System and method for measuring free ionomer content of high-solid-content catalyst slurry of fuel cell

Abstract

The invention relates to a system and a method for measuring the content of free ionomers in high-solid-content catalyst slurry of a fuel cell, and belongs to the technical field of analysis of catalyst slurry of the fuel cell. Separating the catalyst slurry into a supernatant containing free ionomers and a catalyst aggregate precipitate; the filtering device is used for filtering the supernate and removing residual solid particles in the supernate to obtain filtrate; the evaporation device is used for carrying out drying treatment on the filtrate obtained after filtration, and completely evaporating solvent components in the liquid to obtain free ionomer solids; and the weighing device is used for accurately weighing the materials in the centrifuging, filtering and drying processes. Compared with the prior art, the system and the method for measuring the content of the free ionomer in the catalyst slurry of the fuel cell, which are provided by the invention, are accurate in measurement result and wide in applicability through the processes of centrifuging, filtering and drying and accurate weighing.

Description

Technical Field

[0001] This invention relates to the field of fuel cell catalyst slurry analysis technology, and in particular to a system and method for measuring the free ionomer content of high solids content fuel cell catalyst slurry. Background Technology

[0002] The catalyst layer (CL) is one of the core components of a proton exchange membrane fuel cell (PEMFC), serving as the site of electrochemical reactions. Its structure and composition significantly influence the cell's performance, lifespan, and cost. The catalyst layer is typically prepared by coating and drying a catalyst slurry, which mainly consists of three components: a catalyst, used to catalyze the electrochemical reaction of hydrogen and oxygen; an ionomer, acting as a binder and forming proton transport channels; and a dispersant, usually a mixture of water and alcohol solvents, which disperses solid particles, regulates the slurry's rheology, and forms a porous structure during drying. The morphology and distribution of the ionomer are key factors determining the microstructure and performance of the catalyst layer.

[0003] In catalyst slurries, ionomers exist in two forms: adsorbed states on the surface of catalyst particles and free states dispersed in the solvent. These two forms directly affect the formation of the ionomer network in the final catalyst layer during the drying process. Currently, research on the distribution of ionomer morphologies in slurries and their evolution during drying is insufficient, largely due to the lack of effective and precise characterization methods to distinguish and measure the content of adsorbed and free ionomers.

[0004] In existing technologies, filtration methods based on syringe filters are commonly used to measure the content of free ionomers. However, this method has significant limitations: First, it is only applicable to systems where the size difference between catalyst particles and ionomer clusters is significant. With the widespread application of nanoscale catalyst support materials and the improvement of dispersion technology, the overlap in their size ranges has increased, resulting in poor separation performance of traditional filtration methods. Second, due to the limited volume of the filter, the sample volume processed each time is small, which is insufficient for high-solids content slurries and introduces a large random error. Third, measurement deviations are easily caused by clogging, adsorption, and other factors during operation.

[0005] Therefore, developing a method applicable to various high-solids-content catalyst slurries and capable of accurately measuring the content of free ionomers is of great practical significance for gaining a deeper understanding of the role of ionomer morphology, optimizing slurry formulation and drying processes, and thus improving fuel cell performance. Summary of the Invention

[0006] The purpose of this invention is to overcome the deficiencies of the prior art by providing a system and method for measuring the free ionomer content of fuel cell catalyst slurry with high solids content. Through centrifugation, filtration, drying, and precise weighing, this invention provides a system and method for measuring the free ionomer content of fuel cell catalyst slurry with accurate measurement results and wide applicability.

[0007] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides a system for measuring the free ionomer content of high-solids catalyst slurry for fuel cells, the system comprising: Centrifuge device is used to centrifuge the catalyst slurry to separate the catalyst slurry into a supernatant containing free ionomers and a catalyst agglomerate precipitate, thereby achieving the initial separation of agglomerate particles from the supernatant containing free ionomers; A filtration device is used to finely filter the supernatant (the supernatant after centrifugation) to completely remove residual solid particles (tiny catalyst aggregate particles) in the supernatant, and obtain filtrate. An evaporation apparatus is used to dry the filtrate obtained after filtration, completely evaporating the solvent components (preferably water and alcohol solvents) in the liquid to obtain a pure free ionomer solid. Weighing devices are used to accurately weigh materials (samples) at multiple key stages throughout the process (centrifugation, filtration, and drying).

[0008] Furthermore, the centrifugation device includes a centrifuge and centrifuge tubes; the centrifuge tubes are used in conjunction with the centrifuge; the centrifuge includes a centrifuge disc; the catalyst slurry to be tested is injected into the centrifuge tubes and placed in the centrifuge disc.

[0009] Furthermore, the centrifuge is a high-speed centrifuge.

[0010] Furthermore, the centrifuge's speed, temperature, and time parameters are adjustable, and these parameters must be precisely controllable.

[0011] Furthermore, the filtration device includes a syringe and a syringe filter; the syringe is connected to the syringe filter.

[0012] Furthermore, the syringe filter is a disposable syringe filter.

[0013] Furthermore, the syringe is a needle-type syringe.

[0014] Furthermore, the filter membrane of the filter is made of hydrophilic PTFE material.

[0015] Furthermore, the evaporation apparatus typically includes a vacuum oven.

[0016] Furthermore, the evaporation apparatus also includes a glass evaporating dish.

[0017] Furthermore, the weighing device includes a high-precision electronic balance with an accuracy of not less than 0.1 mg.

[0018] Further, the supernatant of the centrifuged slurry was aspirated using a syringe.

[0019] Furthermore, the syringe is connected to a syringe filter to squeeze and filter the supernatant.

[0020] Furthermore, a glass evaporating dish is connected below the syringe filter to collect the ionomer separation liquid (filtrate).

[0021] A second aspect of the present invention provides a method for measuring the free ionomer content of fuel cell catalyst slurry using the system, comprising the following steps: S1: Prepare catalyst slurry and record the total mass of catalyst slurry and the initial mass fraction of ionomer; S2: Centrifuge the catalyst slurry and collect the supernatant after separation; S3: Mass of the supernatant obtained by measurement; S4: Filter the obtained supernatant and collect the filtrate, which is the solution of the free ionomer after filtration; S5: Dry the filtrate to obtain free ionomer solid, and determine the dry weight of the free ionomer; S6: Calculate the percentage of free ionomers in the catalyst slurry according to the following formula. : in, and These represent the mass of the catalyst slurry used for centrifugation and the mass of the free ionomer solution after filtration, respectively. This represents the mass fraction of ionomers in the catalyst slurry. This represents the mass fraction of ionomers in the filtered solution of free ionomers.

[0022] Furthermore, ionomers include adsorbed ionomers and free ionomers.

[0023] Furthermore, the proportions of adsorbed ionomer A and free ionomer B in the catalyst slurry relative to the total ionomer content are obtained according to equations (1) and (2), respectively. and : in, and These represent the mass of the catalyst slurry used for centrifugation and the mass of the free ionomer solution after filtration, respectively. The mass fraction of ionomers in the catalyst slurry, in units of wt% ; This represents the mass fraction of ionomers in the filtered free ionomer solution, expressed in units of... wt% .

[0024] Furthermore, the aforementioned How to obtain: Accurately measure the mass of catalyst in the catalyst slurry based on the catalyst slurry formulation. Water quality ionomer solution mass The quality of alcohol solvent Combined with the ionomer solids mass fraction (nominal solids content of the ionomer solution) stated on the product nameplate. ,unit wt% And calculated according to equation (3): The mass fraction (initial mass fraction) of ionomers in the catalyst slurry. Calculated using the following formula: in, The mass of the original ionomer solution (the original ionomer solution added to the original slurry). This refers to the nominal solids content of the ionomer solution. , , The quantities are the mass of the catalyst, water (deionized water), and alcohol solvent, respectively.

[0025] Furthermore, the catalyst slurry includes a catalyst and a solvent; the solvent includes deionized water and alcohol.

[0026] Furthermore, the mass fraction of ionomers in the filtered free ionomer solution Calculated using the following formula (4): in, The dry weight of the free ionomer (the dry weight of the free ionomer solution after complete drying).

[0027] Furthermore, all masses were measured using an electronic balance with an accuracy of not less than 0.1 mg.

[0028] Furthermore, the measurement method based on the above system includes the following steps: Sample preparation and initial parameter determination: Accurately prepare catalyst slurry and calculate or measure the initial mass fraction of ionomers in the catalyst slurry according to the formula.

[0029] Centrifugal separation: Place a quantitative amount of catalyst slurry in a centrifuge tube and centrifuge at a specific speed (e.g., 5000~20000 rpm) and temperature for a certain time (e.g., ≥20 min) to fully separate it into supernatant and precipitate (the supernatant containing free ionomers and the catalyst agglomerate precipitate, respectively).

[0030] Supernatant collection and weighing: Carefully aspirate all the supernatant and accurately weigh the supernatant.

[0031] Fine filtration: The supernatant is filtered using a syringe filter, and the filtrate is collected.

[0032] Furthermore, the centrifugation speed range is 5000~20000 rpm, and the centrifugation time is not less than 20 minutes.

[0033] Furthermore, the drying conditions are: vacuum drying at 100~110℃ for 1~3 hours.

[0034] Furthermore, the drying conditions were: vacuum drying at 105°C for 2 hours.

[0035] Compared with the prior art, the present invention has the following technical advantages: 1. This invention provides a system and method for measuring the free ionomer content of high solids content catalyst slurry in fuel cells. It has wide applicability and effectively overcomes the separation problem caused by the similar size of catalyst and ionomer in traditional methods through centrifugal pretreatment. It can be applied to various high solids content catalyst slurry systems.

[0036] 2. This invention provides a system and method for measuring the free ionomer content of high-solids catalyst slurry in fuel cells. The system has high measurement accuracy, and the centrifugation process can handle a larger number of samples, improving the representativeness and accuracy of sampling. Combined with high-precision weighing, it significantly reduces measurement errors.

[0037] 3. This invention provides a system and method for measuring the free ionomer content of high solids catalyst slurry in fuel cells. It is highly operable, has a clear process, standardized steps, and is easy to repeat and implement in the laboratory.

[0038] 4. This invention provides a system and method for measuring the free ionomer content in high-solids-content catalyst slurry for fuel cells. It has high value for mechanistic research and provides a reliable and accurate analytical tool for in-depth research in this field on the adsorption / free equilibrium of ionomers in catalyst slurry, their morphological transformation during the drying process, and their impact on the performance of the catalyst layer. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a system for measuring the free ionomer content of a high-solids-content catalyst slurry for fuel cells according to the present invention. Figure 2This is a graph showing the change in solid content of the free ionomer solution after centrifugation for 30 minutes and filtration as a function of centrifuge speed in Example 2. Figure 3 The graph shows the change in the solid content of the free ionomer solution after filtration at a centrifuge speed of 20,000 rpm in Example 3 as a function of centrifugation time.

[0040] Figure reference numerals: 1. Catalyst slurry to be tested; 2. Centrifuge device; 21. Centrifuge; 211. Centrifuge lid; 212. Centrifuge tray; 213. Centrifuge tube placement groove; 214. Centrifuge function display screen; 215. Centrifuge function keys; 216. Centrifuge parameter setting knob; 22. Centrifuge tube; 3. Supernatant; 4. Catalyst agglomerate precipitate; 5. Filtration device; 51. Syringe; 52. Syringe filter; 521. Hydrophilic PTFE filter membrane; 54. Filtered free ionomer solution; 6. Evaporation device; 61. Glass evaporating dish; 62. Vacuum oven; 621. Pressure display panel; 622. Oven parameter setting and display interface; 623. Oven switch; 624. Vacuum valve switch; 625. Oven door; 7. Weighing device; 71. Weighing tray; 72. Data display interface; 73. Balance operation button. Detailed Implementation

[0041] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection achieved by screw fastening, welding, or cooperation with a seal; they can also refer to a direct or indirect connection between components, or an interaction relationship achieved through other elements; they can be a fixed connection, a detachable connection, or an integral part; they can be a mechanical connection or an electrical connection; they can be a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction relationship between two components; "upper," "lower," "left," "right," etc., are only used to indicate relative positional relationships, and the relative positional relationship may change when the absolute position of the described object changes. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0043] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as limiting their quantity, order, priority, or importance. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0044] Example 1 This embodiment provides a system for measuring the free ionomer content of high-solids catalyst slurry in fuel cells, the structure of which is as follows: Figure 1 As shown.

[0045] In this embodiment, the fuel cell high solids catalyst slurry free ionomer content measurement system includes: Centrifuge device 2: Used to achieve primary separation of agglomerated particles and free ionomers in the catalyst slurry 1 to be tested, separating the catalyst slurry 1 into a supernatant 3 containing free ionomers and a catalyst agglomerated precipitate 4. Centrifuge device 2 includes a centrifuge 21 and matching centrifuge tubes 22. Centrifuge 21 is a high-speed centrifuge. Centrifuge 21 is equipped with a centrifuge cover 211, a centrifuge tray 212, a centrifuge tube placement groove 213, a centrifuge function display screen 214, centrifuge function keys 215, and a centrifuge parameter setting knob 216, which can realize precise control of speed, time, and temperature.

[0046] Filtration device 5: Used for fine filtration of the supernatant 3 (supernatant after centrifugation) to remove residual fine particles and obtain filtrate, which is the filtered free ionomer solution 54. The filtration device 5 includes a syringe 51, a syringe filter 52 (with a built-in hydrophilic PTFE filter membrane 521), and a glass evaporating dish 61 for receiving the filtrate.

[0047] Evaporation apparatus 6: Used to completely remove solvent from the filtrate. This apparatus includes a glass evaporating dish 61 and a vacuum oven 62. The vacuum oven 62 is equipped with a pressure display panel 621, an oven parameter setting and display interface 622, an oven switch 623, a vacuum valve switch 624, and an oven door 625.

[0048] Weighing device 7: An electronic balance with an accuracy of 0.1 mg, including a weighing tray 71, a data display interface 72 and balance operation buttons 73, used for precise mass measurement at each stage of the entire process.

[0049] Its workflow is as follows: The catalyst slurry 1 to be tested is injected into centrifuge tubes 22 and placed symmetrically in the centrifuge tube placement grooves 213 of centrifuge 21. After setting the centrifugation parameters, the centrifugation program is started. After centrifugation, the catalyst slurry 1 to be tested separates into a supernatant 3 rich in free ionomers and a catalyst agglomerate precipitate 4. All the supernatant 3 is drawn up with a syringe 51 and filtered through a syringe filter 52. The filtrate (the filtered free ionomer solution 54) is collected in a glass evaporating dish 61. The glass evaporating dish 61 is then placed in a vacuum oven 62 to dry to constant weight, and the mass of the material at each stage is weighed using a weighing device 7.

[0050] Example 2 This embodiment provides a method for measuring the free ionomer content of high-solids catalyst slurry for fuel cells. It is implemented according to the free ionomer content measurement system for high-solids catalyst slurry for fuel cells provided in Embodiment 1. By measuring the mass of the sample before and after centrifugation, filtration, and evaporation (drying), the solid content of ionomers in the catalyst slurry and the solid content of the filtrate are calculated, and then the proportion of adsorbed ionomers and free ionomers in the catalyst slurry is accurately calculated.

[0051] A measurement system and method for calculating the free ionomer content in high-solids catalyst slurry based on centrifugation-filtration-evaporation (drying) method is proposed. First, centrifugation is used to preliminarily separate most of the agglomerates and free ionomers. Then, a hydrophilic PTFE filter membrane with micropores (hydrophilic PTFE filter membrane 521) is used to filter the remaining catalyst agglomerate particles in the supernatant 3. Finally, all solvents are evaporated to determine the mass of free ionomers, thereby achieving accurate measurement of the content ratio of adsorbed ionomers and free ionomers in high-solids catalyst slurry.

[0052] In this embodiment, the catalyst to be tested (catalyst slurry 1) formulation includes: 4.0062g Pt / catalyst, 9.0030g Nafion solution (ionomer solid content 20%). wt% ), 16.4310g deionized water and 15.2677g n-propanol, the solid content of catalyst slurry 1 to be tested was 12.99% (corresponding to Figure 2 The slurry solids content), I / C ratio (the ratio of the mass of ionomer solids to the mass of carbon in the catalyst) is 0.90, and the water-to-alcohol ratio is 1.00.

[0053] Mass fraction of ionomers in catalyst slurry The ratio of the mass of the ionomer solids to the total mass of the catalyst slurry can be expressed as: Mass fraction of ionomers in the filtered free ionomer solution The dry mass of the free ionomer obtained after drying (dry weight of the free ionomer) With respect to the mass of the filtered free ionomer solution The ratio of can be expressed as: Therefore, the proportion of adsorbed ionomer A and free ionomer B to the total ionomer content... and It can be calculated using the following expression.

[0054] in, and These represent the mass of the catalyst slurry used for centrifugation and the mass of the free ionomer solution after filtration, respectively. The mass fraction of ionomers in the catalyst slurry, in units of wt% ; This represents the mass fraction of ionomers in the filtered free ionomer solution, expressed in units of... wt% .

[0055] For parameters that need to be calculated after weighing, including , and , can be represented as: in, n This refers to the number of centrifuge tubes used in a single centrifugation. ~ Corresponding to Figure 1 The sample mass measured by the electronic balance (weighing device 7) ①~⑥.

[0056] The method for measuring the free ionomer content in high-solids catalyst slurry for fuel cells specifically includes the following steps: (1) System setup: A system for measuring the free ionomer content of high solids catalyst slurry in fuel cells was built according to Example 1; (2) Slurry centrifugation: The prepared slurry (catalyst slurry 1 to be tested) was injected into centrifuge tube 22 using a dropper, and the mass of each centrifuge tube 22 before and after was weighed. The mass was then calculated. Centrifuge tubes 22 are placed symmetrically in the centrifuge tube placement grooves 213 of centrifuge 21. The centrifuge speed of centrifuge 21 is set to 5000, 10000, 12500, 15000, 17500 and 20000 revolutions per minute respectively. The centrifugation time is uniformly 30 minutes and the centrifugation temperature is 20℃. (3) Filtration of supernatant: Use syringe 51 to draw supernatant 3, connect syringe 51 to syringe filter 52, squeeze syringe 52 to filter supernatant 3, inject the filtrate (free ionomer solution 54 after filtration) into glass evaporating dish, and weigh the mass of filtrate. .

[0057] (4) Evaporation of filtrate: Place the filtered solvent (filtrate) into a vacuum oven to evaporate the water and alcohol solvent. Set the oven temperature to 105℃ and the evaporation time to 2h. Weigh the dry mass of the free ionomer (dry weight of free ionomer). .

[0058] (5) Content Calculation: The mass fraction of ionomers in the slurry and filtrate is calculated by weighing (corresponding to the solid content of ionomers in the slurry calculated in formula (1), respectively). Figure 3 The solid content of the filtered liquid is calculated, and then the proportion of adsorbed ionomers and free ionomers to the total ionomer content is calculated.

[0059] like Figure 2 The graph shows the change in the mass fraction of ionomers in the filtrate as a function of centrifuge speed after 30 minutes of centrifugation. The mass fraction of ionomers in the filtrate initially decreases rapidly with increasing speed, but after 12,500 rpm, the mass fraction of ionomers shows almost no change. Therefore, setting the centrifuge speed to 15,000 rpm can achieve the ideal centrifugation effect.

[0060] Example 3 This embodiment provides a method for measuring the free ionomer content of a high-solids-content catalyst slurry for fuel cells. The difference from Embodiment 2 is that the solids content of the original slurry (catalyst slurry 1 to be tested) is [not specified in the original text]. Figure 3 The slurry solid content is 15%. In step (2), the centrifuge speed is fixed at 20,000 revolutions per minute, the centrifugation time is set in gradient, and the other steps are the same as in Example 2.

[0061] like Figure 3 The graph shows the change in solid content in the filtrate (corresponding to the solid content of the filtrate in the figure) with centrifugation time when the centrifuge speed is 20,000 rpm. The trend of the test results is the same as in Example 2. As the centrifugation time increases, the solid content of the filtrate first decreases rapidly, and then after 20 minutes of centrifugation, the solid content of the filtrate remains almost unchanged. Setting the centrifugation time to 30 minutes can achieve the ideal centrifugation effect.

[0062] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A system for measuring the free ionomer content of high-solids catalyst slurry for fuel cells, characterized in that, The system includes: Centrifuge device is used to centrifuge the catalyst slurry to separate the catalyst slurry into a supernatant containing free ionized polymers and a catalyst agglomerate precipitate. A filtration device is used to filter the supernatant to remove residual solid particles from the supernatant and obtain filtrate. An evaporation apparatus is used to dry the filtrate obtained after filtration, completely evaporating the solvent components in the liquid to obtain a free ionomer solid. Weighing devices are used to accurately weigh materials during centrifugation, filtration, and drying processes.

2. The system for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 1, characterized in that, The centrifugation device includes a centrifuge and centrifuge tubes; The centrifuge tubes are used in conjunction with the centrifuge. The centrifuge includes a centrifuge disc.

3. The system for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 1, characterized in that, The filtration device includes a syringe and a needle-type filter; The syringe is connected to a syringe filter; The filter membrane is made of hydrophilic PTFE material.

4. The system for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 1, characterized in that, The evaporation apparatus includes a vacuum oven.

5. The system for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 1, characterized in that, The weighing device includes an electronic balance with an accuracy of not less than 0.1 mg.

6. A method for measuring the free ionomer content of fuel cell catalyst slurry using the system described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Prepare catalyst slurry and record the total mass of catalyst slurry and the initial mass fraction of ionomer; S2: Centrifuge the catalyst slurry and collect the supernatant after separation; S3: Mass of the supernatant obtained by measurement; S4: Filter the obtained supernatant and collect the filtrate, which is the solution of the free ionomer after filtration; S5: Dry the filtrate to obtain free ionomer solid, and determine the dry weight of the free ionomer; S6: Calculate the percentage of free ionomers in the catalyst slurry according to the following formula. : in, and These represent the mass of the catalyst slurry used for centrifugation and the mass of the free ionomer solution after filtration, respectively. This represents the mass fraction of ionomers in the catalyst slurry. This represents the mass fraction of ionomers in the filtered solution of free ionomers.

7. The method for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 6, characterized in that, The mass fraction of ionomers in the catalyst slurry Calculated using the following formula: in, This refers to the original mass of the ionomer solution. This refers to the nominal solids content of the ionomer solution. , , The quantities are respectively the mass of the catalyst, water, and alcohol solvent; The catalyst slurry includes a catalyst and a solvent; The solvents include water and alcohol.

8. The method for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 6, characterized in that, The mass fraction of ionomers in the filtered free ionomer solution Calculated using the following formula: in, The dry weight of free aggregates.

9. The method for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 6, characterized in that, The centrifugation speed range is 5000~20000 rpm, and the centrifugation time is not less than 20 minutes.

10. The method for measuring the free ionomer content of a high-solids catalyst slurry for fuel cells according to claim 6, characterized in that, The drying conditions are: vacuum drying at 100~110℃ for 1~3 hours.

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