.

6. Use of a nitrogen / phosphine bis-site conjugated polymer organic cathode material, characterized in that, The nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material prepared by the preparation method of the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material according to claim 1 or any one of claims 2-5 is applied to an alkali metal-based battery.

7. The use of a nitrogen-rich conjugated polymer organic cathode material according to claim 6, characterized in that, The alkali metal-based battery includes an alkali metal battery or an alkali metal ion battery.

8. The use of a nitrogen-rich conjugated polymer organic cathode material according to claim 7, characterized in that, The alkali metal includes lithium, sodium or potassium, and the alkali metal ion includes lithium ion, sodium ion or potassium ion.

9. A positive electrode sheet characterized by comprising: The positive electrode sheet includes the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material according to claim 1 or the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material prepared by the preparation method of the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material according to any one of claims 2-5.

10. An alkali metal-based battery, characterized by, The positive electrode material of the battery includes the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material according to claim 1 or the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material prepared by the preparation method of the nitrogen / phosphine biste site-containing conjugated polymer organic positive electrode material according to any one of claims 2-5, or the electrode sheet of the battery includes the positive electrode sheet according to claim 9.

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