CO2 absorption composition, method for detecting CO2 concentration and application

Abstract

The invention relates to the field of supercapacitors, in particular to a CO2 absorption composition, a method for detecting CO2 concentration and application. The CO2 absorption composition comprises modified tubular halloysite and an additive, the modified tubular halloysite is tubular halloysite grafted with a group N, N '-diaryl-dihydrodibenzo [a, c] phenazine, and the structure of the additive has at least one of an amino group, an amidino group and a hydrazone group. The CO2 absorption composition can adsorb CO2 in a chemical and physical combined mode, can detect the concentration of CO2 at the same time, and can eliminate CO2 generated in the high-temperature loading process of a supercapacitor monomer when being used in the supercapacitor.

Description

Technical Field

[0001] The present invention relates to the field of supercapacitors, and in particular to a CO2 absorption composition, a method for detecting CO2 concentration, and applications thereof. Background Art

[0002] Supercapacitors, energy storage devices between traditional capacitors and batteries, offer a range of unique advantages that have led to their widespread application in various fields. However, current supercapacitors are prone to producing gases (such as carbon dioxide) during use, which can cause bloating, rupture, and even fire, shortening their service life and posing safety risks.

[0003] Existing technology involves coating the inner surface of the aluminum-plastic film with a layer of activated carbon material with a high specific surface area and a well-developed pore size distribution at the location corresponding to the bare cell to absorb excess C₂H₄ and CO₂ gases in the electrochemical system. Although activated carbon has a large specific surface area and is porous and porous, its gas adsorption is non-selective and involves physical adsorption, which cannot guarantee whether the activated carbon material has already adsorbed other gases during assembly. Another approach involves mixing a conductive agent slurry with a gas adsorbent slurry, then adding an active substance to create a coating slurry to form electrode plates to absorb gases generated during battery use. However, adding adsorbents to the electrode plates as additives can easily alter the electrode formulation, resulting in reduced product performance. Another approach involves polishing the inner cavity of the aluminum casing, cleaning it of debris, and then evenly spraying a powdered calcium oxide coating onto the surface of the aluminum casing to absorb CO₂ and water vapor. However, CaO does not react directly with CO₂ at room temperature, only at high temperatures (above 500°C). Furthermore, the reaction between CaO and water generates significant heat, which can accelerate capacitor failure and even pose safety risks. Therefore, there is an urgent need to solve the gas production phenomenon during the use of supercapacitors. Summary of the Invention

[0004] The present invention aims to at least partially address one of the technical problems in the related art. To this end, the present invention provides a CO2 absorption composition, a method for detecting CO2 concentration, and its application. The CO2 absorption composition can adsorb CO2 through a combination of chemical and physical methods, while also enabling CO2 concentration detection. Its use in supercapacitors can eliminate CO2 generated during high-temperature loads within supercapacitor cells.

[0005] To this end, the first aspect of the present invention provides a CO2 absorption composition, which includes a modified tubular halloysite and an additive, wherein the modified tubular halloysite is a tubular halloysite grafted with a group N,N'-diaryl-dihydrodibenzo[a,c]phenazine, and the additive structure has at least one of an amino group, an amidine group or a hydrazone group.

[0006] The CO2 absorption composition comprises modified tubular halloysite and an additive, wherein the halloysite (HNTs) has a hollow tubular structure with a helical conformation, a high tube cavity capacity, and can absorb CO2 by physical action as a nano reservoir, and the halloysite is modified, that is, grafted with a fluorescent group N,N'-diaryl-dihydrodibenzo[a,c]phenazine, and can be combined with the additive by intermolecular forces to achieve fluorescence indication. In addition, the additive can react with CO2 due to the amino, amidine or hydrazone groups in the structure, that is, absorb CO2 by chemical reaction, so that the composition can realize the absorption and indication of CO2.

[0007] According to an embodiment of the present application, the modified tubular halloysite is tubular halloysite grafted with a group N,N'-diphenyl-dihydrodibenzo[a,c]phenazine.

[0008] According to an embodiment of the present application, the additive has an amino group in the structure.

[0009] According to an embodiment of the present application, the additive comprises N,N-dimethyl-1-dodecylamine.

[0010] According to an embodiment of the present application, the mass of the modified tubular halloysite to the volume of the additive is (1-3) g:(1-3) mL.

[0011] According to an embodiment of the present application, the mass of the modified tubular halloysite to the volume of the additive is 1 g:1 mL.

[0012] The second aspect of the present application provides a method for detecting the concentration of CO2 in a liquid, which comprises detecting the concentration of CO2 in the liquid in the presence of the CO2 absorption composition of the first aspect.

[0013] The modified tubular halloysite in the composition can realize the physical absorption of CO2, the additive can realize the chemical absorption of CO2, and the additive and the modified tubular halloysite are combined by intermolecular forces to obtain a CO2 response system. The system produces different fluorescence intensities before and after the reaction with CO2, so the change in the concentration of CO2 can be monitored according to the change in the fluorescence intensity. According to experiments, the fluorescence intensity of the composition (CO2 response system) at 450 nm is almost linearly positively correlated with the amount of CO2 added (when the absorption amount is not saturated, the amount added is the absorption amount, that is, the reaction amount), and the linear correlation coefficient of the fitting curve is about 0.998, so the composition can realize the accurate testing of the concentration of CO2.

[0014] According to an embodiment of the present application, the method further comprises contacting the modified tubular halloysite and the additive to realize the detection of the concentration of CO2 in the liquid by the change in the fluorescence intensity.

[0015] A third aspect of the present invention provides a method for reducing gas production in a supercapacitor, characterized in that it comprises the following steps:

[0016] Chemically modifying the tubular halloysite so that the tubular halloysite is grafted with an N,N'-diaryl-dihydrodibenzo[a,c]phenazine group to obtain a modified tubular halloysite;

[0017] coating the modified tubular halloysite on the inner wall of a supercapacitor housing to obtain a pretreated housing;

[0018] Assembling the pretreated housing and the supercapacitor core, injecting an electrolyte containing additives, and performing an aging treatment;

[0019] Wherein, the additive structure has at least one of amino, amidine or hydrazone groups.

[0020] This method can eliminate the CO2 generated during the high-temperature load of the supercapacitor monomer through physical and chemical dual adsorption, while also avoiding the increase in internal pressure of the supercapacitor closed system due to limited physical adsorption or CO2 desorption under high temperature conditions. As a result, the supercapacitor has better consistency and longer cycle life. In addition, this method can also monitor the CO2 concentration in the working supercapacitor system, further improving safety performance.

[0021] According to an embodiment of the present invention, the method further comprises: performing a first chemical modification on the tubular halloysite to obtain amino-modified tubular halloysite;

[0022] subjecting the amino-modified tubular halloysite to an acyl chloride reaction to obtain an acyl chloride product;

[0023] The acyl chloride product is contacted with (dibenzo[a,c]phenazine-9,14-diylbis(4,1-phenylene))dimethanol (DPAC-OH) to obtain modified tubular halloysite.

[0024] According to an embodiment of the present invention, the additive includes N,N-dimethyl-1-dodecylamine.

[0025] According to an embodiment of the present invention, the ratio of the volume of the additive added to the electrolyte containing the additive to the mass of the electrolyte before adding the additive is (0.1-1.5) mL:22 g.

[0026] According to an embodiment of the present invention, the ratio of the volume of the additive added to the electrolyte containing the additive to the mass of the electrolyte before adding the additive is (0.5-1.5) mL:22 g.

[0027] According to an embodiment of the present invention, the volume ratio of the mass of the modified tubular halloysite to the additive is (1-3) g:(1-3) mL.

[0028] A fourth aspect of the present invention provides a supercapacitor, which is obtained according to the method described in the third aspect.

[0029] As a result, the supercapacitor has better consistency, longer cycle life, and higher safety performance.

[0030] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0032] Figure 1 The SEM images of the halloysite in Example 1 of the present invention are shown. Figure A is a SEM image of the purified halloysite obtained in step (1) of Example 1; Figure B is a SEM image of the HNTs-DPAC material obtained in step (6) of Example 1;

[0033] Figure 2 The EDS test results of the halloysite in Example 1 of the present invention are shown. Figure A is a distribution diagram of carbon elements in the purified halloysite obtained in step (1) of Example 1; Figure B is a distribution diagram of nitrogen elements in the purified halloysite obtained in step (1) of Example 1; Figure C is a result diagram of the content of each major element in the purified halloysite obtained in step (1) of Example 1; Figure D is a distribution diagram of carbon elements in the HNTs-DPAC material obtained in step (6) of Example 1; Figure E is a distribution diagram of nitrogen elements in the HNTs-DPAC material obtained in step (6) of Example 1; Figure F is a result diagram of the content of each major element in the HNTs-DPAC material obtained in step (6) of Example 1;

[0034] Figure 3 The internal resistance curves of supercapacitor cells prepared in Examples 1-3 and Comparative Example 1 after aging and 2000 hours of high-temperature load testing are shown. The "untreated" curve corresponds to Comparative Example 1, the "0.5g" curve corresponds to Example 2, the "1.0g" curve corresponds to Example 1, and the "1.5g" curve corresponds to Example 3.

[0035] Figure 4 The following figure shows the capacity change curves of supercapacitor cells prepared in Examples 1-3 and Comparative Example 1 after aging and undergoing a 2000-hour high-temperature load test. The "untreated" curve corresponds to Comparative Example 1, the "0.5g" curve corresponds to Example 2, the "1.0g" curve corresponds to Example 1, and the "1.5g" curve corresponds to Example 3.

[0036] Figure 5 The capacity change curves of the supercapacitor monomers prepared in Example 1 and Comparative Examples 1-4 of the present invention after aging and 2000 hours of high temperature load test are shown. The "HNTs-DPAC-Ty" curve corresponds to Example 1, the "untreated" curve corresponds to Comparative Example 1; the "with HNTs-DPAC but without C" curve corresponds to Comparative Example 1. 12 A” curve corresponds to the corresponding ratio 2; “HNTs-Cl+C 12 A” curve corresponds to the ratio 3; “DPAC-OH+C 12 The A” curve corresponds to the proportion 4;

[0037] Figure 6 The internal resistance change curves of the supercapacitor monomers prepared in Example 1 and Comparative Examples 1-4 of the present invention after aging and 2000 hours of high temperature load test are shown. Figure 5 Description;

[0038] Figure 7 The embodiment 2 provided by the present invention includes HNTs-DPAC material and C 12 The results of the response test of the system A to CO2. (a) shows the fluorescence spectrum of the system after reacting with different contents of CO2; (b) shows the pictures after adding 0, 1, 2, 3, 4 and 5 mL of CO2 to the system under 365 nm ultraviolet light; (c) shows the linear relationship between the I / I0 ratio at 450 nm and different CO2 volumes, where I and I0 are the fluorescence intensities of the system before and after the introduction of CO2, and V is the volume of CO2; (d) shows the fluorescence intensity ratio (I 450 / I 590 ) and the linear relationship between different CO2 volumes, where I 450 and I 590 represent the fluorescence intensity of the system at 450 nm and 590 nm, respectively, and V is the volume of CO2;

[0039] Figure 8 The figure shows the fluorescence spectrum of the wall coating obtained by disassembling the supercapacitor subjected to high temperature load in Example 2 of the present invention. DETAILED DESCRIPTION

[0040] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0041] It should be noted that the terms "first", "second" are used only for descriptive purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, the features defined with "first", "second" can include one or more of the features explicitly or implicitly. Further, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0042] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The ranges and values should be construed to be roughly about the ranges or values stated to include amounts in close proximity to the exact values stated. For numerical ranges having an upper and lower limit, the endpoints of the ranges are included in the range. For ranges having an upper limit only, the upper limit is included in the range. For ranges having a lower limit only, the lower limit is included in the range. For ranges having both an upper and lower limit, the upper and lower limits are included in the range.

[0043] In order that the application can be more readily understood, certain technical and scientific terms are specifically defined below. Unless specifically defined herein, all other technical and scientific terms used in this document concur in meaning with the general use of those terms by those skilled in the art to which the application pertains.

[0044] In this document, the terms "comprising" or "including" are open-ended, that is, the inclusion of unspecified features or components is not precluded.

[0045] In this document, the terms "optionally", "optional" or "optional" generally mean that the subsequently described event or circumstance can or can not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0046] According to embodiments of the present application, the first aspect of the present application provides a CO2 absorption composition, the CO2 absorption composition comprising modified tubular halloysite and an additive, the modified tubular halloysite being tubular halloysite grafted with a group N,N'-diaryl-dihydrodibenzo[a,c]phenazine, the additive having at least one of an amino group, an amidine group or a hydrazone group in its structure.

[0047] Halloysite (HNTs) is a naturally occurring two-layer aluminosilicate with a hollow tubular structure of helical conformation, with a large number of hydroxyl groups distributed in the cavity, only a few on the outer surface, so the surface of HNTs is negatively charged (the surface is mainly composed of silicon oxygen tetrahedron, at pH > 2.5, Si-O- is formed), the inner cavity is positively charged (the inner wall of the tube is composed of aluminum oxygen octahedron, Al 3+ Easy to H + Combined to form Al-OH2 +Group), HNTs have a high lumen carrying capacity and are a good nano-reservoir that can absorb large and complex molecules (such as proteins and polymers) as well as small molecules (such as pharmaceutically active chemicals and gas molecules). The hollow tubular structure of HNTs can adsorb some CO2. However, since this adsorption is a physical process, when the temperature of the closed system to be adsorbed rises to near the desorption temperature of HNTs, the CO2 adsorbed in the hollow tubular structure of HNTs will be released back into the closed system, causing the internal pressure of the closed system to increase. Therefore, the adsorption effect of HNTs on CO2 is limited and desorption is prone to occur. Based on this, the present invention proposes a method that combines physical and chemical adsorption to ensure the adsorption of CO2. Specifically, the present invention provides a CO2 absorption composition, including modified tubular halloysite and an additive. Because the additive structure contains at least one of amino, amidine or hydrazone groups, chemical adsorption of CO2 can be achieved, and at the same time, the additive can be combined with the modified tubular halloysite through intermolecular forces. The modified tubular halloysite not only retains the physical adsorption of CO2 by halloysite, but also can monitor the CO2 concentration by grafting fluorescent groups.

[0048] According to an embodiment of the present invention, the modified tubular halloysite is tubular halloysite grafted with a group N,N'-diphenyl-dihydrodibenzo[a,c]phenazine.

[0049] According to a specific embodiment of the present invention, the type of the additive is not particularly limited, and the additive has an amino group in its structure; as some specific examples, the additive may be N,N-dimethyl-1-dodecylamine.

[0050] Specifically, the additive is preferably N,N-dimethyl-1-dodecylamine (C 12 A). Because the molecule has strong hydrophobic properties, it can form an oil-in-water (W / O) emulsion system with H2O (liquid or water vapor) and acetonitrile in the electrolyte, thereby absorbing the CO2 gas generated by the closed system under high temperature load. When CO2 enters the emulsion system, C 12 A is protonated and carries a positive charge (C 12 AH + ), the hydrophilicity is enhanced, and the water-in-oil (W / O) emulsion is destroyed. 12 AH + The change in amphiphilicity forms smaller micelles, thereby alleviating the gas production and swelling phenomenon in the closed system.

[0051] According to a specific embodiment of the present invention, the volume ratio of the mass of the modified tubular halloysite to the additive is (1-3) g: (1-3) mL; specifically, the volume ratio of the mass of the modified tubular halloysite to the additive is 1 g: 1 mL, 2 g: 1 mL, 3 g: 1 mL, 1 g: 2 mL, 1 g: 3 mL or any ratio within the above range.

[0052] According to an embodiment of the present invention, a second aspect of the present invention provides a method for detecting the CO2 concentration in a liquid, the method comprising detecting the CO2 concentration in the liquid in the presence of the CO2 absorption composition described in the first aspect.

[0053] The modified tubular halloysite in the CO2 absorption composition carries a fluorescent group, which emits different fluorescent indications before and after the additive reacts with CO2. Therefore, the composition can be used to monitor and detect the CO2 concentration of the system.

[0054] According to a specific embodiment of the present invention, the method further comprises: contacting the modified tubular halloysite with an additive, and detecting the CO2 concentration in the liquid by changing the fluorescence intensity.

[0055] According to an embodiment of the present invention, a third aspect of the present invention provides a method for reducing gassing of a supercapacitor, comprising the following steps:

[0056] Chemically modifying the tubular halloysite so that the tubular halloysite is grafted with an N,N'-diaryl-dihydrodibenzo[a,c]phenazine group to obtain a modified tubular halloysite;

[0057] coating the modified tubular halloysite on the inner wall of a supercapacitor housing to obtain a pretreated housing;

[0058] Assembling the pretreated housing and the supercapacitor core, injecting an electrolyte containing additives, and performing an aging treatment;

[0059] Wherein, the additive structure has at least one of amino, amidine or hydrazone groups.

[0060] The modified tubular halloysite can come into contact with the additive and combine through intermolecular forces, thereby eliminating the CO2 gas generated during the high-temperature load of the supercapacitor, thereby reducing the internal pressure of the monomer and improving the high-temperature load performance of the supercapacitor.

[0061] According to a specific embodiment of the present invention, the volume ratio of the additive added to the electrolyte containing the additive to the mass ratio of the electrolyte before the addition of the additive is (0.1-1.5) mL:22 g, preferably (0.5-1.5) mL:22 g. Specifically, the volume ratio of the additive added to the electrolyte containing the additive to the mass ratio of the electrolyte before the addition of the additive is 0.1 mL:22 g, 0.5 mL:22 g, 1 mL:22 g, 1.5 mL:22 g or any value within the above range.

[0062] According to a specific embodiment of the present invention, the specific composition of the electrolyte before the addition of the additive is not particularly limited, and can be adjusted by those skilled in the art according to the circumstances. As some specific examples, the electrolyte before the addition of the additive can be a mixture of 1,1-dimethylpyrrolidine tetrafluoroborate (DMPBF4) and acetonitrile (AN). The concentration of 1,1-dimethylpyrrolidine tetrafluoroborate in the electrolyte before the addition of the additive is not particularly limited, and can be adjusted by those skilled in the art according to the circumstances. As some specific examples, it can be 0.1-10 mol / L, specifically 0.1 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, or any value within the above range.

[0063] According to a specific embodiment of the present invention, the mass ratio of the modified tubular halloysite to the additive is (1-3) g:(1-3) mL. Specifically, the mass ratio of the modified tubular halloysite to the additive is 1 g:1 mL, 2 g:1 mL, 3 g:1 mL, 1 g:2 mL, 1 g:3 mL, or any ratio within the above range.

[0064] According to a specific embodiment of the present invention, the assembly, injection and aging treatment of the product are not particularly limited and conventional technical means can be used.

[0065] According to a specific embodiment of the present invention, the method further comprises:

[0066] The tubular halloysite is subjected to a first chemical modification to obtain amino-modified tubular halloysite (HNTs-NH2);

[0067] performing an acyl chloride reaction on the amino-modified tubular halloysite to obtain an acyl chloride product (HNTs-Cl);

[0068] The acyl chloride product is contacted with (dibenzo[a,c]phenazine-9,14-diylbis(4,1-phenylene))dimethanol (DPAC-OH) to obtain modified tubular halloysite (HNTs-DPAC).

[0069] Specifically, the first chemical modification is based on the grafting of amino groups on the hydroxyl groups in the tubular halloysite structure. As some specific examples, the tubular halloysite can be contacted with aminosiloxane to obtain amino-modified tubular halloysite.

[0070] Specifically, the acyl chloride reaction can convert an amino group into an acyl chloride, and the acyl chloride product can be obtained by contacting the amino-modified tubular halloysite with the acyl chloride.

[0071] Specifically, the tubular halloysite may be pretreated to improve its solubility and dispersion stability. This pretreatment can be performed by adding the tubular halloysite to deionized water, adding a dispersant in batches, adjusting the pH to 8-9, centrifuging to remove impurities, and drying to obtain purified halloysite. The type of dispersant is not particularly limited and can be adjusted by those skilled in the art according to circumstances. As some specific examples, the dispersant may be sodium hexametaphosphate.

[0072] Specifically, the tubular halloysite used for the first chemical modification of the tubular halloysite is purified halloysite.

[0073] According to a specific embodiment of the present invention, the preparation method of (dibenzo[a,c]phenazine-9,14-diylbis(4,1-phenylene))dimethanol (DPAC-OH) is not particularly limited, and can be obtained by the following method:

[0074]

[0075] Benzoquinone and aniline are contacted to obtain compound 3 (N9,N10-diphenylphenanthrene-9,10-diamine); compound 3 is contacted with an iodoaryl compound (iodobenzene) to obtain N,N'-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC); DPAC is subjected to a Vilsmeier reaction to obtain 4,4'-(dibenzo[a,c]phenazine-9,14-diyl)dibenzaldehyde (DPAC-CHO); DPAC-CHO is reduced to obtain (dibenzo[a,c]phenazine-9,14-diylbis(4,1-phenylene))dimethanol (DPAC-OH).

[0076] According to an embodiment of the present invention, a fourth aspect of the present invention provides a supercapacitor, which is obtained according to the method described in the third aspect.

[0077] As a result, the supercapacitor has better consistency, longer cycle life, and higher safety performance.

[0078] Below, the scheme of the present invention will be explained in conjunction with embodiment.It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.In the embodiment, if specific technology or conditions are not indicated, the technology or conditions described in the literature in this area or the product instructions are used.The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be obtained by commercial purchase.

[0079] Example 1

[0080] This embodiment provides a CO2 absorption composition and a supercapacitor, and the specific preparation method is as follows:

[0081] (1) Purification of halloysite

[0082] Add about 50g of halloysite and 500mL of deionized water to a flask and stir for 2h. During the stirring process, gradually add 1.25g of sodium hexametaphosphate [(NaPO3)6], adjust the pH value between 8-9, react for 12h, and let it stand for 6h. Impurities and large pieces of halloysite will precipitate at the bottom of the flask, and single halloysite particles will mainly remain in the supernatant. Retain the supernatant and centrifuge it at 3000rpm for 5min. Take the supernatant, then centrifuge it at 7000rpm for 10min. After solid-liquid separation, wash the precipitate repeatedly with deionized water to obtain a milky white solid. The halloysite (HNTs) is dried by vacuum freeze drying to obtain purified halloysite;

[0083] (2) Synthesis of HNTs-NH2

[0084] Purified halloysite (0.73 g) and anhydrous Na₂CO₃ (0.20 g) were added to (3-aminopropyl)triethoxysilane (30 mL) and reacted at 80°C for 48 hours. The mixture was then cooled to room temperature and centrifuged to obtain a precipitate. The precipitate was washed with water, anhydrous ethanol, and tetrahydrofuran, respectively, by centrifugation. The solid was collected and dried under vacuum to obtain HNTs-NH₂ as a white solid in a yield of 0.52 g.

[0085] FTIR (KBr): 3697s, 3624s, 2925w, 1645w, 1560w, 1493w, 1036vs, 910v, 754w, 691m, 534vs, 469s; TGA: 14.8% (200–550°C); solid-state 1H NMR: 4.453, 3.625, 1.154.

[0086] (3) Synthesis of HNTs-Cl

[0087] HNTs-NH2(0.3 g) obtained in step (2) was added to a round bottom flask with oxalyl chloride (160 μL), triethylamine (500 μL), and 3.0 mL of dimethyl sulfoxide, and the reaction was allowed to proceed at 35°C for 12 h. After the reaction was stopped, the precipitate was collected by centrifugation at 8000 rpm for 3 min after cooling to room temperature, and then the precipitate was washed with ethyl acetate and dichloromethane in this order, and dried under vacuum to obtain HNTs-Cl as a yellowish solid in a yield of 330 mg.

[0088] (4) Synthesis of 4,4'-(dibenzo[a,c]phenazine-9,14-diyl)dibenzaldehyde (DPAC-CHO)

[0089] (4-1) Synthesis of N9,N10-diphenylphenanthrene-9,10-diamine

[0090] TiCl4(4 mL) was added dropwise to a cooled solution (0°C) of benzoquinone (5.4 g) and aniline (8 mL) in toluene (150 mL) using a syringe, and the reaction was allowed to proceed at room temperature for 12 h. The product was separated under reduced pressure, and the solid product was dissolved in THF / EtOH (1 / 1, v / v) (100 mL). After NaBH4(1.0 g) was added at room temperature and refluxed for 2 h, water was added, and extraction was performed using DCM. The organic phase was dried using MgSO4, and the DCM was removed. The obtained solid was refluxed in ethanol, filtered, and the solid was washed with ethanol and dried under vacuum to obtain N9,N10-diphenylphenanthrene-9,10-diamine as a yellowish solid (yield: 4.1 g).

[0091] 1 H NMR (300 MHz, DMSO-d6) δ: 8.87 (d, J = 3.0 Hz, 2H), 7.94 (d, J = 6.0 Hz, 2H), 7.66 (t, J = 9.0 Hz, 2H), 7.61 (s, 2H), 7.56 (t, J = 9.0 Hz, 2H), 7.01 (t, J = 9.0 Hz, 4H), 6.62 (t, J = 9.0 Hz, 2H), 6.52 (d, J = 3.0 Hz, 4H).

[0092] (4-2) Synthesis of N,N'-diphenyl-dihydrodibenzo[a,c]phenazine (DPAC)

[0093] N9,N10-diphenylphenanthrene-9,10-diamine (500 mg), iodobenzene (428 mg), K2CO3 (387 mg), and Cu(OTf)2 (127 mg) were added to trichlorobenzene (10 mL) and reacted at 210°C for 6 h. Most of the trichlorobenzene was removed by vacuum distillation to obtain a black residue. After cooling to room temperature, the residue was washed with water, extracted with dichloromethane, and purified by column chromatography (developing solvent: a mixture of dichloromethane and petroleum ether, with a volume ratio of petroleum ether to dichloromethane of 1:20) to obtain (DPAC) (yield: 160 mg). 1 H NMR (300MHz, CDCl3) δ: 8.76 (d, J = 9Hz, 2H), 8.16 (d, J = 6Hz, 2H), 7.76 (s, 2H), 7 .65(d,J=6Hz,2H),7.56(d,J=6Hz,2H),7.35(s,2H),7.01(s,8H),6.80(s,2H).

[0094] (4-3) Synthesis of DPAC-CHO

[0095] Phosphorus oxychloride (3.5 g) was added to N,N'-dimethylformamide (5.0 mL) at 0°C under a nitrogen atmosphere and stirred vigorously for 1 hour to obtain the Vilsmeier reagent. A solution of DPAC (1.0 g) in N,N'-dimethylformamide was then added dropwise to the Vilsmeier reagent (10 mL). The mixture was heated to 85°C and allowed to react for 12 hours. After cooling to room temperature, the reaction mixture was poured into ice water and the pH was adjusted to neutral, yielding a dark yellow precipitate. This was purified by column chromatography in a mixture of dichloromethane and petroleum ether (volume ratio of petroleum ether to dichloromethane:1:5) to obtain the pale yellow product, 4,4'-(dibenzo[a,c]phenazine-9,14-diyl)dibenzaldehyde (DPAC-CHO) (yield: 0.9 g). 1 H NMR (300MHz, CDCl3) δ: 9.69 (s, 2H), 8.81 (d, J = 6Hz, 2H), 8.07 (d, J = 9.0Hz, 2H), 7.85 (dd, J1 = 3Hz, J2 = 6Hz, 2H), 7. 76(t,J=15Hz,2H),7.63(t,J=15Hz,2H),7.54(d,J=9Hz,4H),7.49(dd,J1=3Hz,J2=6Hz,2H),7.01(d,J=9Hz,4H). 13C NMR (125 MHz, DMSO-d6) δ: 190.72, 150.78, 142.89, 137.06, 131.04, 129.70, 129.18, 127.91, 127.72, 127.69, 127.56, 126.77, 123.95, 123.72, 114.72. HRMS (m / z): [M+H] + calcd for C 34 H 23 N2O2, 491.1754; found, 491.1754.

[0096] (5) Synthesis of (dibenzo[a,c]phenazine-9,14-diylbis(4,1-phenylene)) dimethanol (DPAC-OH)

[0097] DPAC-CHO (1.0 g) was dissolved in 30 mL of methanol to give a mixture, which was placed in an ice bath, and sodium borohydride (0.8 g) was added in portions, followed by reaction at room temperature for 12 h, pouring into ice water, and filtration to give a beige precipitate DPAC-OH (yield: 0.9 g). 1 HNMR (300 MHz, DMSO d6) δ: 8.92 (d, J = 6.0 Hz, 2H), 7.96 (d, J = 6.0 Hz, 2H), 7.88 (s, 2H), 7.69 (s, 2H), 7.59 (s, 2H), 7.40 (s, 2H), 7.03 (m, 8H), 4.95 (s, 2H), 4.30 (d, J = 3.0 Hz, 4H). 13 C NMR (125 MHz, DMSO-d6) δ: 190.72, 150.78, 142.89, 137.06, 131.04, 129.70, 129.18, 127.91, 127.72, 127.69, 127.56, 126.77, 123.95, 123.72, 114.72. HRMS (m / z): [M+H] + calcd for C 34 H 27 N2O2, 495.2067; found, 495.2063.

[0098] (6) Synthesis of HNTs-DPAC

[0099] Steps (1) to (5) were repeated multiple times. The resulting HNTs-Cl (2.00 g) and DPAC-OH (1.5 g) obtained in step (5) were added to 8.0 mL of DMSO. The mixture was reacted at room temperature for 72 h, followed by centrifugation at 8000 rpm for 3 min. After solid-liquid separation, the solid was washed sequentially with ethanol, methanol, and dichloromethane, and vacuum dried to obtain a light yellow solid HNTs-DPAC material in a yield of 1.25 g.

[0100] Material characterization:

[0101] The purified halloysite obtained in step (1) and the HNTs-DPAC material obtained in step (6) were subjected to scanning electron microscopy (SEM) tests to obtain Figure 1 The results show that the structure of halloysite is a tubular hollow structure, and its morphology is clearly visible (see Figure 1 (Figure A in the middle). Furthermore, the amino-functionalization of halloysite did not alter the original structure of the halloysite tubes. Furthermore, numerous small, irregular particles were observed on the outer surface of the halloysite tubes. Compared to the smooth surface of halloysite, the surface of the HNTs-DPAC material was significantly rougher. This roughness and irregularity correspond to the organic groups modified on the halloysite surface, indicating that the tubular halloysite was successfully modified.

[0102] The purified halloysite obtained in step (1) and the HNTs-DPAC material obtained in step (6) were subjected to surface scanning (EDS test), and the results are shown in FIG. Figure 2 . By comparison, it can be seen that the signals of C and N elements in the HNTs-DPAC material are significantly enhanced compared with the unmodified halloysite, and the C and N elements are evenly distributed in the modified tubular halloysite. The mass percentages of C and N increased from 7.20% and 0.57% to 12.91% and 0.91%. The atomic percentages of C and N increased from 10.24% and 0.81% to 17.33% and 1.18%. These results indicate that the organic fluorophore was successfully grafted onto the halloysite nanomaterial.

[0103] (7) Cleaning of aluminum shell

[0104] The Φ35×61 aluminum shell was ultrasonically cleaned with deionized water for about 15 minutes, the inner wall of the aluminum shell was cleaned with 0.5 mol / L dilute hydrochloric acid, and then rinsed with ethanol solution to obtain a clean aluminum shell.

[0105] (8) Electrostatic spraying of the inner wall of the aluminum shell

[0106] 1.25 g of the HNTs-DPAC material obtained in step (6) was added to an electrostatic gun to impart a positive charge to the HNTs-DPAC material. The material was then directed mechanically or through compressed air toward the inner cavity of a grounded, clean aluminum shell, accelerated, and evenly sprayed onto the inner wall of the clean aluminum shell to form an adherent powder. The amount of HNTs-DPAC material sprayed onto the clean aluminum shell was controlled to be 1 g. The sprayed clean aluminum shell was then heated to melt the powder into a uniform film, and finally cooled to form a hard coating, thereby obtaining a pretreated aluminum shell.

[0107] (9) Product assembly

[0108] The pretreated aluminum shell obtained in step (8) was used to assemble a Φ35×61 solder pin supercapacitor monomer. The assembly was carried out in a glove box. The injection volume of the supercapacitor electrolyte (the electrolyte consists of 1,1-dimethylpyrrolidine tetrafluoroborate and acetonitrile, wherein the concentration of 1,1-dimethylpyrrolidine tetrafluoroborate is 1 mol / L) was controlled to be 22 g, and then 1 mL C 12 A then seals the product and puts it into a plastic cover. Finally, the product is placed at high temperature for aging to obtain a Φ35×61 solder pin type supercapacitor monomer.

[0109] Example 2

[0110] The HNTs-DPAC material was prepared according to the method described in Example 1. When spraying the inner wall of the clean aluminum shell with an electrostatic gun, the amount of HNTs-DPAC material was 0.5g. During product assembly, the amount of supercapacitor electrolyte injection was controlled to be 22g, and then 0.5mL C 12 A then seals and plastic-covers the product, and finally leaves it to stand at high temperature and ages it to obtain a Φ35×61 solder pin-type supercapacitor monomer.

[0111] Example 3

[0112] The HNTs-DPAC material was prepared according to the method described in Example 1. When spraying the inner wall of the clean aluminum shell with an electrostatic gun, the amount of HNTs-DPAC material used was 1.5 g. During product assembly, the amount of supercapacitor electrolyte injected was controlled to be 22 g, and then 1.5 mL C 12 A then seals and plastic-covers the product, and finally leaves it to stand at high temperature and ages it to obtain a Φ35×61 solder pin-type supercapacitor monomer.

[0113] Comparative Example 1

[0114] The only difference between it and Example 1 is that: an unsprayed Φ35×61 aluminum shell is used, and C is not added to the supercapacitor electrolyte. 12 A, a Φ35×61 welding pin type supercapacitor monomer is obtained.

[0115] Comparative Example 2

[0116] The only difference between this embodiment and Example 1 is that no C is added to the supercapacitor electrolyte. 12 A, a Φ35×61 welding pin type supercapacitor monomer is obtained.

[0117] Comparative Example 3

[0118] The only difference from Example 1 is that HNTs-Cl is used instead of HNTs-DPAC to be sprayed on the inner wall of the aluminum shell to obtain a Φ35×61 welding pin-type supercapacitor monomer.

[0119] Comparative Example 4

[0120] The only difference between it and Example 1 is:

[0121] The only difference from Example 1 is that DPAC-OH is used instead of HNTs-DPAC to be sprayed on the inner wall of the aluminum shell to obtain a Φ35×61 welding pin-type supercapacitor monomer.

[0122] Test Case

[0123] (1) The supercapacitors prepared in each embodiment and comparative example were subjected to a 2000h high temperature load test. The results are shown in Figure 3-6 .

[0124] Among them Figure 3-4 It can be seen that when 1g of HNTs-DPAC material is sprayed on the inner wall of the aluminum shell, the capacity attenuation rate and DC internal resistance growth rate of the Φ35×61 solder pin supercapacitor monomer are minimized after 2000 hours of high temperature load. Figure 5-6 It can be seen that the untreated supercapacitor (Comparative Example 1) and the supercapacitor with HNTs-DPAC but without C 12 The supercapacitor of A (Comparative Example 2) has the worst reaction ability with CO2, and the difference between the two is not much, because there is no response system that reacts with CO2. 12 A (Comparative Example 3), DPAC-OH+C 12 A (Comparative Example 4) has C that responds strongly to CO2 12 A functional group, so after 2000 hours of high temperature loading, the capacity decay is basically similar. 12 A has no fluorophore and cannot detect the CO2 content by fluorescence analysis. 12 ASince there is no adsorption of HNTs, the capacity decay will be lower than that of HNTs-DPAC.

[0125] (2) In order to explore the responsiveness of the system to CO2, the reaction system (HNTs-DPAC and C 12 A mixture of mHNTs-DPAC :V C12A =1 g:1 mL) was passed through 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 mL of CO2 gas at a flow rate of 6 mL / min. The gas flow rate was adjusted by a rotameter. Fluorescence spectra were obtained on a Hitachi F-7000 fluorescence spectrometer with an excitation wavelength of 365 nm. Figure 7 The results showed that the HNTs-DPAC material and C 12 The fluorescence change of the reaction system A can be directly detected with the naked eye.

[0126] In addition, in the volume range of 0-5 mL, the fluorescence intensity ratio (I / I0) of the reaction system after the introduction of CO2 and before the introduction of CO2 at 450 nm increased almost linearly with the addition of CO2, and the linear correlation coefficient of the fitting curve was 0.998 (see Figure 7 In addition, the ratio of the fluorescence intensity at 450 nm to that at 590 nm (I 450 / I 590 ) and plotted its relationship with CO2 content (see Figure 7 The two showed a good linear relationship with a linear correlation coefficient of 0.997, and the detection limit obtained by the current determination method was 325 ppm. Figure 7 Where V is the volume of CO2 introduced, in mL.

[0127] (3) After the high temperature load, the product of Example 2 was disassembled, the residual electrolyte was ultrasonically treated, and then analyzed by fluorescence spectrometer. The results are shown in Figure 8 The fluorescence intensity of the electrolyte at 470nm (the electrolyte will also react after loading, causing the curve to red-shift from 450nm to 470nm) is 3612, and the fluorescence intensity at 590nm is 660. 470 / I 590 =0.93+1.59V Calculate the volume of CO2 and get HNTs-DPAC+C 12 Material A reacted with 2.86 mL of CO2.

[0128] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0129] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A CO2 absorption composition, characterized in that The CO2 absorption composition comprises modified tubular halloysite and an additive, wherein the modified tubular halloysite is tubular halloysite grafted with a group N,N'-diaryl-dihydrodibenzo[a,c]phenazine, and the additive structure has at least one of an amino group, an amidine group or a hydrazone group.

2. The CO2 absorption composition according to claim 1, characterized in that The modified tubular halloysite is a tubular halloysite grafted with a group N,N'-diphenyl-dihydrodibenzo[a,c]phenazine; Preferably, the additive has an amino group in its structure; Preferably, the additive includes N,N-dimethyl-1-dodecylamine; Optionally, the mass ratio of the modified tubular halloysite to the volume ratio of the additive is (1-3) g: (1-3) mL; Preferably, the mass ratio of the modified tubular halloysite to the volume ratio of the additive is 1 g:1 mL.

3. A method for detecting CO2 concentration in a liquid, characterized in that: The method comprises detecting the CO 2 concentration in the liquid in the presence of the CO 2 absorption composition according to claim 1 or 2.

4. The method according to claim 3, characterized in that The method further comprises: contacting the modified tubular halloysite with an additive, and detecting the CO2 concentration in the liquid by changing the fluorescence intensity.

5. A method for reducing gas production in supercapacitors, characterized in that: The following steps are involved: Chemically modifying the tubular halloysite so that the tubular halloysite is grafted with an N,N'-diaryl-dihydrodibenzo[a,c]phenazine group to obtain a modified tubular halloysite; coating the modified tubular halloysite on the inner wall of a supercapacitor housing to obtain a pretreated housing; Assembling the pretreated housing and the supercapacitor core, injecting an electrolyte containing additives, and performing an aging treatment; Wherein, the additive structure has at least one of amino, amidine or hydrazone groups.

6. The method according to claim 5, characterized in that The method further comprises: performing a first chemical modification on the tubular halloysite to obtain amino-modified tubular halloysite; subjecting the amino-modified tubular halloysite to an acyl chloride reaction to obtain an acyl chloride product; The acyl chloride product is contacted with (dibenzo[a,c]phenazine-9,14-diylbis(4,1-phenylene))dimethanol to obtain modified tubular halloysite.

7. The method according to claim 5, characterized in that The additive includes N,N-dimethyl-1-dodecylamine.

8. The method according to claim 5, characterized in that The mass ratio of the volume of the additive added to the electrolyte containing the additive to the electrolyte before the addition of the additive is (0.1-1.5) mL:22 g; preferably (0.5-1.5) mL:22 g.

9. The method according to claim 5, characterized in that The mass ratio of the modified tubular halloysite to the volume ratio of the additive is (1-3) g: (1-3) mL.

10. A supercapacitor, characterized in that: The supercapacitor is obtained according to the method according to any one of claims 5 to 9.

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