Carbon fiber-based electrode of flow battery

Abstract

The utility model discloses a carbon fiber-based electrode of a flow battery, which comprises an electrode substrate, and a plurality of groups of electrolyte mass transfer holes are uniformly arranged on the surface of the electrode substrate, so that an electrolyte transmission channel is formed on the electrode side of the electrode substrate and is used for electrolyte to flow from the electrode side to the diaphragm side; the density of the electrolyte mass transfer holes is 1-15 / cm < 2 >; and the hole depth of the electrolyte mass transfer hole is at least half of the thickness of the electrode substrate. According to the utility model, the electrolyte mass transfer holes with uniform density are designed on the electrode side of the electrode substrate, so that the electrolyte mass transfer capability of the electrode substrate in the direction perpendicular to the diaphragm is improved, the rapid transmission of active substances in the section close to the diaphragm is accelerated, the thickness of an ion transmission layer on the surface of the electrode on the diaphragm side is reduced, and the electrochemical reaction speed is improved; polarization caused by mass transfer is reduced, and the voltage efficiency and the electrolyte utilization rate in the charging and discharging process are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid flow batteries, in particular to a carbon fiber-based electrode for a liquid flow battery. Background Art

[0002] A flow battery is an energy storage device that converts chemical energy into electrical energy using electrochemical reactions. Its core components include positive and negative electrodes, electrolytes, and diaphragms. Electrodes are the site of electrochemical reactions in flow batteries, and their performance directly affects the voltage efficiency and energy density of flow batteries. However, due to the disordered structure of the electrodes, the electrolyte tends to be transmitted along the direction of the bipolar plate or the flow channel plate, while the convection perpendicular to the diaphragm is slow, which causes additional polarization losses and reduces the voltage efficiency and electrolyte utilization of the flow battery. Existing technologies mainly improve the mass transfer capacity of the electrolyte by optimizing electrode materials and structures. For example, some researchers increase the specific surface area and conductivity of the electrode by coating conductive materials such as graphene and carbon nanotubes on the surface of the electrode, thereby improving the mass transfer capacity of the electrolyte. In addition, some researchers have improved the flow state of the electrolyte inside the electrode by optimizing the porosity and pore size distribution of the electrode, thereby improving the mass transfer capacity of the electrolyte. However, in the above, it is often necessary to perform complex processing on the electrode material itself, which increases the production cost and process complexity. Secondly, while these technologies improve the mass transfer capacity of the electrolyte, they often ignore the mechanical strength and stability of the electrode material itself, which may cause the electrode material to deform or be damaged during use. Therefore, the existing technology has limited effect in improving the mass transfer capacity of the electrolyte and still cannot meet the requirements of high efficiency and long life of liquid flow batteries. Utility Model Content

[0003] In view of this, the purpose of the utility model is to provide a carbon fiber-based electrode for a liquid flow battery to solve the technical problems mentioned in the prior art.

[0004] A carbon fiber-based electrode for a flow battery, comprising an electrode substrate, wherein a plurality of groups of electrolyte mass transfer holes are evenly arranged on the surface of the electrode substrate to form an electrolyte transmission channel on the electrode side of the electrode substrate for the electrolyte to flow from the electrode side to the diaphragm side;

[0005] The density of the electrolyte mass transfer holes is 1-15 needles / cm 2 ;

[0006] The depth of the electrolyte mass transfer holes is at least half of the thickness of the electrode substrate.

[0007] Optionally, the electrode substrate is a carbon felt electrode, a graphite felt electrode, a carbon cloth electrode or a carbon paper electrode.

[0008] Optionally, the electrolyte mass transfer holes are arranged in a rectangular array on the electrode substrate.

[0009] Optionally, the thickness of the electrode substrate is 0.5 - 5 mm.

[0010] Optionally, the aperture of the electrolyte mass transfer holes is 0.2 - 3 mm.

[0011] Optionally, the density of the electrolyte mass transfer holes is 2.5 per cm 2 , the aperture of the electrolyte mass transfer holes is 1.5 mm, and the depth of the electrolyte mass transfer holes is 2.0 mm.

[0012] Optionally, the density of the electrolyte mass transfer holes is 2 per cm 2 , the aperture of the electrolyte mass transfer holes is 1.5 mm, and the depth of the electrolyte mass transfer holes is 1.8 mm.

[0013] Optionally, the density of the electrolyte mass transfer holes is 2 per cm 2 , the aperture of the electrolyte mass transfer holes is 2.3 mm, and the depth of the electrolyte mass transfer holes is 1.6 mm.

[0014] Optionally, the density of the electrolyte mass transfer holes is 2 per cm 2 , the aperture of the electrolyte mass transfer holes is 2.3 mm, and the depth of the electrolyte mass transfer holes is 1.6 mm.

[0015] The beneficial effects that the present utility model can produce include:

[0016] A carbon fiber-based electrode for a flow battery provided by the present utility model designs electrolyte mass transfer holes with uniform density on the electrode side of the electrode substrate, so as to improve the electrolyte mass transfer ability of the electrode substrate in the direction perpendicular to the diaphragm, accelerate the rapid transfer of active substances in the near-diaphragm interval, reduce the thickness of the ion transport layer on the surface of the electrode on the diaphragm side, improve the electro-chemical reaction rate, reduce the polarization caused by mass transfer, and enhance the voltage efficiency and electrolyte utilization rate during the charge and discharge process. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of a carbon fiber-based electrode for a flow battery of the present utility model;

[0018] In the figure: 1. Electrode substrate, 2. Electrolyte mass transfer holes. Detailed Embodiments

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Please refer to Figure 1 As shown, the present invention provides a carbon fiber-based electrode for a flow battery, including an electrode substrate 1, which is a flow battery electrode such as a carbon felt electrode, a graphite felt electrode, a carbon cloth electrode, or a carbon paper electrode. A plurality of groups of electrolyte mass transfer holes 2 are arranged on the surface of the electrode substrate 1 in a rectangular array to form an electrolyte transmission channel on the electrode side of the electrode substrate 1 for the electrolyte to flow from the electrode side to the diaphragm side; wherein, the thickness of the electrode substrate 1 is 2-8 mm, and the density of the electrolyte mass transfer holes 2 is 1-15 per cm 2 ; the aperture of the electrolyte mass transfer holes 2 is 0.2-3 mm; the depth of the electrolyte mass transfer holes 2 is at least half of the thickness of the electrode substrate 1.

[0021] Example 1: The thickness of the electrode substrate 1 is 2.5 mm, the density of the electrolyte mass transfer holes 2 is 2.5 per cm 2 , the aperture of the electrolyte mass transfer holes 2 is 1.5 mm, and the depth of the electrolyte mass transfer holes 2 is 2.0 mm.

[0022] Example 2: The thickness of the electrode substrate 1 is 2.5 mm, the density of the electrolyte mass transfer holes 2 is 2 per cm 2 , the aperture of the electrolyte mass transfer holes 2 is 1.5 mm, and the depth of the electrolyte mass transfer holes 2 is 1.8 mm.

[0023] Example 3: The thickness of the electrode substrate 1 is 2.5 mm, the density of the electrolyte mass transfer holes 2 is 2 per cm 2 , the aperture of the electrolyte mass transfer holes 2 is 2.3 mm, and the depth of the electrolyte mass transfer holes 2 is 1.6 mm.

[0024] Example 4: The thickness of the electrode substrate 1 is 2.5 mm, the density of the electrolyte mass transfer holes 2 is 2 per cm 2 , the aperture of the electrolyte mass transfer holes 2 is 2.3 mm, and the depth of the electrolyte mass transfer holes 2 is 1.6 mm.

[0025] Comparative Example 1: The thickness of the electrode substrate 1 is 2.5 mm, and no electrolyte mass transfer holes 2 are provided on the surface of the electrode substrate 1.

[0026] In the above, the overall performance of the battery was tested by using the carbon fiber-based electrodes of Flow Batteries prepared in Examples 1-4 and Comparative Example 1 as the positive or negative electrodes of the flow battery, respectively. The test results are shown in Table 1:

[0027] Table 1

[0028]

[0029]

[0030] As can be seen from Table 1, in the present utility model, by designing electrolyte mass transfer holes 2 with uniform density on the electrode side of the electrode substrate 1, the electrolyte mass transfer ability of the electrode substrate 1 in the direction perpendicular to the diaphragm is improved, the rapid transport of active substances in the near-diaphragm interval is accelerated, the thickness of the ion transport layer on the surface of the electrode on the diaphragm side is reduced, the electro-chemical reaction rate is increased, the polarization caused by mass transfer is reduced, and the voltage efficiency and electrolyte utilization rate during the charge and discharge process are improved.

[0031] Specifically, a corresponding needle plate can be designed according to the design density of the electrolyte mass transfer holes 2 on the surface of the electrode substrate 1, as well as their pore size and pore depth, so as to improve the optimization of the punching depth by controlling the needle density and needle head size of the needle plate, and further regulate to meet the different requirements of the flow battery electrode. For example, the arrangement pattern of the electrolyte mass transfer holes 2 can be uniformly arrayed in shapes such as rectangles, rhombuses, and triangles.

Claims

1. A carbon fiber-based electrode for a flow battery, characterized in that, It includes an electrode substrate (1), and a plurality of electrolyte mass transfer holes (2) are uniformly arranged on the surface of the electrode substrate (1) to form an electrolyte transmission channel on the electrode side of the electrode substrate (1) for the electrolyte to flow from the electrode side to the diaphragm side; The density of the electrolyte mass transfer holes (2) is 1 - 15 holes / cm 2 ; The hole depth of the electrolyte mass transfer hole (2) is at least half of the thickness of the electrode substrate (1).

2. The carbon fiber-based electrode for a flow battery according to claim 1, wherein The electrode substrate (1) is a carbon felt electrode, a graphite felt electrode, a carbon cloth electrode or a carbon paper electrode.

3. The carbon fiber-based electrode for a flow battery according to claim 1, wherein The electrolyte mass transfer holes (2) are arranged in a rectangular array on the electrode substrate (1).

4. A carbon fiber-based electrode for a flow battery according to claim 1, characterized in that, The thickness of the electrode substrate (1) is 0.5 - 5 mm.

5. A carbon fiber-based electrode for a flow battery according to claim 1, characterized in that, The aperture of the electrolyte mass transfer hole (2) is 0.2 - 3 mm.

6. The carbon fiber-based electrode for a flow battery according to claim 5, characterized in that The density of the electrolyte mass transfer holes (2) is 2.5 holes / cm 2 , the pore diameter of the electrolyte mass transfer holes (2) is 1.5 mm, and the hole depth of the electrolyte mass transfer holes (2) is 2.0 mm.

7. A carbon fiber-based electrode for a flow battery according to claim 5, characterized in that, The density of the electrolyte mass transfer holes (2) is 2 holes / cm 2 , the pore diameter of the electrolyte mass transfer holes (2) is 1.5 mm, and the hole depth of the electrolyte mass transfer holes (2) is 1.8 mm.

8. A carbon fiber-based electrode for a flow battery according to claim 5, characterized in that, The density of the electrolyte mass transfer holes (2) is 2 holes / cm 2 , the aperture of the electrolyte mass transfer holes (2) is 2.3 mm, and the depth of the electrolyte mass transfer holes (2) is 1.6 mm.

9. A carbon fiber-based electrode for a flow battery according to claim 5, wherein, The density of the electrolyte mass transfer holes (2) is 2 holes / cm 2 , the aperture of the electrolyte mass transfer holes (2) is 2.3 mm, and the depth of the electrolyte mass transfer holes (2) is 1.6 mm.

Images