CN113328092B - Aqueous holozine secondary battery based on oxazine compounds with multiple oxidation states - Google Patents

Abstract

The invention belongs to the field of new energy, and particularly relates to a water system holozine secondary battery based on oxazine compounds with various oxidation states. Electrical energy is stored chemically in molecules of oxazines having multiple oxidation states. Upon charging, the negative electrode is oxidized to release electrons and protons, while the positive electrode is reduced by accepting electrons and protons. During discharging, the reaction of the positive electrode and the negative electrode is reversed to output electric energy. The flow battery can avoid the problems of diaphragm cross permeation, electrode polarity reversal, complicated recovery and the like, and has wide application prospect.

Description

Aqueous holozine secondary battery based on oxazine compounds with multiple oxidation states

Technical Field

The invention belongs to the field of new energy, and particularly relates to a water system holozine secondary battery based on oxazine compounds with various oxidation states.

Background

The design and development of secondary batteries, such as lithium ion batteries, which have the characteristics of low cost, environmental friendliness, high energy density and high power density, are always hot and difficult points of energy storage technology research. Lithium ion batteries dominate in the fields of portable electronic products, electric vehicles and the like due to high specific Energy and high efficiency, however, the wide application of lithium ion batteries is hindered by serious safety problems caused by the use of flammable organic electrolytes (Renewable stable Energy rev.2018,89,292). In addition, the cost of lithium ion batteries is also high due to the expensive cathode materials and the relative scarcity of lithium resources. Therefore, from the sustainable development perspective, it is imperative to develop a new battery system with low cost, high capacity, long lifetime, and safety and reliability by using elements rich in earth crust reserves to replace lithium ion batteries.

Organic substances are considered to be one of the most promising electrode active materials in the future due to the characteristics of abundant resources, various varieties, environmental friendliness and the like. Especially, the secondary battery based on the organic active material is very suitable for the application of future electric automobiles and large-scale energy storage power stations. The all-organic secondary battery using the low-cost aqueous electrolyte and the organic electroactive material has the following advantages:

first, the aqueous electrolyte is inexpensive, highly safe, has much higher ionic conductivity than the nonaqueous electrolyte, and can withstand overcharge (electrochemical. acta,2000,45, 2467). Secondly, organic materials are composed of elements with high abundance of the crust (e.g. carbon, hydrogen, oxygen, nitrogen, etc.) and their synthesis temperature (less than 200 ℃) is usually much lower than inorganic materials (nat. chem.2015,7, 19).

Furthermore, organic materials have a high degree of designability in terms of their molecular structure, i.e., their potential, theoretical specific capacity, and key properties such as electrochemical kinetics can be controlled by the selection and increase and decrease of structural units and functional groups (Energy Fuels 2020,34, 13384).

Therefore, the development of all-organic secondary battery materials having high specific capacity and cycle stability has been a hot research in the battery field.

Common electroactive organic materials include quinones, oxazines, indigoids, viologens, nitroxides (TEMPO), diazo compounds (N ═ N), sulfur-containing compounds, metal-containing compounds (e.g., ferrocene and cobaltocene), and the like (Energy Fuels 2020,34, 13384). Among them, quinone molecules are widely present in nature and can be conveniently synthesized from petrochemical raw materials. Quinones have extremely low activation Energy due to structural reorganization based on quinone/phenol interconversion, exhibit extremely excellent reversibility in electrochemical reactions, and are used as electrode materials for nonaqueous and aqueous batteries and redox active electrolytes for flow batteries (Nano Energy 2017,37, 46; Nature 2014,505,195; nat. mater.2017,16,841). At present, most of the reported organic couples have low oxidation-reduction potentials and are often used as negative electrode materials. Only a few types of electric pairs have higher potential and can be used as anode materials. And most of organic electric pairs have the problems of poor chemical and electrochemical stability. Therefore, most organic flow batteries reported so far are usually operated under a nitrogen or argon atmosphere.

The existing researches on oxazine mainly focus on the research in the field of lithium ions, and the oxazine is rarely used for the research on metal-organic secondary batteries, and is not used for the research on all-organic secondary batteries which are used as a cathode and an anode simultaneously. Metals as electrode materials have the disadvantages of high cost, large pollution, few varieties and the like.

Disclosure of Invention

The invention selects proper oxazine as the positive electrode active substance and the negative electrode active substance of the flow battery respectively, and the oxazine is matched with supporting electrolyte, a diaphragm, a porous carbon electrode and a current collector to form a novel flow battery. Compared with the prior flow battery design, the flow battery can avoid the problems of diaphragm cross permeation, electrode polarity reversal, complicated recovery and the like, and has wide application prospect.

In one embodiment, the oxazine has multiple oxidation states (e.g., 3), allowing the same oxazine backbone to be used for the positive and negative electrodes of the battery. Such a design is advantageous to avoid the effect of cross-contamination of active species, since the oxazines of the positive and negative electrodes are the same molecule or can be oxidized (or reduced) to the same molecule. Fig. 1 shows an exemplary scheme of a secondary battery using oxazines having 3 oxidation states at both the positive and negative electrodes. During discharge, Z is reduced to ZH on the positive electrode side₂On the negative electrode side ZH₄Oxidation to ZH₂Wherein Z represents the same oxazine skeleton. Thus, ZH₄Is a reduced form of the oxazine and Z is an oxidized form of the oxazine. And ZH₂Is not only ZH₄Is also a reduced form of Z.

In another embodiment, different oxazines are used for the positive and negative electrodes of the cell. Fig. 2 shows an exemplary scheme of a battery using different oxazines for the positive and negative electrodes of the battery. X and Y represent different substituents or substituents at different positions or different combinations of substituents, and the oxazine on the positive or negative electrode side may have the same or different number of aromatic rings. Upon charging, ZX is reduced to ZXH₂，ZYH₂Oxidized to ZY, where ZX and ZY are oxazine derivatives having different backbones.

Reduction of oxazines to hydrooxazines by bonding double bonds to sp²The nitrogen ("═ N") of the six-membered nitrogen heterocycle is converted into a singly bound amine group ("> NH")And (4) forming. The electrodes donate electrons when the supporting electrolyte system provides protons. This typically occurs with the nitrogen para (pyrazine structure) in the para configuration. In acidic or basic aqueous solutions, the transition from a hydrozine to an oxazine involves simple removal of protons and electrons associated with the nitrogen without destroying the rest of the bond, and therefore such molecules not only have fast reaction kinetics, but are also very stable.

In addition to potential and redox kinetics, important molecular properties include solubility resistance, chemical stability, toxicity, and cost. Ultra-low solubility is important because dissolution of the electrode active material in full cell operation will result in gradual capacity reduction, or even cell failure. Their solubility in aqueous electrolyte systems can be reduced by the attachment of non-polar groups (e.g., hydrocarbon groups). Chemical stability is required to prevent chemical loss of the electrode material during long-term charge-discharge cycles and to suppress the degradation of the electrode performance which may be caused by its polymerization on the electrode surface. Stability against water and polymerization can be improved by introducing more stable groups such as C-R, where R is optionally substituted C1-6 alkyl, optionally substituted C1-6 fluoroalkyl, halogen, amino, aryl, nitro, carboxyl, or nitrile groups, in place of the vulnerable C-H group adjacent to the C ═ N group.

Oxazines having multiple oxidation states include:

wherein each of R1-R12 is independently selected from H, optionally substituted C1-6 alkyl, aryl, halogen, amino, nitro, carboxyl, nitrile, optionally substituted C1-6 fluoroalkyl, optionally substituted C1-6 alkyl ester. The double bonds in the ring represent the complete conjugation of the ring system.

Preferably, the oxazine compound is selected from:

the supporting electrolyte of the battery is potassium chloride, sodium chloride, lithium chloride, potassium sulfate, potassium nitrate, potassium perchlorate, sodium sulfate, sodium nitrate, sodium perchlorate, lithium sulfate, lithium nitrate or a mixture thereof, the pH of the supporting electrolyte solution is 8-12, and the solvent for dissolving the supporting electrolyte is water.

The membrane may be a selective ion exchange membrane that allows passage of hydrated ions but blocks redox active species on the electrode, such as Nafion series perfluorosulfonic acid membranes and Fumasep series hydrocarbon based polymer ion exchange membranes. In addition, the membrane may also employ a porous physical barrier or a size exclusion membrane.

The electrode may be any porous carbon electrode, such as a carbon paper electrode, a carbon felt electrode, a carbon cloth electrode, or a porous graphene or nitrogen doped porous graphene electrode. Titanium nitride electrodes may also be used. Electrodes suitable for use with other redox active materials are known in the art.

The current collector is a gold-plated copper net, a gold-plated copper sheet or a gold-plated copper film.

The aqueous all-organic secondary battery is used for electrochemical storage.

Compared with the prior art, the invention has the following advantages: the oxazinyl electrode material with multiple oxidation states provided by the invention has low synthesis cost and is easy to industrialize. The oxazine compound has rich sources, has a theoretical specific capacity higher than 20% compared with the conventional quinone material, and has wide application prospects in the aspects of energy storage of portable electronic products, electric automobiles, power grids and the like. Compared with the prior secondary battery design, the secondary battery can avoid the problems of diaphragm cross permeation, electrode polarity reversal, complex recovery and the like.

Drawings

Fig. 1 is a schematic diagram of a cell structure using the same oxazine on both sides of the cell. Wherein said oxazine has a formula of Z, ZH₂And ZH₄Three oxidation states are represented.

Fig. 2 is a schematic diagram of a cell structure using different oxazines on both sides of the cell.

FIG. 3 is a cyclic voltammogram of 5,6,11,12,17, 18-Hexaazatrinaphthalene (HATN) of example 1 in 1mol/L KCl at pH 11.

FIG. 4 is a NMR spectrum of 1,5, 9-tribromo-5, 6,11,12,17, 18-hexaazatrinaphthalene (Br-HATN) and 3,3 ' - (biquinoxaline [2,3-a: 2', 3 ' -c ] phenazine-1, 7, 13-triacyltriadienyl) tripropionic acid (TAHATN) of example 2.

FIG. 5 is a cyclic voltammogram of TAHATN in example 2 in 1mol/L KCl at pH 10.

Fig. 6 is a graph of charge and discharge curves for HATN negative electrodes at different current densities.

Fig. 7 is a graph of the charge-discharge cycle at 2A/g in 1mol/L KCl at pH 11 for a HATN negative electrode.

FIG. 8 is a graph of the charge-discharge cycle at 2A/g in 1mol/L KCl at pH 10 for a TAHATN cell.

Detailed Description

Electrochemical Properties of example 15, 6,11,12,17, 18-Hexaazatrinaphthalene (HATN)

The electrochemical properties of 5,6,11,12,17, 18-hexaazatrinaphthalene in weakly alkaline aqueous electrolyte solutions were investigated by Cyclic Voltammetry (CV). 2 mg of 5,6,11,12,17, 18-hexaazatrinaphthalene and 2 mg of conductive carbon Black (Ketjen Black) were mixed, 0.5 ml each of isopropanol and deionized water was added, the mixture was vigorously sonicated for 1 hour, followed by addition of 75. mu.l of perfluorosulfonic acid ionomer solution (5%), and sonication continued for 1 hour to form a homogeneous slurry. And (3) dropwise adding the slurry into the surface of a clean glassy carbon electrode, and naturally airing to serve as a working electrode. The electrochemical properties of 5,6,11,12,17, 18-hexaazatrinaphthalene were examined in a standard three-electrode system with a platinum sheet electrode as the counter electrode, a mercury/mercury oxide electrode (0.098V vs. standard hydrogen electrode) as the reference electrode, a supporting electrolyte solution of 1mol/L KCl, and the pH of the solution adjusted using KOH. Before testing, nitrogen is firstly introduced into the electrolyte solution to remove dissolved oxygen, and the whole testing process is carried out in a nitrogen atmosphere. FIG. 3 is a graph of Cyclic Voltammetry (CV) for 5,6,11,12,17, 18-hexaazatrinaphthalene in a 1mol/L KCl solution at pH 11. FIG. 3 is a CV curve of hexaazatrinaphthalenes showing 3 sets of reversible redox peaks at the standard equilibrium potential E₁ ⁰、E₂ ⁰And E₃ ⁰Are-0.72, +0.16 and +0.49V, respectively. Thus, the open circuit voltage of aqueous holooxazine cells based on the redox chemistry of hexaazatrinaphthaleneThe (OCV) values are predicted to be 0.88 and 1.21V (average 1.05V), respectively.

EXAMPLE 2 Synthesis and electrochemical Properties of 3,3 ' - (Diquinoxaline [2,3-a: 2', 3 ' -c ] phenazine-1, 7, 13-triacyltriazadienyl) tripropionic acid (TAHATN)

Firstly, synthesizing 1,5, 9-tribromo-5, 6,11,12,17, 18-hexaazatrinaphthalene (Br-HATN) by Schiff base condensation reaction: 1, 2-diamino-3-bromobenzene (1.0 mmol) and hexa-ketocyclohexane octahydrate (0.33 mmol) were mixed in 10mL of acetic acid, and the mixture was heated to 120 ℃ for reaction at 12 hours. And (3) carrying out suction filtration to collect a solid initial product, washing the solid initial product with water, ethyl acetate and acetone in sequence, and carrying out vacuum drying at the temperature of 60 ℃ for 24 hours to obtain a product with the yield of 75%.

Subsequently TAHATN was synthesized via a substitution reaction: to 20mL of t-butanol were added Br-HATN (0.94 mmol), β -alanine (4.7 mmol), potassium t-butoxide (7.0 mmol), and dibenzylideneacetone dipalladium (Pd) in that order₂(dba)₃0.028 mmol) and dicyclohexyl [3, 6-dimethoxy-2 ',4',6 '-triisopropyl [1,1' -biphenyl]-2-yl]Phosphine (BrettPhos,0.056 mmol). After the solution is fully dissolved, the solution is vacuumized through a double-row pipe, heated to 100 ℃ and stirred for reaction for 16 hours. Both Br-HATN and TAHATN exhibit high insolubility in water and have a solubility of less than 10^-9mol/L。

FIG. 4 is the NMR spectra of Br-HATN and TAHATN: (¹H NMR) graph. The electrochemical properties of TAHATN were investigated by cyclic voltammetry. The working electrode preparation procedure and electrochemical testing procedure were the same as in example 1. FIG. 5 is a cyclic voltammogram of TAHATN in 1mol/L KCl solution at pH 10 (100 mVs)^-1). FIG. 5 shows that the TAHATN electrode has two main groups of reversible redox reactions, one group having a standard equilibrium potential of about-0.66V and the other group having a standard equilibrium potential of about 0.18V. From this, it is predicted that the Open Circuit Voltage (OCV) of the aqueous fully-oxazine cell based on TAHATN is 0.84V.

Example 3 aqueous Whole-oxazine cell based on HATN

The HATN of example 1 was used as a positive electrode material and a negative electrode material (the relative proportions of an active material, conductive carbon black and a binder were 7:2:1), 1mol/L KCl (adjusted to pH 11 using KOH) was used as a supporting electrolyte solution, a Nafion membrane was a separator, and carbon paper (or carbon cloth) was used as an electrode material support, to construct an aqueous all-organic battery cell. In order to prevent the electrode active material from being oxidized by oxygen in the air during charge and discharge, nitrogen gas is continuously introduced into the battery system to isolate the air. Fig. 6 is a graph of charge and discharge curves for HATN negative electrodes at different current densities. The charging specific capacity and the discharging specific capacity of the HATN negative electrode under the current density of 0.6A/g are respectively 134 mAh/g and 74mAh/g, and the HATN negative electrode shows better rate capability. FIG. 7 is a graph showing charge and discharge cycles at 2A/g for a HATN negative electrode. After 100 charge-discharge cycles, the capacity retention rate is about 97%, and the current efficiency is close to 90%.

Example 4 aqueous Whole-oxazine cell based on TAHATN

TAHATN of example 2 was used as a positive electrode material and a negative electrode material (the relative proportions of an active material, conductive carbon black and a binder were 4.5:4.5:1), 1mol/L KCl (pH was adjusted to-10 using KOH) was used as a supporting electrolyte solution, a Nafion membrane was used as a separator, and carbon paper was used as an electrode material support, to construct an aqueous all-organic battery cell. In order to prevent the electrode active material from being oxidized by oxygen in the air during charge and discharge, nitrogen gas is continuously introduced into the battery system to isolate the air. The specific discharge capacity of the TAHATN negative electrode under 0.5A/g is 60.2mAh/g, and the material utilization rate is about 72.3%. FIG. 8 is a graph showing the charge-discharge cycle at 2A/g for a TAHATN full cell. After 100 charge-discharge cycles, the capacity retention rate of the battery is close to 72%, and the current efficiency is close to 99%. The capacity retention rate and current efficiency of the TAHATN cell were superior to those of the water-based all-quinone cell in the comparative example.

Example 5 aqueous all-oxazine cell based on HATN negative and Br-HATN positive

The HATN of example 1 was used as a negative electrode material, the Br-HATN of example 2 was used as a positive electrode material (the relative proportions of the active material, the conductive carbon black and the binder were 4.5:4.5:1), 1mol/L KCl (pH adjusted to-11 using KOH) was used as a supporting electrolyte solution, a Nafion film was used as a separator, and carbon paper (or carbon cloth) was used as an electrode material support, to construct an aqueous all-organic battery cell. In order to prevent the electrode active material from being oxidized by oxygen in the air during charge and discharge, nitrogen gas is continuously introduced into the battery system to isolate the air. The specific discharge capacity of the fully-oxazine battery at 0.5A/g is about 86.3 mAh/g. After 100 charge-discharge cycles, the capacity retention rate of the battery is about 85%, and the current efficiency is close to 98%.

EXAMPLE 6 aqueous Whole oxazine cell based on quinoxalino [2,3-b ] phenazine

Commercial quinoxalino [2,3-b ] phenazine is respectively used as the positive and negative electrodes of a flow battery, the relative proportion of an active substance, conductive carbon black and a binder is 4.5:4.5:1, 1mol/L KCl (the pH is adjusted to 8 by KOH) is used as a supporting electrolyte solution, a Nafion film is used as a diaphragm, carbon paper (or carbon cloth) is used as an electrode material carrier, and a water system all-organic battery single cell is constructed. The specific discharge capacity of the fully-oxazine battery at 0.5A/g is about 82.2 mAh/g. After 100 charge-discharge cycles, the capacity retention rate of the battery is about 89%, and the current efficiency is close to 97%.

Example 7 aqueous Whole oxazine cell based on quinoxalino [2,3-a ] phenazine

Commercial quinoxalino [2,3-a ] phenazine is respectively used as the positive and negative electrodes of a flow battery, the relative proportion of an active substance, conductive carbon black and a binder is 4.5:4.5:1, 1mol/L KCl (the pH is adjusted to-12 by KOH) is used as a supporting electrolyte solution, a Nafion film is used as a diaphragm, carbon paper (or carbon cloth) is used as an electrode material carrier, and a water system all-organic battery single cell is constructed. The specific discharge capacity of the full-oxazine battery at 0.5A/g is about 76.8 mAh/g. After 100 charge-discharge cycles, the capacity retention rate of the battery is about 85%, and the current efficiency is close to 96%.

Example 8 aqueous Whole oxazine cell based on quinoxalino [2,3-a ] phenazine

With commercial quinoxalino- [2,3-a ]]Phenazine is respectively used as the positive pole and the negative pole of the flow battery, and the relative proportion of the active substance, the conductive carbon black and the binder is 4.5:4.5:1, 1mol/L Na₂SO₄KOH is used for adjusting the pH value to 8 to be used as a supporting electrolyte solution, a Nafion membrane is used as a diaphragm, carbon paper (or carbon cloth) is used as an electrode material carrier, and a water system all-organic battery single cell is formed. The specific discharge capacity of the full-oxazine battery at 0.5A/g is about 83.3 mAh/g. After 100 charge-discharge cycles, the capacity retention rate of the battery is about 88%, and the current efficiency is close to 93%.

EXAMPLE 9 aqueous Whole oxazine cell based on quinoxalino [2,3-a ] phenazine

With commercial quinoxalino- [2,3-a ]]Phenazine is respectively used as the positive pole and the negative pole of the flow battery, and the relative proportion of the active substance, the conductive carbon black and the binder is 4.5:4.5:1, 1mol/L LiNO₃KOH is used for adjusting the pH value to 9 to be used as a supporting electrolyte solution, a Nafion membrane is used as a diaphragm, carbon paper (or carbon cloth) is used as an electrode material carrier, and a water system all-organic battery single cell is formed. The specific discharge capacity of the fully-oxazine battery at 0.5A/g is about 74.8 mAh/g. After 100 charge-discharge cycles, the capacity retention rate of the battery is about 90%, and the current efficiency is close to 95%.

Comparative example: aqueous all-organic battery based on polypyrrole quinoxaline

Polypyrrole quinoxaline is used as a positive electrode material and a negative electrode material, the relative proportion of an active substance, conductive carbon black and a binder is 4.5:4.5:1, 1mol/L KCl (the pH is adjusted to 10 by KOH) is used as a supporting electrolyte solution, a Nafion film is used as a diaphragm, carbon paper (or carbon cloth) is used as an electrode material carrier, and an aqueous all-organic battery single cell is constructed. The specific discharge capacity of the all-organic battery at 0.5A/g is about 32.4 mAh/g. After 100 charge-discharge cycles, the capacity retention rate of the battery is about 56%, and the current efficiency is close to 81%.

Claims (7)

1. An aqueous holo-zine secondary battery characterized in that: the secondary battery is composed of a negative electrode active material, a positive electrode active material, a supporting electrolyte, a diaphragm, a porous carbon electrode and a current collector, wherein the positive electrode active material and the negative electrode active material are both insoluble oxazine compounds with multiple oxidation states;

the oxazine compounds having multiple oxidation states have the following structure:

wherein R is₁-R₁₂Independently selected from H, optionally substituted C_1-6Alkyl, aryl, halogen, amino, nitro, carboxyl, nitrile, optionally substituted C_1-6Fluoroalkyl, optionally substituted C_1-6Alkyl esters, in ringsThe double bonds represent the complete conjugation of the ring system.

2. The aqueous holozine secondary battery according to claim 1, characterized in that: the supporting electrolyte is potassium chloride, sodium chloride, lithium chloride, potassium sulfate, potassium nitrate, potassium perchlorate, sodium sulfate, sodium nitrate, sodium perchlorate, lithium sulfate, lithium nitrate or a mixture thereof, the pH of the supporting electrolyte solution is 8-12, and the solvent for dissolving the supporting electrolyte is water.

3. The aqueous holozine secondary battery according to claim 1, characterized in that: the membrane is an ion conductive membrane, a porous physical membrane, or a size exclusion membrane.

4. The aqueous holozine secondary battery according to claim 1, characterized in that: the oxazine compound is selected from:

5. the aqueous holozine secondary battery according to claim 1, characterized in that: the porous carbon electrode is carbon paper, carbon cloth, carbon felt or porous graphene felt.

6. The aqueous holozine secondary battery according to claim 1, characterized in that: the current collector is a gold-plated copper net, a gold-plated copper sheet or a gold-plated copper film.

7. The water-based holozine secondary battery of claim 1 for electrochemical storage.

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