N-substituted phenothiazine derivatives and aqueous organic flow batteries
Patent Information
- Application Number
- CN202510350951.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2026-09-25
AI Technical Summary
其中吩噻嗪类分子具有较好的氧化还原活性和稳定性，但是作为正极活性分子，氧化还原电位不够高，难以实现较高的电池电压和能量密度
[0032]本发明提供的一种水系有机液流电池，将N取代吩噻嗪衍生物作为液流电池的正极电解质，其具有较高的氧化还原电位、可逆的氧化还原活性和较高的溶解度。特别的，在酸性支持电解质中，N取代吩噻嗪衍生物具有较高的氧化还原电位(0.63～0.71V vs.SHE)，与合适的负极电解质匹配得到的有机液流电池具有优异的循环稳定性，进一步提升了吩噻嗪基水系有机液流电池的性能，促进了水系有机液流电池的实际应用。
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Abstract
Description
Technical Field
[0001] This application relates to an N-substituted phenothiazine derivative and its application in an aqueous organic flow battery system, belonging to the field of flow batteries. Background Technology
[0002] The overexploitation and use of traditional fossil fuels has led to resource shortages and severe environmental pollution. Achieving the "dual carbon" goal necessitates a transformation of the energy structure, reducing dependence on fossil fuels and vigorously developing clean and renewable energy sources. However, renewable energy sources such as solar and wind power are intermittent and volatile, and large-scale grid connection poses challenges to the stability and reliability of the power grid. Therefore, efficient and safe large-scale energy storage technologies are needed to achieve energy storage and stable output. Among these, flow batteries, with their advantages of high safety, long cycle life, independently designable capacity and power, and ease of scalability, have become a promising energy storage technology.
[0003] Aqueous organic flow batteries use water-soluble electrochemically active organic molecules as active materials, offering advantages such as abundant resources, wide availability, and potentially low cost. Most importantly, the physicochemical properties of these organic active molecules (solubility, redox potential, and stability) can be flexibly controlled. In the past decade or so, numerous organic active molecules have been developed, such as quinones, viologens, TEMPO compounds, ferrocene compounds, fluorenones, and heterocyclic aromatic compounds. Among these, phenothiazine molecules exhibit good redox activity and stability; however, as positive electrode active molecules, their redox potential is not high enough, making it difficult to achieve high battery voltage and energy density.
[0004] In summary, it is crucial to develop phenothiazine derivatives with high potential, high stability, and high solubility. Summary of the Invention
[0005] This invention provides an N-substituted phenothiazine derivative aqueous organic flow battery, which features high battery voltage and good cycle stability.
[0006] The N-substituted phenothiazine derivative of the aforementioned flow battery has the following structural formula:
[0007]
[0008] In the formula, R1 is selected from C1 to C10 alkyl groups, -(CH2) n OH, -(CH2) n NH2、-(CH2) n N(CH3)2、-(CH2) n N(CH3)3 + -(CH2) n COOH, -(CH2) nSO3H, -(CH2) n At least one of PO3H2; preferably a C1 to C3 alkyl group.
[0009] Ra and Rb may be the same or different, and are independently selected from: -H, C1 to C10 alkyl groups, and -(CH2). n OH, -(CH2) n NH2、-(CH2) n N(CH3)2、-(CH2) n N(CH3)3 + -(CH2) n COOH, -(CH2) n SO3H, -(CH2) n At least one of PO3H2;
[0010] Wherein: -(CH2) n OH, -(CH2) n NH2、-(CH2) n N(CH3)2、-(CH2) n N(CH3)3 + -(CH2) n COOH, -(CH2) n SO3H, -(CH2) n In PO3H2, n is a natural number, and the value of n ranges from 1 to 10.
[0011] Optionally, in the flow battery, the concentration of N-substituted phenothiazine derivatives in the positive electrode electrolyte is 0.05–5 mol / L, preferably 0.05–2.5 mol / L.
[0012] Optionally, in the flow battery, the concentration of the N-substituted phenothiazine derivative in the positive electrode electrolyte is independently selected from any value or a range between 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, and 5 mol / L.
[0013] The flow battery includes a positive electrode, a negative electrode, a separator, and an electrolyte;
[0014] The electrolyte includes a positive electrode electrolyte and a negative electrode electrolyte;
[0015] The space between the positive electrode and the separator is filled with a positive electrode electrolyte;
[0016] The space between the negative electrode and the diaphragm is filled with a negative electrode electrolyte;
[0017] The positive electrode electrolyte is selected from the positive electrode electrolytes described above.
[0018] Optionally, the positive and negative electrolytes may also independently include a supporting electrolyte.
[0019] Optionally, the supporting electrolyte is selected from at least one of hydrochloric acid, sulfuric acid, perchloric acid, phosphoric acid, acetic acid, methanesulfonic acid, and trifluoromethanesulfonic acid.
[0020] Optionally, the concentration of the supporting electrolyte is 0.05–6 mol / L.
[0021] Optionally, the concentration of the supporting electrolyte is independently selected from any value among 0.05 mol / L, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, and 6 mol / L, or a range between any two of the above.
[0022] Optionally, the positive and negative electrodes are independently selected from at least one of carbon felt, carbon cloth, carbon paper, graphite plate, and metal plate.
[0023] Optionally, the negative electrode electrolyte includes a negative electrode electrolyte;
[0024] The negative electrode electrolyte is selected from at least one of vanadium sulfate, silicotungstic acid, tin chloride, cadmium chloride, chromium chloride, lead sulfate, and titanium sulfate.
[0025] Optionally, the negative electrode electrolyte is a solution with a total concentration of negative electrode electrolyte from 0.05 mol / L to its saturation concentration.
[0026] Optionally, the membrane is selected from ion exchange membranes and / or porous membranes.
[0027] To achieve the above objectives, the specific technical solution of the present invention is as follows:
[0028] This invention provides an aqueous organic flow battery, comprising a single cell or a stack composed of two or more single cells; the single cell includes a positive electrode, a separator, and a negative electrode, wherein a positive electrode electrolyte is introduced into the positive electrode or between the positive electrode and the separator, and a negative electrode electrolyte is introduced into the negative electrode or between the negative electrode and the separator; the positive electrode electrolyte in the positive electrode electrolyte is an N-substituted phenothiazine derivative.
[0029] The substituents on the N atom in the N-substituted phenothiazine derivatives disclosed in this invention give the molecule a higher redox potential, and the N-containing side chain group at the para position of the N atom can serve as a redox active center, giving the molecule excellent redox reversibility and electrochemical stability. When applied to aqueous organic flow batteries, it exhibits excellent cycle stability and is a very promising positive electrode active molecule.
[0030] Preferably, the positive electrode electrolyte is a 0.05M to 1.8M substituted phenothiazine derivative, the negative electrode electrolyte is 1.6M vanadium sulfate, the supporting electrolyte is 3M sulfuric acid, the separator is a polybenzimidazole membrane, and the positive and negative electrodes are carbon felt.
[0031] Beneficial effects of this invention:
[0032] This invention provides an aqueous organic flow battery that uses an N-substituted phenothiazine derivative as the positive electrode electrolyte, exhibiting high redox potential, reversible redox activity, and high solubility. Specifically, in an acidic supporting electrolyte, the N-substituted phenothiazine derivative demonstrates a high redox potential (0.63–0.71 V vs. SHE), and when matched with a suitable negative electrode electrolyte, the resulting organic flow battery exhibits excellent cycle stability, further enhancing the performance of phenothiazine-based aqueous organic flow batteries and promoting their practical application.
[0033] In particular, when the N-substituted group of the N-substituted phenothiazine derivative is methyl, ethyl or propyl, according to the Hammit constant of the substituent group, these alkyl groups are electron-donating groups, which theoretically would reduce the redox potential of the molecule. However, in this invention, these substituents significantly increase the redox potential of the molecule, and these electron-donating groups are beneficial to improving the conjugation degree and electrochemical stability of the molecule, resulting in better battery performance. Attached Figure Description
[0034] Figure 1 This is the cyclic voltammogram of methylene blue in Comparative Example 1 of this invention;
[0035] Figure 2 For compound 1 1 H NMR spectrum;
[0036] Figure 3 The cyclic voltammogram of compound 1 in 3M H2SO4 solution;
[0037] Figure 4 For compound 2 1 H NMR spectrum;
[0038] Figure 5 The cyclic voltammetry diagram of compound 2 in 3M H2SO4 solution;
[0039] Figure 6 For compound 3 1 H NMR spectrum;
[0040] Figure 7 The cyclic voltammetry diagram of compound 3 in 3M H2SO4 solution;
[0041] Figure 8For compound 4 1 H NMR spectrum;
[0042] Figure 9 The cyclic voltammogram of compound 4 in 3M H2SO4 solution;
[0043] Figure 10 The battery assembled in Embodiment 6 of the present invention has an energy density of 160 mA / cm. 2 Cyclic performance at current density;
[0044] Figure 11 The battery assembled in Example 7 of this invention has a current rating of 160 mA / cm. 2 Cyclic performance at current density;
[0045] Figure 12 The image shows the cyclic voltammetry of toluidine blue in 3M H2SO4 solution in Comparative Example 2. Detailed Implementation
[0046] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0047] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0048] This application uses a Bruker AVANCE III 400MHz processor. 1 Characterization was performed by 1H NMR and Q-TOF 6540 for high-resolution time-of-flight mass spectrometry; solubility was measured using a TU-1901 UV-Vis spectrophotometer (190-900 nm); cyclic voltammetry was performed using a Biologic VSP 3, with a 3 mm glassy carbon electrode as the working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode; battery performance was measured using a Xinwei electrochemical workstation.
[0049] Comparative Example 1
[0050] Methylene blue (purchased from Shanghai Aladdin Biochemical Co., Ltd.) was weighed and dissolved in 10 mL of 3 mol / L sulfuric acid solution. The solution was shaken and stirred until a homogeneous solution was formed, resulting in a 10 mmol / L solution. Its redox behavior was studied by cyclic voltammetry at a scan rate of 50 mV / s and a scan voltage range of 0.2–0.8 V.
[0051] like Figure 1 As shown, methylene blue has a pair of reversible redox peaks at 0.53 V vs. SHE.
[0052] Example 1
[0053] Weigh 2 g (9.4 mmol, purchased from Anhui Zesheng Technology Co., Ltd.) into a two-necked flask, add 10 mL of acetic acid (purchased from Shanghai Aladdin Biochemical Co., Ltd.), and then slowly add a mixed solution of HNO3 (4.8 mL, 75.24 mmol, purchased from Shanghai Aladdin Biochemical Co., Ltd.) and 12 mL of acetic acid. After reacting at 35 °C for 48 hours, add ice water to precipitate the solid, filter, and dry under vacuum to obtain N-methyl-3,7-dinitrophenthiazide.
[0054] N-methyl-3,7-dinitrophenthiazide (1 g, 3 mmol) and SnCl₂·2H₂O (10 g, 45 mmol, purchased from Shanghai Aladdin Biochemical Co., Ltd.) were placed in a two-necked flask, and 50 mL of ethanol was added. The mixture was heated under reflux overnight, cooled to room temperature, and then cold water was added. The pH was adjusted to 7 with 5% NaHCO₃. The mixture was then extracted with ethyl acetate. The extract was washed with saturated NaCl, dried over anhydrous sodium sulfate, and filtered. The solution was concentrated until a small amount of ethyl acetate remained, and a large amount of petroleum ether was added to precipitate the precipitate. The precipitate was then filtered and dried under vacuum to obtain a blue powder, N-methyl-3,7-diaminophenthiazide. 1 H NMR ( Figure 2 The molecular structure was analyzed by liquid chromatography and high-resolution time-of-flight mass spectrometry, confirming the presence of the target product compound 1.
[0055]
[0056] The redox behavior of compound 1 was studied by cyclic voltammetry. Compound 1 was weighed and dissolved in 10 mL of 3 mol / L sulfuric acid solution. The solution was shaken and stirred until a homogeneous solution was formed, resulting in a 1 mmol / L solution. The scan rate was 50 mV / s, and the scan voltage range was 0.4–1.1 V.
[0057] like Figure 3 As shown, compound 1 has a pair of reversible redox peaks at 0.71 V vs. SHE, indicating that compound 1 has reversible redox activity. Moreover, its potential is 0.18 V higher than that of methylene blue in comparative example 1, indicating that the methyl group on the N atom can significantly increase the redox potential of the molecule.
[0058] Example 2
[0059] N-methyl-3,7-diaminophenthiazide (0.486 g, 2 mmol) was placed in a pressure-resistant flask, and anhydrous formic acid (1.52 mL, 40 mmol, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory), triethylamine (5.56 mL, 40 mmol, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory), and 5 mL of DMSO (purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory) were added. The mixture was reacted at 150°C for 24 hours. After cooling, NaOH solution was added for neutralization, followed by extraction with dichloromethane. The organic phase was washed with saturated NaCl, dried over Na2SO4, and purified by column chromatography. The product was then recrystallized from acetone to obtain the green solid N-methyl-3,7-dimethylaminophenthiazide. 1 H NMR ( Figure 4 The molecular structure was analyzed by liquid chromatography and high-resolution time-of-flight mass spectrometry, confirming the presence of the target product compound 2.
[0060]
[0061] The redox behavior of compound 2 was studied by cyclic voltammetry. Compound 2 was weighed and dissolved in 10 mL of 3 mol / L sulfuric acid solution. The solution was shaken and stirred until a homogeneous solution was formed, followed by a 5 mmol / L solution. The scan rate was 50 mV / s, and the scan voltage range was 0.2–1.0 V.
[0062] like Figure 5 As shown, compound 2 has a pair of reversible redox peaks at 0.66 V vs. SHE, indicating that compound 2 has reversible redox activity. Moreover, its potential is 0.13 V higher than that of methylene blue in comparative example 1, indicating that substitution on the N atom can significantly increase the redox potential of the molecule.
[0063] Example 3
[0064] Phenothiazine (1 g, 5 mmol, purchased from Anhui Zesheng Technology Co., Ltd.) was placed in a two-necked flask and dissolved in 15 mL of anhydrous tetrahydrofuran. NaH (0.42 g, 10 mmol) was added in small portions under ice bath conditions. After stirring at 50 °C for 1 hour, bromoethane (0.75 mL, 10 mmol, purchased from Anhui Zesheng Technology Co., Ltd.) was added. After reacting for 12 hours, the reaction was quenched with ice water, extracted with ethyl acetate, and column chromatography was performed to obtain N-ethylphenhiazine.
[0065] Weigh 2 g (9.4 mmol, purchased from Anhui Zesheng Technology Co., Ltd.) into a two-necked flask, add 10 mL of acetic acid (purchased from Shanghai Aladdin Biochemical Co., Ltd.), and then slowly add a mixed solution of HNO3 (4.5 mL, 75.24 mmol, purchased from Shanghai Aladdin Biochemical Co., Ltd.) and 12 mL of acetic acid. After reacting at 35 °C for 48 hours, add ice water to precipitate the solid, filter, and dry under vacuum to obtain N-ethyl-3,7-dinitrophenthiazide.
[0066] N-ethyl-3,7-dinitrophenthiazide (1.58 g, 5 mmol) and SnCl₂·2H₂O (16.6 g, 75 mmol, purchased from Shanghai Aladdin Biochemical Co., Ltd.) were placed in a two-necked flask, and 50 mL of ethanol was added. The mixture was heated under reflux overnight, cooled to room temperature, and then cold water was added. The pH was adjusted to 7 with 5% NaHCO₃. The extract was extracted with ethyl acetate, washed with saturated NaCl, dried over anhydrous sodium sulfate, filtered, and concentrated until a small amount of ethyl acetate remained. A large amount of petroleum ether was added to precipitate the precipitate, which was then filtered and dried under vacuum to obtain N-ethyl-3,7-diaminophenthiazide.
[0067] N-Ethyl-3,7-diaminophenthiazide (0.51 g, 2 mmol) was placed in a pressure-resistant flask, and anhydrous formic acid (1.52 mL, 40 mmol, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory), triethylamine (5.56 mL, 40 mmol, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory), and 5 mL of DMSO (purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory) were added. The mixture was reacted at 150 °C for 24 hours. After cooling, NaOH solution was added for neutralization, followed by extraction with dichloromethane. The organic phase was washed with saturated NaCl, dried over Na2SO4, and purified by column chromatography. The product was then recrystallized from acetone to obtain the green solid N-ethyl-3,7-dimethylaminophenthiazide. 1 HNMR ( Figure 6 The molecular structure was analyzed by liquid chromatography and high-resolution time-of-flight mass spectrometry, which confirmed the presence of the target product compound 3.
[0068]
[0069] The redox behavior of compound 3 was studied by cyclic voltammetry. Compound 3 was dissolved in 10 mL of 3 mol / L sulfuric acid solution, and the solution was shaken and stirred until a homogeneous solution was formed, followed by a 5 mmol / L solution. The scan rate was 50 mV / s, and the scan voltage range was 0.3–1.0 V.
[0070] like Figure 7 As shown, compound 3 has a pair of reversible redox peaks at 0.63 V vs. SHE, which is 0.1 V higher than the methylene blue potential in comparative example 1.
[0071] Example 4
[0072] Phenothiazine (1 g, 5 mmol, purchased from Anhui Zesheng Technology Co., Ltd.) was placed in a two-necked flask and dissolved in 15 mL of anhydrous tetrahydrofuran. NaH (0.42 g, 10 mmol) was added in small portions under ice bath conditions. After stirring at 50 °C for 1 hour, isopropane (0.94 mL, 10 mmol, purchased from Anhui Zesheng Technology Co., Ltd.) was added. After reacting for 12 hours, the reaction was quenched with ice water, extracted with ethyl acetate, and column chromatography was performed to obtain N-isopropylphenhiazine.
[0073] Weigh 1.2 g (5 mmol) of N-isopropylphenthiazide into a two-necked flask, add 10 mL of acetic acid (purchased from Shanghai Aladdin Biochemical Co., Ltd.), and then slowly add a mixed solution of HNO3 (2.55 mL, 40 mmol, purchased from Shanghai Aladdin Biochemical Co., Ltd.) and 12 mL of acetic acid. After reacting at 35 °C for 48 hours, add ice water to precipitate the solid, filter, and dry under vacuum to obtain N-isopropyl-3,7-dinitrophenthiazide.
[0074] N-Isopropyl-3,7-dinitrophenthiazide (1.65 g, 5 mmol) and SnCl₂·2H₂O (16.6 g, 75 mmol, purchased from Shanghai Aladdin Biochemical Co., Ltd.) were placed in a two-necked flask, and 50 mL of ethanol was added. The mixture was heated under reflux overnight, cooled to room temperature, and then cold water was added. The pH was adjusted to 7 with 5% NaHCO₃. The extract was extracted with ethyl acetate, washed with saturated NaCl, dried over anhydrous sodium sulfate, filtered, and concentrated until a small amount of ethyl acetate remained. A large amount of petroleum ether was added to precipitate the precipitate, which was then filtered and dried under vacuum to obtain N-isopropyl-3,7-diaminophenthiazide.
[0075] N-Isopropyl-3,7-diaminophenthiazide (0.54 g, 2 mmol) was placed in a pressure-resistant flask, and anhydrous formic acid (1.52 mL, 40 mmol, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory), triethylamine (5.56 mL, 40 mmol, purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory), and 5 mL of DMSO (purchased from Tianjin Jindong Tianzheng Fine Chemical Reagent Factory) were added. The mixture was reacted at 150 °C for 24 hours, cooled, neutralized with NaOH solution, extracted with dichloromethane, washed with saturated NaCl on the organic phase, dried over Na2SO4, and passed through a column. The product was recrystallized from acetone to obtain a green solid, N-isopropyl-3,7-dimethylaminophenthiazide. 1 H NMR ( Figure 8 The molecular structure was analyzed by liquid chromatography and high-resolution time-of-flight mass spectrometry, which confirmed the presence of the target product compound 4.
[0076]
[0077] The redox behavior of compound 4 was studied by cyclic voltammetry. Compound 4 was weighed and dissolved in 10 mL of 3 mol / L sulfuric acid solution. The solution was shaken and stirred until a homogeneous solution was formed, followed by a 5 mmol / L solution. The scan rate was 50 mV / s, and the scan voltage range was 0.4–0.9 V.
[0078] like Figure 9 As shown, compound 4 has a pair of reversible redox peaks at 0.7 V vs. SHE, which is 0.17 V higher than the potential of methylene blue in comparative example 1.
[0079] Example 5
[0080] Solubility test: First, a series of electrolyte standards with different concentrations were prepared. A UV spectrophotometer was used to perform a linear spectral scan in the 190-900 nm range. The absorbance values at characteristic peaks were then linearly fitted to the concentration to obtain the standard absorption curve of the electrolyte. The sample powder was added to the supporting electrolyte until no solid dissolved, resulting in a saturated solution. After centrifugation, the supernatant was diluted to the desired concentration. The solubility was calculated based on the standard curve.
[0081] Finally, the solubility of compound 2 in 3M H2SO4 was measured to be 1.7M, the solubility of compound 3 was 1.9M, and compound 4 was miscible with 3M H2SO4, indicating that N-substituted phenothiazine molecules all have high solubility.
[0082] Example 6
[0083] Commercially available vanadium (1.6MV(III) / V(IV)+3M H2SO4) electrolyte was used as the positive and negative electrode electrolytes. The battery was assembled in the following order and position: graphite current collector-carbon felt electrode-ion-conducting membrane PBI-graphite felt electrode-graphite current collector (effective electrode area 48cm²). 2 A magnetic pump is used to drive the positive and negative electrolytes into the battery cavity. After the discharge is completed, the negative electrode V(III) electrolyte is taken as the negative electrode electrolyte.
[0084] Compound 2 was weighed and dissolved in 8 mL of 3 mol / L sulfuric acid aqueous solution. The solution was shaken and stirred until a homogeneous solution was formed, then a 0.5 mol / L solution was prepared as the positive electrode electrolyte. The battery was assembled in the following order and position: graphite current collector - carbon felt electrode - ion-conducting membrane PBI - graphite felt electrode - graphite current collector (effective electrode area 9 cm²). 2 A peristaltic pump drives the positive and negative electrolytes into the battery cavity for charging and discharging.
[0085] like Figure 10 As shown, this flow battery operates at 160 mA cm⁻¹ -2 The discharge capacity at the specified current density is 21.7 Ah L. -1After 200 cycles, the capacity retention rate was 93.3%, indicating that compound 2 has good stability.
[0086] Example 7
[0087] Commercially available vanadium (1.6MV(III) / V(IV)+3M H2SO4) electrolyte was used as the positive and negative electrode electrolytes. The battery was assembled in the following order and position: graphite current collector-carbon felt electrode-ion-conducting membrane PBI-graphite felt electrode-graphite current collector (effective electrode area 48cm²). 2 A magnetic pump is used to drive the positive and negative electrolytes into the battery cavity. After the discharge is completed, the negative electrode V(III) electrolyte is taken as the negative electrode electrolyte.
[0088] Compound 3 was dissolved in 8 mL of 3 mol / L sulfuric acid aqueous solution. The solution was shaken and stirred until a homogeneous solution was formed, then a 0.5 mol / L solution was prepared as the positive electrode electrolyte. The battery was assembled in the following order and position: graphite current collector - carbon felt electrode - ion-conducting membrane PBI - graphite felt electrode - graphite current collector (effective electrode area 9 cm²). 2 A peristaltic pump drives the positive and negative electrolytes into the battery cavity for charging and discharging.
[0089] like Figure 11 As shown, this flow battery operates at 160 mA cm⁻¹ -2 Compound 3 was subjected to long charge-discharge cycles at a current density of 150 cycles, and its efficiency and capacity did not show significant decay after 150 cycles, indicating that compound 3 has excellent stability.
[0090] Comparative Example 2
[0091] Toluidine blue (purchased from Shanghai Aladdin Biochemical Co., Ltd.) was weighed and dissolved in 10 mL of 3 mol / L sulfuric acid solution. The solution was shaken and stirred until a homogeneous solution was formed, resulting in a 10 mmol / L solution. Its redox behavior was studied by cyclic voltammetry at a scan rate of 50 mV / s and a scan voltage range of 0.2–0.8 V.
[0092]
[0093] like Figure 12 As shown, toluidine blue exhibits a pair of reversible redox peaks at 0.52 V vs. SHE. The redox potential of toluidine blue is significantly lower than that of compound 1 in Example 1, indicating that the redox potential of the molecule cannot be increased when the methyl group is not on the N atom.
Claims
1. An N-substituted phenothiazine derivative, characterized in that, The structure is as follows: In the formula, R1 is selected from C1 to C10 alkyl groups, -(CH2) n OH, -(CH2) n NH2、-(CH2) n N(CH3)2、-(CH2) n N(CH3)3 + -(CH2) n COOH, -(CH2) n SO3H, -(CH2) n At least one of PO3H2; Ra and Rb may be the same or different, and are independently selected from: -H, C1 to C10 alkyl groups, and -(CH2). n OH, -(CH2) n NH2、-(CH2) n N(CH3)2、-(CH2) n N(CH3)3 + -(CH2) n COOH, -(CH2) n SO3H, -(CH2) n At least one of PO3H2; Wherein: -(CH2) n OH, -(CH2) n NH2、-(CH2) n N(CH3)2、-(CH2) n N(CH3)3 + -(CH2) n COOH, -(CH2) n SO3H, -(CH2) n In PO3H2, n is a natural number, and the value of n ranges from 1 to 10.
2. An aqueous organic flow battery, comprising a positive electrode electrolyte, characterized in that, The positive electrode electrolyte is selected from the N-substituted phenothiazine derivatives according to claim 1.
3. The flow battery according to claim 2, characterized in that, The concentration of N-substituted phenothiazine derivatives in the positive electrode electrolyte is 0.05–5 mol / L.
4. The flow battery according to claim 2, characterized in that, A flow battery consists of a positive electrode, a negative electrode, a separator, and an electrolyte. The electrolyte includes a positive electrode electrolyte and a negative electrode electrolyte; The space between the positive electrode and the separator is filled with a positive electrode electrolyte; The space between the negative electrode and the separator is filled with negative electrode electrolyte.
5. The flow battery according to claim 4, characterized in that, The positive and negative electrolytes also independently include a supporting electrolyte.
6. The flow battery according to claim 5, characterized in that, The supporting electrolyte is selected from at least one of hydrochloric acid, sulfuric acid, perchloric acid, phosphoric acid, acetic acid, methanesulfonic acid, and trifluoromethanesulfonic acid.
7. The flow battery according to claim 5, characterized in that, The concentration of the supporting electrolyte is 0.05–6 mol / L.
8. The flow battery according to claim 4, characterized in that, The positive and negative electrodes are independently selected from at least one of carbon felt, carbon cloth, carbon paper, graphite plate, and metal plate.
9. The flow battery according to claim 4, characterized in that, The negative electrode electrolyte includes a negative electrode electrolyte; The negative electrode electrolyte is selected from at least one of vanadium sulfate, silicotungstic acid, tin chloride, cadmium chloride, chromium chloride, lead sulfate, and titanium sulfate.
10. The flow battery according to claim 4, characterized in that, The diaphragm is selected from ion exchange membranes and / or porous membranes.