CN112563443A

CN112563443A - Flexible battery electrode and manufacturing process thereof

Info

Publication number: CN112563443A
Application number: CN202011310235.2A
Authority: CN
Inventors: 王赪胤; 陈鹏; 李家宝; 杨剑
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2021-03-26
Anticipated expiration: 2040-11-20
Also published as: CN112563443B

Abstract

The invention belongs to the field of flexible batteries, and relates to a flexible battery electrode and a manufacturing process thereof. The surface of a first electrode of the electrode is provided with an irregular convex structure, and the surface of a second electrode is provided with a layer of solid electrolyte; the convex structure on the first electrode and the solid electrolyte on the second electrode are embedded into each other and are tightly combined. The invention enables two poles of the fibrous flexible battery to be tightly connected, ensures that the two flexible devices are always tightly bonded in the bending process, and the flexible battery prepared by the method has more excellent flexibility and electrochemical performance.

Description

Flexible battery electrode and manufacturing process thereof

Technical Field

The invention belongs to the field of chemical batteries, and particularly relates to a stable and efficient flexible battery.

Background

With the aggravation of energy demand, renewable energy is more and more valued in the world, and energy storage batteries are brought along with the aggravation of energy demand, and flexible batteries, as one type of energy storage batteries, have extremely high energy density, light weight and extremely strong use sense and are paid attention to by people. However, in the operation process of folding and stretching the flexible fibrous battery at present, the flexible fibrous battery has the situations of falling off, poor contact, disconnection and the like, and the use of the flexible fibrous battery is seriously influenced, so that a method for ensuring the close contact between the flexible fibrous battery and ensuring the normal work of the flexible fibrous battery under the long-time, random folding and stretching operation is particularly urgent.

Disclosure of Invention

The invention aims to solve the problem that the connection between two electrodes is not firm in the long-term use process of a flexible fibrous battery, and provides a flexible battery electrode and a manufacturing process thereof, so that the electrode can be used for a long time and can keep good circulation stability under the conditions of arbitrary folding and stretching.

In order to achieve the purpose, the invention adopts the technical scheme that: a flexible battery electrode comprising a first electrode (1), a second electrode (2);

the surface of the first electrode (1) of the flexible battery is provided with an irregular convex structure (100);

a layer of solid electrolyte (3) is arranged on the surface of the second electrode (2) of the flexible battery, and the protruding structures (100) on the first electrode (1) and the solid electrolyte (3) on the second electrode (2) are embedded into each other to be firmly combined.

Preferably, after the first electrode (1) and the second electrode (2) are respectively brushed with a layer of polyurethane solution, the convex structure (100) on the first electrode (1) and the solid electrolyte (3) on the second electrode (2) are embedded into each other.

Preferably, the convex structure (100) comprises a three-dimensional structure such as a triangular pyramid, a cone, a sphere, a cylinder, and the like.

Preferably, the protruding structure (100) is obtained by etching, laser sintering or spraying.

Preferably, the first electrode (1) is prepared by the following steps:

step 1, extruding, drying and molding an active material, a conductive agent and a binder according to a certain ratio to obtain a first electrode (1);

step 2, etching the surface of the first electrode (1) by using an acid solution or an alkali solution to prepare an irregular convex structure (100);

and 3, leaching with distilled water for multiple times, leaching with electrolyte solution for increasing the performance, and drying.

Preferably, the first electrode (1) is prepared by the following steps:

step 2, leaching with electrolyte;

and 3, randomly sintering and punching by laser, spraying electrolyte liquid for overheat protection, controlling the laser punching depth to be 0.01-10 mm, and drying.

Preferably, the first electrode (1) is prepared by the following steps:

step 1, preparing an active material, a conductive agent and a binder according to a certain formula, and then extruding, drying and molding to obtain a first electrode (1);

step 2, leaching with 5-30 mg/ml binder solution;

and 3, adding active material particles of 0.1 mu m-1 mm by using a spray gun, and drying.

Specifically, the active material is any one of metal, metal compound, nonmetal or nonmetal compound, preferably a metal simple substance such as lithium, sodium, potassium, iron, zinc, calcium, magnesium, aluminum, lead and the like, or a metal salt or a metal oxide thereof, and the conductive agent is one or more of acetylene black, graphite, a carbon nanotube and graphene; the binder is one or more of polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyethyleneimine, carboxymethyl cellulose, gelatin and other binding materials.

Specifically, an active material, a conductive agent and a binder are extruded according to a certain proportion, wherein the weight of the active material is 10-40%, the weight of the conductive agent is 0-20%, and the weight of the binder is 40-90%.

Specifically, the acid solution consists of the following substances in percentage by weight: 20-30% of sulfuric acid, 5-10% of nitric acid, 40-60% of metal salt, 1-5% of hydrogen peroxide and the balance of water or an organic solvent, wherein the metal salt is selected according to active materials and main reaction ions of the first electrode (1) and the second electrode (2), and can be selected from any one of manganese sulfate, zinc sulfate, sodium sulfate, lead sulfate, sodium hexafluorophosphate, lithium hexafluorophosphate and the like; the organic solvent includes N-methyl pyrrolidone, ethylene glycol, etc.

Specifically, the alkali solution comprises the following substances in percentage by weight: 20-30% of sodium hydroxide, 5-10% of potassium hydroxide, 40-60% of metal salt, 0.1-5% of aluminum hydroxide and the balance of water or an organic solvent, wherein the metal salt is selected according to active materials and main reaction ions of the first electrode (1) and the second electrode (2), and can be selected from any one of manganese sulfate, zinc sulfate, sodium sulfate, lead sulfate, sodium hexafluorophosphate, lithium hexafluorophosphate and the like; the organic solvent includes N-methyl pyrrolidone, ethylene glycol, etc.

Specifically, the etching time is 10 seconds to 120 seconds.

Specifically, the electrolyte solution comprises the following substances in percentage by weight: 40-60% of metal salt, 0.1-1% of aluminum hydroxide, 1-5% of conductive agent and the balance of water or organic solvent, wherein the metal salt is selected according to active materials and main reactive ions of the first electrode (1) and the second electrode (2), and can be selected from any one of manganese sulfate, zinc sulfate, sodium sulfate, lead sulfate, sodium hexafluorophosphate, lithium hexafluorophosphate and the like; the organic solvent includes N-methyl pyrrolidone, ethylene glycol, etc.

Preferably, forming a layer of solid electrolyte (3) on the second electrode (2) comprises the following steps:

a, extruding, drying and molding an active material, a conductive agent and a binder according to a certain ratio to obtain a second electrode (2);

b, soaking in a gel electrolyte solution for 10-1200 s;

c, drying for 2-5 hours at the temperature of 30-150 ℃;

d, repeating the step b and the step c for 2-5 times;

e, drying for 24 hours at the temperature of 30-150 ℃.

Preferably, in step 4, a layer of solid electrolyte (3) is formed on the second electrode (2), and the method specifically comprises the following steps:

b, soaking in a gel electrolyte solution for 10-1200 s;

c, soaking in an organic volatile solvent, and drying for 2-5 hours;

d, repeating the step b and the step c for 2-5 times;

e, drying for 24 hours at the temperature of 30-150 ℃.

Specifically, the gel electrolyte solution is composed of 10-90 wt% of gel and the rest of metal ion solution, wherein the initial concentration of the metal ion solution is 0.1-10 mol/L; the gel is selected from one or more of resin, silica gel, gelatin, xanthan gum, sodium cellulose, sodium alginate, etc.; the cation in the metal ion solution is any one or more of sodium, potassium, zinc, lithium, calcium, aluminum, iron, lead, cobalt, vanadium and the like, and the anion is any one or more of sulfate radical, nitrate radical, chloride ion, oxalate radical and the like.

Specifically, the active material is selected from graphite, activated carbon, silicon, and any one of simple metal substances such as lithium, sodium, potassium, iron, zinc, calcium, magnesium, aluminum, lead, and the like, or metal salts thereof, or metal oxides thereof, and the active material of the first electrode (1) and the active material of the second electrode (2) may be the same or different.

Specifically, the organic volatile solvent comprises methanol, ethanol and acetone, the soaking time is 1 s-600 s, and the organic volatile solvent is mainly used for solidifying and is convenient to take out and dry at the later stage.

Compared with the prior art, the invention has the following advantages: firstly, an electrode structure of a flexible battery is creatively designed, so that an irregular convex structure on a first electrode and a solid electrolyte on a second electrode are embedded into each other, and the irregular convex structure and the solid electrolyte can be effectively and tightly combined; secondly, multiple processes are invented to realize the manufacture of the electrode, and the formulas of electrolyte, acid-base solution and gel electrolyte in the processes are designed; in addition, the invention can realize long-time stable charge and discharge through the structural design, and ensure that the flexible electrode can ensure the excellent electrochemical performance in the random stretching and folding processes; and a plurality of processes and formulas are designed at the same time, and the preparation of the electrode can be effectively tested through the processes and the formulas.

Drawings

Fig. 1 is a schematic diagram of a positive electrode structure with an irregular triangular pyramidal convex structure on the surface according to the present invention.

FIG. 2 is a schematic view of a negative electrode structure having a layer of solid electrolyte on the surface thereof according to the present invention.

Fig. 3a is an assembly diagram of the positive electrode and the negative electrode of the invention, and fig. 3b is a structural schematic diagram of the flexible battery electrode of the invention.

Detailed Description

In order to illustrate the invention more clearly, the following examples are given without any limitation thereto.

With reference to fig. 1 to 3, the present invention provides a method for manufacturing a flexible battery electrode, in which an etching method is adopted to etch and manufacture an irregular protrusion structure 100 on the surface of a positive electrode, and the method includes the following steps:

s1 preparation of Positive electrode

1. Preparing an active material, a conductive agent and a binder according to a certain formula, and then extruding, drying and molding to obtain a positive electrode 1;

2. placing the material in an acid solution or an alkali solution for 10 to 120 seconds according to the type and the property of the material;

3. leaching with distilled water for many times;

4. then, leaching for 1-3 times by using electrolyte liquid;

5. drying for 24 hours at the temperature of 30-150 ℃.

S2 preparation of negative electrode

1. Preparing an active material, a conductive agent and a binder according to a certain formula, and then extruding, drying and molding to obtain a negative electrode 2;

2. placing the membrane in a gel electrolyte solution for soaking for 10-1200 s;

3. drying at 30-150 ℃ for 2-5 h, or soaking in an organic volatile solvent for 1-600 s and drying for 2-5 h to form a layer of solid electrolyte 3 on the surface of a negative electrode 2, drying and forming the negative electrode after soaking in electrolyte liquid, wherein certain gaps exist on the surface of the negative electrode, although the solid electrolyte 3 can be closely matched with a convex structure on the surface of a positive electrode, if partial areas are dried, no electrolyte exists, the positive electrode and the negative electrode are in short circuit, and the negative electrode cannot be used, and the surface of the negative electrode is uniformly dried by using the organic volatile solvent for coagulation bath, so that the electrolyte is uniformly attached, and the organic volatile solvent comprises ethanol, acetone and the like;

4. repeating the

steps

2 and 3 for 2-5 times;

5. drying for 24 hours at the temperature of 30-150 ℃.

S3 preparation of flexible battery electrode

After the positive electrode 1 and the negative electrode 2 are manufactured, a layer of gel electrolyte solution can be selectively brushed on the surfaces of the positive electrode 1 and the negative electrode 2, and then the assembly is carried out, as shown in figure 3a, the positive electrode 1 and the negative electrode 2 are mutually wound to form a flexible battery electrode, as shown in figure 3 b;

or, before the electrode is assembled, if a layer of polyurethane solution is brushed on the surface of the negative electrode, a layer of flexible film is formed on the surface of the negative electrode, and then the negative electrode is assembled, the negative electrode can be tightly combined.

The invention provides a preparation method of a flexible battery electrode, wherein other steps are the same as the above, a laser sintering method is adopted to prepare an irregular convex structure (100) on the surface of a positive electrode by laser sintering, and the specific steps are as follows:

1. preparing an active material, a conductive agent and a binder according to a certain formula, and then extruding, drying and molding to obtain a positive electrode;

2. leaching with electrolyte;

3. randomly sintering and punching by laser, and spraying electrolyte liquid for overheat protection, wherein the laser punching depth is controlled to be 0.01-10 mm;

4. drying for 24 hours at the temperature of 30-150 ℃.

The invention provides a preparation method of a flexible battery electrode, wherein other steps are the same as the above, a spraying method is adopted to prepare an irregular convex structure (100) on the surface of a positive electrode by spraying, and the preparation method comprises the following steps:

2. leaching with 5-30 mg/ml binder solution;

3. adding active material particles of 0.1 mu m-1 mm by using a spray gun;

4. drying for 24 hours at the temperature of 30-150 ℃.

The first embodiment is as follows:

a preparation method of a zinc-manganese flexible fibrous battery comprises the following steps:

1. preparing a positive electrode material: the anode adopts manganese dioxide as an active material, graphene as a conductive agent and polytetrafluoroethylene as a binder, and the specific mixture ratio is as follows: 30 wt% of manganese dioxide, 20 wt% of graphene and 50 wt% of polytetrafluoroethylene. Taking 100mg of the cathode material as an example, the cathode material contains 30mg of manganese dioxide, 20mg of graphene and 50mg of polytetrafluoroethylene.

2. Dry grinding: the materials are added into a mortar and stirred for 600s, and the materials are stirred and mixed uniformly.

3. Wet grinding: the above ground material was added with N-methylpyrrolidone solvent, 2ml of N-methylpyrrolidone solvent per 100mg of powder, and stirred until viscous.

4. Extruding: injecting the wet-milled material into a syringe, and extruding the material at a constant speed.

5. And (3) drying: and (3) placing the extruded fibrous positive electrode in a vacuum drying oven, and drying for 24h at 100 ℃.

6. Etching: and (3) placing the dried fibrous anode into an acid solution for soaking for 20s, wherein the acid solution contains 30 wt% of sulfuric acid, 5 wt% of nitric acid, 50 wt% of manganese sulfate, 2 wt% of hydrogen peroxide and 13 wt% of distilled water.

7. Cleaning: and (4) washing the anode which is etched to form the irregular triangular pyramid-shaped convex structure for 3 times by using distilled water, and removing acid liquor residues.

8. Enhancing the performance: and (3) washing the anode prepared in the step (7) for 1 time by using electrolyte liquid, wherein the electrolyte liquid contains 60 wt% of manganese sulfate, 0.5 wt% of aluminum hydroxide, 5 wt% of graphene and 34.5 wt% of distilled water.

9. And (3) drying: placing the anode prepared in the step 8 in a vacuum drying oven, drying for 24 hours at 100 ℃ to finally prepare a fibrous manganese dioxide anode with a triangular pyramid-shaped convex structure on the surface;

10. preparing an anode material: the cathode adopts zinc powder as an active material and polytetrafluoroethylene as a binder, and the mixture ratio is as follows: 40 wt% of zinc powder and 60 wt% of polytetrafluoroethylene. Taking 100mg of negative electrode material as an example, 40mg of zinc powder and 60mg of polytetrafluoroethylene are contained;

11. dry grinding: adding the materials into a mortar, stirring for 600s, and uniformly stirring and mixing;

12. wet grinding: adding N-methylpyrrolidone solvent into the ground material, adding 2.4ml of N-methylpyrrolidone solvent into every 100mg of powder, and stirring until the mixture is viscous;

13. extruding: injecting the wet-milled material into a needle cylinder, and extruding the material at a constant speed;

14. and (3) drying: placing the extruded fibrous negative electrode in a vacuum drying oven, and drying for 24h at 100 ℃;

15. soaking: placing the dried fibrous negative electrode in a gel electrolyte solution for soaking for 120s, wherein the gel electrolyte solution contains 30 wt% of gelatin, and the rest metal salt solution is 70 wt%, wherein the metal salt solution is a mixed solution of 0.5mol/L manganese sulfate and 2mol/L zinc sulfate solution, taking 100g of the gel electrolyte solution as an example, 30g of gelatin, and 70g of a mixed solution of manganese sulfate and zinc sulfate (zinc sulfate 16.15g, manganese sulfate 3.78g, and water 50.07 g);

16. and (3) drying: placing the fibrous negative electrode obtained in the step 15 in a conventional forced air drying oven for drying at 80 ℃ for 2 hours;

17. repeating: repeating the steps 15 and 16 for 2 times;

18. and (3) drying: placing the sample obtained in the step 17 in a vacuum drying oven, drying for 24 hours at 100 ℃, and finally preparing the fibrous cathode with the solid electrolyte shell;

19. assembling: brushing a layer of polyurethane solution on the fibrous manganese dioxide anode with the triangular pyramid-shaped convex structure on the surface prepared in the step 9 and the fibrous cathode with the solid electrolyte shell prepared in the step 18 respectively, embedding the two into each other, and spirally winding to finally prepare a fibrous flexible battery;

example two:

a preparation method of a lithium ion flexible fibrous battery comprises the following steps:

1. preparing a positive electrode material: the anode adopts lithium iron phosphate as an active material, the carbon nano tube is a conductive agent, the polytetrafluoroethylene is a binder, and the proportion is as follows: 30% of lithium iron phosphate, 10% of carbon nano tube and 60% of polytetrafluoroethylene by weight. Taking 100mg of the cathode material as an example, 30mg of lithium iron phosphate, 10mg of carbon nanotubes and 60mg of polytetrafluoroethylene are used.

3. Wet grinding: the above ground material was added with N-methylpyrrolidone solvent, 2.4ml of N-methylpyrrolidone solvent per 100mg of powder, and stirred until viscous.

6. Spraying glue: and (3) spraying 25mg/ml of polytetrafluoroethylene solution on the fibrous positive electrode obtained in the step (5) to enhance the surface adhesiveness of the fibrous positive electrode.

7. Making a bulge: and (4) spraying polyethylene particles on the fibrous positive electrode obtained in the step (6) by using a spray gun to preliminarily prepare the fibrous lithium iron phosphate positive electrode with the triangular pyramid-shaped convex structure.

8. And (3) drying: and (4) placing the positive electrode prepared in the step (7) in a vacuum drying oven, and drying for 24 hours at 100 ℃. (ii) a

9. Preparing an anode material: the negative electrode adopts graphite as an active material, the carbon nano-tube as a conductive agent and the polytetrafluoroethylene as a binder, and the proportion is as follows: 20 wt% of graphite, 20 wt% of carbon nano-tubes and 60 wt% of polytetrafluoroethylene. Taking 100mg of negative electrode material as an example, the material contains 20mg of graphite, 20mg of carbon nanotubes and 60mg of polytetrafluoroethylene;

10. dry grinding: adding the materials into a mortar, stirring for 600s, and uniformly stirring and mixing;

11. wet grinding: adding N-methylpyrrolidone solvent into the ground material, adding 2.4ml of N-methylpyrrolidone solvent into every 100mg of powder, and stirring until the mixture is viscous;

12. extruding: injecting the wet-milled material into a needle cylinder, and extruding the material at a constant speed;

13. and (3) drying: placing the extruded fibrous negative electrode in a vacuum drying oven, and drying for 24h at 100 ℃;

14. soaking: placing the dried fibrous negative electrode in a gel electrolyte solution for soaking for 120s, wherein the gel electrolyte solution contains 40% of gelatin, and the rest metal salt solution is 60 wt%, wherein the metal salt solution is a 1mol/L lithium hexafluorophosphate solution, and the metal salt solution contains 40g of gelatin and 60g of lithium hexafluorophosphate solution (the concentration of the solution is 1 mol/L) by taking 100g of the gel electrolyte solution as an example;

15. and (3) drying: soaking the fibrous negative electrode obtained in the step 14 in ethanol for 1-600 s, and then drying in a conventional forced air drying oven at 80 ℃ for 5 h;

16. repeating: repeating the steps 14 and 15 for 2 times;

17. and (3) drying: placing the obtained product in the step 16 in a vacuum drying oven, drying at 120 ℃ for 24h, and finally preparing the fibrous negative electrode with the smooth solid electrolyte shell;

18. assembling: brushing a layer of polyurethane solution on the fibrous lithium iron phosphate anode with the triangular pyramid-shaped convex structure on the surface prepared in the step 8 and the fibrous cathode with the solid electrolyte shell prepared in the step 17, embedding the two into each other, and spirally winding to finally prepare a fibrous flexible battery;

the anode and the cathode prepared by the method have extremely strong flexibility and electrochemical stability after being wound, and can always keep stable electrochemical performance in the bending and stretching processes.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims

1. A flexible battery electrode comprising a first electrode (1) and a second electrode (2), characterized in that the first electrode (1) has an irregular convex structure (100) on its surface;

the surface of the second electrode (2) is provided with a layer of solid electrolyte (3);

the convex structure (100) on the first electrode (1) and the solid electrolyte (3) on the second electrode (2) are embedded into each other and are tightly combined.

2. The flexible battery electrode of claim 1, wherein the protrusion structure (100) comprises a three-dimensional structure selected from the group consisting of a triangular pyramid-shaped structure, a conical structure, a spherical structure and a cylindrical structure.

3. The flexible battery electrode of claim 1, wherein the raised structure (100) is formed by etching, laser sintering or spraying.

4. The flexible battery electrode according to claim 1, wherein the protruding structures (100) on the first electrode (1) and the solid electrolyte (3) on the second electrode (2) are embedded into each other after the first electrode (1) and the second electrode (2) are coated with a polyurethane solution.

5. A flexible battery electrode according to claim 1, characterized in that the raised structure (100) on the first electrode (1) and the solid electrolyte (3) on the second electrode (2) are embedded in each other, are tightly bonded and are wound in a spiral.

6. The flexible battery electrode according to claim 3, wherein the raised structure (100) is obtained by acid etching, wherein the acid solution comprises the following components in percentage by weight: 20-30% of sulfuric acid, 5-10% of nitric acid, 40-60% of metal salt, 1-5% of hydrogen peroxide and the balance of water or an organic solvent, wherein the metal salt is any one of manganese sulfate, zinc sulfate, sodium sulfate, lead sulfate, sodium hexafluorophosphate and lithium hexafluorophosphate; the organic solvent is N-methyl pyrrolidone or ethylene glycol.

7. The flexible battery electrode of claim 3, wherein the raised structure (100) is obtained by alkaline etching, wherein the alkaline solution comprises, in weight percent: 20-30% of sodium hydroxide, 5-10% of potassium hydroxide, 40-60% of metal salt, 0.1-5% of aluminum hydroxide and the balance of water or an organic solvent, wherein the metal salt is selected from any one of manganese sulfate, zinc sulfate, sodium sulfate, lead sulfate, sodium hexafluorophosphate and lithium hexafluorophosphate; the organic solvent is N-methyl pyrrolidone or ethylene glycol.

8. The flexible battery electrode according to claim 3, wherein the protrusion structure (100) is obtained by etching, and the etching time is 10 seconds to 120 seconds.

9. The flexible battery electrode according to claim 1, wherein the active materials of the first electrode (1) and the second electrode (2) are selected from lithium, sodium, potassium, iron, zinc, calcium, magnesium, aluminum, lead simple metal or metal salt thereof or metal oxide thereof, and the conductive agent is one or more of acetylene black, graphite, carbon nano-tube and graphene; the binder is one or more of polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, polyethyleneimine, carboxymethyl cellulose and gelatin.

10. The flexible battery electrode of claim 9, wherein the weight of the active material is 10% to 40%, the weight of the conductive agent is 0% to 20%, and the weight of the binder is 40% to 90%.