CN103259024B - Cerium zinc redox flow batteries composite negative plate and preparation method thereof - Google Patents

Abstract

The invention provides a composite negative plate of a cerium-zinc redox flow battery and a preparation method thereof, belonging to the field of electrochemical batteries. The composite negative plate includes a metal titanium plate and a surface active layer, the surface active layer is composed of a binder, an activator and an additive, the binder is polyvinylidene fluoride or polytetrafluoroethylene, and the activator is zinc powder and A mixture of conductive materials, the additive is one or more of indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide, and the weight ratio of the binder, activator and additive is (5-15) : (50-90): (5-50), the present invention also provides a preparation method for a composite negative plate of a cerium-zinc redox flow battery. The composite negative plate is assembled into a battery, and the charge and discharge test is carried out with a current of 100mA. The cycle number of the battery reaches more than 550 times, the average voltage efficiency of the battery is 88.4%, the average Coulombic efficiency is 96.4%, and the average energy efficiency is 82.9%.

Description

Cerium-zinc redox flow battery composite negative plate and preparation method thereof

technical field

The invention belongs to the field of electrochemical batteries, and in particular relates to a composite negative plate of a cerium-zinc redox flow battery and a preparation method thereof.

technical background

In the research of cerium-zinc flow batteries, graphite, graphite felt or pure zinc are generally used as the negative electrode material of the battery. For example, in 2011, P.K.Leung et al. reported the research results on the cerium-zinc flow battery in Journal of Power Sources196 (2011) 5174-5185. They used a carbon-polyethylene composite electrode as the negative electrode of the battery in the assembled battery, and found that in the long-term of the battery During operation, the pH in the negative electrode electrolyte will decrease, which will have a greater corrosion effect on the zinc deposited on the negative electrode, and ultimately affect the capacity and cycle life of the battery. In 2011, Xie Zhipeng used pure zinc sheet as the negative electrode of the battery in his doctoral thesis "Research on the positive electrode electrolyte of zinc-cerium flow battery". Dissolution occurs and the battery cycle life is short. In addition, when using the currently more common graphite felt electrode as the negative electrode, zinc will be deposited on the interlaced parts of the graphite felt fibers during charging, which is not conducive to the dissolution of zinc during discharge, resulting in a decrease in capacity and affecting the performance of the battery.

Contents of the invention

The purpose of the present invention is to solve the problem that the zinc sheet of the negative plate of the existing cerium-zinc redox flow battery is easily dissolved, and to provide a composite negative plate of the cerium-zinc redox flow battery and a preparation method thereof.

The present invention firstly provides a composite negative plate of a cerium-zinc redox flow battery, the composite negative plate includes a metal titanium plate and a surface active layer, the surface active layer is composed of a binder, an activator and an additive, and the The binder is polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), the activator is a mixture of zinc powder and conductive materials, and the additive is one of indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide. One or several kinds, the weight ratio of the binder, activator and additive is (5-15): (50-90): (5-50).

Preferably, the weight-number ratio of the zinc powder and the conductive material in the activator is (1-5):1.

Preferably, the conductive material is selected from one or more of activated carbon, graphene or acetylene black.

Preferably, the weight ratio of the binder, the activator and the additive is (5-10): (60-80): (20-40).

Preferably, the coating amount of the surface active layer on the surface of the metal titanium plate is 50-300 mg/cm ² .

The present invention also provides a method for preparing a composite negative plate of a cerium-zinc redox flow battery, comprising the following steps:

1) According to the weight fraction, the binder, the activator and the additive are mixed to obtain the active layer slurry; the binder is polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), and the activator is A mixture of zinc powder and conductive materials, the additive is one or more of indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide, and the weight and number ratio of the binder, activator and additive is (5 ~15): (50~90): (5~50);

2) Coating the active layer slurry obtained in step 1) on one side of the metal titanium plate, and drying in vacuum to obtain a composite negative plate for a cerium-zinc redox flow battery.

Preferably, the weight-number ratio of the zinc powder and the conductive material in the activator is (1-5):1.

Preferably, the conductive material is selected from one or more of activated carbon, graphene or acetylene black.

Preferably, the weight ratio of the binder, the activator and the additive is (5-10): (60-80): (20-40).

Preferably, the coating amount of the surface active layer on the surface of the metal titanium plate is 50-300 mg/cm ² .

Beneficial effects of the present invention

The present invention firstly provides a composite negative plate of a cerium-zinc redox flow battery. The composite negative plate is coated with a high-activity layer on the surface of a metal titanium plate with high corrosion resistance. Due to the high mechanical properties of the metal titanium plate, it is beneficial to The battery stack is assembled, and the active layer has high electrical conductivity and high hydrogen evolution overpotential. The activator is a mixture of zinc powder and conductive material. The addition of zinc powder is to ensure that when zinc is deposited, there is already more The nucleation point, which can save the preparation time of zinc deposition, improve the deposition efficiency of zinc, the addition of conductive materials can not only improve the activity of the electrode, but also improve the conductivity of the electrode, reduce the internal resistance of the battery, and improve the efficiency of the battery; additives The main function is to increase the hydrogen evolution overpotential of the electrode, inhibit the formation of zinc dendrites and optimize the cross-sectional current distribution of the battery charge and discharge process. Compared with the currently used graphite electrodes and metal zinc electrodes, the composite negative plate of the present invention has high electrochemical activity and high hydrogen evolution potential, which can significantly improve the energy efficiency and service life of the battery. Experimental results show that: the composite negative plate of the present invention The board is assembled into a battery, and the charge and discharge test is carried out with a current of 100mA. The cycle number of the battery reaches more than 550 times, the average voltage efficiency of the battery is 88.4%, the average Coulombic efficiency is 96.4%, and the average energy efficiency is 82.9%.

The present invention also provides a method for preparing a composite negative plate of a cerium-zinc redox flow battery. In the method, zinc powder with higher activity and conductive The material is mixed with an appropriate amount of additives such as bismuth oxide, indium oxide, titanium oxide, and cerium oxide, and is coated on a titanium or titanium metal alloy material plate with high corrosion resistance to prepare a composite negative plate for a cerium-zinc flow battery. The preparation method Simple and inexpensive.

Description of drawings

1 is a schematic diagram of a monolithic electrode of a composite negative plate of a cerium-zinc redox flow battery of the present invention;

Among them, 1. Metal titanium plate, 2. Surface active layer.

Detailed ways

The present invention firstly provides a composite negative plate of a cerium-zinc redox flow battery. As shown in FIG. Activator and additive composition, described binding agent is polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), and activator is the mixture of zinc powder and conductive material, and described conductive material is preferably selected from activated carbon, One or more of graphene or acetylene black, more preferably activated carbon or acetylene black, the weight ratio of zinc powder and conductive material in the activator is preferably (1-5): 1, more preferably (1.5～3): 1; the additive is one or more of indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide, and the weight ratio of the binder, activator and additive is (5 -15): (50-90): (5-50), preferably (5-10): (60-80): (20-40).

The coating amount of the surface active layer on the surface of the metal titanium plate is preferably 50-300 mg/cm ² , more preferably 100-200 mg/cm ² , most preferably 120-160 mg/cm ² .

The metal titanium plate of the present invention has high mechanical properties, which is beneficial to the assembly of the battery stack. The active layer has high electrical conductivity and high hydrogen evolution overpotential. The activator is a mixture of zinc powder and conductive materials, zinc powder The addition of zinc is to ensure that there are more nucleation points on the electrode surface when zinc is deposited, which can save the preparation time for zinc deposition and improve the deposition efficiency of zinc. The addition of conductive materials can not only improve the activity of the electrode, but also improve the electrode surface. The conductivity of the battery reduces the internal resistance of the battery and improves the efficiency of the battery; the additive has three main functions: one is that it has a higher potential than zinc, and it is deposited on the surface of zinc during charge and discharge, which can avoid the dissolution of zinc; the other is that it has a higher The hydrogen evolution overpotential of , its existence will not promote the release of hydrogen, but may inhibit the hydrogen reaction; the third is to make the deposition of zinc more uniform.

The present invention also provides a method for preparing a composite negative plate of a cerium-zinc redox flow battery, comprising the following steps:

1) According to the weight fraction, the binder, the activator and the additive are mixed to obtain the active layer slurry; the binder is polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), and the activator is The mixture of zinc powder and conductive material, the conductive material is preferably selected from one or more of activated carbon, graphene or acetylene black, more preferably activated carbon or acetylene black, zinc powder and conductive material in the activator The ratio of parts by weight is preferably (1-5): 1, more preferably (1.5-3): 1; the additive is one or more of indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide, The weight ratio of the binder, activator and additive is (5-15): (50-90): (5-50), preferably (5-10): (60-80): (20 ~40);

2) Coating the active layer slurry obtained in step 1) on one side of the metal titanium plate, and drying in vacuum to obtain a composite negative plate for a cerium-zinc redox flow battery.

For the active layer slurry described in step 1) of the present invention, when the binder is polyvinylidene fluoride, the binder, activator and additives are added to an organic solvent to dissolve to obtain the active layer slurry. The organic The solvent is preferably N-methylpyrrolidone; when the binder is polytetrafluoroethylene, directly mix the polytetrafluoroethylene emulsion, the activator and the additive to obtain the active layer slurry.

The coating amount of the surface active layer of the present invention on the surface of the metal titanium plate is preferably 50-300 mg/cm ² , more preferably 100-200 mg/cm ² , most preferably 120-160 mg/cm ² .

In step 2 of the present invention, the active layer can be coated on the metal titanium plate by conventional methods such as brushing, scraping or spraying.

In the present invention, the metal titanium plate coated with the active layer slurry is vacuum-dried, the drying temperature is preferably 50-120°C, the time is 5-24h, and the vacuum degree is 1×10 ⁻¹ to 1×10 ^-3 MPa, and then keep the pressure and cool down to room temperature to obtain a composite negative plate for a cerium-zinc redox flow battery.

The present invention will be further described in detail below in conjunction with specific embodiments.

Example 1

1) Weigh 0.1g of binder polyvinylidene fluoride, 0.5g of zinc powder, 0.4g of activated carbon, 0.05g of acetylene black, 0.1g of indium oxide, tin oxide and titanium oxide, add 2000ml of N-methylpyrrolidone and grind Dissolving to obtain the active layer slurry;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by brushing to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 140mg/cm ² , which is active for coating The metal titanium plate on the first layer is subjected to vacuum high-temperature drying treatment, the drying temperature is 70°C, the drying time is 15h, the relative vacuum degree is 1×10 ^-1 MPa, the pressure is kept and the temperature is lowered to room temperature, and the composite negative electrode of the cerium-zinc redox flow battery is obtained plate. As shown in Figure 1.

The cerium-zinc redox flow battery composite negative plate obtained in Example 1 is combined with the positive graphite felt electrode to assemble the battery, and a 40mA current is used to charge and discharge. The number of cycles of the battery reaches more than 200 times, and the average voltage efficiency of the battery is 87.1%. The Coulombic efficiency is 94.7%, and the average energy efficiency is 80.4%.

Example 2

1) Weigh 0.08g of binder polyvinylidene fluoride, 0.6g of zinc powder, 0.15g of activated carbon, 0.05g of acetylene black, 0.1g each of tin oxide, bismuth oxide, titanium oxide and cerium oxide, and add 2000ml of N-formazan Grinding and dissolving base pyrrolidone to obtain active layer slurry;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by scraping to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 135mg/cm ² , which is active for coating The metal titanium plate on the first layer was vacuum dried at a temperature of 80°C for 10 hours, with a relative vacuum of 1×10 ^-3 MPa, and was kept under pressure and cooled to room temperature to obtain a composite negative plate for a cerium-zinc redox flow battery. .

The composite negative plate of the cerium-zinc redox flow battery obtained in Example 2 is combined with the positive graphite electrode to assemble the battery, and a current of 80 mA is used to charge and discharge. The number of cycles of the battery reaches more than 100 times, the average voltage efficiency of the battery is 84.1%, and the average Coulomb The efficiency is 90.4%, and the average energy efficiency is 75.7%.

Example 3

1) Weigh 0.1g of binder polyvinylidene fluoride, 0.5g of zinc powder, 0.1g of activated carbon, 0.1g of acetylene black, 0.1g each of indium oxide, titanium oxide and cerium oxide, add 2000ml of N-methylpyrrolidone and grind Dissolving to obtain the active layer slurry;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by brushing to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 120mg/cm ² , which is active for coating The metal titanium plate on the first layer is dried at high temperature at 80°C for 12 hours, the relative vacuum is 1×10 ^-2 MPa, and the temperature is kept at room temperature to obtain the composite negative plate of the cerium-zinc redox flow battery. .

The cerium-zinc redox flow battery composite negative plate obtained in Example 3 is combined with the positive graphite felt electrode to assemble the battery, and a 100mA current is used for charge and discharge tests. The number of cycles of the battery reaches more than 550 times, and the average voltage efficiency of the battery is 88.4%. The average Coulombic efficiency is 96.4%, and the average energy efficiency is 82.9%.

Example 4

1) Weigh 0.45g of zinc powder, 0.2g of activated carbon, 0.1g each of bismuth oxide, titanium oxide and cerium oxide, and add 2000ml of polytetrafluoroethylene emulsion to obtain the active layer slurry, wherein the polytetrafluoroethylene emulsion contains polytetrafluoroethylene The mass of ethylene is 0.1g;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by brushing to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 160mg/cm ² , which is active for coating The metal titanium plate on the first layer is subjected to vacuum high-temperature drying treatment, the drying temperature is 120°C, the drying time is 20h, the relative vacuum degree is 1×10 ^-2 MPa, the pressure is kept and the temperature is lowered to room temperature, and the composite negative electrode of the cerium-zinc redox flow battery is obtained plate.

The cerium-zinc redox flow battery composite negative plate obtained in Example 4 is combined with the positive graphite felt electrode to assemble the battery, and a 100mA current is used for charge and discharge tests. The number of cycles of the battery reaches more than 170 times, and the average voltage efficiency of the battery is 84.4%. The average Coulombic efficiency is 97.4%, and the average energy efficiency is 82.0%.

Example 5

1) Weigh 0.5g of zinc powder, 0.1g of activated carbon, 0.1g each of indium oxide, titanium oxide and cerium oxide, and add 1500ml of polytetrafluoroethylene emulsion to obtain the active layer slurry, wherein the polytetrafluoroethylene emulsion contains polytetrafluoroethylene Mass is 0.075g;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by brushing to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 160mg/cm ² , which is active for coating The metal titanium plate on the first layer was dried under normal pressure and high temperature, the drying temperature was 120°C, the drying time was 24h, and the pressure was maintained and the temperature was lowered to room temperature to obtain the composite negative plate of the cerium-zinc redox flow battery.

The cerium-zinc redox flow battery composite negative plate obtained in Example 5 is combined with the positive graphite felt electrode to assemble the battery, and a 100mA current is used for charge and discharge tests. The number of cycles of the battery reaches more than 120 times, and the average voltage efficiency of the battery is 78.2%. The average Coulombic efficiency is 90.1%, and the average energy efficiency is 68.4%.

Example 6

1) Weigh 0.05g of binder polyvinylidene fluoride, 0.3g of zinc powder, 0.15g of activated carbon, 0.05g of acetylene black, 0.02g of indium oxide, titanium oxide and cerium oxide, add 800ml of N-methylpyrrolidone and grind Dissolving to obtain the active layer slurry;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by scraping to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 120mg/cm ² , which is active for coating The metal titanium plate on the first layer was vacuum dried at a temperature of 80°C for 10 hours, with a relative vacuum of 1×10 ^-3 MPa, and was kept under pressure and cooled to room temperature to obtain a composite negative plate for a cerium-zinc redox flow battery. .

The cerium-zinc redox flow battery composite negative plate obtained in Example 6 is combined with the positive graphite electrode to assemble the battery, and a current of 80mA is used to charge and discharge. The number of cycles of the battery reaches more than 80 times, the average voltage efficiency of the battery is 78.6%, and the average Coulomb The efficiency is 93.4%, and the average energy efficiency is 72.7%.

Example 7

1) Weigh 0.15g of binder polyvinylidene fluoride, 0.5g of zinc powder, 0.2g of activated carbon, 0.2g of acetylene black, 0.15g each of indium oxide, titanium oxide and cerium oxide, add 2200ml of N-methylpyrrolidone and grind Dissolving to obtain the active layer slurry;

2) Apply the above active layer slurry evenly on one side of the metal titanium plate by scraping to prepare the active layer. The coating amount of the active layer on the surface of the metal titanium plate is 120mg/cm ² , which is active for coating The metal titanium plate on the first layer was vacuum dried at a temperature of 80°C for 10 hours, with a relative vacuum of 1×10 ^-3 MPa, and was kept under pressure and cooled to room temperature to obtain a composite negative plate for a cerium-zinc redox flow battery. .

The cerium-zinc redox flow battery composite negative plate obtained in Example 7 is combined with the positive graphite electrode to assemble the battery, and the battery is charged and discharged with a current of 120mA. The number of cycles of the battery reaches more than 300 times, the average voltage efficiency of the battery is 87.2%, and the average Coulomb The efficiency is 85.2%, and the average energy efficiency is 73.8%.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (10)

1. cerium zinc redox flow batteries composite negative plate, it is characterized in that, this composite negative plate comprises metallic titanium plate and surface activity layer, described surface activity layer is made up of binding agent, activator and additive, described binding agent is Kynoar or polytetrafluoroethylene, activator is the mixture of zinc powder and electric conducting material, additive is one or more in indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide, and described binding agent, activator and weight of additive portion rate are (5 ~ 15): (50 ~ 90): (5 ~ 50).

2. cerium zinc redox flow batteries composite negative plate according to claim 1, it is characterized in that, in described activator, the ratio of weight and number of zinc powder and electric conducting material is (1 ~ 5): 1.

3., according to the cerium zinc redox flow batteries composite negative plate of claim 1-2 described in any one, it is characterized in that, described electric conducting material is selected from one or more in active carbon, Graphene or acetylene black.

4. cerium zinc redox flow batteries composite negative plate according to claim 1, it is characterized in that, described binding agent, activator and weight of additive portion rate are (5 ~ 10): (60 ~ 80): (20 ~ 40).

5. cerium zinc redox flow batteries composite negative plate according to claim 1, is characterized in that, described surface activity layer is 50 ~ 300mg/cm in the painting amount of pickling metal titanium plate ².

6. the preparation method of cerium zinc redox flow batteries composite negative plate, is characterized in that, comprises as follows:

1) according to weight fraction meter, binding agent, activator and additive are mixed, obtains active layer slurry; Described binding agent is Kynoar or polytetrafluoroethylene, activator is the mixture of zinc powder and electric conducting material, additive is one or more in indium oxide, tin oxide, bismuth oxide, titanium oxide or cerium oxide, and described binding agent, activator and weight of additive portion rate are (5 ~ 15): (50 ~ 90): (5 ~ 50);

2) by step 1) the active layer slurry that obtains is coated in the side of metallic titanium plate, obtains cerium zinc redox flow batteries composite negative plate after vacuum drying.

7. the preparation method of cerium zinc redox flow batteries composite negative plate according to claim 6, it is characterized in that, in described activator, the ratio of weight and number of zinc powder and electric conducting material is (1 ~ 5): 1.

8., according to the preparation method of the cerium zinc redox flow batteries composite negative plate of claim 6-7 described in any one, it is characterized in that, described electric conducting material is selected from one or more in active carbon, Graphene or acetylene black.

9. the preparation method of cerium zinc redox flow batteries composite negative plate according to claim 6, it is characterized in that, described binding agent, activator and weight of additive portion rate are (5 ~ 10): (60 ~ 80): (20 ~ 40).

10. the preparation method of cerium zinc redox flow batteries composite negative plate according to claim 6, is characterized in that, surface activity layer is 50 ~ 300mg/cm in the painting amount of pickling metal titanium plate ².