Method for electrolyzing beta-manganese dioxide on surface of dielectric layer

Abstract

The invention relates to the technical field of manufacturing of beta-manganese dioxide, in particular to a method for electrolyzing beta-manganese dioxide on the surface of a dielectric layer, which comprises the following steps of: firstly, depositing manganese dioxide on the surface of a non-conductive dielectric layer by adopting a thermal decomposition method, and then electrolytically depositing the beta-manganese dioxide; according to the method, after a layer of beta-MnO2 is deposited on the surface of the dielectric layer through a chemical thermal decomposition method, the dielectric layer is connected to an electrochemical workstation, then beta-MnO2 electrolytic deposition is carried out, and a beta-MnO2 layer which is small in particle, compact and good in electroactivity is deposited through electrolytic deposition; the beta-MnO2 layer generated through electrolysis can greatly improve the ESR, surge current resistance and instantaneous large current resistance of the capacitor, improves the high-frequency working characteristic, is suitable for assembling tantalum capacitor products with large capacity, low ESR value and high-frequency working environment, and is beneficial to widening the application range of the chip solid electrolyte tantalum capacitor.

Description

Technical Field

[0001] The invention relates to the technical field of beta-manganese dioxide manufacturing, and in particular to a method for electrolyzing beta-manganese dioxide on the surface of a dielectric layer. Background Art

[0002] At present, electrolytic manganese dioxide is widely used as an electrode material in the fields of batteries and supercapacitors due to its strong activity, small size, and long life. Compared with chemical manganese dioxide, electrolytic manganese dioxide has a small particle size, high purity, and excellent charge and discharge performance. It has the prospect and potential to be used as a capacitor cathode in the solid electrolyte capacitor industry.

[0003] Electrolytic manganese dioxide is usually a method of depositing manganese dioxide on the anode by connecting a conductive material to an electrolyte and applying electricity. The resulting manganese dioxide crystal is usually γ-manganese dioxide. γ-manganese dioxide with crystal water has excellent electrochemical activity. Li-MnO 2 It is widely used as a positive electrode material in batteries. However, in a non-aqueous solution environment, the activity of γ-manganese dioxide is poor. In structures such as batteries and capacitors, it manifests itself in the form of large equivalent circuit resistance and low charging and discharging efficiency. In the application of solid electrolyte capacitors, water vapor can easily cause the migration of conductive ions inside the electrolyte capacitor after penetrating into the electrolyte capacitor, which is an important inducing factor leading to the failure of the electrolyte capacitor. Therefore, γ-manganese dioxide is not suitable for use as a cathode material for electrolyte capacitors. β-manganese dioxide, which has stronger electrochemical activity in a dry environment, is a more ideal manganese dioxide crystal form. Generally speaking, β-manganese dioxide is obtained by heat treating γ-manganese dioxide prepared by electrolysis within the phase transition temperature range of β-manganese dioxide (300℃~600℃). However, because the dielectric oxide film is sensitive to the ambient temperature, excessively high temperatures may damage the dielectric oxide film, affecting the reliability of the capacitor. Usually, the processing temperature is not higher than 300°C. Therefore, in this field, it is unreliable to directly transform the crystal phase of electrolytically deposited γ-manganese dioxide into β-manganese dioxide through heat treatment.

[0004] In the current application of solid electrolyte capacitors, β-manganese dioxide is usually deposited by chemical thermal decomposition by soaking in manganese nitrate solution. The manganese dioxide obtained by this method has a large particle size, which leads to weak conductivity and poor charge and discharge performance. In addition, solid electrolyte capacitors need to deposit manganese dioxide on the surface of the dielectric oxide film. This dielectric oxide film is not conductive. Therefore, it is impossible to directly use electrolysis to deposit manganese dioxide on this dielectric oxide film.

[0005] Patent application number CN202011010238.4 discloses a method for preparing a solid electrolyte for a tantalum capacitor, comprising: (1) intermediate layer coating: at least one slurry coating is performed on the surface of a first intermediate by a slurry coating method to obtain a second intermediate. The slurry coating method comprises: coating the surface of the coated object with a slurry containing β-MnO 2 The first intermediate is a porous tantalum sintered body with a dielectric oxide layer on the surface and micropores filled with manganese dioxide; (2) surface coating: coating the surface of the third intermediate with manganese dioxide again to fill the surface of the second intermediate with β-MnO 2 Gaps between particles; Although the manganese dioxide electrolyte layer formed on the surface of the solid electrolyte in this patent is harder and denser, the leakage current stability of the capacitor prepared by the solid electrolyte is better and the ESR of the capacitor is lower, but due to the complex microporous structure inside the anode of the solid electrolyte tantalum capacitor and the uneven distribution of micropore size, the internal environmental conditions of the manganese nitrate solution are different during the thermal decomposition reaction, resulting in poor consistency of the obtained manganese dioxide particles. From the perspective of industrial production, there will be large differences between individual performances, which is manifested in the large differences in the electrical performance parameters of the obtained solid electrolyte tantalum capacitors on a macro scale. However, the conditions of manganese dioxide deposited by electrolysis are more controllable than those of thermal decomposition, and the manganese dioxide particles obtained by the reaction are more consistent in microstructure. On a macro scale, the electrical performance parameters of the solid electrolyte tantalum capacitors obtained by processing are more consistent, which is a more ideal state for industrial production control.

[0006] Therefore, how to apply electrolytic manganese dioxide with stronger electrical activity and better stability in the field of electrolyte capacitors has become a technical challenge in manufacturing low ESR and high capacitance manganese dioxide chip solid electrolyte tantalum capacitors. Summary of the invention

[0007] In view of the shortcomings and defects of the prior art, the object of the present invention is to provide a method for electrolyzing β-manganese dioxide on the surface of a dielectric layer.

[0008] The present invention deposits a continuous layer of manganese dioxide on the surface of the capacitor anode dielectric layer by thermal decomposition, and then electrolytically processes the manganese dioxide through an external anode, which is specifically achieved through the following technical solutions:

[0009] A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer comprises the following steps:

[0010] S1: Deposition of manganese dioxide on the surface of dielectric oxide film by thermal decomposition

[0011] After the anode of the capacitor and the dielectric oxide film on its surface are immersed in a manganese salt solution, manganese dioxide is deposited by thermal decomposition, and the above method is repeated 6 to 20 times until a continuous manganese dioxide structure is formed on the surface of the dielectric oxide film of the capacitor; the thermal decomposition temperature is 180° C. to 300° C.;

[0012] S2: Electrolytic manganese dioxide

[0013] The capacitor obtained in step S1 is immersed in an electrolyte, and then the manganese dioxide obtained by thermal decomposition is connected to the anode of the power supply to perform an electrolytic reaction to obtain an electrolytic manganese dioxide structure;

[0014] S3: Rinse electrolytic manganese dioxide

[0015] The capacitor after the electrolytic deposition of manganese dioxide is washed to remove acid and impurities.

[0016] The manganese salt solution is any one of manganese nitrate and manganese sulfate.

[0017] The specific gravity of the manganese salt solution is 1.10 g / cm 2 ~2.1g / cm 2 .

[0018] The soaking temperature is 30° C. to 60° C., and the soaking time is 4 min to 20 min.

[0019] The thermal decomposition is performed by applying a water vapor atmosphere in a decomposition furnace, the content of which is between 0.05 and 1.0 kPa, and the single decomposition time is between 4 minutes and 15 minutes.

[0020] Optionally, there is a dehydration step between the infiltration and the thermal decomposition; the dehydration temperature is 60° C. to 90° C., and the dehydration time is 2 min to 15 min.

[0021] Furthermore, the electrolysis of manganese dioxide comprises the following specific steps:

[0022] S2.1 First electrolytic deposition: The capacitor obtained in step S1 is immersed in an electrolyte, and the continuous manganese dioxide layer formed in step S1 is connected to the anode of the electrochemical workstation. When the electrolyte temperature is 60℃~90℃ and the current density is 50A / m 2 ~100A / m 2 , electrolyze for 30min to 120min under the condition of applying voltage of 2V to 5V;

[0023] The electrolyte is any one of a manganese nitrate / nitric acid mixture and a manganese sulfate / sulfuric acid mixture, the pH of the electrolyte is 1 to 2, and the molar ratio of the acid to the zinc compound or the acid to the manganese compound is between 0.2 and 0.5;

[0024] S2.2 Second electrolytic deposition: The capacitor obtained in step S2.1 is coated with a mixed solution of manganese dioxide and 50% manganese nitrate, and then connected to the anode of the electrochemical workstation. The electrolyte temperature is 60°C to 90°C and the current density is 50A / m 2 ~250A / m 2 , electrolyze for 60min to 300min under the condition of applying voltage of 2V to 10V;

[0025] Furthermore, in the manganese dioxide-manganese nitrate mixed solution described in step S2.2, the mass ratio of the 50% manganese nitrate solution to the solid manganese dioxide is between 2:1 and 5:1;

[0026] Further, step S3 of rinsing the electrolytic manganese dioxide specifically comprises the following steps:

[0027] S3.1 Place the capacitor obtained in step S2 into a rinse tank A and use an alkaline buffer to rinse and remove acid; the alkaline buffer is NH 4 Cl / NH 3 ·H 2 O mixed solution, Na 2 HPO 4 Any one of the mixed solutions of / NaOH, pH 11 to 14, rinsing time 30min to 120min;

[0028] S3.2 Place the capacitor obtained in step S3.1 into a rinsing tank B and rinse it with deionized water. The rinsing temperature is 60°C to 90°C, the conductivity of the deionized water is ≤2μS / cm, and the rinsing time is 30min to 120min.

[0029] Furthermore, in step S1, the content of β-manganese dioxide in the continuous manganese dioxide structure is 15% to 90%, and the particle size is 10 to 800 μm.

[0030] Furthermore, the content of β-manganese dioxide obtained after S2 completes electrolytic processing is between 15% and 90%, and the particle size is between 1 μm and 200 μm.

[0031] Beneficial effects:

[0032] A layer of β-MnO was deposited on the surface of the dielectric layer by chemical thermal decomposition. 2 After that, the electrochemical workstation was connected to conduct β-MnO 2 The electrolytic deposition method deposits a layer of small, dense and electrically active β-MnO 2 layer, electrolytically generated β-MnO 2The layer can greatly improve the ESR, surge current resistance, and instantaneous large current resistance of the capacitor, and improve the high-frequency working characteristics. It is suitable for assembling tantalum capacitor products with large capacity, low ESR value, and high-frequency working environment, which is conducive to expanding the application scope of chip solid electrolyte tantalum capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The particle size distribution of manganese dioxide obtained in Example 1;

[0034] Figure 2 The particle size distribution of manganese dioxide obtained for Example 2;

[0035] Figure 3 The particle size distribution of manganese dioxide was obtained by thermal decomposition. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further defined below in conjunction with specific implementation methods, but the scope of protection required is not limited to the description.

[0037] Example 1

[0038] The method for electrolytically depositing manganese dioxide on the surface of a capacitor dielectric layer comprises the following steps:

[0039] 1. Assembling and grouping: Assemble the chip-type solid electrolyte tantalum capacitor 16V330μF-H tantalum core that has completed the capacitor dielectric layer processing, and then immerse it in manganese nitrate solution. Divide the two assembled products into two groups, I and II, with one frame in each group.

[0040] 2. Impregnation in manganese nitrate solution:

[0041] 2.1 The assembled chip solid electrolyte tantalum capacitor is immersed in a solution with a temperature of 45°C and a specific gravity of 1.12g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0042] 2.2 Immerse the chip-type solid electrolyte tantalum capacitor in a solution with a temperature of 45°C and a specific gravity of 1.18 g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0043] 2.3 Immerse the chip-type solid electrolyte tantalum capacitor in a solution with a temperature of 45°C and a specific gravity of 1.32 g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0044] 2.4 Immerse the chip-type solid electrolyte tantalum capacitor in a solution with a temperature of 45°C and a specific gravity of 1.52 g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0045] 3. Thermal decomposition: Take the capacitor obtained in step 2 out of the oven and put it into a decomposition furnace for chemical thermal decomposition to deposit manganese dioxide on the surface of the capacitor's dielectric oxide film. The decomposition temperature is 250°C. During decomposition, a water vapor atmosphere is applied in the decomposition furnace with a content of between 0.15 kPa. The single decomposition time is 6 minutes.

[0046] Repeat step 2.1 and step 3 four times; then repeat step 2.2 and step 3 ten times; then repeat step 2.3 and step 3 three times; then repeat step 2.4 and step 3 twice;

[0047] 4. First electrolysis of manganese dioxide: Place the above-mentioned Group II product into an electrochemical workstation containing an electrolyte, connect the manganese dioxide layer obtained by thermal decomposition to the electrochemical reaction anode, and perform manganese dioxide electrolysis reaction; the electrolyte is a manganese sulfate / sulfuric acid mixture, the electrolyte pH is controlled at 1.8, the molar ratio of acid to manganese compound is 0.4, the electrolyte temperature is 80°C, the current density is 20A / g, the applied voltage is 3.5V, and the electrolysis time is 60min;

[0048] 5. Second electrolysis of manganese dioxide: The capacitor coating manganese dioxide-manganese nitrate mixed solution obtained in step 4, wherein the mass ratio of 50% manganese nitrate solution to manganese dioxide is 3:1, is then connected to the anode of the electrochemical workstation to perform the second electrolysis of manganese dioxide deposition. The electrolyte temperature is 80°C, the current density is 20A / g, the applied voltage is 3.5V, and the electrolysis time is 60min;

[0049] 6. Alkaline solution rinsing: Put the capacitor obtained in step 5 into the alkaline solution rinsing tank and use NH 4 Cl / NH 3 ·H 2 The O mixed solution is used as an alkaline buffer for rinsing and removing acid, the pH of the alkaline buffer is 12, and the rinsing time is between 90 minutes;

[0050] 7. Deionized water rinsing: Place the capacitor obtained in step 6 into a deionized water rinsing tank and rinse with deionized water. The rinsing temperature is between 85°C and the conductivity of the deionized water is ≤2μS / cm -1 , rinse for 60 minutes;

[0051] 8. Thermally decompose, strengthen, densify and form the products of group I according to the normal coating process.

[0052] 9. After the coating of group I products is completed, group I and group II products will be produced normally according to the processing technology of chip solid electrolyte tantalum capacitors.

[0053] Wait until the production of group I and group II capacitors is completed.

[0054] Ten samples were randomly selected from two batches of chip tantalum capacitors processed by the embodiment of the present invention (Group II) and the control group (Group I) for equivalent circuit resistance testing. The test results are shown in Table 1.

[0055] Table 1 Equivalent circuit resistance test

[0056]

[0057] It can be seen from Table 1 above that, compared with the 16V330μF-H chip solid electrolyte tantalum capacitor (Group I) processed by the normal process, the equivalent series resistance of the 16V330μF-H chip solid electrolyte tantalum capacitor (Group II) processed by the method of the present invention is reduced by an average of 16.4mΩ.

[0058] From the two batches of chip tantalum capacitors processed in the embodiment of the present invention and the control group, the pass rate of the production process was statistically analyzed, and the specific situation is shown in 2.

[0059] Table 2 Production process qualification rate and input-output ratio

[0060]

[0061] It can be seen from Table 2 that, compared with the 16V330μF-H chip type solid electrolyte tantalum capacitor (Group I) processed by the normal process, the input-output ratio of the 16V330μF-H chip type solid electrolyte tantalum capacitor (Group II) processed by the method of the present invention is increased by 3.86%, among which the difference in the qualified rate in the surge current process is particularly obvious.

[0062] The particle size distribution of the mixture of thermally decomposed manganese dioxide and electrolytic manganese dioxide prepared according to the process is shown in Figure 1 .

[0063] Example 2

[0064] The method for electrolytically depositing manganese dioxide on the surface of a capacitor dielectric layer comprises the following steps:

[0065] 1. Assembling and grouping: Assemble the chip-type solid electrolyte tantalum capacitor 16V330μF-H tantalum core that has completed the capacitor dielectric layer processing, and then immerse it in manganese nitrate solution. Divide the two assembled products into two groups, I and II, with one frame in each group.

[0066] 2. Impregnation in manganese nitrate solution:

[0067] 2.1 The assembled chip solid electrolyte tantalum capacitor is immersed in a solution with a temperature of 45°C and a specific gravity of 1.12g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0068] 2.2 Immerse the chip-type solid electrolyte tantalum capacitor in a solution with a temperature of 45°C and a specific gravity of 1.18 g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0069] 2.3 Immerse the chip-type solid electrolyte tantalum capacitor in a solution with a temperature of 45°C and a specific gravity of 1.32 g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0070] 2.4 Immerse the chip-type solid electrolyte tantalum capacitor in a solution with a temperature of 45°C and a specific gravity of 1.52 g / cm 3 After immersion in manganese nitrate solution for 6 min, it was transferred to an oven at 85 °C for dehydration for 6 min.

[0071] 3. Thermal decomposition: Take the capacitor obtained in step 2 out of the oven and put it into a decomposition furnace for chemical thermal decomposition to deposit manganese dioxide on the surface of the capacitor's dielectric oxide film. The decomposition temperature is 250°C. During decomposition, a water vapor atmosphere is applied in the decomposition furnace with a content of between 0.15 kPa. The single decomposition time is 6 minutes.

[0072] Repeat step 2.1 and step 3 four times; then repeat step 2.2 and step 3 ten times; then repeat step 2.3 and step 3 three times; then repeat step 2.4 and step 3 twice;

[0073] 4. First electrolysis of manganese dioxide: Place the above-mentioned Group II product into an electrochemical workstation containing an electrolyte, connect the manganese dioxide layer obtained by thermal decomposition to the electrochemical reaction anode, and perform manganese dioxide electrolysis reaction; the electrolyte is a manganese sulfate / sulfuric acid mixture, the electrolyte pH is controlled at 1.2, the molar ratio of acid to manganese compound is 0.2, the electrolyte temperature is 80°C, the current density is 40A / g, the applied voltage is 7.5V, and the electrolysis time is 60min;

[0074] 5. Second electrolysis of manganese dioxide: The capacitor coating manganese dioxide-manganese nitrate mixed solution obtained in step 4, wherein the mass ratio of 50% manganese nitrate solution to manganese dioxide is 3:1, is then connected to the anode of the electrochemical workstation to perform the second electrolysis of manganese dioxide deposition. The electrolyte temperature is 80°C, the current density is 40A / g, the applied voltage is 7.5V, and the electrolysis time is 60min;

[0075] 6. Alkaline solution rinsing: Put the capacitor obtained in step 5 into the alkaline solution rinsing tank and use NH 4 Cl / NH 3 ·H 2 The O mixed solution is used as an alkaline buffer for rinsing and removing acid, the pH of the alkaline buffer is 12, and the rinsing time is between 90 minutes;

[0076] 7. Deionized water rinsing: Place the capacitor obtained in step 6 into a deionized water rinsing tank and rinse with deionized water. The rinsing temperature is between 85°C and the conductivity of the deionized water is ≤2μS / cm -1 , rinse for 60 minutes;

[0077] 8. Thermally decompose, strengthen, densify and form the products of group I according to the normal coating process.

[0078] 9. After the coating of group I products is completed, group I and group II products will be produced normally according to the processing technology of chip solid electrolyte tantalum capacitors.

[0079] Wait until the production of group I and group II capacitors is completed.

[0080] Ten samples were randomly selected from two batches of chip tantalum capacitors processed by the embodiment of the present invention (Group II) and the control group (Group I) for equivalent circuit resistance testing. The test results are shown in Table 1.

[0081] Table 3 Equivalent circuit resistance test

[0082]

[0083] It can be seen from Table 3 above that, compared with the 16V330μF-H chip type solid electrolyte tantalum capacitor (Group I) processed by the normal process, the equivalent series resistance of the 16V330μF-H chip type solid electrolyte tantalum capacitor (Group II) processed by the method of the present invention is reduced by an average of 18.96mΩ.

[0084] From the two batches of chip tantalum capacitors processed in the embodiment of the present invention and the control group, the pass rate of the production process was statistically analyzed, and the specific situation is shown in 2.

[0085] Table 4 Production process qualification rate and input-output ratio

[0086]

[0087]

[0088] It can be seen from Table 2 that, compared with the 16V330μF-H chip type solid electrolyte tantalum capacitor (Group I) processed by the normal process, the input-output ratio of the 16V330μF-H chip type solid electrolyte tantalum capacitor (Group II) processed by the method of the present invention is increased by 8.39%, among which the difference in the qualified rate in the surge current process is particularly obvious.

[0089] The particle size distribution of the mixture of thermally decomposed manganese dioxide and electrolytic manganese dioxide prepared according to the process is shown in Figure 2 .

[0090] In order to clarify the improvement of the particle size distribution of manganese dioxide by the present invention, the particle size distribution diagram of manganese dioxide particles prepared by thermal decomposition method is shown in Figure 3 .

[0091] The above tests show that the chip-type solid electrolyte tantalum capacitor of the present invention has significantly better withstand voltage and input-output ratio than the existing process.

[0092] It is necessary to point out here that the above embodiments and test examples are limited to further elaboration and understanding of the technical solution of the present invention, and cannot be understood as further limitation of the technical solution of the present invention. Inventions and creations with non-outstanding essential features and significant progress made by those skilled in the art still fall within the protection scope of the present invention.

Claims

1. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer, characterized in that: Firstly, manganese dioxide is deposited on the surface of a non-conductive dielectric layer by a thermal decomposition method, and then beta-manganese dioxide is deposited by electrolysis; the particle size of the beta-manganese dioxide is 1 μm to 200 μm.

2. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 1, characterized in that: The steps include: S1: Deposition of manganese dioxide on the surface of dielectric oxide film by thermal decomposition After the anode of the capacitor and the dielectric oxide film on its surface are immersed in a manganese salt solution, manganese dioxide is deposited by thermal decomposition, and the above method is repeated 6 to 20 times until a continuous manganese dioxide structure is formed on the surface of the dielectric oxide film of the capacitor; the thermal decomposition temperature is 180° C. to 300° C.; S2: Electrolytic manganese dioxide The capacitor obtained in step S1 is immersed in an electrolyte, and then the manganese dioxide obtained by thermal decomposition is connected to the anode of the power supply to perform an electrolytic reaction to obtain an electrolytic manganese dioxide structure; S3: Rinse electrolytic manganese dioxide The capacitor after the electrolytic deposition of manganese dioxide is washed to remove acid and impurities.

3. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 1 or 2, characterized in that: The manganese salt solution is any one of manganese nitrate and manganese sulfate; the specific gravity of the manganese salt solution is 1.10 g / cm 2 ~2.1g / cm 2 ; The soaking temperature is 30℃~60℃, and the soaking time is 4min~20min.

4. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 1 or 2, characterized in that: The thermal decomposition is performed by applying a water vapor atmosphere in a decomposition furnace, the content of which is between 0.05 and 1.0 kPa, and the single decomposition time is between 4 minutes and 15 minutes.

5. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 2, characterized in that: The electrolysis of manganese dioxide comprises the following specific steps: S2.1 First electrolytic deposition: The capacitor obtained in step S1 is immersed in an electrolyte, and the continuous manganese dioxide layer formed in step S1 is connected to the anode of the electrochemical workstation. When the electrolyte temperature is 60℃~90℃ and the current density is 50A / m 2 ~100A / m 2 , electrolyze for 30min to 120min under the condition of applying voltage of 2V to 5V; S2.2 Second electrolytic deposition: The capacitor obtained in step S2.1 is coated with strengthening liquid, and then connected to the anode of the electrochemical workstation. When the electrolyte temperature is 60℃~90℃ and the current density is 50A / m 2 ~250A / m 2 , electrolyze for 60min to 300min under the condition of applying voltage of 2V to 10V.

6. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 5, characterized in that: The electrolyte is any one of a zinc nitrate / nitric acid mixture, a zinc sulfate / sulfuric acid mixture, a manganese nitrate / nitric acid mixture, and a manganese sulfate / sulfuric acid mixture. The pH of the electrolyte is 1-2, and the molar ratio of the acid to the zinc compound or the acid to the manganese compound is between 0.2 and 0.

5.

7. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 2, characterized in that: The rinsing electrolytic manganese dioxide specifically comprises the following steps: S3.1 Place the capacitor obtained in step S2 into a rinsing tank A and use an alkaline buffer solution to rinse and remove acid; the alkaline buffer solution is any one of a NH4Cl / NH3·H2O mixed solution and a Na2HPO4 / NaOH mixed solution, with a pH of 11 to 14 and a rinsing time of 30 min to 120 min; S3.2 Place the capacitor obtained in step S3.1 into a rinsing tank B and rinse it with deionized water. The rinsing temperature is 60°C to 90°C, the conductivity of the deionized water is ≤2μS / cm, and the rinsing time is 30min to 120min.

8. A method for electrolyzing β-manganese dioxide on the surface of a dielectric layer as claimed in claim 2, characterized in that: In step S1, the content of β-manganese dioxide in the continuous manganese dioxide structure is 15% to 90%, and the particle size is 10 to 800 μm.

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