AN ELECTRODE STRUCTURE AND PREPARATION METHODS THEREOF

Abstract

An electrode structure and preparation methods thereof, the electrode structure includes a substrate and a sintered body, wherein the sintered body is formed on the surface of the substrate, and the sintered body is provided with cracks that are formed after the hydration treatment of the sintered body. The continuity of cracks of the electrode structure was good, and the preparation method is suitable for industrial production. The electrode structure with cracks can effectively increase the bending strength and reduce the stress during the winding process of the electrode structure, thereby reducing the risk of fracture during the application process. It can also improve the flexural strength of the electrode structure while maintaining the original high electrostatic capacity and lower leakage current value of the electrode structure, without negatively affecting the performance of the electrode structure.

Claims

1. An electrode structure comprising a substrate and a sintered body, wherein the sintered body is formed on the surface of the substrate, and the sintered body is provided with cracks that are formed after the hydration treatment of the sintered body.

2. The electrode structure according to claim 1, wherein the cracks are formed after the hydration treatment of the sintered body and before formation process of the sintered body.

3. The electrode structure according to claim 1, wherein the sintered body further comprises a formation process with a voltage of 0-160 V after the hydration treatment and before the crack formation, and the formation process voltage is not 0 V.

4. The electrode structure according to claim 3, wherein the sintered body further comprises a formation process with a voltage of 0-120 V after the hydration treatment and before the crack formation, and the formation process voltage is not 0 V.

5. The electrode structure according to claim 1, wherein the sintered body is formed on one side of the substrate; or, the sintered body is formed on two sides of the substrate.

6. The electrode structure according to claim 1, wherein the substrate is a foil including one or more of valve metals, valve metal oxides, and valve metal nitrides.

7. The electrode structure according to claim 1, wherein the sintered body has a porous structure.

8. The electrode structure according to claim 1, wherein the sintered body is a sintered layer including one or more of valve metals, valve metal oxides, and valve metal nitrides.

9. The electrode structure according to claim 6, wherein the valve metal is selected from one or more of magnesium, thorium, cadmium, tungsten, tin, iron, silver, silicon, tantalum, titanium, hafnium, aluminum, zirconium, niobium, and alloys of the above metals.

10. The electrode structure according to claim 9, wherein the valve metal is aluminum or aluminum alloy.

11. The electrode structure according to claim 1, wherein the cracks penetrate both ends of the electrode structure.

12. The electrode structure according to claim 1, wherein the cracks extend in the same direction.

13. The electrode structure according to claim 1, wherein the width of the cracks is not greater than 100 μm.

14. The electrode structure according to claim 1, wherein the interval between the cracks is not more than 0.5 mm.

15. The electrode structure according to claim 1, wherein the interval between the cracks is not more than 0.3 mm.

16. The electrode structure according to claim 1, wherein the interval between the cracks is not more than 0.15 mm.

17. The electrode structure according to claim 1, wherein the interval between the cracks is not more than 0.05 mm.

18. A method for preparing an electrode structure includes the following steps: S10, providing a sintered body formed on the surface of the substrate; S20, performing hydration treatment on the above-mentioned sintered body; S40, performing physical treatment on the above-mentioned sintered body that has been hydrated to generate cracks; S50, performing formation process on the above-mentioned sintered body with cracks.

19. The method for preparing an electrode structure according to claim 18 comprising the following steps: S10, providing a sintered body formed on the surface of the substrate; S20, performing hydration treatment on the above-mentioned sintered body; S30, performing formation process on the above-mentioned sintered body that has been hydrated; S40, performing physical treatment on the above-mentioned sintered body that has been performed formation process to generate cracks; S50, performing formation process on the above-mentioned sintered body with cracks.

20. The method for preparing an electrode structure according to claim 19, wherein the voltage of the formation process in step S30 is 0-160 V, and not 0 V.

21. The method for preparing an electrode structure according to claim 20, wherein the voltage of the formation process in step S30 is 0-120 V.

22. The method for preparing an electrode structure according to claim 18, wherein the temperature of the hydration treatment in step S20 is 70° C.-100° C., and the hydration treatment time is 0.5 min-20 min.

Description

DESCRIPTION OF THE DRAWINGS

[0120] Hereinafter, the present invention will be further described in detail based on the drawings and examples.

[0121] FIG. 1 is a schematic top view of an electrode structure according to an example of the present invention;

[0122] FIG. 2 is a schematic cross-sectional view of an electrode structure according to an example of the present invention;

[0123] FIG. 3 is SEM photographs of the electrode structure described in Example 1A: (a) surface photograph; (b) cross-sectional photograph;

[0124] FIG. 4 is SEM photographs of the electrode structure described in Comparative Example 1: (a) surface photograph; (b) cross-sectional photograph;

[0125] In FIG. 1 to FIG. 4:

[0126] 11. Substrate; 12. Sintered body; 13. Crack; 14. Oxide film; i. Crack interval.

EXAMPLES

[0127] The technical solutions of the present invention will be further described below in conjunction with the drawings and specific examples.

Example 1A

[0128] A method for preparing an electrode structure includes the following steps:

[0129] providing aluminum foil substrate and coating liquid prepared from aluminum alloy powder. Wherein, the thickness of the aluminum foil substrate was 30 the aluminum alloy powder was a high-purity spherical aluminum powder of 99.9% or more, and the average particle size of the aluminum alloy powder was 3.5 μm.

[0130] A comma scraper was used to coat the coating liquid on the front and back of the aluminum foil substrate to form a coating film, and the coating film was dried.

[0131] The coating film was degreased at 400° C. in an argon-filled environment, and then was sintered for 8 hours at a temperature of 635° C. to form a porous sintered body. Among them, the thickness of the aluminum foil substrate was 30 and the thickness of the sintered body covering the front and back sides of the aluminum foil substrate was 50 μm each, making a total of 130 μm.

[0132] The sintered body described above was hydrated in pure water of 97° C. for 4 minutes.

[0133] The sintered body after the hydration treatment was rolled with a round rod to generate cracks on the sintered body, the diameter of the round rod was 6 mm, and the interval between the cracks was about 0.106 mm.

[0134] The sintered body that had undergone rolling treatment was placed in a boric acid aqueous solution, and anodized with a voltage of 520 V to form an electrode structure. In this example, the electrode structure was an anode structure.

[0135] The SEM photographs of the electrode structure were shown in FIGS. 3(a) and (b). The crack 13 extended along the width direction of the aluminum foil substrate and was basically continuously distributed, and the interval between the cracks was about 0.106 mm. The depth of the crack 13 was basically equivalent to the thickness of the sintered body 12. The sintered body 12 was porous.

[0136] In other examples, the substrate may also be an aluminum alloy foil substrate, the sintered body 12 may also be formed on only one side surface of the substrate 11, and the sintered body may be a sintered layer made of one or more powders of magnesium, thorium, cadmium, tungsten, tin, iron, silver, silicon, tantalum, titanium, hafnium, aluminum, zirconium, niobium, and alloys of the foregoing metals.

[0137] In this example, that the crack 13 extended in the same direction meant that the crack 13 extended substantially or basically in the same direction, which allowed any possible bifurcation cracks to exist on the surface of the electrode structure without adversely affecting the bending strength. By setting up the crack 13 to extend in the same direction, the forces on the various parts of the electrode structure tended to be consistent during winding applications, and excessive force differences between different parts on the surface of the electrode structure could be avoided, thereby making the bending strength of the electrode structure more stable.

Example 1B

[0138] The difference between this example and the example 1A was: [0139] The sintered body after the hydration treatment was performed formation process with a voltage of 40 V and then subjected to the same rolling treatment to generate cracks, and the interval between the cracks was about 0.147 mm. The operation and parameters of all other steps were unchanged, and the electrode structure was obtained.

Example 1C

[0140] The difference between this example and the example 1A was: [0141] The sintered body after the hydration treatment was performed formation process with a voltage of 80 V and then subjected to the same rolling treatment to generate cracks, and the interval between the cracks was about 0.179 mm. The operation and parameters of all other steps were unchanged, and the electrode structure was obtained.

Example 1D

[0142] The difference between this example and the example 1A was: [0143] The sintered body after the hydration treatment was performed formation process with a voltage of 120 V and then subjected to the same rolling treatment to generate cracks, and the interval between the cracks was about 0.227 mm. The operation and parameters of all other steps were unchanged, and the electrode structure was obtained.

Example 1E

[0144] The difference between this example and the example 1A was that the sintered body after the hydration treatment was performed formation process with a voltage of 160 V and then subjected to the same rolling treatment, resulting in cracks, and the interval between the cracks was about 0.455 mm. The operation and parameters of all other steps were unchanged, and the electrode structure was obtained.

Example 1F

[0145] The difference between this example and the example 1A was: [0146] The sintered body after the hydration treatment was performed formation process with a voltage of 200 V and then subjected to the same rolling treatment, resulting in cracks, and the interval between the cracks was about 0.670 mm. The operation and parameters of all other steps were unchanged, and the electrode structure was obtained.

Example 1G

[0147] The difference between this example and the example 1A was: [0148] The sintered body after the hydration treatment was performed formation process with a voltage of 330 V and then subjected to rolling treatment, and the foil was broken due to excessive hardness.

Comparative Example 1

[0149] The difference between this comparative example and example 1A was: [0150] The rolling treatment was carried out before the hydration treatment. The operation and parameters of all other steps were unchanged, and the electrode structure was obtained.

[0151] The SEM photographs of the electrode structure were shown in FIGS. 4(a) and (b). The continuity of the cracks was poor, the interval between the cracks was large and irregular, and the depth of the cracks was shallow, much smaller than the thickness of the sintered body.

Comparative Example 2

[0152] The difference between this comparative example and example 1A was: [0153] The rolling treatment was omitted, the operating parameters of the step of all other steps were unchanged, and an electrode structure without microcracks was obtained.

[0154] Using the electrode structures in the example 1 and comparative example 1 and comparative example 2 as the test objects, samples were taken along the foil winding direction to test the bending strength R1.0 and the electrostatic capacity test at 520 V. The specific results were shown in Table 1:

TABLE-US-00001 TABLE 1 Bending Example/ Crack strength Electrostatic Comparative interval R1.0 capacity Example (mm) (return) (μf/10 cm.sup.2) Comparative example 1 / 10 10 Comparative example 2 / 0 10.5 Example 1A 0.106 123 10.4 Example 1B 0.147 97 10.4 Example 1C 0.179 85 10.4 Example 1D 0.227 70 10.4 Example 1E 0.455 35 10.4 Example 1F 0.670 18 10.4

[0155] According to the data analysis in Table 1, the bending strength of the electrode structure with microcracks on the surface was significantly improved, and the best time for cracking in the sintered body by rolling treatment was after the hydration treatment and before the formation process, which had the smallest crack interval, the most obvious improvement in strength, and the least impact on capacity.

Example 2A

[0156] The difference between this example and example 1A was:

[0157] The sintered body was rolled by using a round rod to generate cracks cracks on the sintered body. The diameter of the round rod was 30 mm, and the interval between the cracks was about 1.625 mm.

Example 2B

[0158] The difference between this example and example 1A was:

[0159] The sintered body was rolled by using a round rod to generate cracks cracks on the sintered body. The diameter of the round rod was 22 mm, and the interval between the cracks was about 0.955 mm.

Example 2C

[0160] The difference between this example and example 1A was:

[0161] The sintered body was rolled by using a round rod to generate cracks microcracks on the sintered body. The diameter of the round rod was 16 mm, and the interval between the cracks was about 0.783 mm.

Example 2D

[0162] The difference between this example and example 1A was:

[0163] The sintered body was rolled by using a round rod to generate cracks microcracks on the sintered body. The diameter of the round rod was 10 mm, and the interval between the cracks was about 0.440 mm.

Example 2E

[0164] The difference between this example and example 1A was:

[0165] The sintered body was rolled by using a round rod to generate cracks on the sintered body. The diameter of the round rod was 8 mm, and the interval between the cracks was about 0.220 mm.

Example 2F

[0166] The difference between this example and example 1A was:

[0167] The sintered body was rolled by using a round rod to generate cracksmicrocracks on the sintered body. The diameter of the round rod was 4 mm, and the interval between the cracks was about 0.101 mm.

[0168] Of course, in other examples, the interval between the cracks could also be 1 mm, 0.8 mm, 0.6 mm, 0.5 mm, 0.3 mm, 0.2 mm, 0.15 mm, 0.10 mm, 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm or 0.05 mm.

[0169] Using the electrode structures in the example 2 and the example 1A as the test objects, the bending strength R1.0 test and the electrostatic capacity test at 520 V were performed respectively. The specific results were shown in Table 2:

TABLE-US-00002 TABLE 2 Bending Example/ Round rod Crack strength Electrostatic Comparative diameter interval R1.0 capacity Example (mm) (mm) (return) (μf/10 cm.sup.2) Comparative — — 0 10.5 example 2 Example 2A 30 1.625 0 10.5 Example 2B 22 0.955 2 10.5 Example 2C 16 0.783 5 10.5 Example 2D 10 0.44 38 10.4 Example 2E 8 0.22 69 10.4 Example 1A 6 0.106 123 10.4 Example 2F 4 0.101 127 10.1

[0170] According to the data analysis in Table 2, as the diameter of the round rod decreased, the interval between the cracks gradually decreased and the bending strength gradually increased. When the diameter of the round rod decreased to 4 mm, the descend range in the interval of microcracks decreased, but the capacity attenuation range increased.

Example 3A

[0171] The difference between this example and the example 2E was: [0172] The hydration treatment time was 24 min, and the interval between the cracks was about 0.470 mm.

Example 3B

[0173] The difference between this example and the example 2E was: [0174] The hydration treatment time was 20 min, and the interval between the cracks was about 0.392 mm.

Example 3C

[0175] The difference between this example and the example 2E was: [0176] The hydration treatment time was 16 min, and the interval between the cracks was about 0.294 mm.

Example 3D

[0177] The difference between this example and the example 2E was: [0178] The hydration treatment time was 12 min, and the interval between the cracks was about 0.235 mm.

Example 3E

[0179] The difference between this example and the example 2E was: [0180] The hydration treatment time was 6 min, and the interval between the cracks was about 0.147 mm.

Example 3F

[0181] The difference between this example and the example 2E was: [0182] The hydration treatment time was 2 min, and the interval between the cracks was about 0.102 mm.

Example 3G

[0183] The difference between this example and the example 2E was: [0184] The hydration treatment time was 1 min, and the interval between the cracks was about 0.106 mm.

Example 3H

[0185] The difference between this example and the example 2E was: [0186] The hydration treatment time was 0.5 min, the interval between the cracks was about 0.335 mm, and the cracks were discontinuous cracks.

[0187] Using the electrode structures in the example 3, the example 1A, and the example 2E as the test objects, the bending strength R1.0 test and the electrostatic capacity test under 520 V were performed respectively. The specific results were shown in Table 3:

TABLE-US-00003 TABLE 3 Hydration Bending treatment Crack strength Electrostatic time interval R1.0 capacity Example (min) (mm) (return) (μf/10 cm.sup.2) Example 3A  24 min 0.47 18 6.2 Example 3B  20 min 0.392 43 8.7 Example 3C  16 min 0.294 52 9.2 Example 3D  12 min 0.235 68 10 Example 2E   8 min 0.22 75 10.4 Example 3E   6 min 0.147 101 10.4 Example 1A   4 min 0.106 123 10.4 Example 3F   2 min 0.102 125 10.4 Example 3G   1 min 0.106 118 7 Example 3H 0.5 min 0.335 69 6.4

[0188] According to the data analysis in Table 3, as the strength of the hydration treatment decreased, the interval between the cracks gradually decreased and the bending strength gradually increased. However, when the hydration treatment time reduced to 1 min, the interval between the cracks increased, and the bending strength decreased instead. The main reason was that the strength of the hydration treatment was too weak, which caused the foil to be too soft and easy to pull up, and it was not easy to crack. And different hydration treatment strength had a greater impact on the capacity of the foil. Therefore, controlling the appropriate hydration treatment strength played a vital role in the subsequent crack morphology generated by rolling, and would directly affect the bending strength and capacity of the electrode structure. In this example, it was more appropriate to control the hydration treatment strength at 97° C. for 2-12 minutes.

[0189] The aforementioned hydration treatment strength was controlled by the hydration treatment time, and could also be controlled by the hydration treatment temperature, which could be any value between 70° C. and 100° C., or can be controlled by the hydration treatment time and temperature together.

Example 4

[0190] The difference between this example and example 1A was:

[0191] The thickness of the aluminum foil substrate was 20 μm. Of course, in other examples, the thickness of the aluminum foil substrate may also be 10 μm, 40 μm, 50 μm or 60 μm.

Example 5A

[0192] The difference between this example and example 1A was:

[0193] The thickness of the aluminum foil substrate was 30 μm, and the thickness of the sintered body covering the front and back sides of the aluminum foil substrate was 41 μm each, making a total of 112 μm. The interval between the cracks was about 0.084 mm.

Example 5B

[0194] The difference between this example and example 1A was:

[0195] The thickness of the aluminum foil substrate was 30 μm, and the thickness of the sintered body covering the front and back sides of the aluminum foil substrate was 32 μm each, making a total of 94 μm. The interval between the cracks was about 0.071 mm.

[0196] Using the electrode structures in the above-mentioned example 5A, example 5B, and example 1A as the test objects, the bending strength test was performed respectively. The specific results were shown in Table 4:

TABLE-US-00004 TABLE 4 Bending Total Crack strength thickness interval R1.0 Number (μm) (mm) (return) Example 1A 130 0.106 123 Example 5A 112 0.084 135 Example 5B 94 0.071 151

[0197] According to the data analysis in Table 4, as the thickness of the sintered body decreased, the interval between the cracks gradually decreased and the bending strength gradually increased.

Example 6

[0198] The difference between this example and example 1A was:

[0199] The average particle size of the powder was 6.5 μm. Of course, in other examples, the average particle size of the powder is 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm or 10 μm.

Example 7

[0200] The difference between this example and example 1A was:

[0201] The width of the crack was 10 μm. Of course, in other examples, the width of the crack may also be 20 μm, 30 μm, 40 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0202] It should be stated that the above-mentioned specific implementations are only the preferred embodiments of the present invention and the applied technical principles. Within the technical scope disclosed in the present invention, any changes or substitutions that can be easily conceived by those skilled in the art should be covered within the protection scope of the present invention.