1,4-Naphthoquinone imidazole salt anode materials and their application in aqueous flow batteries

Abstract

This invention belongs to the field of new energy, specifically disclosing a 1,4-naphthoquinone zimidazole salt anode material and its application in aqueous flow batteries. The chemical structural formula of the 1,4-naphthoquinone zimidazole salt anode material is as follows: This invention, through molecular engineering, introduces pyrazole salt into the naphthoquinone conjugated system, which not only greatly improves its solubility in water but also retains the two-electron redox active center and excellent electrochemical stability. When applied to organic flow batteries, it exhibits excellent electrochemical performance, achieving a coulombic efficiency of 99.38-99.40%, an energy efficiency of 82.1-90.3%, a capacity retention of 98.77-99.75% after 100 cycles, and an average capacity retention per cycle of 99.988-99.997%.

Description

Technical Field

[0001] This invention belongs to the field of new energy, specifically to the field of aqueous flow batteries, and particularly to a 1,4-naphthoquinone zimidazole salt anode material and its application in aqueous flow batteries. Background Technology

[0002] Flow batteries, as a type of large-scale electrochemical energy storage system, achieve energy storage and conversion through valence state transitions between different redox active materials. Because the redox active materials are stored externally, their energy and power output are decoupled, allowing for independent optimization of the battery system to meet power requirements and optimizing the concentration / volume of the active materials to meet energy requirements. Currently, the mainstream redox flow batteries use vanadium as the active material; however, the scarcity, high price, and high toxicity of vanadium-based electroactive materials have limited the application of all-vanadium systems. Therefore, it is desirable to use resources-rich materials for the active material.

[0003] In the prior art, Chinese invention patent publication number CN 115710230 A discloses a naphtho[2,3-d]imidazolium-4,9-dione derivative for use as a cathode in organic lithium-ion batteries and its preparation method. This derivative is prepared by first using 2,3-dichloro-1,4-naphthoquinone and potassium phthalimide as raw materials to prepare 2,3-diamino-1,4-naphthoaldehyde; then, 2,3-diamino-1,4-naphthoaldehyde is grafted onto glacial acetic acid, terephthalaldehyde, or 1,3,5-pyromellitic tricarboxaldehyde to obtain naphtho[2,3-d]imidazolium-4,9-dione derivatives with different substitutions. Organic lithium-ion batteries using this derivative as a cathode can achieve high capacity and good cycle stability. However, this structure cannot be applied to aqueous organic flow batteries.

[0004] Therefore, it is of great significance to design and develop aqueous organic flow battery electrode materials with high solubility, high energy density, high stability and low cost. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a 1,4-naphthoquinone imidazole salt anode material and its application in an aqueous flow battery. The anode material improves the solubility of 1,4-naphthoquinone in water and can induce a two-step reversible redox reaction. When applied to the charge and discharge of an organic flow battery, it exhibits excellent electrochemical performance.

[0006] The inventive concept of this invention is as follows: through molecular engineering, imidazole salts are introduced into the 1,4-naphthoquinone conjugated system, which greatly improves the solubility of 1,4-naphthoquinone in water and exhibits excellent two-electron redox performance. When applied to the charging and discharging of organic flow batteries, it exhibits excellent coulombic efficiency, energy efficiency and capacity retention, providing a new approach for the modification of 1,4-naphthoquinone molecules in the field of aqueous organic flow batteries.

[0007] To solve the above-mentioned technical problems, the first aspect of the present invention provides a 1,4-naphthoquinone zimidazole salt anode material, the chemical structural formula of which is shown in formula (1):

[0008]

[0009] Where: R 1 R 2 R 3 R 4 Each group is independently selected from hydrogen, halogen, hydroxyl, nitro, carboxyl, trifluoromethyl, alkoxy, alkyl, hydroxyalkyl, heteroalkyl, haloalkyl, or aryl;

[0010] R 5 R 6 R 7 Each group is independently selected from halogen, hydroxyl, nitro, carboxyl, trifluoromethyl, alkoxy, alkyl, hydroxyalkyl, heteroalkyl, haloalkyl, and aryl groups;

[0011] X is selected from halogens.

[0012] Preferably, the R 1 R 2 R 3 R 4 Each of the following is independently selected from hydrogen, hydroxyl, C1-C6 alkyl or C1-C6 alkoxy groups.

[0013] Preferably, the R 5 R 6 R 7 Each is independently selected from C1-C6 alkyl or C1-C6 hydroxyalkyl.

[0014] Preferably, the halogen is selected from bromine or chlorine.

[0015] Preferably, the solubility of the 1,4-naphthoquinone imidazole salt anode material in water is 0.1-10 mol / L.

[0016] A second aspect of the present invention provides a negative electrode electrolyte comprising the 1,4-naphthoquinone zimidazole salt negative electrode material described in the first aspect, water, and a supporting electrolyte.

[0017] Preferably, the supporting electrolyte is selected from at least one of sodium chloride, potassium chloride, lithium chloride, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium nitrate, and potassium nitrate.

[0018] A third aspect of the present invention provides an aqueous flow battery, comprising the negative electrode electrolyte, positive electrode electrolyte, electrode, and separator described in the second aspect.

[0019] Preferably, the positive electrode electrolyte comprises potassium ferrocyanide, water, and a supporting electrolyte.

[0020] Preferably, the supporting electrolyte in the positive electrode electrolyte is the same as the supporting electrolyte in the negative electrode electrolyte.

[0021] Preferably, the electrode is selected from graphite or carbon paper.

[0022] Preferably, the diaphragm is selected from any one of KVFM212, DM8115A, nafion117, nafion115, and nafion212.

[0023] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages:

[0024] This invention, through molecular engineering, introduces pyrazole salts into the naphthoquinone conjugated system, significantly improving its solubility in water while retaining the two-electron redox active center and excellent electrochemical stability. When the 1,4-naphthoquinone zimidazole salt-based anode material of this invention is applied to organic flow batteries, it exhibits excellent electrochemical performance, achieving a coulombic efficiency of 99.38-99.40%, an energy efficiency of 82.1-90.3%, a capacity retention of 98.77-99.75% after 100 cycles, and an average capacity retention per cycle of 99.988-99.997%. Attached Figure Description

[0025] Figure 1 The cyclic voltammetry curves are for the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 1.

[0026] Figure 2 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 2;

[0027] Figure 3 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 3;

[0028] Figure 4 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 4;

[0029] Figure 5 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 5;

[0030] Figure 6 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 6;

[0031] Figure 7 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 7;

[0032] Figure 8 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 8;

[0033] Figure 9 Cyclic voltammetry curves of the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of Example 9;

[0034] Figure 10 The graph shows the constant current charge-discharge experimental data of the aqueous flow battery assembled from the 1,4-naphthoquinone imidazole salt anode material of Example 3.

[0035] Figure 11 The graph shows the constant current charge-discharge experimental data of the aqueous flow battery assembled from the 1,4-naphthoquinone imidazole salt anode material of Example 6.

[0036] Figure 12 The graph shows the constant current charge-discharge experimental data of the aqueous flow battery assembled from the 1,4-naphthoquinone imidazole salt anode material of Example 9. Detailed Implementation

[0037] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0038] The synthetic routes of the 1,4-naphthoquinone zimidazole salt anode materials in the following examples are as follows:

[0039]

[0040] Where: a represents R 1 NH2, ethanol, room temperature, 1 h;

[0041] b represents (R) 2 CO)O, concentrated sulfuric acid, room temperature, 1 h;

[0042] c represents R 3 NH2, acetonitrile, 45℃, 1h;

[0043] d indicates HX acid, ethanol / ethyl acetate 1:1, 45℃, overnight.

[0044] Example 1

[0045] A method for preparing a 1,4-naphthoquinone zimidazole salt anode material includes the following steps:

[0046] S1: 2,3-Dichloro-1,4-naphthoquinone (2.3 g, 10 mmol) was dissolved in 50 mL of ethanol, and n-butylamine (2.19 g, 30 mmol) was slowly added dropwise. The mixture was reacted at room temperature for 1 h, extracted, concentrated, and purified to give a red solid 2-(butanoamino)-3-chloronaphtho-1,4-dione.

[0047] S2: After thoroughly mixing the 2-(butanoamino)-3-chloronaphth-1,4-dione obtained in S1 with acetic anhydride (100 mmol, 9.4 ml), add concentrated sulfuric acid (20 drops), react at room temperature for 1 h, quench with water slowly, extract, concentrate, and purify to obtain the yellow liquid N-(3-chloro-1,4-dioxo-1,4-dihydronaphth-2-yl)-N-butylacetamide;

[0048] S3: The N-(3-chloro-1,4-dioxo-1,4-dihydronaphth-2-yl)-N-butylacetamide obtained in S2 was dissolved in 40 mL of acetonitrile, and n-butylamine (2.19 g, 30 mmol) was slowly added dropwise. The mixture was heated to 45 °C and reacted for 1 h. After cooling to room temperature, the mixture was extracted, concentrated, and purified to obtain a light red liquid n-butyl-N-(3-(butanoamino)-1,4-dioxo-1,4-dihydronaphth-2-yl)acetamide.

[0049] S4: The n-butyl-N-(3-(butano)-1,4-dioxo-1,4-dihydronaphth-2-yl)acetamide obtained in S3 was dissolved in 50 mL of a mixture (ethanol:ethyl acetate = 1:1). A 40% HBr solution (30 g, 150 mmol) was slowly added dropwise, and the mixture was stirred overnight at 45 °C. After cooling, a saturated NaHCO3 aqueous solution was slowly added dropwise to neutralize excess acid. Finally, the mixture was concentrated and purified to obtain 2.48 g of a bright yellow solid, 1,3-dibutyl-2-methyl-4,9-dioxo-4,9-dihydro1H-naphtho[2,3-d]imidazolium-3-bromonium, with a total yield of 61%. Its chemical structure is as follows:

[0050]

[0051] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0052] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.22–8.15 (m, 2H), 8.06–7.81 (m, 2H), 4.61 (t, J = 7. 6Hz, 4H), 2.94 (s, 3H), 2.03–1.68 (m, 4H), 1.55–1.29 (m, 4H), 0.95 (t, J = 7.3Hz, 6H).

[0053] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 174.78, 151.89, 135.24, 131.63, 130.12, 126.87, 47.04, 30.74, 19.08, 13.52, 9.96.

[0054] Example 2

[0055] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 1, only the 40% HBr (30g, 150mmol) solution in step S4 was replaced with a 37% HCl (14.8g, 150mmol) solution, resulting in 2.34g of a yellow solid, 1,3-dibutyl-2-methyl-4,9-dioxo-4,9-dihydro1H-naphtho[2,3-d]imidazolium-3-chloroonium, with an overall yield of 65%. Its chemical structure is as follows:

[0056]

[0057] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0058] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.25–8.13 (m, 2H), 8.06–7.93 (m, 2H), 4.63 (t, J = 7. 5Hz, 4H), 2.96 (s, 3H), 1.87–1.70 (m, 4H), 1.50–1.33 (m, 4H), 0.95 (t, J = 7.3Hz, 6H).

[0059] 13C NMR (101MHz, DMSO-d6) δ (ppm): 174.83, 151.97, 135.28, 131.67, 130.15, 126.91, 47.07, 30.76, 19.13, 13.56, 9.97.

[0060] Example 3

[0061] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 2, only the n-butylamine (2.19 g, 30 mmol) in step S3 was replaced with ethanolamine (1.83 g, 30 mmol), ultimately yielding 1.95 g of reddish-brown solid 1-butyl-3-(2-hydroxyethyl)-2-methyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-chloroonium, with an overall yield of 56%. Its chemical structural formula is as follows:

[0062]

[0063] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0064] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.29–8.10 (m, 2H), 8.06–7.91 (m, 2H), 5.55 (t, J = 6.0Hz, 1H), 4.70 (t, J = 4.8Hz, 2H), 4. 62(t,J=7.6Hz,2H),3.82(q,J=5.3Hz,2H),2.94(s,3H),1.86–1.73(m,2H),1.51–1.34(m,2H),0.95(t,J=7.3Hz,3H).

[0065] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 174.83,174.75,152.97,135.24,131.60,131.55,1 30.25,130.19,126.90,126.86,58.95,50.05,47.00,30.77,19.09,13.51,10.62.

[0066] Example 4

[0067] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 1, only the n-butylamine (2.19 g, 30 mmol) in steps S1 and S3 was replaced with a 70% aqueous solution of ethylamine (1.93 g, 30 mmol). This yielded 2.1 g of a bright yellow solid, 1,3-diethyl-2-methyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-3-bromoonium, with an overall yield of 60%. Its chemical structure is as follows:

[0068]

[0069] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0070] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.28–8.13 (m, 2H), 8.06–7.95 (m, 2H), 4.64 (q, J = 7.1Hz, 4H), 2.90 (s, 3H), 1.42 (t, J = 7.2Hz, 6H).

[0071] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 174.74, 151.81, 135.28, 131.62, 129.98, 126.90, 42.87, 14.24, 9.69.

[0072] Example 5

[0073] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 4, only the 70% ethylamine (1.93 g, 30 mmol) aqueous solution in step S3 was replaced with ethanolamine (1.83 g, 30 mmol), ultimately yielding 1.86 g of reddish-brown solid 1-ethyl-3-(2-hydroxyethyl)-2-methyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-3-bromoonium, with an overall yield of 51%. Its chemical structural formula is as follows:

[0074]

[0075] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0076] 1H NMR (400MHz, DMSO-d6) δ (ppm): 8.28–8.14 (m, 2H), 8.05–7.93 (m, 2H), 5.19 (t, J = 5.8H z,1H),4.82–4.62(m,4H),3.84(q,J=5.2Hz,2H),2.93(s,3H),1.43(t,J=7.1Hz,3H).

[0077] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 174.83, 174.73, 152.78, 135.30, 131.62, 131.58, 130.18, 130.12, 126.93, 59.10, 49.93, 42.89, 14.24, 10.35.

[0078] Example 6

[0079] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 2, only the n-butylamine (2.19 g, 30 mmol) in steps S1 and S3 was replaced with a 70% aqueous solution of ethylamine (1.93 g, 30 mmol). This yielded 1.82 g of a yellow solid, 1,3-diethyl-2-methyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-3-chloroonium, with an overall yield of 60%. Its chemical structure is as follows:

[0080]

[0081] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0082] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.33–8.14 (m, 2H), 8.08–7.93 (m, 2H), 4.66 (q, J = 7.1Hz, 4H), 2.94 (s, 3H), 1.42 (t, J = 7.2Hz, 6H).

[0083] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 174.73, 151.86, 135.26, 131.61, 129.95, 126.88, 42.82, 14.22, 9.60.

[0084] Example 7

[0085] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 6, only the 70% ethylamine (1.93 g, 30 mmol) aqueous solution in step S3 was replaced with ethanolamine (1.83 g, 30 mmol), ultimately yielding 1.76 g of brown solid 1-ethyl-3-(2-hydroxyethyl)-2-methyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-3-chloroonium, with an overall yield of 55%. Its chemical structural formula is as follows:

[0086]

[0087] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0088] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.23–8.12 (m, 2H), 8.05–7.97 (m, 2H), 5.50 (t, J = 6.1H z,1H),4.77–4.61(m,4H),3.82(q,J=5.4Hz,2H),2.94(s,3H),1.43(t,J=7.2Hz,3H).

[0089] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 174.82, 174.73, 152.86, 135.27, 131.59, 131.56, 130.18, 130.12, 126.89, 59.00, 50.01, 42.82, 14.19, 10.39.

[0090] Example 8

[0091] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 2, only the n-butylamine (2.19 g, 30 mmol) in steps S1 and S3 was replaced with an aqueous solution of methylamine hydrochloride (2 g, 30 mmol) and sodium hydroxide (1.2 g, 30 ml). This yielded 1.63 g of a pale yellow solid, 1,2,3-trimethyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-3-chloroonium, with an overall yield of 59%. Its chemical structure is as follows:

[0092]

[0093] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0094] 1H NMR (400MHz, DMSO-d6) δ (ppm): 8.26–8.15 (m, 2H), 8.05–7.96 (m, 2H), 4.17 (s, 6H), 2.87 (s, 3H).

[0095] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 175.04, 153.22, 135.32, 131.62, 130.04, 126.89, 34.13, 10.01.

[0096] Example 9

[0097] Following the preparation method of 1,4-naphthoquinone imidazole salt anode material in Example 8, only the n-butylamine (2.19 g, 30 mmol) in step S3 was replaced with ethanolamine (1.83 g, 30 mmol), finally yielding 1.53 g of light brown solid 3-(2-hydroxyethyl)-1,2-dimethyl-4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d]imidazolium-3-chloroonium, with an overall yield of 50%. Its chemical structural formula is as follows:

[0098]

[0099] The characterization results of the proton and carbon NMR spectra of the product obtained in this embodiment are as follows:

[0100] 1 H NMR (400MHz, DMSO-d6) δ (ppm): 8.27–8.12 (m, 2H), 8.04–7.95 (m, 2H), 5.53 (t, J = 6 .3Hz, 1H), 4.72 (t, J = 4.9Hz, 2H), 4.16 (s, 3H), 3.80 (q, J = 5.4Hz, 2H), 2.90 (s, 3H).

[0101] 13 C NMR (101MHz, DMSO-d6) δ (ppm): 175.12, 174.79, 153.62, 135.33, 135.30, 13 1.65,131.56,130.62,129.73,126.94,126.89,59.21,49.95,34.14,10.67.

[0102] Comparative Example 1

[0103] The chemical structure of commercially available 1,4-naphthoquinone (purity >97%) is as follows:

[0104]

[0105] Performance testing

[0106] 1. Solubility

[0107] The 1,4-naphthoquinone imidazole salt anode materials prepared in Examples 1-9 and the 1,4-naphthoquinone of Comparative Example 1 were dissolved in pure water or deionized water at room temperature. The solution was continuously added until a precipitate was formed and a saturated solution was created. After 24 hours, 1 mL of the saturated solution was dried, and the saturated solubility was calculated by the mass of the residual solids. The results are shown in Table 1.

[0108] Table 1:

[0109] saturated solution Saturated solubility (mol / L) Example 1 0.065 Example 2 0.872 Example 3 2.236 Example 4 0.372 Example 5 0.175 Example 6 1.380 Example 7 0.549 Example 8 0.453 Example 9 1.160 Comparative Example 1 <0.001

[0110] As can be seen from Table 1, 1,4-naphthoquinone is almost insoluble in water. By introducing imidazole salt into the molecular structure of 1,4-naphthoquinone, its solubility can be significantly enhanced. Increased solubility means increased capacity.

[0111] 2. Electrochemical performance

[0112] The 1,4-naphthoquinone-imidazole salt anode materials prepared in Examples 1-9 were each prepared in 2.5 mmol solutions and dissolved in 1 mol / L NaCl solution to obtain electrolytes. The electrolytes were purged with nitrogen for 20 min, and voltage / current curves were plotted using cyclic voltammetry. A glassy carbon electrode was used as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum electrode as the counter electrode. The scan rate was set to 50 mV / s for testing.

[0113] Figure 1-9 The cyclic voltammetry curves corresponding to the electrolytes prepared in Examples 1-9 are shown in Table 2, and their redox potential values ​​are shown in Table 2.

[0114] Table 2:

[0115]

[0116] pass Figure 1-9 As shown in Table 2, the electrolyte prepared from the 1,4-naphthoquinone imidazole salt anode material of this invention exhibits significant two-electron redox reactions with minimal potential change, indicating that this type of structure possesses excellent electrochemical performance. Since Comparative Example 1 is insoluble in water, it cannot form redox centers in water, demonstrating that the introduction of imidazole salts can significantly improve the electrochemical performance of the 1,4-naphthoquinone structure in water.

[0117] 3. Flow battery performance

[0118] Comparative analysis of solubility and cyclic voltammetry curves supports the use of potassium hydroxide as the electrolyte. The corresponding negative electrode electrolytes were prepared using 1,4-naphthoquinone zimidazole salt anode materials prepared in Examples 3, 6, and 9, and used in conjunction with a positive electrode electrolyte prepared with potassium ferrocyanide. The electrode material used was graphite felt (GFD-2.5-EA, purchased from the Materials Science Station), and the separator was DM8115A (purchased from Shandong Dongyue Future Hydrogen Energy Materials Co., Ltd.). Before testing, the electrolyte was bubbled with nitrogen to remove air, and the battery was assembled into a flow battery. Then, the current density was 20 mA / cm² at 0.3-1.4 V. -2 Constant current charge and discharge performance tests were conducted.

[0119] Figure 10-12 The figures show experimental data for 100 cycles of constant current charge-discharge of aqueous flow batteries assembled from 1,4-naphthoquinone imidazole salt anode materials of Examples 3, 6, and 9 in combination with potassium ferrocyanide. The coulombic efficiency, energy efficiency, capacity retention rate after 100 cycles, and average capacity retention rate per cycle are shown in Table 3.

[0120] Table 3:

[0121]

[0122] pass Figure 10-12 As can be seen from Table 3, the aqueous flow battery assembled with the 1,4-naphthoquinone imidazole salt anode material prepared by this invention and potassium ferrocyanide exhibits excellent coulombic efficiency, energy efficiency and capacity retention.

[0123] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. The application of a 1,4-naphthoquinone zimidazole salt anode material in an aqueous flow battery, characterized in that, The chemical structural formula of the 1,4-naphthoquinone zimidazole salt anode material is shown in formula (1): Equation (1) Where: R 1 R 2 R 3 R 4 Each of the following groups is independently selected from hydrogen, halogen, hydroxyl, nitro, carboxyl, trifluoromethyl, C1-C6 alkoxy, C1-C6 alkyl, or C1-C6 hydroxyalkyl. R 5 R 6 R 7 Each is independently selected from C1-C6 alkyl or C1-C6 hydroxyalkyl; X is selected from halogens.

2. The application according to claim 1, characterized in that, The R 1 R 2 R 3 R 4 Each of the following is independently selected from hydrogen, hydroxyl, C1-C6 alkyl or C1-C6 alkoxy groups.

3. The application according to claim 1, characterized in that, The halogen is selected from bromine or chlorine.

4. The application according to any one of claims 1-3, characterized in that, The 1,4-naphthoquinone imidazole salt anode material has a solubility of 0.1-10 mol / L in water.

5. A negative electrode electrolyte, characterized in that, It includes the 1,4-naphthoquinone imidazole salt anode material as described in any one of claims 1-4, water, and supporting electrolyte.

6. The negative electrode electrolyte according to claim 5, characterized in that, The supporting electrolyte is selected from at least one of sodium chloride, potassium chloride, lithium chloride, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium nitrate, and potassium nitrate.

7. An aqueous flow battery, characterized in that, Includes the negative electrode electrolyte, positive electrode electrolyte, electrode, and separator as described in claim 5 or 6.

8. The aqueous flow battery according to claim 7, characterized in that, The positive electrode electrolyte includes potassium ferrocyanide, water, and a supporting electrolyte.

9. The aqueous flow battery according to claim 7, characterized in that, The electrodes are selected from graphite or carbon paper.

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