阅读说明：本技术 一种正极材料、正极极片、水系锌离子电池及其制备方法 (Positive electrode material, positive electrode plate, water-based zinc ion battery and preparation method thereof ) 是由 黄可贤 李驰麟 尹东光 于 2020-05-11 设计创作，主要内容包括：本发明提供一种正极材料、正极极片、水系锌离子电池及其制备方法。该正极材料的制备方法包括如下步骤：1)在惰性气体气氛下,将1,4,5,8-萘四甲酸酐与氨水进行缩合反应,获得固体悬浮物；2)将所述固体悬浮物分离、洗涤并干燥,获得所述正极材料。该正极材料为1,4,5,8-萘四甲酰二亚胺,表面形貌为颗粒堆叠成交织连续多孔网状。本发明使用富含羰基活性位点的1,4,5,8-萘四甲酰二亚胺作为正极材料,可以通过锌离子与羰基的烯醇化反应实现高度可逆的锌离子存储,与过渡金属无机正极材料相比,酰亚胺来源广泛,易于制备,活性位点多,理论比容量大,减少对不可再生过渡金属的使用,更绿色环保,符合可持续发展的理念。(The invention provides a positive electrode material, a positive electrode plate, a water-based zinc ion battery and a preparation method thereof. The preparation method of the cathode material comprises the following steps: 1) under the atmosphere of inert gas, 1,4,5, 8-naphthalene tetracarboxylic anhydride and ammonia water are subjected to condensation reaction to obtain solid suspended matters; 2) and separating, washing and drying the solid suspension to obtain the cathode material. The anode material is 1,4,5, 8-naphthalimide, and the surface appearance is that particles are stacked into an interwoven continuous porous net. The invention uses 1,4,5, 8-naphthalimide rich in carbonyl active sites as the anode material, can realize highly reversible zinc ion storage through the enolization reaction of zinc ions and carbonyl, has wide imide source, easy preparation, more active sites and large theoretical specific capacity compared with transition metal inorganic anode materials, reduces the use of non-renewable transition metals, is more green and environment-friendly, and conforms to the concept of sustainable development.)

1. A preparation method of a positive electrode material is characterized by comprising the following steps:

1) under the atmosphere of inert gas, 1,4,5, 8-naphthalene tetracarboxylic anhydride and ammonia water are subjected to condensation reaction to obtain solid suspended matters;

2) and separating, washing and drying the solid suspension to obtain the cathode material.

2. The method for preparing a positive electrode material according to claim 1, further comprising at least one of the following technical features:

1) in the step 1), the inert gas is at least one selected from nitrogen and argon;

2) in the step 1), the concentration of ammonia water is 25 wt% -28 wt%;

3) in the step 1), the molar ratio of 1,4,5, 8-naphthalene tetracarboxylic anhydride to ammonia water is (5-20): 100;

4) in the step 2), the drying temperature is 50-80 ℃.

3. A positive electrode material obtained by the production method according to claim 1 or 2.

4. The positive electrode material according to claim 3, further comprising at least one of the following technical features:

1) the anode material is 1,4,5, 8-naphthalimide, and the surface appearance is that particles are stacked into an interwoven continuous porous net;

2) the particle size of the anode material is 50 nm-500 nm;

3) the pore size of the anode material is 50 nm-100 nm.

5. The positive pole piece is characterized by comprising a positive current collector and positive slurry coated on the surface of the positive current collector; the positive electrode slurry includes the positive electrode material according to claim 3 or 4, a conductive agent, a binder, and a solvent.

6. The positive electrode sheet according to claim 5, further comprising at least one of the following technical features:

1) the mass percent of the positive electrode material is 25-90% by taking the positive electrode material, the conductive agent and the binder as the total mass;

2) the mass percent of the conductive agent is 10-70% by taking the positive electrode material, the conductive agent and the binder as the total mass;

3) the mass percent of the binder is 5-20% based on the total mass of the positive electrode material, the conductive agent and the binder;

4) the volume ratio of the mass of the binder to the solvent is 1mg/20 muL-1 mg/60 muL;

5) the conductive agent is selected from at least one of acetylene black, Ketjen black, Super P, graphite and carbon nanotubes;

6) the binder is selected from at least one of polyacrylic acid, polyvinyl alcohol and polyvinylidene fluoride;

7) the positive current collector is selected from at least one of carbon paper, titanium foil and stainless steel mesh;

8) the solvent is at least one selected from the group consisting of N-methylpyrrolidone, dimethylformamide and water.

7. The method for preparing the positive electrode plate according to claim 5 or 6, comprising the steps of:

1) uniformly mixing a positive electrode material, a conductive agent, a binder and a solvent to obtain positive electrode slurry;

2) and coating the positive electrode slurry on the surface of the positive electrode current collector and drying to obtain the positive electrode piece.

8. An aqueous zinc ion battery, characterized in that the aqueous zinc ion battery comprises a positive electrode sheet, and the positive electrode sheet is the positive electrode sheet according to claim 5 or 6.

9. The aqueous zinc-ion battery of claim 8, wherein the aqueous zinc-ion battery comprises an aqueous electrolyte comprising a water-soluble zinc salt and water.

10. The aqueous zinc-ion battery of claim 9, further comprising at least one of the following technical features:

1) the water-soluble zinc salt is at least one selected from zinc sulfate heptahydrate, zinc nitrate, zinc trifluoromethanesulfonate and zinc chloride;

2) the concentration of the water-soluble zinc salt is 0.1-3 mol/L;

3) the aqueous electrolyte also comprises sodium sulfate, and the concentration of the sodium sulfate is 0.5-1 mol/L.

Technical Field

The invention belongs to the technical field of energy storage, and particularly relates to a positive electrode material, a positive electrode plate, a water-based zinc ion battery and a preparation method thereof.

Background

With the rapid development of human society, renewable clean energy including wind energy, solar energy and nuclear energy gradually becomes the main energy supply of a power system, and the demand of energy storage equipment is increasing to obtain stable power supply. The development of the lithium ion battery has become the first choice of energy storage devices for hybrid electric vehicles, mobile electronic devices and off-peak energy storage at present after the last thirty years, and supports the high informatization and digitization of the modern society. The development of new energy automobiles is continuously strong, which means that the demand of the future society for large-scale energy storage equipment is increasingly increased, and the self limitation of lithium ion batteries restricts the application prospect of the lithium ion batteries in the future large-scale energy storage field. At present, the lithium ion battery anode material applied to new energy automobiles is mainly a ternary system, and the reserves of main components of lithium, cobalt and other metal resources in the material in the nature are small, so that the lithium ion battery has certain potential safety hazards on one hand, and on the other hand, the cost is high in practical application and is difficult to meet the market demand of future continuous development. In order to solve the inherent defects of the lithium ion battery, a safe, environment-friendly and economical novel secondary battery system is imperatively researched and explored.

The water system zinc ion battery is a green environment-friendly novel secondary battery system with great prospect, and has the main advantages that: has higher energy density and power density, and the power density can reach 12KW kg at most^-1The energy density can reach 320Wh kg at most^-1About 15 times of that of the super capacitor. The zinc metal is used as a negative electrode, and the zinc metal has high theoretical volume specific capacity (5854mAh cm)^-3) And a low standard reduction potential (-0.76V). In addition, the zinc has abundant reserves in the earth and stable chemical properties, and can be used as a battery cathode material to assemble a battery in the air, thereby reducing the difficulty of the preparation process and the production cost of the battery. The electrolyte of the water-based zinc ion battery takes water as a solvent, has the advantages of safety and environmental protection compared with an organic electrolyte system, does not produce pollutants in the production and application processes of the battery, and belongs to a green and environment-friendly battery.

The bottleneck of the development of the water-based zinc ion battery is mainly the lack of a positive electrode material suitable for reversible intercalation/deintercalation of zinc ions, most of the currently reported positive electrode materials are transition metal inorganic materials, but the transition metal resources are limited, and the transition metal inorganic materials often contain toxicity, so that the water-based zinc ion battery is not beneficial to future large-scale production.

Disclosure of Invention

The invention provides a positive electrode material, a positive electrode plate, a water-system zinc ion battery and a preparation method thereof, which can reduce the use of non-renewable transition metal and realize highly reversible zinc ion storage.

The invention is realized by the following technical scheme:

the first aspect of the present invention provides a method for preparing a positive electrode material, including the steps of:

1) 1,4,5, 8-naphthalenetetracarboxylic anhydride (CAS NO: 81-30-1) and ammonia water to obtain solid suspended substances;

2) and separating, washing and drying the solid suspension to obtain the cathode material.

Preferably, at least one of the following technical features is also included:

1) in the step 1), the inert gas is at least one selected from nitrogen and argon;

2) in the step 1), the concentration of ammonia water is 25 wt% -28 wt%;

3) in the step 1), the molar ratio of 1,4,5, 8-naphthalene tetracarboxylic anhydride to ammonia water is (5-20): 100;

4) in the step 2), the drying temperature is 50-80 ℃.

The invention provides a cathode material, which is obtained by the preparation method.

Preferably, at least one of the following technical features is also included:

1) the positive electrode material is 1,4,5, 8-naphthalimide (CAS NO: 5690-24-4), the surface topography is that the particles are stacked into an interwoven continuous porous network;

2) the particle size of the anode material is 50 nm-500 nm;

3) the pore size of the anode material is 50 nm-100 nm.

The invention provides a positive pole piece, which comprises a positive pole current collector and positive pole slurry coated on the surface of the positive pole current collector; the positive electrode slurry comprises the positive electrode material, a conductive agent, a binder and a solvent.

Preferably, at least one of the following technical features is also included:

1) the mass percent of the positive electrode material is 25-90% by taking the positive electrode material, the conductive agent and the binder as the total mass;

2) the mass percent of the conductive agent is 10-70% by taking the positive electrode material, the conductive agent and the binder as the total mass;

3) the mass percent of the binder is 5-20% based on the total mass of the positive electrode material, the conductive agent and the binder;

4) the volume ratio of the mass of the binder to the solvent is 1mg/20 muL-1 mg/60 muL;

5) the conductive agent is selected from at least one of acetylene black, Ketjen black, Super P, graphite and carbon nanotubes;

6) the binder is selected from at least one of polyacrylic acid, polyvinyl alcohol and polyvinylidene fluoride;

7) the positive current collector is selected from at least one of carbon paper, titanium foil and stainless steel mesh;

8) the solvent is at least one selected from the group consisting of N-methylpyrrolidone, dimethylformamide and water.

The fourth aspect of the present invention provides a method for preparing the positive electrode plate, wherein the method comprises the following steps:

1) uniformly mixing a positive electrode material, a conductive agent, a binder and a solvent to obtain positive electrode slurry;

2) and coating the positive electrode slurry on the surface of the positive electrode current collector and drying to obtain the positive electrode piece.

The fifth aspect of the invention provides a water-based zinc ion battery, which comprises a positive pole piece, wherein the positive pole piece is the positive pole piece.

Preferably, the aqueous zinc-ion battery includes an aqueous electrolyte including a water-soluble zinc salt and water.

More preferably, at least one of the following technical characteristics is also included:

1) the zinc salt is at least one selected from zinc sulfate heptahydrate, zinc nitrate, zinc trifluoromethanesulfonate and zinc chloride;

2) the concentration of the water-soluble zinc salt is 0.1-3 mol/L;

3) the aqueous electrolyte also comprises sodium sulfate, and the concentration of the sodium sulfate is 0.5-1 mol/L. The sodium sulfate inhibits the growth of zinc dendrites in the circulation process of the water-system zinc ion battery, so that the multiplying power performance and the long circulation performance of the battery are improved, and the water-system zinc ion battery has good circulation stability.

Compared with the prior art, the invention has at least one of the following beneficial effects:

1) the invention uses 1,4,5, 8-naphthalimide rich in carbonyl active sites as the anode material, can realize highly reversible zinc ion storage through the enolization reaction of zinc ions and carbonyl, has wide imide source, easy preparation, more active sites and large theoretical specific capacity compared with transition metal inorganic anode materials, reduces the use of non-renewable transition metals, is more green and environment-friendly, and conforms to the concept of sustainable development.

2) Compared with the organic electrolyte of the lithium ion battery, the aqueous electrolyte used in the invention is nontoxic, cheap and nonflammable, and has the characteristics of greenness, environmental protection, safety and better performance. And the growth of zinc dendrite can be effectively inhibited by adding sodium sulfate into the electrolyte.

3) The water system zinc ion battery has excellent rate performance, can realize quick discharge under large current density, can also realize slow discharge under small current density, and can realize overlong circulation stability under large current density.

Drawings

FIG. 1 is a schematic diagram of a synthetic route of a positive electrode material 1,4,5, 8-naphthalimide.

FIG. 2 is a Fourier infrared spectrum of the positive electrode material 1,4,5, 8-naphthalimide of the present invention.

FIG. 3 is an X-ray diffraction analysis chart of the positive electrode material 1,4,5, 8-naphthalimide of the present invention.

FIG. 4 is an SEM image of the positive electrode material 1,4,5, 8-naphthalimide in the present invention.

FIG. 5 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄The battery is 50mAg^-1Charge and discharge curves at current density.

FIG. 6 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The battery is 50mAg^-1Charge and discharge curves at current density.

FIG. 7 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄1,4,5, 8-naphthalimide/ZnSO as battery and anode material₄+Na₂SO₄The battery is 50mAg^-1Rate capability at current density.

FIG. 8 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄1,4,5, 8-naphthalimide/ZnSO as battery and anode material₄+Na₂SO₄Batteries are at 3A g^-1Multiple long cycle performance at current density.

Fig. 9 is an SEM image of the zinc sheet after various cycles in the electrolyte.

(a) The surface of an original zinc sheet; (b) positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄A zinc negative surface of the cell; (c) positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The zinc negative surface of the cell.

Detailed Description

The technical solution of the present invention is illustrated by specific examples below. It is to be understood that one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step or that other method steps may be inserted between the explicitly mentioned steps; it should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

The first embodiment is as follows: preparation of positive electrode material 1,4,5, 8-naphthalimide

FIG. 1 is a schematic diagram of a synthetic route of a positive electrode material 1,4,5, 8-naphthalimide, and the specific method comprises the following steps: introducing nitrogen into a three-neck flask to ensure that the experiment is completed in a nitrogen atmosphere, firstly putting 50mL of ammonia water (the concentration: 25 wt%) into the three-neck flask, adding 46mmol of 1,4,5, 8-naphthalene tetracarboxylic anhydride (CAS NO: 81-30-1) into the ammonia water under the stirring state, continuously stirring for 6h to form yellow solid suspended matter in the three-neck flask, collecting a pre-product by centrifugation, washing the pre-product with deionized water for three times, drying the pre-product in a vacuum oven at 60 ℃ for 12h, and grinding the pre-product into powder to obtain a light yellow anode material 1,4,5, 8-naphthalene tetracarboxylic diimide sample.

Successful synthesis of the 1,4,5, 8-naphthalimide molecule was confirmed by fourier infrared spectroscopy (fig. 2), X-ray diffraction analysis (fig. 3).

The surface morphology of the 1,4,5, 8-naphthalimide is shown to be a cross-linked network morphology by a scanning electron microscope (figure 4), and the surface morphology is beneficial to full contact with an electrolyte when being used as an electrode material.

Example two: preparation of positive pole piece

Uniformly grinding a positive electrode material 1,4,5, 8-naphthalimide, conductive carbon (Ketjen black) and a binder (PVDF) in a mortar according to the mass ratio of 60:30:10, selecting N-methylpyrrolidone (NMP) as a solvent, adding the solvent with the mass of the binder and the volume of the solvent being 1mg/60 mu L into the mortar, continuously grinding the powder into thick paste, then coating the paste sample on a carbon paper current collector with the diameter of 10mm, putting the coated positive electrode piece into a vacuum oven at 60 ℃ for drying for 12h, taking out, weighing the recorded mass of an active substance, and then filling the positive electrode piece into a sample bag for later use.

Example three: preparation of the electrolyte

Will be suitable forAmount of ZnSO₄Dissolving in 2mL deionized water to prepare 2M (i.e. mol/L) ZnSO₄And (3) an electrolyte.

To the prepared 2M ZnSO₄Adding 0.5M anhydrous sodium sulfate to prepare 2M ZnSO₄+0.5M Na₂SO₄And (3) an electrolyte.

Example four: positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄An aqueous zinc ion battery and electrochemical performance thereof.

The cell was assembled in air using a 2032 cell housing by first placing the positive electrode piece of example 2 into a positive electrode can, followed by placing a fiberglass separator and dropping 120 μ L of 2M ZnSO₄And (3) sequentially putting the electrolyte into a negative electrode zinc metal foil, a stainless steel current collector and a spring plate, finally buckling a negative electrode shell, and tightly pressing and sealing the battery by using a battery packaging machine.

FIG. 5 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄The battery is at 50mA g^-1The charging and discharging curve under the current density, the charging and discharging interval of the battery is between 0.1V and 1.5V, and the first discharging specific capacity reaches 320mAh g^-1Then shows a certain capacity decay, and the capacity is stabilized at 220mAh g after circulating to the eighth circle^-1The positive electrode material 1,4,5, 8-naphthalimide is explained to have the ability to reversibly store zinc ions.

FIG. 7 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄Rate capability of the battery when the current density is from 50mA g^-1Increased to 1A g^-1When the discharge specific capacity of the battery shows a more obvious decrease phenomenon, and when the current density is from 1A g^-1Suddenly reduced to 50mA g^-1In the process, the discharge specific capacity of the battery can be recovered to an initial state, and the battery has good rate capability.

FIG. 8 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄Batteries are at 3A g^-1The discharge specific capacity of the battery is 190mAh g when the battery is circulated to 1200 circles^-1Attenuating to 92mAh g^-1Indicating poor cycling stability.

By performing SEM characterization analysis on the circulated zinc sheet cathode,comparing with the original zinc sheet (FIG. 9a), the positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄The surface of the zinc cathode of the cell showed a rough surface topography (fig. 9b), illustrating that the cell was 2M ZnSO₄The electrolyte circulates, the growth speed of the zinc dendrite is high, and the long-time stable circulation of the battery is not facilitated.

Example five: positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The assembly of the cell and its electrochemical performance.

The battery is assembled as in the fourth embodiment, only the electrolyte species is replaced by 2M ZnSO₄+0.5M Na₂SO₄。

FIG. 6 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The battery is at 50mA g^-1The charge-discharge curve under the current density, the charge-discharge curve shape of the battery and the positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄The battery is consistent, better cycle stability is shown, and the capacity is stabilized at 220mAh g after the cycle is circulated to the fourth circle^-1Is described in 2M ZnSO₄+0.5M Na₂SO₄The battery cycle stability is improved in the electrolyte, and the positive electrode material 1,4,5, 8-naphthalimide has the capability of reversibly storing zinc ions.

FIG. 7 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄Rate capability of battery, when current density is from 50mAg^-1Increased to 1Ag^-1When the discharge specific capacity of the battery is reduced, the discharge specific capacity of the battery is not obviously reduced, and when the current density is reduced from 1Ag^-1Suddenly reduced to 50mAg^-1During the process, the specific discharge capacity of the battery can be quickly recovered to the initial state, the coulombic efficiency is always maintained at 100 percent, and the surface anode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The battery has better rate performance.

FIG. 8 shows a positive electrode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The battery is in 3Ag^-1The long cycle performance under the heavy current density, and the discharge specific capacity of the battery after 3000 cyclesFrom 162mAh g^-1Attenuating to 145mAh g^-1Indicating that the battery has good long-cycle stability.

Comparing the anode of the zinc sheet after the circulation with the original zinc sheet by SEM characterization analysis (figure 9a), the anode material 1,4,5, 8-naphthalimide/ZnSO₄+Na₂SO₄The zinc negative electrode surface of the cell exhibited a smoother surface topography (fig. 9c), indicating that the cell was in the presence of Na₂SO₄The added electrolyte is circulated, so that the growth of zinc dendrite of the negative electrode can be effectively delayed, and the rate capability and the circulation stability of the battery are obviously improved.

While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that the foregoing and other changes, omissions and deviations in the form and detail thereof may be made without departing from the scope of this invention. Those skilled in the art can make various changes, modifications and equivalent arrangements, which are equivalent to the embodiments of the present invention, without departing from the spirit and scope of the present invention, and which may be made by utilizing the techniques disclosed above; meanwhile, any changes, modifications and variations of the above-described embodiments, which are equivalent to those of the technical spirit of the present invention, are within the scope of the technical solution of the present invention.