CN115275226B - Electrode preparation method, electrode and flow battery - Google Patents
Electrode preparation method, electrode and flow battery Download PDFInfo
- Publication number
- CN115275226B CN115275226B CN202211072336.XA CN202211072336A CN115275226B CN 115275226 B CN115275226 B CN 115275226B CN 202211072336 A CN202211072336 A CN 202211072336A CN 115275226 B CN115275226 B CN 115275226B
- Authority
- CN
- China
- Prior art keywords
- temperature
- electrode
- carbonization
- porous fiber
- porosity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
- H01M8/184—Regeneration by electrochemical means
- H01M8/188—Regeneration by electrochemical means by recharging of redox couples containing fluids; Redox flow type batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/8605—Porous electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
- H01M4/88—Processes of manufacture
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Life Sciences & Earth Sciences (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Inert Electrodes (AREA)
Abstract
The invention provides an electrode preparation method, an electrode and a flow battery, wherein the electrode preparation method comprises the following steps: placing the porous fiber felt into a high-temperature furnace cavity, wherein the high-temperature furnace is provided with a plurality of temperature areas, and each temperature area can independently control the temperature; discharging oxygen in the high-temperature furnace; heating the porous fiber felt from the same initial temperature in each temperature zone at different heating rates until the temperature of the porous fiber felt reaches a first carbonization temperature, and preserving heat at the first carbonization temperature; heating the porous fiber felt from the first carbonization temperature in each temperature zone at different heating rates until the temperature of the porous fiber felt reaches a second carbonization temperature, and preserving heat at the second carbonization temperature; the porous fiber mat is cooled from the second carbonization temperature to room temperature. The invention can generate electrodes with different porosity areas meeting the requirements of the flow battery, finally increase the area of an electrode active reaction area in the flow battery, and reduce the concentration polarization phenomenon, thereby improving the overall performance of a battery system.
Description
Technical Field
The invention mainly relates to the technical field of flow batteries, in particular to an electrode preparation method, an electrode and a flow battery.
Background
Flow batteries (electrochemical flow batteries), also known as redox flow batteries, are a new class of large electrochemical energy storage devices. The Vanadium redox flow battery (VFB) is called a Vanadium redox flow battery (VFB) in which the positive electrode and the negative electrode are all made of Vanadium salt solution, and the VFB is an electrochemical energy storage device with great commercial prospect at present.
In the flow battery, in order to uniformly distribute the electrolyte in the electrode, the electrode material is generally selected from a carbon-based material with a porous structure. The porosity of the electrode directly affects the electrochemical reaction area, the distribution uniformity of the electrolyte and the like, and further affects the battery performance. Taking the vanadium redox flow battery as an example, the electrode is one of the key components, and is the place where the vanadium ions with different valence states undergo oxidation-reduction reaction, and the speed of the oxidation-reduction reaction and the amount of the reaction are closely related to the power density of the battery. In the running process of the battery, when electrolyte flows through the electrode with single porosity, the concentration of vanadium ions which can participate in the reaction at each part of the electrode is different (the concentration distribution is that the front end is larger than the middle end is larger than the tail end), so that concentration polarization is generated at part of the electrode, and the energy efficiency of the battery is reduced.
The porosity of the whole electrode is increased, so that the flow resistance of electrolyte in the electrode can be reduced, the electrolyte is uniformly distributed, the concentration polarization of the battery is effectively reduced, the energy efficiency of a battery system is improved, the electrochemical reaction area and the mechanical strength of the electrode are reduced, and the power density and the service life of the pile are reduced. The porosity of the whole electrode is reduced, and although the reaction area can be increased, the concentration polarization is increased.
Disclosure of Invention
The invention aims to provide an electrode preparation method, an electrode and a flow battery, and aims to solve the problems of insufficient area of an electrode active reaction area and concentration polarization in the flow battery.
In a first aspect, the present invention provides a method for preparing an electrode, comprising: putting a porous fiber felt into a high-temperature furnace cavity, wherein the high-temperature furnace is provided with a plurality of temperature zones, and each temperature zone can independently control the temperature; discharging oxygen from the high temperature furnace; heating the porous fiber felt from the same initial temperature in each temperature zone at different heating rates until the temperature of the porous fiber felt reaches a first carbonization temperature, and preserving heat at the first carbonization temperature; heating the porous fiber felt from the first carbonization temperature in various temperature zones at different heating rates until the temperature of the porous fiber felt reaches a second carbonization temperature, and preserving the heat at the second carbonization temperature; reducing the porous fiber mat from the second carbonization temperature to room temperature.
Optionally, the porous fiber mat comprises a pre-oxidized fiber mat.
Optionally, the pre-oxidized fiber mat comprises a polyacrylonitrile-based pre-oxidized fiber mat and a viscose-based fiber mat.
Optionally, discharging the oxygen in the high temperature furnace comprises: the high temperature furnace is evacuated and backfilled with an inert gas.
Optionally, in the step of heating the porous fiber felt in each temperature zone from the same initial temperature at different heating rates, the heating rate of each temperature zone is 1-15 ℃/min, and the difference of the heating rates of two adjacent temperature zones is not more than 5 ℃/min.
Optionally, the first carbonization temperature is 260-750 ℃, and the holding time of the first carbonization temperature is 15-300 minutes.
Optionally, the first carbonization temperature is 600-700 ℃, and the holding time of the first carbonization temperature is 30-200 minutes.
Optionally, in the step of heating the porous fiber mat in each temperature zone from the first carbonization temperature at different heating rates, the heating rate of each temperature zone is 2-20 ℃/min, and the difference of the heating rates of two adjacent temperature zones is not more than 5 ℃/min.
Optionally, the second carbonization temperature is 1000-1700 ℃, and the holding time of the second carbonization temperature is 60-300 minutes.
Optionally, the second carbonization temperature is 1400 to 1650 ℃, and the holding time of the second carbonization temperature is 120 to 180 minutes.
In a second aspect, the present invention provides an electrode comprising: the electrode comprises a left electrode area, a middle electrode area and a right electrode area, wherein the porosity of the left electrode area is 86.7% -92.7%, the porosity of the middle electrode area is 87.5% -93%, and the porosity of the right electrode area is 93% -97%.
In a third aspect, the present disclosure provides a flow battery comprising the electrode of the second aspect.
Optionally, in the flow battery, the region with the highest porosity of the electrode is placed at a liquid inlet or a liquid outlet of the electrolyte.
Compared with the prior art, the invention has the following advantages: different areas of the porous fiber felt are respectively subjected to temperature control firing, so that the porosity of the porous fiber felt in different areas can be adjusted according to actual requirements, electrodes with different porosity areas meeting the requirements of the flow battery can be generated, the area of an active reaction area of the electrode in the flow battery is increased, the concentration polarization phenomenon is reduced, and the overall performance of a battery system is improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the principle of the application. In the drawings:
FIG. 1 is a schematic flow chart of a method of preparing an electrode according to an embodiment of the present invention;
FIG. 2 is a schematic view of a high temperature furnace having a plurality of temperature zones according to the present invention;
FIG. 3 is a schematic representation of the porosity of electrode A produced under firing conditions in accordance with the present invention;
FIG. 4 is a scanning electron micrograph of each region of electrode A produced under one firing condition in the present invention;
FIG. 5 is a graph showing the porosity of electrode B produced under another firing condition in the present invention;
FIG. 6 is a schematic representation of the porosity levels of electrode C produced under another firing condition in accordance with the present invention;
fig. 7 is a schematic diagram of the structure of electrodes having different porosities according to an embodiment of the present invention.
In the figure: 201-a first temperature zone; 202-a second temperature zone; 203-a third temperature zone; 204-porous fiber felt; 205-a heat insulation module; 206-high temperature furnace cavity; 701-left electrode region; 702-a middle electrode region; 703-right electrode region.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly described below. It is obvious that the drawings in the following description are only examples or embodiments of the application, from which the application can also be applied to other similar scenarios without inventive effort for a person skilled in the art. Unless otherwise apparent from the context, or otherwise indicated, like reference numbers in the figures refer to the same structure or operation.
As used in this application and the appended claims, the terms "a," "an," "the," and/or "the" are not intended to be inclusive in the singular, but rather are intended to be inclusive in the plural unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that steps and elements are included which are explicitly identified, that the steps and elements do not form an exclusive list, and that a method or apparatus may include other steps or elements.
The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the directional terms such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc., are generally based on the orientation or positional relationship shown in the drawings, and are used for convenience of description and simplicity of description only, and in the case of not making a reverse description, these directional terms do not indicate and imply that the device or element being referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore, should not be considered as limiting the scope of the present application; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.
For ease of description, spatially relative terms such as "over 8230 \ 8230;,"' over 8230;, \8230; upper surface "," above ", etc. may be used herein to describe the spatial relationship of one device or feature to another device or feature as shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary terms "at 8230; \8230; above" may include both orientations "at 8230; \8230; above" and "at 8230; \8230; below". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, so that the scope of the present application is not to be construed as being limited. Further, although the terms used in the present application are selected from publicly known and used terms, some of the terms mentioned in the specification of the present application may be selected by the applicant at his or her discretion, the detailed meanings of which are described in relevant parts of the description herein. Further, it is required that the present application is understood, not simply by the actual terms used but by the meaning of each term lying within.
Flowcharts are used herein to illustrate the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in the exact order in which they are performed. Rather, various steps may be processed in reverse order or simultaneously. Meanwhile, other operations are added to or removed from these processes.
Example one
Fig. 1 is a schematic flow diagram of a method for preparing an electrode according to an embodiment of the present invention, and referring to fig. 1, the method 100 includes:
s110, placing the porous fiber felt into a high-temperature furnace cavity, wherein the high-temperature furnace is provided with a plurality of temperature zones, and each temperature zone can independently control the temperature.
In this embodiment, a high temperature furnace with multiple temperature zones is used for firing the porous fiber mat 204, and each temperature zone of the high temperature furnace can independently control the temperature, that is, each temperature zone can independently perform heating, heat preservation and cooling. In some implementations, the high temperature furnace shown in fig. 2 may be used, and fig. 2 is a schematic structural diagram of a high temperature furnace with multiple temperature zones according to the present invention, the high temperature furnace has 3 temperature zones from left to right, which are a first temperature zone 201, a second temperature zone 202 and a third temperature zone 203, respectively, when the porous fiber mat 204 is placed into the high temperature furnace, i.e., into the high temperature furnace cavity 206, the left, middle and right regions of the porous fiber mat 204 are respectively located in the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203. Since each temperature zone can be controlled independently, the porous fiber mat 204 can be fired independently in each zone, although in a high temperature furnace. Obviously, the high temperature furnace has 3 temperature zones only for explaining the related functions of each temperature zone in the embodiment, and the number of the temperature zones is not limited, for example, according to the actual needs, 4 temperature zones, 5 temperature zones, or even more temperature zones may be set, and no specific limitation is made herein.
In order to fire electrodes having different porosities in different regions, the high temperature furnace generally has more than two temperature zones. In addition, in order to achieve better thermal insulation effect between the temperature zones of the high temperature furnace, a thermal insulation module 205 is disposed on the porous fiber mat 204 at the boundary of the adjacent temperature zones for avoiding mutual interference caused by temperature difference between the adjacent temperature zones in the high temperature furnace cavity 206. Illustratively, if the high temperature furnace has 3 temperature zones, 2 heat insulation modules 205 are required, if the high temperature furnace has 4 temperature zones, 3 heat insulation modules 205 and the like are required. The insulation module 205 may employ graphite felt insulation.
In some implementations, the porous fiber mat 204 may be selected from a pre-oxidized fiber mat, in which case a polyacrylonitrile-based pre-oxidized fiber mat or a glue-based fiber mat may be selected.
And S120, discharging oxygen in the high-temperature furnace.
In this embodiment, in order to smoothly fire the porous fiber mat 204, it is necessary to exhaust oxygen in the high temperature furnace so that the porosity of the fired porous fiber mat 204 can meet the requirement. In some implementations, the discharging of the oxygen from the high temperature furnace may be performed by evacuating the high temperature furnace and refilling with an inert gas to fill the high temperature furnace with the inert gas. Schematically, in actual operation, the method of vacuumizing the high-temperature furnace and refilling inert gas is adopted to discharge oxygen, and the method is generally repeated for 2 to 3 times. For example, the inert gas used may be argon, nitrogen, helium, etc., with argon or nitrogen being preferred.
S130, heating the porous fiber felt from the same initial temperature in each temperature zone at different heating rates until the temperature of the porous fiber felt reaches a first carbonization temperature (low carbonization temperature), and preserving heat at the first carbonization temperature.
In this embodiment, depending on the firing characteristics of the porous fiber mat 204, the porosity is higher in the region where the temperature rise rate is high and the carbonization heat retention time is long, and the porosity is lower in the region where the temperature rise rate is low and the carbonization heat retention time is short. The porous fiber mat 204 is heated at different heating rates from the same initial temperature in each temperature zone until the porous fiber mat 204 reaches the first carbonization temperature and is held at the first carbonization temperature. It should be noted that, in most cases, although each temperature zone has an independent temperature rise rate, temperature holding temperature and temperature holding time in the process of raising the temperature of the porous fiber mat 204 to the first carbonization temperature and holding the temperature, the first carbonization temperature for firing the porous fiber mat 204 is the same, so that even if the porosity of each zone is different, the electrical properties of the prepared electrode do not have great difference, and the electrical properties of the prepared electrode meet the requirements of the electrode.
In some implementations, the heating rate of each temperature zone is 1-15 ℃/min, and the difference between the heating rates of two adjacent temperature zones is not more than 5 ℃/min.
In some implementations, the first carbonization temperature is 260 to 750 ℃ and the incubation time for the first carbonization temperature is 15 to 300 minutes. Preferably, the first carbonization temperature is 600-700 ℃, and the heat preservation time of the first carbonization temperature is 30-200 minutes.
And S140, heating the porous fiber felt from the first carbonization temperature in each temperature zone at different heating rates until the temperature of the porous fiber felt reaches a second carbonization temperature (high carbonization temperature), and preserving heat at the second carbonization temperature.
In this embodiment, depending on the firing characteristics of the porous fiber mat 204, the porosity is higher in the region where the temperature rise rate is high and the carbonization heat retention time is long, and the porosity is lower in the region where the temperature rise rate is low and the carbonization heat retention time is short.
In some implementations, the heating rate of each temperature zone is 2-20 ℃/min, and the difference between the heating rates of two adjacent temperature zones is no more than 5 ℃/min.
In some implementations, the second carbonization temperature is 1000 to 1700 ℃, and the holding time at the second carbonization temperature is 60 to 300 minutes. Preferably, the second carbonization temperature is 1400-1650 ℃, and the heat preservation time at the second carbonization temperature is 120-180 minutes.
In this embodiment, it should be noted that, in most cases, although each temperature zone has independent temperature-rising rate, holding temperature and holding time in the process of raising the temperature of the porous fiber mat 204 to the second carbonization temperature and holding the temperature, the second carbonization temperature for firing the porous fiber mat 204 is the same, so that even if the porosity of each region is different, the electrical properties of the prepared electrode will not be greatly different, and the electrical properties of the prepared electrode meet the requirements of the electrode.
S150, cooling the porous fiber felt from the second carbonization temperature to room temperature.
In this embodiment, the porous fiber mat 204 is lowered from the second carbonization temperature to room temperature. For example, after the carbonization, the temperature of the high-temperature furnace is naturally lowered to room temperature. Of course, other cooling methods can be adopted, and the cooling requirement in the electrode preparation process can be met, which is not described herein again.
To more clearly illustrate the above-described electrode preparation process and firing parameters, the present example is described below in terms of the firing of the porous fiber mat 204 under several firing parameters (or firing conditions).
Firing conditions one
Fig. 2 is a schematic structural diagram of a high-temperature furnace with multiple temperature zones according to the present invention, the high-temperature furnace shown in fig. 2 is used for electrode preparation, a porous fiber mat 204 (such as a polyacrylonitrile-based pre-oxidized fiber mat) is placed in a high-temperature furnace cavity 206, a heat insulation module 205 is placed on the porous fiber mat 204 at the boundary of adjacent temperature zones in the high-temperature furnace cavity 206, a graphite mat heat insulation material can be used as the heat insulation module 205 to prevent mutual interference between adjacent temperature zones due to different heating rates and temperature differences, and the size of the heat insulation module 205 is far smaller than that of the porous fiber mat 204. The high temperature furnace chamber 206 was sealed, evacuated and backfilled with nitrogen, and repeated 3 times. Temperature-raising programs are respectively arranged for three temperature zones of the high-temperature furnace, the temperature-raising rates of the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 are respectively 6 ℃/min, 3 ℃/min and 8 ℃/min, the temperature of each temperature zone is raised to 600 ℃ in a nitrogen atmosphere, the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 are respectively kept for 130 min, 30 min and 155 min at the temperature, and the porous fiber felt 204 is carbonized at low temperature. After the low-temperature carbonization is completed, the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 are heated to 1100 ℃ at the heating rates of 10 ℃/minute, 8 ℃/minute and 13 ℃/minute respectively, and the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 are respectively kept at the temperature for 133 minutes, 120 minutes and 144 minutes, so that the porous fiber felt 204 is carbonized at high temperature. And after the high-temperature carbonization is finished, naturally cooling the high-temperature furnace to room temperature, and taking out the prepared carbon felt to obtain the electrode A with gradient change of porosity.
The porosity of the fired electrode a is shown in fig. 3, and fig. 3 is a schematic view showing the porosity of the electrode a produced under one firing condition in the present invention. As can be seen from fig. 3, under the above firing conditions, the porosity of the electrode made of the porous fiber mat 204 was 92.7% in the first temperature zone 201, 87.5% in the second temperature zone 202, and 96.6% in the third temperature zone 203. FIG. 4 is a scanning electron microscope image of each area of the electrode A produced under a firing condition in the present invention, and referring to FIG. 4, the three areas of the electrode A are a1, a2 and a3, respectively, and the scanning electron microscope images corresponding to the electrode areas a1, a2 and a3 are b, c and d, respectively, and it can be seen that the porosity of the middle area of the electrode is smaller than that of the two side areas.
Therefore, different firing conditions (heating rate, heat preservation temperature and the like) are adopted for controlling different temperature zones, so that the prepared electrode has different porosities in different zones, and the porosity requirements of the redox flow battery on the electrode can be further met.
Firing conditions two
A high-temperature furnace with 3 independent temperature zones is adopted, a porous fiber felt 204 (such as a polyacrylonitrile-based pre-oxidized fiber felt) is placed in a high-temperature furnace cavity 206, a heat insulation module 205 is placed on the porous fiber felt 204 at the junction of the adjacent temperature zones in the high-temperature furnace cavity 206, and a graphite felt heat insulation material can be adopted as the heat insulation module 205 to prevent mutual interference caused by different heating rates and temperature differences between the adjacent temperature zones. The high temperature furnace cavity 206 was sealed, evacuated and backfilled with nitrogen for 3 times. Setting temperature-raising programs for three temperature zones of the high-temperature furnace respectively, wherein the temperature-raising rates of the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 are respectively 3 ℃/minute, 7 ℃/minute and 12 ℃/minute, raising the temperature of each temperature zone to 500 ℃ in a nitrogen atmosphere, respectively preserving the temperature of the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 for 20 minutes, 115 minutes and 147 minutes at the temperature, and carbonizing the porous fiber felt 204 at a low temperature. After the low-temperature carbonization is completed, the temperature of the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 is raised to 1200 ℃ at the heating rates of 5 ℃/minute, 8 ℃/minute and 12 ℃/minute respectively, the temperature of the first temperature zone 201, the second temperature zone 202 and the third temperature zone 203 is maintained at the temperature for 60 minutes, 112 minutes and 141 minutes respectively, and the fiber felt 204 is carbonized at high temperature. And after the high-temperature carbonization is finished, naturally cooling the high-temperature furnace to room temperature, and taking out the prepared carbon felt to obtain the electrode B with the gradient change of the porosity.
The porosity of the fired electrode B is shown in fig. 5, and fig. 5 is a schematic view showing the porosity of the electrode B under another firing condition of the present invention, and it can be seen from fig. 5 that the porosity of the porous fiber mat 204 is 86.7% in the first temperature zone 201, 93% in the second temperature zone 202, and 96.9% in the third temperature zone 203 under the above firing condition. Therefore, different firing conditions (heating rate, heat preservation temperature and the like) are adopted for controlling different temperature zones, so that the prepared electrode has different porosities in different zones, and the porosity requirements of the redox flow battery on the electrode can be further met.
Firing conditions III
A high-temperature furnace with 4 independent temperature zones is adopted, a porous fiber felt 204 (such as polyacrylonitrile-based pre-oxidized fiber felt) is placed in a high-temperature furnace cavity 206, a heat insulation module 205 is placed on the porous fiber felt 204 at the junction of adjacent temperature zones in the high-temperature furnace cavity 206, and a graphite felt heat insulation material can be adopted as the heat insulation module 205 to prevent mutual interference between adjacent temperature zones due to different heating rates and temperature differences. The high temperature furnace chamber 206 was sealed, evacuated and backfilled with nitrogen, and repeated 3 times. Heating programs are respectively set for the four temperature zones, the heating rates of the first temperature zone 201, the second temperature zone 202, the third temperature zone 203 and the fourth temperature zone (not shown in the figure) are respectively 3 ℃/min, 6 ℃/min, 9 ℃/min and 12 ℃/min, the temperature of each temperature zone is raised to 750 ℃ in a nitrogen atmosphere, the temperature of the first temperature zone 201, the second temperature zone 202, the third temperature zone 203 and the fourth temperature zone is respectively kept for 10 min, 135 min, 176 min and 197 min at the temperature, and the porous fiber felt 204 is carbonized at low temperature. After the low-temperature carbonization is completed, the temperature of the first temperature zone 201, the second temperature zone 202, the third temperature zone 203 and the fourth temperature zone is raised to 1500 ℃ at the heating rates of 6 ℃/min, 8 ℃/min, 10 ℃/min and 12 ℃/min respectively, and the temperature of the first temperature zone 201, the second temperature zone 202, the third temperature zone 203 and the fourth temperature zone is kept at the temperature for 30 minutes, 60 minutes, 80 minutes and 92 minutes respectively, so that the porous fiber felt 204 is carbonized at high temperature. And after the high-temperature carbonization is finished, naturally cooling the high-temperature furnace to room temperature, and taking out the prepared carbon felt to obtain the electrode C with the gradient change of the porosity.
The porosity of the fired electrode C is shown in fig. 6, fig. 6 is a schematic view of the porosity of the electrode C under another firing condition of the present invention, and it can be seen from fig. 6 that, under the above firing condition, the porosity of the porous fiber mat 204 is 86.9% in the first temperature zone 201, 92.5% in the second temperature zone 202, 96.9% in the third temperature zone 203, and 97.0% in the fourth temperature zone. Therefore, different firing conditions (heating rate, heat preservation temperature and the like) are adopted for controlling different temperature zones, so that the prepared electrode has different porosities in different zones, and the porosity requirements of the redox flow battery on the electrode can be further met.
According to the electrode preparation method provided by the embodiment, different areas of the porous fiber felt 204 are respectively subjected to temperature-controlled firing, so that the porosity of the different areas of the porous fiber felt 204 can be adjusted according to actual requirements, and then electrodes with different porosity areas meeting the requirements of the flow battery can be generated, and finally, the area of an active reaction area of the electrode in the flow battery is increased, and the concentration polarization phenomenon is reduced, so that the overall performance of a battery system is improved.
Example two
Fig. 7 is a schematic diagram of the structure of electrodes having different porosities according to an embodiment of the present invention. The electrode provided in this embodiment may be prepared by the method shown in the first embodiment, or may be prepared by other methods. Referring to fig. 7, the electrode includes a left electrode region 701, a middle electrode region 702, and a right electrode region 703, wherein the porosity of the left electrode region 701 is 86.7% to 92.7%, the porosity of the middle electrode region 702 is 87.5% to 93%, and the porosity of the right electrode region 703 is 93% to 97%.
The electrode provided by the embodiment has different porosities in different regions, and finally the area of an active reaction region of the electrode in the flow cell can be increased, and the concentration polarization phenomenon can be reduced, so that the overall performance of a cell system can be improved.
EXAMPLE III
The present embodiment provides a flow battery including electrodes of different porosities as shown in example two. In some implementations, the electrodes are arranged in the flow battery in the following manner: the area with the largest porosity of the electrode is arranged at the liquid inlet or the liquid outlet of the electrolyte. In most cases, there is a gradient porosity electrode, where the porosity is greater on one side of the electrode, and the side of the electrode is placed at the inlet or outlet of the electrolyte. Taking the electrode shown in fig. 7 as an example, the porosity of the electrode may be, for example, left electrode region 701 < middle electrode region 702 < right electrode region 703, or, for example, middle electrode region 702 < left electrode region 701 < right electrode region 703, the porosity of the right electrode region 703 is larger. Illustratively, if the electrode a is used, the region with a porosity of 96.6% in the electrode a is placed at the liquid inlet or the liquid outlet of the electrolyte. If the electrode B is adopted, the area with the porosity of 96.9 percent in the electrode B is placed at the liquid inlet or the liquid outlet of the electrolyte. If the electrode C is adopted, the area with the porosity of 97 percent in the electrode C is placed at the liquid inlet or the liquid outlet of the electrolyte.
The flow battery provided by the embodiment adopts the electrodes with different porosity in different areas, so that the area of the active reaction area of the electrode in the flow battery is increased, and the concentration polarization phenomenon is reduced, thereby improving the overall performance of the battery system.
Having thus described the basic concept, it should be apparent to those skilled in the art that the foregoing disclosure is by way of example only, and is not intended to limit the present application. Various modifications, improvements and adaptations to the present application may occur to those skilled in the art, although not explicitly described herein. Such modifications, improvements and adaptations are proposed in the present application and thus fall within the spirit and scope of the exemplary embodiments of the present application.
Also, this application uses specific language to describe embodiments of the application. Reference throughout this specification to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with at least one embodiment of the present application is included in at least one embodiment of the present application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, certain features, structures, or characteristics may be combined as suitable in one or more embodiments of the application.
Similarly, it should be noted that in the preceding description of embodiments of the application, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the embodiments. This method of disclosure, however, is not intended to require more features than are expressly recited in the claims. Indeed, the embodiments may be characterized as having less than all of the features of a single embodiment disclosed above.
Where numerals describing the number of components, attributes or the like are used in some embodiments, it is to be understood that such numerals used in the description of the embodiments are modified in some instances by the modifier "about", "approximately" or "substantially". Unless otherwise indicated, "about", "approximately" or "substantially" indicates that the number allows a variation of ± 20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximations that may vary depending upon the desired properties of the individual embodiments. In some embodiments, the numerical parameter should take into account the specified significant digits and employ a general digit preserving approach. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the range are approximations, in the specific examples, such numerical values are set forth as precisely as possible within the scope of the application.
Although the present application has been described with reference to the present specific embodiments, it will be appreciated by those skilled in the art that the above embodiments are merely illustrative of the present application and that various equivalent changes or substitutions may be made without departing from the spirit of the application, and therefore, it is intended that all changes and modifications to the above embodiments within the spirit of the application fall within the scope of the claims of the application.
Claims (9)
1. A method of preparing an electrode, comprising:
putting a porous fiber felt into a high-temperature furnace cavity, wherein the high-temperature furnace is provided with a plurality of temperature zones, and each temperature zone can independently control the temperature;
discharging oxygen in the high-temperature furnace;
heating the porous fiber felt from the same initial temperature at different heating rates in each temperature zone until the temperature of the porous fiber felt reaches a first carbonization temperature, and preserving heat at the first carbonization temperature; wherein the heating rate of each temperature zone is 1-15 ℃/min, the difference of the heating rates of two adjacent temperature zones is not more than 5 ℃/min, the first carbonization temperature is 260-750 ℃, and the heat preservation time of the first carbonization temperature is 15-300 min;
heating the porous fiber felt from the first carbonization temperature in various temperature zones at different heating rates until the temperature of the porous fiber felt reaches a second carbonization temperature, and preserving the heat at the second carbonization temperature; wherein the heating rate of each temperature zone is 2-20 ℃/min, the difference of the heating rates of two adjacent temperature zones is not more than 5 ℃/min, the second carbonization temperature is 1000-1700 ℃, and the heat preservation time of the second carbonization temperature is 60-300 min;
reducing the porous fiber mat from the second carbonization temperature to room temperature.
2. The method of claim 1, wherein the porous fiber mat comprises a pre-oxidized fiber mat.
3. The method of claim 2, wherein the pre-oxidized fiber mat comprises a polyacrylonitrile-based pre-oxidized fiber mat and a viscose-based fiber mat.
4. The electrode preparation method of claim 1, wherein discharging the oxygen gas in the high temperature furnace comprises: the high temperature furnace is evacuated and backfilled with an inert gas.
5. The method for preparing an electrode according to claim 1, wherein the first carbonization temperature is 600 to 700 ℃ and the holding time at the first carbonization temperature is 30 to 200 minutes.
6. The method for preparing an electrode according to claim 1, wherein the second carbonization temperature is 1400 to 1650 ℃, and the holding time of the second carbonization temperature is 120 to 180 minutes.
7. An electrode prepared by the electrode preparation method according to any one of claims 1 to 6, wherein the electrode comprises: the electrode comprises a left electrode area (701), a middle electrode area (702) and a right electrode area (703), wherein the porosity of the left electrode area (701) is 86.7% -92.7%, the porosity of the middle electrode area (702) is 87.5% -93%, and the porosity of the right electrode area (703) is 93% -97%.
8. A flow battery, comprising the electrode of claim 7.
9. The flow battery of claim 8, wherein the region of maximum porosity of the electrode in the flow battery is positioned at an inlet or an outlet of the electrolyte.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211072336.XA CN115275226B (en) | 2022-09-02 | 2022-09-02 | Electrode preparation method, electrode and flow battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211072336.XA CN115275226B (en) | 2022-09-02 | 2022-09-02 | Electrode preparation method, electrode and flow battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115275226A CN115275226A (en) | 2022-11-01 |
| CN115275226B true CN115275226B (en) | 2023-04-11 |
Family
ID=83755557
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211072336.XA Active CN115275226B (en) | 2022-09-02 | 2022-09-02 | Electrode preparation method, electrode and flow battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115275226B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116072890B (en) * | 2022-12-06 | 2023-09-19 | 寰泰储能科技股份有限公司 | Preparation method and system of carbon felt electrode with runner |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103151537A (en) * | 2013-03-20 | 2013-06-12 | 辽宁金谷炭材料股份有限公司 | Production method of graphite felt for vanadium cell |
| CN105762369A (en) * | 2014-12-16 | 2016-07-13 | 中国科学院大连化学物理研究所 | All-vanadium flow battery porous carbon fiber felt electrode material and preparation and application thereof |
| CN108878900A (en) * | 2018-06-20 | 2018-11-23 | 湖南国昶能源科技有限公司 | A kind of preparation method of the modified carbon felt of nitrogen-doped graphene |
| WO2019089926A1 (en) * | 2017-11-01 | 2019-05-09 | University Of Virginia Patent Foundation | Sintered electrode cells for high energy density batteries and related methods thereof |
| CN110718708A (en) * | 2019-09-11 | 2020-01-21 | 浙江大学 | Variable porosity electrode structure flow battery capable of improving battery efficiency |
| CN113054203A (en) * | 2021-03-17 | 2021-06-29 | 电子科技大学 | Graphite felt electrode for all-vanadium redox flow battery and modification method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3601581B2 (en) * | 1999-06-11 | 2004-12-15 | 東洋紡績株式会社 | Carbon electrode material for vanadium redox flow battery |
-
2022
- 2022-09-02 CN CN202211072336.XA patent/CN115275226B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103151537A (en) * | 2013-03-20 | 2013-06-12 | 辽宁金谷炭材料股份有限公司 | Production method of graphite felt for vanadium cell |
| CN105762369A (en) * | 2014-12-16 | 2016-07-13 | 中国科学院大连化学物理研究所 | All-vanadium flow battery porous carbon fiber felt electrode material and preparation and application thereof |
| WO2019089926A1 (en) * | 2017-11-01 | 2019-05-09 | University Of Virginia Patent Foundation | Sintered electrode cells for high energy density batteries and related methods thereof |
| CN108878900A (en) * | 2018-06-20 | 2018-11-23 | 湖南国昶能源科技有限公司 | A kind of preparation method of the modified carbon felt of nitrogen-doped graphene |
| CN110718708A (en) * | 2019-09-11 | 2020-01-21 | 浙江大学 | Variable porosity electrode structure flow battery capable of improving battery efficiency |
| CN113054203A (en) * | 2021-03-17 | 2021-06-29 | 电子科技大学 | Graphite felt electrode for all-vanadium redox flow battery and modification method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115275226A (en) | 2022-11-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN115275226B (en) | Electrode preparation method, electrode and flow battery | |
| CN114436237B (en) | Hard carbon material and preparation method and application thereof | |
| CN109950547B (en) | Three-dimensional current collector decorated with non-noble metal coating | |
| CN109802129B (en) | Metal sodium battery negative electrode material and preparation method and application thereof | |
| CN114988390A (en) | Preparation method of porous hard carbon material of sodium ion battery, product and application thereof | |
| CN108832081B (en) | Preparation method of composite lithium metal cathode for enabling lithium metal to grow transversely | |
| CN109244374B (en) | Three-dimensional porous lithium metal composite negative electrode material, and preparation method and application thereof | |
| CN110048124A (en) | A kind of polysulfide barrier layer and preparation method thereof for lithium-sulfur cell | |
| CN115036480B (en) | Lithium-sulfur battery positive electrode material, preparation method thereof and lithium-sulfur battery | |
| CN114127986B (en) | Negative pole piece, electrochemical device and electronic device | |
| CN116247203A (en) | High-capacity sodium ion battery anode material, preparation method thereof and battery | |
| CN117558881B (en) | Nickel oxide modified carbon cloth, preparation method and application thereof, and nickel/carbon cloth metal lithium composite negative electrode | |
| US9847520B1 (en) | Thermal processing of interconnects | |
| KR101250259B1 (en) | Fabrication method of the electrolyte-impregnated metal electrode for molten carbonate fuel cells | |
| CN114628635B (en) | Lithium metal battery negative electrode and manufacturing method thereof | |
| CN115763774A (en) | Poor lithium composite negative electrode material and preparation method thereof | |
| CN116864706A (en) | Flow battery double-scale electrode based on infrared laser perforation and preparation method | |
| CN117525299A (en) | Surface dendrite-free lithium anode material, battery and preparation method | |
| CN116826050A (en) | Tin/graphene anode material, preparation method thereof and sodium metal battery | |
| CN116799169A (en) | Carbon-silicon composite material, preparation method and application thereof, lithium battery cathode and lithium battery | |
| CN114335696A (en) | Membrane electrode integrated structure, preparation method and application | |
| CN116936751A (en) | Ultrathin high-efficiency graphene composite membrane-based lithium carrier and application of lithium metal battery thereof | |
| CN113140738A (en) | Gas diffusion layer, preparation method thereof, corresponding membrane electrode assembly and fuel cell | |
| CN117819509A (en) | Preparation method of porous carbon coated lithium iron phosphate positive electrode active material | |
| CN116845333A (en) | All-solid-state thin-film lithium ion battery and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |