A method for the use of a multi-active site pyrene-based fused ring compound in a primary battery

Abstract

The application provides a method for applying a multi-active-site pyrene-based condensed ring compound to a primary battery, and a primary battery is assembled by taking the multi-active-site pyrene-based condensed ring compound as a positive electrode active material, taking an alkali metal as a negative electrode, and taking an alkali metal salt solution as an electrolyte. Through in-situ carbon loading of the active material, a solid multi-hydroxyl proton-donating additive, and a liquid proton-donating additive, the performance of the multi-active-site organic positive electrode material in the primary battery is greatly improved. By taking such an organic substance as the positive electrode, an alkali metal as the negative electrode, and an alkali metal salt solution as the electrolyte, the multi-electron reduction of the organic functional group can be realized in the battery, and the specific capacity and energy density of the organic electrode material are greatly improved. The organic positive electrode material has the advantages of high energy density, low cost, easy scale production, and the like, and has great application value.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of battery organic positive electrode materials, and particularly relates to application of a polycyclic organic material with multiple active sites in a primary battery and a performance improvement method. BACKGROUND

[0002] The demand for new energy structure is increasingly urgent in today's society. In the new energy system, batteries become the key to the development of many fields such as new energy vehicles and large-scale energy storage. As an important branch of lithium batteries, lithium primary batteries have the advantages of high energy density, high working voltage, long storage life, and wide working temperature range, and have been widely used in aerospace, military, medical, transportation, and people's livelihood. With the development of military equipment, aerospace, and polar exploration, high-energy-density primary batteries have once again become the focus of attention. Therefore, it is of great significance to explore positive electrode materials with high energy density, high power density, and excellent safety.

[0003] The currently commercialized lithium primary batteries include lithium-fluorinated carbon (Li-CFx) batteries, lithium-sulfur dioxide (Li-SO2) batteries, lithium-thionyl chloride (Li-SOCl2) batteries, and lithium-manganese dioxide (Li-MnO2) batteries. Among them, lithium-fluorinated carbon (Li-CFx) primary batteries are the highest energy density chemical power source at present, but their preparation requires the use of fluorine gas (F2), which is highly toxic, high in energy consumption, and seriously pollutes the environment; Li-SO2 and Li-SOCl2 have gas or liquid positive electrodes, and the active substances are easy to leak during use, thereby causing safety problems; the cost of MnO2 electrode material is relatively low, but the overall energy density of the battery is low, and the low-temperature performance and output power need to be improved.

[0004] In addition, organic small molecules have few reactive sites and small conjugated structures, which are easy to dissolve, resulting in the inability to further improve the capacity of the battery. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a method for applying a polycyclic compound with multiple active sites to a primary battery, which solves the problems of low energy density, relatively low working voltage, high production cost, high toxicity, safety to be improved, easy dissolution of organic molecules, and poor conductivity of the existing lithium primary battery positive electrode material.

[0006] The technical solution for achieving the purpose of the present application is as follows:

[0007] The present application provides a method for applying a polycyclic compound with multiple active sites to a primary battery, which uses a polycyclic compound with multiple active sites as a positive electrode active material to prepare a positive electrode, uses an alkali metal as a negative electrode, and uses an electrolyte to assemble a primary battery.

[0008] The multi-active point pyrene-based fused ring compound is:

[0009]

[0010] The main body is pyrene with a fused ring structure, and a series of fused ring nitro compounds are obtained by changing the reaction conditions to regulate the number of functional group substitutions. The fused ring structure can enhance the pi-pi effect, improve the conductivity of the material, and have more active sites to increase the number of active functional groups, so that the specific capacity and discharge voltage are improved, thereby improving the energy density of the battery as a whole.

[0011] Further, the synthesis method of the multi-active point pyrene-based fused ring compound is: dispersing pyrene in nitric acid, refluxing under the condition of heating and stirring, and obtaining the multi-active point pyrene-based fused ring nitro compound through filtration, washing and drying. According to different reaction conditions, different numbers of substitutions of the positive electrode material with nitro as the active functional group can be obtained.

[0012] Further, the multi-active point pyrene-based fused ring compound is in-situ loaded with conductive carbon during the synthesis process, and the preparation method is: dispersing pyrene in nitric acid, adding conductive carbon (the mass ratio of added conductive carbon to raw material pyrene is between 1:4 and 1:10), refluxing under the condition of heating and stirring, and obtaining the in-situ carbon-loaded multi-active point pyrene-based fused ring nitro compound through filtration, washing and drying.

[0013] Further, the conductive carbon is one or more of graphene, ketjen black and carbon nanotube.

[0014] Further, a solid multi-hydroxyl proton donor additive is added during the preparation of the positive electrode, and the preparation method is: uniformly mixing the multi-active point pyrene-based fused ring compound, the conductive agent, the binder and the solid multi-hydroxyl proton donor additive, forming a uniform slurry, and then coating it on the current collector and drying to obtain a positive electrode sheet.

[0015] Further, the conductive agent is preferably Super P, ketjen black and graphene, and the binder is preferably water-based binder sodium alginate SA, sodium carboxymethyl cellulose CMC and polyacrylic acid PAA.

[0016] Further, the solid multi-hydroxyl proton donor additive is one or more of multi-hydroxy aldehyde or multi-hydroxy ketone, preferably one or more of glucose, fructose, galactose, mannose and ribose.

[0017] Further, the addition amount of the solid multi-hydroxyl proton donor additive is 1% to 10% of the total mass of the positive electrode.

[0018] Further, the electrolyte is a solution of lithium salt with a concentration of 0.3-5 mol / L; the lithium salt is lithium bistrifluoromethylsulfonylimide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4) or lithium tetrafluoroborate (LiBF4); the solvent of the electrolyte is a mixed solution of chain ethers, cyclic ethers and cyclic carbonates in different proportions.

[0019] Further, the electrolyte is a solution of 0.5M LiClO4 DME added with 10-20% FEC (V / V) as the electrolyte.

[0020] Further, a liquid proton donor additive is added to the electrolyte in an amount of 1%-10% of the total mass of the electrolyte.

[0021] Further, the liquid proton donor additive is a compound containing hydroxyl or amino groups that can provide protons in an ionized state, including but not limited to water, methanol, ethanol, ethylene glycol, glycerol, ethylamine, ethylenediamine, amide compounds, etc.

[0022] Pyrene is used as the main body, the reactive site is increased, and the conjugated structure is also increased, which can not only improve the specific capacity of the battery but also improve the conductivity of the material, nitro is used as the active group, which can improve the discharge capacity and also serve as an electron-withdrawing group to improve the discharge voltage, thereby improving the energy density of the battery as a whole.

[0023] Advantages and beneficial effects of the present application:

[0024] (1) The present application provides a method for applying a multi-active-site pyrene-based fused ring compound to a primary battery. The multi-active-site pyrene-based fused ring compound is a series of fused ring aromatic compounds with pyrene as the main body material, and the active functional groups can be nitro groups with different substitution numbers. The pyrene-based main body increases the conjugated structure, enhances the pi-pi effect, improves the conductivity of the material, and uses nitro groups with different substitution numbers as active groups to improve the discharge capacity and also serve as electron-withdrawing groups to improve the discharge voltage, thereby improving the energy density of the battery as a whole.

[0025] (2) The present application realizes a substantial improvement in the performance of multi-active-site organic positive electrode materials in primary batteries through in-situ carbon loading of active materials, introduction of solid multi-hydroxyl proton donor additives and liquid proton donor additives.

[0026] (3) The lithium organic primary battery assembled by the positive electrode material obtained according to the present application has a specific capacity of 1400 mAh / g or more and a specific energy of 3600 Wh / kg or more, which exceeds the energy density of all currently reported organic electrode materials and most high-specific-energy inorganic electrode materials, and can be stored for a long time. Moreover, the raw material cost is low, the synthesis method is simple, and batch production can be realized, which has great application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Liquid chromatography-quadrupole time-of-flight mass spectra of mononitropyrene, dinitropyrene, trinitropyrene, and tetranitropyrene prepared according to Examples 1-4 of the present application;

[0028] Figure 2 Discharge curves of lithium primary batteries assembled using mononitropyrene, dinitropyrene, trinitropyrene, and tetranitropyrene prepared according to Examples 1-4 of the present application as positive electrode materials;

[0029] Figure 3 Discharge curves of lithium primary batteries assembled using trinitropyrene prepared according to Examples 5-7 of the present application and trinitropyrene prepared according to Example 3 as positive electrode materials;

[0030] Figure 4 Discharge curves of lithium primary batteries assembled using positive electrodes prepared according to Example 8 and positive electrodes prepared according to Example 3 without adding glucose.

[0031] Figure 5 Discharge curves of lithium primary batteries using electrolyte according to Example 9 and electrolyte according to Example 3. DETAILED DESCRIPTION

[0032] The present application will be further explained by the accompanying drawings and specific examples, which are only illustrative and should not be construed as limiting the scope of the present application, and the scope of protection of the present application is not limited to the following examples.

[0033] Example 1

[0034] The preparation method of mononitropyrene (1-NP) is as follows: a mixture of pyrene (1.00 g) and glacial acetic acid (30 mL) is added to a flask, and the mixture is heated at 60°C to dissolve the pyrene. While stirring, a mixture of glacial acetic acid (5 mL) and concentrated nitric acid (0.49 g, nitric acid concentration 68%) is added dropwise, and the mixture is continuously stirred at room temperature for 4 hours, and then poured into ice water. The solid is filtered off, washed with deionized water, and dried.

[0035] Preparation of positive electrode: mononitropyrene, conductive carbon (Superp), and binder (sodium alginate) are mixed uniformly in a mass ratio of 6:3:1, and transferred to a homogenizing box, and an appropriate amount of deionized water is added. After being mixed uniformly in a mortar and a homogenizer, the slurry is coated on an aluminum foil using a spatula, and first dried in a 60°C air oven for 6 hours, and then dried in a 60°C vacuum oven for 12 hours. A tablet machine is used to obtain a round tablet with a diameter of 10 mm, which is quickly transferred to a glove box (O2<0.1 ppm, H2O<0.1 ppm) in a high-purity argon atmosphere for use.

[0036] The electrolyte 0.5 M LiClO4 DME (dimethoxyethane) + FEC (fluoroethylene carbonate) (FEC 20% by volume of electrolyte) was prepared in a glove box, using a polypropylene (PP) separator, model Celgard 2400, lithium metal as the negative electrode, and the positive electrode described above, to assemble a coin cell, model CR2032, for electrochemical performance testing. Constant current charge-discharge tests were performed using a blue-circuit test system, with a current density of 20 mA g -1 , and a voltage test range of 3.0 V - 2.0 V. The discharge curve is shown in Figure 2 .

[0037] Example 2

[0038] The method for preparing dinitropyrene (DNP) was as follows: pyrene (2.5 g) was added to glacial acetic acid (25 mL), and a mixture of concentrated nitric acid (1.9 mL of nitric acid at 68% concentration) and glacial acetic acid (5 mL) was slowly added, and the reaction mixture was stirred at 75 °C for 1 hour. The reaction mixture was cooled to room temperature, and the resulting precipitate was filtered, washed with ethanol, and dried under vacuum. The crude product contained a mixture of 1,6-dinitropyrene, 1,8-dinitropyrene, 1,3-dinitropyrene, and 1-nitropyrene. The resulting mixture was separated by column chromatography to obtain the dinitropyrene product. Electrodes were prepared using the same method as in Example 1, and the batteries were assembled and tested, and the discharge curve is shown in Figure 2 .

[0039] Example 3

[0040] The method for preparing trinitropyrene (1,3,6-TNP) was as follows: ground pyrene (4 g) was added to concentrated nitric acid (320 mL of nitric acid at 68% concentration), and refluxed and stirred at 80 °C for 24 hours. After cooling to room temperature, the mixture was diluted with deionized water, and filtered several times through a 0.22 pm membrane to remove the acid. Electrodes were prepared using the same method as in Example 1, and the batteries were assembled and tested, and the discharge curve is shown in Figure 2 .

[0041] Example 4

[0042] The method for preparing tetranitropyrene (1,3,6,8-TNP) was as follows: ground pyrene (1.5 g) was added to 25 (mL) fuming nitric acid cooled to 0 °C, and the suspension was stirred for 2 hours, then warmed to room temperature and stirred for another 12 hours. The resulting mixture was filtered, washed several times with deionized water until neutral, and centrifuged several times with dimethyl sulfoxide (DMSO), and the dark filtrate was removed, and the resulting yellow powder was thoroughly washed with ethanol, and dried to obtain a bright yellow product, which was dried under vacuum. Electrodes were prepared using the same method as in Example 1, and the batteries were assembled and tested, and the discharge curve is shown in Figure 2 .

[0043] Example 5

[0044] Step one, the ground pyrene (0.5 g) and Superp (0.1 g) were added to 40 mL of concentrated nitric acid with a concentration of 68%, refluxed and stirred at 80°C for 24 hours. After cooling to room temperature, the mixture was diluted with deionized water and filtered through a 0.22 μm microporous membrane several times to remove the acid. After drying the resulting product at 60°C under vacuum for 12 h, Supperp in-situ loaded with trinitro-pyrene was obtained.

[0045] Step two, according to the test results of elemental analysis, the carbon content was calculated, which accounted for about 10% of the total mass of the loaded product. By calculation, the mass of the active material in the resulting product was transferred to the homogenizer box by grinding the total amount of conductive carbon (Superp) and the binder (sodium alginate) in a mass ratio of 6:3:1, dried in a 60°C air oven for 6 hours, and then dried in a 60°C vacuum oven for 12 hours. A tablet press was used to obtain a round tablet with a diameter of 10 mm. In an argon glove box, the above in-situ carbon-loaded trinitro-pyrene positive electrode sheet was assembled with a metal lithium negative electrode into a coin cell with 0.5M LiClO4 DME added 20% FEC (V / V) as electrolyte and Celgard 2400 as separator for electrochemical performance test under the same test conditions as above.

[0046] Example 6

[0047] The difference from Example 5 is that the Superp in Step one is replaced by carbon nanotubes to obtain carbon nanotube in-situ loaded trinitro-pyrene.

[0048] Example 7

[0049] The difference from Example 5 is that the Superp in Step one is replaced by graphene to obtain graphene in-situ loaded trinitro-pyrene.

[0050] Figure 3 The discharge curves of lithium primary batteries assembled with the conductive carbon in-situ loaded trinitro-pyrene prepared in Examples 5-7 and the trinitro-pyrene prepared in Example 3 as positive electrode material are shown in the figure. It can be seen from the figure that the discharge specific capacity of the trinitro-pyrene in-situ loaded with carbon is greatly improved compared with the trinitro-pyrene without loading. The performance of carbon nanotubes in the trinitro-pyrene in-situ loaded with carbon is the best, reaching 1272 mAh g -1 .

[0051] Example 8

[0052] The trinitro-pyrene (120 mg) prepared in Example 3, Superp (60 mg), sodium alginate (20 mg), glucose (20 mg) were mixed in a mortar in a mass ratio of 6:3:1:1, and then transferred into a homogenizing box. After mixing into a uniform slurry with an appropriate amount of deionized water, the slurry was scraped onto a current collector, dried in a 60°C air oven for 6 hours, and then dried in a 60°C vacuum oven for 12 hours. A round sheet with a diameter of 10 mm was obtained by using a sheet breaker, and a positive electrode sheet with a solid-state multi-hydroxyl compound added proton donor additive was obtained. In an argon glove box, the positive electrode sheet with a solid-state multi-hydroxyl compound added proton donor additive was assembled into a coin cell with a metal lithium negative electrode, using 0.5M LiClO4 DME added with 20% FEC (V / V) as the electrolyte and Celgard 2400 as the separator, for electrochemical performance testing under the same conditions as above. Figure 4 The discharge curves of the positive electrodes prepared with and without the addition of glucose assembled into lithium primary batteries are shown in the figure. It can be seen that the discharge capacity and discharge voltage of the positive electrode with the addition of glucose are improved compared with those without the addition of glucose. Glucose as a solid-state proton donor additive can interact with the active material on the positive electrode side to increase the discharge voltage, and provide certain protons during the reduction of nitro groups.

[0053] Example 9

[0054] The difference between Example 3 is that the electrolyte of the assembled battery is different, and the electrolyte is: 0.5M LiClO4 DME added with 20% FEC, 5% ethylene glycol (V / V), for electrochemical performance testing. From Figure 5 It can be seen that the electrolyte with the addition of ethylene glycol exhibits better electrochemical performance than the original electrolyte, and the specific discharge capacity reaches 1301 mAh g -1 . Ethylene glycol as a liquid-state proton donor additive has a significant improvement effect on the electrochemical performance of the primary battery.

[0055] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application.

Claims

1. A method for preparing a primary battery, characterized in that, A primary battery is assembled using a multi-active-site pyrene-based fused-ring compound as the positive electrode active material, an alkali metal as the negative electrode, and an electrolyte. The multi-active-site pyrene-based fused-ring compound is tetranitropyrene, with the following structural formula: ; The multi-active-site pyrene-based fused-ring compound is in-situ supported on conductive carbon during the synthesis process. The preparation method is as follows: pyrene is dispersed in nitric acid, conductive carbon is added, and the mixture is refluxed under heating and stirring conditions. After filtration, washing, and drying, the in-situ carbon-supported multi-active-site pyrene-based fused-ring nitro compound is obtained. The conductive carbon is one or more of graphene, Ketjen Black, and carbon nanotubes. A solid polyhydroxy proton-donating additive is added during the preparation of the positive electrode. The preparation method is as follows: the multi-active-site pyrene-based fused-ring compound, conductive agent, binder, and solid polyhydroxy proton-donating additive are uniformly mixed to form a homogeneous slurry, which is then coated onto a current collector and dried to obtain the positive electrode sheet; the solid polyhydroxy proton-donating additive is a polyhydroxy aldehyde or polyhydroxy ketone; the polyhydroxy aldehyde or polyhydroxy ketone is one or more of glucose, fructose, galactose, mannose, and ribose; A liquid proton-donating additive is added to the electrolyte, wherein the liquid proton-donating additive is one or more of water, methanol, ethanol, ethylene glycol, glycerol, ethylamine, ethylenediamine, and amide compounds. By in-situ carbon loading of active materials, introducing solid-state multi-hydroxyl proton-donating additives and liquid proton-donating additives, the performance of multi-active-site organic cathode materials in primary batteries can be significantly improved.

2. The method for preparing a primary battery according to claim 1, characterized in that, The amount of the solid polyhydroxy proton donor additive added is 1% to 10% of the total mass of the cathode.

3. The method for preparing a primary battery according to claim 1, characterized in that, The amount of the liquid proton-donating additive added is 1% to 10% of the total mass of the electrolyte.

Images