TWI525891B - High-Performance Semi-Vanadium Flow Battery - Google Patents

Description

High efficiency semi-vanadium flow energy storage battery

The invention relates to a high-efficiency semi-vanadium redox flow energy storage battery, in particular to an electrode material prepared by a sol-gel method and an electroless plating process, in particular to using iodine-vitamin C as an electrolyte. The negative electrode electrolyte, combined with the positive vanadium ion (VO ²⁺ /VO ²⁺ ) electrolyte, constitutes a high-efficiency semi-vanadium flow energy storage battery.

Among the energy storage technologies in the world today, Redox Flow Battery (RFB) has many advantages over other energy storage technologies. For example, the flow cell has small electrochemical polarization and can be 100% deep. Discharge, long storage life, rated power and capacity are independent of each other, can increase the amount of electrolyte or increase the concentration of electrolyte to increase the battery capacity, and can freely design storage and freely choose the shape according to the setting situation.

One of the main advantages of RFB is the flexibility during charging and discharging, which can be completely discharged without damaging the battery, which is a decisive advantage that the current lead-acid battery technology cannot achieve.

Although RFB has various systems such as vanadium/bromine, total vanadium, and sodium polysulfide/bromine depending on the electrolyte, it is still in demonstration applications to verify its performance and long-term stability. Among them, the all-Vanadium Redox Flow Battery (All-VRFB) has the most commercial development potential. All-VRFB is a positive and negative electrode reactive material with different vanadium ions dissolved in a certain concentration of sulfuric acid solution. The positive and negative electrodes of the battery are separated by an ion exchange membrane into two half cells which are independent of each other. Normally, the All-VRFB positive redox couple is VO ²⁺ /VO ²⁺ and the negative electrode is V ²⁺ /V ³⁺ . Since vanadium is used in both half-cells of All-VRFB, the problem of contamination caused by electrolytes crossing the proton exchange membrane is overcome. Therefore, in recent years, the international energy community has been increasingly focusing on the development of All-VRFB.

However, All-VRFB still has some technical problems. First, the pentavalent vanadium in All-VRFB cathode liquid is easy to precipitate vanadium pentoxide precipitate when it is still at or above 45 degrees Celsius, and the precipitate will block the flow channel. The carbon felt fiber is coated to deteriorate the performance of the battery stack until the battery stack is scrapped, and the electrolyte temperature easily exceeds 45 degrees Celsius during long-term operation. Secondly, the graphite plate will be etched by the positive electrode. If the user operates it properly, the graphite plate can be used for two years. If the user operates improperly, the graphite plate can be completely etched by one charge, and the battery stack can only be scrapped. Therefore, in normal use, maintenance is performed by a professional every two months, and such high-frequency maintenance is costly and laborious.

In addition, the cost of All-VRFB is too high. Take a five-kilowatt battery as an example, the cost is more than 400,000, which is several times higher than the cost of the lead-acid battery of the same specification. Moreover, the volume is often extremely large, requiring 10 times or even tens of times the volume or weight of the lithium battery in order to store the same energy, and thus is not suitable for use in mobile devices or automobiles.

Furthermore, vanadium compounds are toxic, including the original materials used in the preparation of electrolytes. From an environmental point of view, All-VRFB is completely environmentally friendly. For example, the positive electrode precipitates and the thin layer formed by the leaked catholyte after air drying are present. One of the same substances, vanadium pentoxide, is a highly toxic chemical. Therefore, in the application of the mature technology of vanadium salt electrolyte, it should be developed toward reducing the use of vanadium salt or increasing its power density.

In view of the fact that the above-mentioned All-VRFB contains a large volume, low energy density, high cost and environmental protection, and many other problems need to be solved, at present, no scientific research institutions have made breakthroughs in China, so the system is not able to provide solutions to the actual situation. The opportunity for the problem.

The main object of the present invention is to overcome the above problems encountered in the prior art and to provide an electrode material which can reduce the amount of vanadium salt, reduce the economic cost, and prepare the iodine-vitamin C terminal by the sol-gel method and the electroless plating process. A high-efficiency semi-vanadium flow energy storage battery that can increase electrochemical characteristics such as diffusion coefficient and electric double layer capacitance.

A secondary object of the present invention is to provide a highly efficient semi-vanadium flow energy storage battery that can increase the battery voltage through a series connection and maintain the overall battery efficiency at a certain level.

For the purpose of the above, the present invention is a high-efficiency semi-vanadium redox flow energy storage battery, comprising: a positive electrolyte tank in which a positive electrode electrolyte is stored, the positive electrode electrolyte is a vanadium ion electrolyte; a tank in which a negative electrode electrolyte is stored, the negative electrode electrolyte is an iodine-vitamin C electrolyte; and a battery stack containing a positive electrode; a negative electrode containing carbon (C) and titanium dioxide (TiO ₂ )/metal or alloy As an electrode material; a separator is disposed between the positive electrode and the negative electrode; a positive electrode plate is disposed at the front end of the positive electrode; and a negative electrode plate is disposed at the front end of the negative electrode, the battery The stack is configured to supply the positive electrode electrolyte and the negative electrode electrolyte, and charge and discharge by electrochemical reaction between the positive electrode electrolyte and the vanadium ion and the iodine-vitamin C in the negative electrode electrolyte.

In the above embodiment of the present invention, the negative electrode is a structural layer composed of titanium dioxide/carbon/titanium dioxide (TiO ₂ /C/TiO ₂ ), and the titanium dioxide layer in the structure is disposed at the front end of the separator and the negative electrode. The rear end of the plate, and the carbon layer is disposed between the titanium dioxide layers.

In the above embodiment of the present invention, the negative electrode is a structural layer composed of titanium dioxide/palladium/carbon/palladium/titanium dioxide (TiO ₂ /Pd/C/Pd/TiO ₂ ), and the titanium dioxide layer in the structure is provided in the structure. The front end of the separator and the rear end of the negative electrode plate, and the carbon layer is disposed between the palladium layers.

In the above embodiment of the present invention, the negative electrode is a structural layer composed of palladium/titanium dioxide/carbon/titanium dioxide/palladium (Pd/TiO ₂ /C/TiO ₂ /Pd), and the palladium layer in the structure is provided in the structure. The front end of the separator and the rear end of the negative electrode plate, and the carbon layer is disposed between the titanium dioxide layers.

In the above embodiment of the present invention, the positive electrolyte solution tank is connected with a positive electrode circulation pump, and the negative electrode electrolyte tank is connected with a negative circulation pump.

100‧‧‧Semi-vanadium flow energy storage battery

10‧‧‧ positive electrolyte tank

11‧‧‧ positive circulation pump

20‧‧‧Negative electrolyte tank

21‧‧‧Negative Circulating Pump

30‧‧‧Battery stack

31‧‧‧ positive electrode

32‧‧‧Negative electrode

321‧‧‧ carbon layer

322‧‧‧Titanium dioxide layer

323‧‧‧Palladium layer

33‧‧‧Separator

34‧‧‧ positive electrode plate

35‧‧‧Negative electrode plate

Fig. 1 is a schematic view showing the structure of a semi-vanadium liquid flow energy storage battery of the present invention.

Fig. 2A is a schematic view showing the structure of a negative electrode of the first embodiment of the present invention.

2B is a schematic view showing the structure of a negative electrode of a second embodiment of the present invention.

2C is a schematic view showing the structure of a negative electrode of a third embodiment of the present invention.

Fig. 3 is a schematic view showing the charging and discharging of the unit cell and the series battery of the present invention.

Please refer to the structure of the semi-vanadium redox flow energy storage battery of the present invention, and the structure of the negative electrode of the first embodiment of the present invention, and the second embodiment of the present invention, as shown in the "1, 2, 2, 2, and 3," The schematic diagram of the structure of the negative electrode of the example, the schematic diagram of the structure of the negative electrode of the third embodiment of the present invention, and the charging and discharging diagram of the single cell and the series battery of the present invention. As shown in the figure: the present invention is a high-efficiency semi-Vanadium flow battery (Semi-Vanadium Flow Battery, Semi-VFB) 100, comprising a positive electrolyte tank 10, a negative electrolyte tank 20, and a battery. The pile 30 is composed.

In the positive electrode electrolyte tank 10 mentioned above, a positive electrode electrolyte is stored in the tank, and the positive electrode electrolyte is a vanadium ion electrolyte.

A negative electrode electrolyte is stored in the tank of the negative electrode solution tank 20, and the negative electrode electrolyte is an iodine-vitamin C electrolyte.

The battery stack 30 comprises a positive electrode 31, the electrode material of which may be carbon felt, carbon paper or graphite felt; a negative electrode 32 containing carbon (C) and titanium dioxide (TiO ₂ ) / metal or alloy as an electrode material; The separator 33 is disposed between the positive electrode 31 and the negative electrode 32; a positive electrode plate 34 is disposed at the front end of the positive electrode 31; and a negative electrode plate 35 is disposed at the front end of the negative electrode 32. The battery stack 30 is configured to supply the positive electrode electrolyte and the negative electrode electrolyte, and charge and discharge by electrochemical reaction between the positive electrode electrolyte and the vanadium ion and the iodine-vitamin C in the negative electrode electrolyte. If so, a new high-efficiency semi-vanadium flow energy storage battery is constructed by the above disclosed device.

The present invention further includes a positive-electrode circulating pump 11 connected to the positive electrode electrolyte tank 10, and a negative-electrode circulating pump 21 connected to the negative electrode electrolyte tank 20 for continuously transmitting the positive electrode electrolyte and the negative electrode electrolyte respectively to the The positive electrode plate 34 and the negative electrode plate 35.

In a specific embodiment, the negative electrode 32 is a structural layer composed of titanium dioxide/carbon/titanium dioxide (TiO ₂ /C/TiO ₂ ). As shown in FIG. 2A, the titanium dioxide layer 322 in the structure is disposed in the structure. The front end of the separator 33 and the rear end of the negative electrode plate 35, and the carbon layer 321 is disposed between the titanium dioxide layer 322.

In another embodiment, the negative electrode 32 is a structural layer composed of titanium dioxide/palladium/carbon/palladium/titanium dioxide (TiO ₂ /Pd/C/Pd/TiO ₂ ), as shown in FIG. 2B. The titanium dioxide layer 322 is disposed at the front end of the separator 33 and the rear end of the negative electrode plate 35, and the palladium layer 323 is disposed between the carbon layer 321 and the titanium dioxide layer 322, and the carbon layer 321 is provided on the palladium layer. Between layers 323, the palladium layer 323 can be other metals or alloys.

In another embodiment, the negative electrode 32 is a structural layer composed of palladium/titanium dioxide/carbon/titanium dioxide/palladium (Pd/TiO ₂ /C/TiO ₂ /Pd), as shown in FIG. 2C. The palladium layer 323 is disposed at the front end of the separator 33 and the rear end of the negative electrode plate 35, and the titanium dioxide layer 322 is disposed between the carbon layer 321 and the palladium layer 323, and the carbon layer 321 is disposed thereon. Between the titanium dioxide layers 322.

When used, the present invention mainly utilizes iodine-vitamin C as an electrolyte as a negative electrode (V ³⁺ /V ²⁺ ) electrolyte, and combines positive electrode vanadium ion (VO ²⁺ /VO ²⁺ ) electrolyte to form a high-efficiency semi-vanadium flow energy storage. Battery 100. Preparation of iodine-vitamin C-terminal electrode by sol-gel method and electroless plating procedure (materials include TiO ₂ /C/TiO ₂ , Pd/TiO ₂ /C/TiO ₂ /Pd or TiO ₂ /Pd /C/Pd/TiO ₂ ), which has the advantages of large effective reaction surface area and high chemical activity, and has been experimentally proven that the battery stack can effectively increase the voltage and efficiency values.

From the experimental results in Table 1, it can be found that when the electrode sheet is fabricated by the sol-gel method and the electroless plating process, the electric double layer charging capacitance value (C _d ) and the diffusion coefficient (D ₀ ) have a tendency to increase significantly. It can help to increase the effective reaction area between the electrode and the electrolyte to meet the requirements of improving efficiency. At the surface closest to the electrode, there is a layer of liquid that is not affected by the agitation. The electrolyte must diffuse to reach the surface of the electrode. Therefore, a high diffusion coefficient (D ₀ ) means a high diffusion rate. The reaction current, in addition to having a higher electric double layer charging capacitance ( _Cd ) value, can increase the effective reaction area between the electrode and the electrolyte to meet the energy storage requirements.

Table 1

Moreover, the coulombic efficiency value (CE), voltage efficiency (VE), and energy efficiency (EE) of the single cell and the series battery can be found through Table 2, wherein the CE of the maximum value is 96%, 92%, and the minimum value. The EE is 84% and 67% each, and has the charge and discharge capacity of the energy storage battery. From Fig. 3, it can be found that the voltage can be increased from the original 1 volt to 2.5 volt, which represents the development feasibility of the series battery.

Table 2

Thereby, the semi-vanadium liquid energy storage battery of the invention can reduce the amount of vanadium salt and reduce the economic cost, and the iodine-vitamin C-end electrode material can be prepared by the sol-gel method and the electroless plating process, and the diffusion coefficient and the electric double can be increased. Electrochemical characteristics such as layer capacitance values; moreover, the present invention can increase the battery voltage through the series connection, and maintain the overall battery efficiency at a certain level.

In summary, the present invention is a high-efficiency semi-vanadium flow energy storage battery, which can effectively improve various disadvantages of the conventional use, reduce the amount of vanadium salt, reduce the economic cost, and utilize the sol-gel method. Electroless plating procedure to produce iodine-vitamin C-terminal electrodes (materials including TiO ₂ /C/TiO ₂ , Pd/TiO ₂ /C/TiO ₂ /Pd or TiO ₂ /Pd/C/Pd/TiO ₂ ), which can increase diffusion The electrochemical characteristics of the coefficient and the electric double layer capacitance value; moreover, the invention can increase the battery voltage through the series connection, and maintain the overall battery efficiency to a certain level, thereby making the invention more progressive, more practical and more suitable for use. The needs of the applicants have indeed met the requirements of the invention patent application, and the patent application has been filed according to law.

However, the above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto; therefore, the simple equivalent changes and modifications made in accordance with the scope of the present invention and the contents of the invention are modified. All should remain within the scope of the invention patent.

100‧‧‧Semi-vanadium flow energy storage battery

10‧‧‧ positive electrolyte tank

11‧‧‧ positive circulation pump

20‧‧‧Negative electrolyte tank

21‧‧‧Negative Circulating Pump

30‧‧‧Battery stack

31‧‧‧ positive electrode

32‧‧‧Negative electrode

33‧‧‧Separator

34‧‧‧ positive electrode plate

35‧‧‧Negative electrode plate

Claims (5)

[Item 1] A high efficiency semi-vanadium flow energy storage battery, comprising:
a positive electrolyte tank in which a positive electrode electrolyte is stored, the positive electrode electrolyte is a vanadium ion electrolyte;
a negative electrolyte tank in which a negative electrode electrolyte is stored, the negative electrode electrolyte is an iodine-vitamin C electrolyte; and a battery stack containing a positive electrode; and a negative electrode containing carbon (C) and titanium dioxide (TiO _{2 )} a metal or an alloy as an electrode material; a separator disposed between the positive electrode and the negative electrode; a positive electrode plate disposed at a front end of the positive electrode; and a negative electrode plate disposed at the negative electrode The electrode front end is configured to supply the positive electrode electrolyte and the negative electrode electrolyte, and charge and discharge by electrochemical reaction between the positive electrode electrolyte and the vanadium ion and the iodine-vitamin C in the negative electrode electrolyte. [Item 2] High efficiency of the item by the first half range patent vanadium redox flow battery, wherein the negative electrode system is titanium dioxide / carbon / titanium dioxide _{(TiO 2 / C / TiO 2} ) layers of the structure, the structure of this The titanium dioxide layer is disposed at a front end of the separator and a rear end of the negative electrode plate, and a carbon layer is disposed between the titanium dioxide layers. [Item 3] The high-efficiency semi-vanadium flow energy storage battery according to claim 1, wherein the negative electrode is composed of titanium dioxide/palladium/carbon/palladium/titanium dioxide (TiO ₂ /Pd/C/Pd/TiO ₂ ). The structural layer, the titanium dioxide layer in the structure is disposed at the front end of the separator and the rear end of the negative electrode plate, and the carbon layer is disposed between the palladium layers. [Item 4] The high-efficiency semi-vanadium redox energy storage battery according to claim 1, wherein the negative electrode is composed of palladium/titanium dioxide/carbon/titanium dioxide/palladium (Pd/TiO ₂ /C/TiO ₂ /Pd). The structural layer, the palladium layer in the structure is disposed at the front end of the separator and the rear end of the negative electrode plate, and the carbon layer is disposed between the titanium dioxide layer. [Item 5] The high efficiency semi-vanadium redox flow energy storage battery according to claim 1, wherein the positive electrolyte solution tank is connected with a positive electrode circulation pump, and the negative electrode electrolyte tank is connected with a negative circulation pump.