Fast activation silver chloride electrode and preparation method thereof

Abstract

The invention discloses a fast-activation silver chloride electrode and a preparation method thereof, and belongs to the technical field of electrochemical electrode materials, under the condition of red light, (1) welding a silver or copper guide lug on a silver foil or a copper foil substrate plated with a silver layer with enough thickness; (2) putting a silver foil with a guide lug or a copper foil plated with a silver layer with enough thickness into a positive electrode clamp, putting the positive electrode clamp into a formation tank, and respectively putting an auxiliary electrode into clamping grooves on two sides; (3) adding a formation solution to completely submerge the positive electrode clamp; (4) connecting the anode of a direct-current power supply with a guide lug, connecting the cathode with an auxiliary electrode wire, and performing electrochemical oxidation; (5) carrying out pre-discharge treatment on the prepared silver chloride electrode through an electronic load; and (6) washing the prepared silver chloride electrode with deionized water, drying or naturally airing, and storing in a dark place. The problem of voltage lag of the silver chloride electrode at the initial stage of discharge is solved, and the activation time of the water activated battery used as the ignition battery is remarkably shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical electrode materials, and particularly to a fast-activation silver chloride electrode and a preparation method thereof. Background Art

[0002] A water-activated battery is a reserve battery. This battery is in a dry state before use and can work after being injected with water or an aqueous electrolyte for activation. Compared with ordinary primary or secondary batteries, the water-activated battery has many advantages: fast activation speed, safe and reliable, good low-temperature performance, long storage life, relatively high specific energy and specific power. The magnesium / silver chloride system is a common electrochemical system for water-activated batteries. Silver chloride is an excellent electrode material with small electrochemical polarization and can carry a large current density.

[0003] The water-activated battery used as an ignition battery has no high requirement for working time, usually within 10 s, but has a high requirement for activation speed, usually requiring the battery to reach the working voltage within 1 s after activation. And the activation speed of this type of water-activated battery is mainly restricted by the silver chloride electrode. Because the resistivity of the silver chloride electrode itself is relatively high, resulting in large ohmic polarization and low voltage at the initial stage of discharge. As the discharge reaction proceeds, silver chloride is reduced to elemental silver with excellent conductivity, and the ohmic polarization decreases, and the voltage rises accordingly. Therefore, at the initial stage of discharge, the voltage of the silver chloride electrode rises slowly, there is a large voltage lag, and when directly used as an electrode after the silver chloride material is prepared, the activation time of the battery is relatively long. Summary of the Invention

[0004] In order to solve the technical problems in the background art, the present invention provides a fast-activation silver chloride positive electrode and a preparation method thereof, which can solve the voltage lag problem of the silver chloride electrode at the initial stage of discharge and significantly shorten the activation time of the water-activated battery used as an ignition battery.

[0005] The present invention is realized as follows. A preparation method of a fast-activation silver chloride electrode includes the following steps under red light conditions:

[0006] (1) Welding a silver or copper ear on a silver foil or a copper foil substrate plated with a thick enough silver layer;

[0007] (2) Loading the silver foil with an ear or the copper foil plated with a thick enough silver layer into a positive electrode fixture, putting it into a formation tank, and placing an auxiliary electrode on each of the two card slots;

[0008] (3) Adding a formation solution to completely submerge the positive electrode fixture;

[0009] (4) Connecting the positive pole of a DC power supply to the ear and the negative pole to the wire of the auxiliary electrode for electrochemical oxidation;

[0010] (5) Pre-discharge the prepared silver chloride electrode through an electronic load;

[0011] (6) Rinse the prepared silver chloride electrode thoroughly with deionized water, and store it in the dark after drying or air-drying.

[0012] The auxiliary electrode is made of a stainless steel plate, a graphite plate or a platinum plate.

[0013] In the copper foil substrate plated with a thick enough silver layer, the thickness of the silver layer is at least 50 μm.

[0014] In step (3), the forming solution is a hydrochloric acid solution with a concentration of 0.05 mol / L to 3 mol / L.

[0015] In step (3), the forming solution is a potassium chloride, sodium chloride or other chloride salt solution with a concentration ranging from 0.05 mol / L to supersaturation.

[0016] In step (4), the current density of the electrochemical oxidation is 5 mA / cm 2 ~500 mA / cm 2 , and the charging time is 3 min to 120 min.

[0017] In step (5), the current density is 5 mA / cm 2 ~500 mA / cm 2 , the pulse width is 10 ms to 10 s, and the number of pulses is 1 to 20 times.

[0018] The fast-activation silver chloride electrode prepared by the above preparation method.

[0019] The advantages and positive effects of the present invention are:

[0020] 1. Since the present invention uses the method of electrochemical oxidation to prepare a silver chloride electrode on a silver foil or a copper foil substrate plated with a thick enough silver layer, the preparation of an ultra-thin silver chloride layer can be realized, and the activation speed can be improved.

[0021] 2. Since the present invention pre-discharges and activates the electrode on the basis of the silver chloride thin layer prepared by electrochemical oxidation, silver grains with improved conductivity are prepared in the silver chloride active material layer of the electrode, and a three-dimensional conductive network of a silver skeleton is constructed to reduce ohmic polarization, thereby improving the voltage response speed.

[0022] 3. The present invention effectively realizes the preparation of an ultra-thin silver chloride electrode, and at the same time pre-discharges the electrode, and silver grains with improved conductivity are prepared in the silver chloride thin layer, solving the problem of voltage hysteresis at the initial stage of discharge of the silver chloride electrode, and significantly improving the activation speed of the water-activated battery used as an ignition battery. Specific embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The preparation method of the fast-activation silver chloride electrode of the present invention, since silver chloride is easily decomposed by light, the following operations should be carried out under red light conditions, and include the following steps:

[0025] (1) Weld silver or copper leads on a silver foil or a copper foil substrate plated with a thick enough silver layer;

[0026] (2) Place the silver foil with leads or the copper foil plated with a thick enough silver layer into the positive electrode fixture, put it into the formation tank, and place an auxiliary electrode on each side of the card slot;

[0027] (3) Add the formation solution to completely submerge the positive electrode fixture;

[0028] (4) Connect the positive pole of the DC power supply to the lead, and the negative pole to the wire of the auxiliary electrode for electrochemical oxidation;

[0029] (5) Perform pre-discharge treatment on the prepared silver chloride electrode through an electronic load;

[0030] (6) Rinse the prepared silver chloride electrode with deionized water, and store it in the dark after drying or air-drying.

[0031] The auxiliary electrode is made of a stainless steel plate, a graphite plate or a platinum plate.

[0032] In the copper foil substrate plated with a thick enough silver layer, the thickness of the silver layer is at least 50 μm.

[0033] In the step (3), the formation solution is a hydrochloric acid solution with a concentration of 0.05 mol / L to 3 mol / L.

[0034] In the step (3), the formation solution is a potassium chloride, sodium chloride or other chloride salt solution with a concentration of 0.05 mol / L to supersaturation.

[0035] In the step (4), the current density of the electrochemical oxidation is 5 mA / cm 2 ~500 mA / cm 2 , and the charging time is 3 min to 120 min.

[0036] In the step (5), the current density is 5 mA / cm 2 ~500 mA / cm 2 , the pulse width is 10 ms to 10 s, and the number of pulses is 1 to 20 times.

[0037] The fast-activation silver chloride electrode prepared by the above preparation method.

[0038] Example 1

[0039] The specific implementation method of Example 1 includes the following steps:

[0040] (1) Weld silver or copper leads on a silver foil or a copper foil substrate plated with a thick enough silver layer;

[0041] (2) Put the silver foil with leads or the copper foil plated with a thick enough silver layer into the positive electrode fixture, place it in the formation tank, and place an auxiliary electrode on each side of the card slot;

[0042] (3) Add the formation solution to completely submerge the positive electrode fixture;

[0043] (4) Connect the positive pole of the DC power supply to the lead, and the negative pole to the auxiliary electrode wire for electrochemical oxidation;

[0044] (5) Perform pre-discharge treatment on the prepared silver chloride electrode through an electronic load;

[0045] (6) Rinse the prepared silver chloride electrode with deionized water, dry it by baking or air-dry it naturally, and store it in the dark.

[0046] In step (1), a silver foil is used.

[0047] In step (2), the auxiliary electrode is made of a stainless steel plate.

[0048] In step (3), the formation solution is a hydrochloric acid solution with a concentration of 0.2 mol / L.

[0049] In step (4), the current density of electrochemical oxidation is 4.5 mA / cm 2 , and the charging time is 17 min.

[0050] In step (5), the current density is 100 mA / cm 2 , the pulse width is 1 s, and the number of pulses is 6 times.

[0051] The fast-activation silver chloride electrode prepared by the above preparation method.

[0052] Example 2

[0053] The specific implementation method of Example 2 includes the following steps:

[0054] (1) Weld silver or copper leads on a silver foil or a copper foil substrate plated with a thick enough silver layer;

[0055] (2) Put the silver foil with leads or the copper foil plated with a thick enough silver layer into the positive electrode fixture, place it in the formation tank, and place an auxiliary electrode on each side of the card slot;

[0056] (3) Add the formation solution to completely submerge the positive electrode fixture.

[0057] (4) Connect the positive pole of the DC power supply to the tab and the negative pole to the auxiliary electrode wire for electrochemical oxidation.

[0058] (5) Perform pre-discharge treatment on the prepared silver chloride electrode through an electronic load.

[0059] (6) Rinse the prepared silver chloride electrode thoroughly with deionized water, and store it in the dark after drying or air-drying.

[0060] The silver foil is used in the step (1).

[0061] The stainless steel plate is used as the auxiliary electrode in the step (2).

[0062] The hydrochloric acid solution with a concentration of 0.2 mol / L is used as the formation solution in the step (3).

[0063] The current density of the electrochemical oxidation in the step (4) is 4.5 mA / cm 2 , and the charging time is 17 min.

[0064] The current density in the step (5) is 100 mA / cm 2 , the pulse width is 1 s, and the number of pulses is 9 times.

[0065] The fast-activation silver chloride electrode prepared by the above preparation method.

[0066] Comparative Example

[0067] The specific implementation of the comparative example includes the following steps:

[0068] (1) Weigh 200 g of silver chloride powder with a ceramic crucible.

[0069] (2) Put the crucible into a muffle furnace, set the furnace temperature to 550 °C, heat for at least 30 min, and take it out after the silver chloride is completely melted.

[0070] (3) Pour the silver chloride solution in the crucible into a special mold to cool, and open the mold to take out the silver chloride electrode after cooling.

[0071] (4) Roll the silver chloride electrode to a thickness of 0.5 mm using a rolling press.

[0072] The die-cast silver chloride electrode prepared by the above preparation method.

[0073] The performance comparison between the silver chloride electrodes manufactured by the method of the present invention and those prepared by the conventional die-casting method is shown in Table 1. It can be seen from Table 1 that for the silver chloride electrodes manufactured by the present invention, compared with those prepared by the conventional die-casting method, the activation speed of the single-cell batteries made is significantly faster and the activation time is significantly shortened.

[0074] Note: The difference between Example 1 and Example 2 of the present invention lies in the different number of pre-discharge treatments in step (5).

[0075] Table 1 Comparison of activation times of single-cell batteries assembled with silver chloride electrodes prepared in different examples of the present invention and die-cast silver chloride electrodes prepared by the conventional method

[0076]

[0077] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a fast activated silver chloride electrode, characterized in that: Under red light conditions, the following steps are included: (1) Welding silver or copper conductors onto silver foil or copper foil substrates plated with a sufficiently thick silver layer; (2) Place the silver foil with lead ears or the copper foil with a sufficiently thick silver layer into the positive electrode fixture and put it into the formation tank, with one auxiliary electrode placed in each of the two slots; (3) Add the formation solution to completely cover the positive electrode fixture; (4) The positive electrode of the DC power supply is connected to the conductor, and the negative electrode is connected to the auxiliary electrode wire to perform electrochemical oxidation; (5) performing a pre-discharge treatment on the prepared silver chloride electrode through an electronic load; (6) The prepared silver chloride electrode is rinsed with deionized water, dried or air-dried, and stored away from light.

2. The method for preparing a fast activated silver chloride electrode according to claim 1, wherein: The auxiliary electrode is made of a stainless steel plate, a graphite plate or a platinum plate.

3. The method for preparing a fast activated silver chloride electrode according to claim 1, characterized in that: In the copper foil substrate plated with a sufficiently thick silver layer, the thickness of the silver layer is at least 50 μm.

4. The method for preparing a fast activated silver chloride electrode according to claim 1, characterized in that: In the step (3), the formation solution is a hydrochloric acid solution with a concentration of 0.05 mol / L to 3 mol / L.

5. The method for preparing a fast activated silver chloride electrode according to claim 1, characterized in that: In the step (3), the formation solution is potassium chloride, sodium chloride or other chloride salt solution, and the concentration is from 0.05 mol / L to supersaturation.

6. According to claim 1, it is characterized in that: The electrochemical oxidation current density in step (4) is 5 mA / cm 2 ~500mA / cm 2 , charging time is 3min~120min.

7. The method for preparing the fast activated silver chloride electrode according to claim 1, characterized in that: The current density in step (5) is 5 mA / cm 2 ~500mA / cm 2 , the pulse width is 10ms~10s, and the number of pulses is 1~20 times.

8. The fast activated silver chloride electrode prepared by the preparation method as described in any one of claims 1 to 7.

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