KR101392230B1 - Membrane electrode assembly including polymer binder and alkaline membrane fuel cell comprising the same - Google Patents

Abstract

The present invention relates to a membrane electrode assembly including a polymer binder and an alkaline membrane fuel cell including the same, and more particularly, to a membrane electrode assembly including a cathode catalyst layer; An anode catalyst layer; And a pore-filling membrane disposed between the cathode catalyst layer and the anode catalyst layer, wherein the catalyst layer comprises a polymeric binder of the same material as the base of the pore-filling membrane, and a membrane electrode assembly To an alkali membrane fuel cell.
According to the present invention, it is possible to effectively solve problems such as poor durability often observed in alkaline fuel cells developed to solve the problems of conventional polymer fuel cells, a problem of bonding of an electrolyte membrane and an electrode layer, a mechanical strength problem, and difficulty in application of a continuous production process And an alkaline membrane fuel cell including the membrane electrode assembly.

Description

TECHNICAL FIELD The present invention relates to a membrane electrode assembly including a polymer binder and an alkaline membrane fuel cell including the membrane electrode assembly,

The present invention relates to a membrane electrode assembly employing a pore-filled membrane and an alkaline membrane fuel cell comprising the membrane electrode assembly.

Polymer electrolyte fuel cells (PEFCs) have attracted much attention as a promising alternative energy conversion device due to their high power density and environmental friendliness. However, due to the slow reaction rate characteristic of Oxygen Reduction Reaction (ORR) A noble metal catalyst, generally a platinum catalyst, should be used on the cathode side. Therefore, many groups are attempting to reduce the amount of supported platinum on the catalyst, or to apply new non-platinum, even non-noble metal catalysts. Alkaline Membrane Fuel Cells (AMFCs) have been used as catalysts for transition metal catalysts (K. Sawai, N. Suzuki, Highly active nonplatinum catalyst for air cathodes, J. Electrochem. Soc., 2004, 151 (12): 2132-2137; C. Coutanceau, L. Demarconnay, C. Lamy, J.-M. Le'ger, Development of electrocatalysts for solid alkaline fuel cell (SAFC), J. Power Sources 2006; 156 (1): 14-19; JR Varcoe , RCT Slade. Prospects for alkaline anion-exchange membranes in low temperature fuel cells, Fuel Cells 2005; 5 (2): 187-200) and hydrocarbon anion-exchange membranes (EH Yu, K. Scott. cells using anion exchange membranes. J Power Sources 2004; 137 (2): 248-256), which has the potential to provide advantages over PEFC. Replacing Nafion with a hydrocarbon-based electrolyte membrane and employing low-cost catalysts is very significant in promoting fuel cell commercialization.

Recently, this approach has attracted much attention in AMFC (EH Yu, K. Scott.) Development of direct methanol alkaline fuel cells using anion exchange membranes. J Power Sources 2004; 137 (2): 248-256; Jin-Soo Park J Seung-Hee Park, Sung-Dae Yim, Young-Gi Yoon, Won-Yong Lee and Chang-Soo Kim J Power Sources 2008; 178 (2): 620- 626; M. Piana, M. Boccia, A. Filpi, E. Flammia, H. Miller, M. Orsini, F. Salusti, S. Santiccioli, F. Ciardelli, A. Pucci, H2 / air alkaline membrane fuel cell performance and durability, using novel ionomer and non-platinum group metal cathode catalyst. J Power Sources 2010; 195 (18): 5875-5881). However, the durability of a fuel cell using a hydrocarbon membrane is difficult to overcome in a PEMFC. This is also true for AMFC, especially when hydrocarbon ionomers are used.

(Wilson, S. Gottesfeld, Thin-film catalyst layers for fuel cell electrodes, J. Appl. Electrochem. 1992; 22 (1): 1-7; SC), which significantly contribute to the improvement of performance and durability Thomas, X. Ren, S. Gottesfeld, Influence of ionomer content in catalyst layers on direct methanol fuel cell performance, J. Electrochem. Soc 1999: 146 (12): 4354-4359; ZX Liang, TS Zhao, J. Prabhuram Unlike the A glue method for fabricating membrane electrode assemblies for direct methanol fuel cells (Electrochim. Acta 2006; 51 (28): 6412-6418), the AMFC ionomer provides contact between the electrode layer and the catalyst in the membrane or electrode layer It is difficult to maintain easily. Bunazawa et al. (H. Bunazawa, Y. Yamazaki, Influence of anionic ionomer content and silver cathode catalyst on the performance of alkaline membrane electrode assemblies (MEAs) for direct methanol fuel cells (DMFCs) J. Power Sources 2008; 182 (1) : 48-51) evaluated Tokuyama's A3 anion-conducting ionomer and estimated the effect of its content in the anode and cathode catalyst layers in alkaline direct methanol fuel cells (DMFCs). They found that the optimum A3 binder content in both catalyst layers was 45.4 wt%. In addition, Li (YS Li, TS Zhao, ZX Liang, J Power Sources 2009; 190 (2): 223-229), an alkaline direct ethanol fuel cell The effect of the polymer binder in the anode catalyst layer was reported. They compared the A3 binder with the hydrophobic PTFE binder and found that the anode containing 10 wt% of the A3 ionomer exhibited the best MEA performance. In both cases, the A3 ionomer was expressed as a binder, but actually improved its performance by acting as a hydroxide ion pathway rather than acting as a binder. Also, both cases are the result of liquid-fuel AMFC. When hydrogen was used as the fuel, some studies focused only on optimization of ionomer content (M. Piana, M. Boccia, A. Filpi, E. Flammia, H. Miller, M. Orsini, F. Salusti, S. et al. Santiccioli, F. Ciardelli, A. Pucci, H2 / air alkaline membrane fuel cell performance and durability, using novel ionomers and non-platinum group metal cathode catalysts. J Power Sources 2010; 195 (18): 5875-5881; , Y. Yamazaki. Influence of anionic ionomer content and silver cathode catalyst on the performance of alkaline membrane electrode assemblies (MEAs) for direct methanol fuel cells (DMFCs) J. Power Sources 2008; 182 (1): 48-51; A Filpi, M. Boccia, and HA Gasteiger, Pt-free cathode catalyst performance in H2 / O2 anion exchange membrane fuel cells (AMFCs), ECS Trans., 16 (2): 1835). However, in the production of the electrodes of AMFC, the commercial anion-conducting ionomer is not sufficient to effectively combine the catalyst particles with the catalyst layer and the catalyst particles, resulting in rapid performance reduction and low durability.

Thus, in order to improve the mechanical properties and minimize membrane swelling and methanol permeation, pore-filled membranes in hydrocarbon membranes have been developed and applied in place of the universal cast hydrocarbon membranes in PEMFC and DMFC (T. Yamaguchi, H. et al. Zhou, S. Nakazawa, N. Hara. An extremely low methanol crossover and highly durable aromatic pore-filling electrolyte membrane for direct methanol fuel cells, Adv. Mater. 2007; 19 (4): 592-596; J., Phys. Chem., 2009; 113 (14): 4656-4663). ≪ tb > < tb > Due to the mechanical strength of the polymer substrate, the pore-filling membrane has only a number of bonds and no free water under fully humidified conditions. This can limit the swelling of the membrane, and the water bound to such membranes effectively blocks the passage of hydrated fuel (KD Kreuer, SJ Paddison, E. Spohr, M. Schuster. Transport in proton conductors for fuel cell applications: simulations , elementary reactions, and phenomenology. Chem. Rev. 2004; 104 (10): 4637-4678). It has also been reported that pore-filled membranes are an effective way to fabricate anion-exchange membranes for lowering liquid-fuel permeation in AMFCs (H. Jung, K. Fujii, T. Tamaki, H. Ohashi, T. Ito, T J. Membrane Science 2011; 373 (1): 107-111).

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a membrane electrode assembly having improved performance and durability, and particularly improved adhesion between an electrolyte membrane and an electrode layer, and an alkaline membrane fuel cell including the membrane electrode assembly.

In order to solve the first problem,

A cathode catalyst layer;

An anode catalyst layer; And

A membrane electrode assembly disposed between the cathode catalyst layer and the anode catalyst layer, the membrane electrode assembly comprising:

Wherein the catalyst layer comprises a polymeric binder of the same material as the base of the pore-filled membrane.

According to an embodiment of the present invention, the polymer binder may be included in an amount of 5 to 40 parts by weight based on 100 parts by weight of the catalyst layer.

According to another embodiment of the present invention, the polymeric binder may be a polyolefin material.

According to another embodiment of the present invention, the polymeric binder may be at least one material selected from the group consisting of polyethylene, polytetrafluoroethylene, polyimide, polyamideimide, polypropylene and polyfluorinated vinylidene.

According to another embodiment of the present invention, 30 to 70 parts by weight of catalyst may be included based on 100 parts by weight of the catalyst layer.

According to another embodiment of the present invention, the catalyst may be at least one material selected from the group consisting of platinum, palladium, silver and a copper-iron alloy.

In order to achieve the second object of the present invention,

There is provided an alkaline membrane fuel cell including the membrane electrode assembly, the gas diffusion layer, and the bipolar plate according to the present invention.

According to the present invention, it is possible to effectively solve problems such as poor durability often observed in alkaline fuel cells developed to solve the problems of conventional polymer fuel cells, a problem of bonding of an electrolyte membrane and an electrode layer, a mechanical strength problem, and difficulty in application of a continuous production process And an alkaline membrane fuel cell including the membrane electrode assembly.

FIG. 1 shows photographs of a catalyst layer transferred to a pore-filling membrane by the decal method and then observed (FIG. 1A: before transfer; FIG. 1B: after transfer, (Right side)).
2 is a schematic view of an alkaline membrane fuel cell according to the present invention.
3 is a photograph of the surface of the cathode catalyst layer observed after 12 hours of constant voltage operation (Fig. 3A: optical image; Fig. 3B: SEM image).
FIG. 4 is a graph showing H ₂ / air (CO ₂ free) performance curves for membrane electrode assemblies with different ionomer contents (anode loading in all MEAs is 0.5 mg _Pt cm ^-2 and cathode loading is 2.0 mg ₄₀₂₀ cm < ² >, using a self-made pore-filled membrane and a commercial ionomer).
5 is a graph showing the effect of polyethylene binder content in the cathode catalyst layer on cell performance when a porous polyethylene membrane of a porous polyethylene material is used.
6 is a graph showing the effect of polytetrafluoroethylene binder content in the cathode catalyst layer on cell performance when using a porous polyethylene membrane of a porous polyethylene material.
7 is a graph showing the Nyquist plots of the impedance spectra at E _app = 0.6 V _SHE obtained from a battery by adding different amounts of binders in the case of using a porous polyethylene-made pore-filled membrane (Fig. 7 Binder; Fig. 7b: polytetrafluoroethylene binder).
FIG. 8 is a graph showing the battery durability by adding different amounts of binders in the case of using a pore-filled membrane of a porous polyethylene material (FIG. 8A: polyethylene binder; FIG. 8B: polytetrafluoroethylene binder).
9 is a photograph showing a result of transferring a catalyst layer to a pore-filling membrane by a decal method when a porous polyethylene membrane of a porous polyethylene material is used (Fig. 9a: 20 wt% polyethylene binder; Fig. 9b: polytetrafluoro 20% by weight of ethylene binder).

A membrane electrode assembly according to the present invention comprises:

A cathode catalyst layer; An anode catalyst layer; And a pore-filled membrane disposed between the cathode catalyst layer and the anode catalyst layer, wherein the catalyst layer comprises a polymeric binder of the same material as the substrate of the pore-filling membrane.

In the present invention, it has been found that the adhesion between the electrolyte membrane and the electrode layer is easily deteriorated in the conventional alkaline membrane fuel cell, and as a result, the durability of the membrane electrode assembly is lowered. Particularly, as the porous filling polymer membrane, which has been actively researched recently, is filled with an electrolyte, as described in more detail in the following examples, a porous membrane having the same material as that of the polymer membrane By bonding the electrode layers using the polymer binder, it is possible to improve the membrane-electrode bonding force without significantly deteriorating the performance of the membrane electrode assembly. Although the addition of such a polymer binder may inevitably result in a slight decrease in performance, the degree of reduction in performance is much smaller than that in the case of using a binder of a material different from that of the base material of the membrane. In consideration of the durability enhancement effect, .

In particular, the content of the polymer binder to be added is an important factor, and the polymer binder may be contained in an amount of 5 to 40 parts by weight based on 100 parts by weight of the catalyst layer. When the content of the polymer binder is less than 5 parts by weight, it is impossible to improve the durability to a desirable level. As the content of the polymer binder increases, the interface contact resistance and the bonding property can be decreased. However, There is a problem that the performance of the membrane electrode assembly can be reduced to an undesirable level.

The polymer binder to be added may be any polymer binder having the same material as that of the pore-filling membrane. The polymer binder may be, for example, a polyolefin material. Examples of the polymer binder include polyethylene, polytetrafluoroethylene, Amide, polyamideimide, polypropylene, and polyfluorinated vinylidene can be used as the polymer binder.

In addition, in addition to the polymer binder, the content of the catalyst, which is another main component of the catalyst layer, in the catalyst layer may be 30 to 70 parts by weight based on 100 parts by weight of the catalyst layer. If the content of the catalyst is less than 30 parts by weight, the performance of the membrane electrode assembly may deteriorate. If the amount of the catalyst is more than 70 parts by weight, the effect of increasing the performance of the membrane electrode assembly is insignificant, There is a problem in that it is not preferable.

As the catalyst contained in the catalyst layer and transferred to the pore-filling membrane, catalysts commonly used in alkaline membrane fuel cells can be used without limitation, for example, selected from the group consisting of platinum, palladium, silver and copper- May be one or more substances. Likewise, the materials of the cathode and the anode as well as the materials used in conventional alkali membrane fuel cells can be used without limitation.

Meanwhile, the present invention provides an alkaline membrane fuel cell including the membrane electrode assembly, wherein the alkaline membrane fuel cell includes the membrane electrode assembly, the gas diffusion layer, and the bipolar plate according to the present invention.

2 is a schematic diagram of an alkaline membrane fuel cell according to the present invention. 2, the membrane electrode assembly 200 described above is disposed at the center of the fuel cell, a pore filling membrane 210 is disposed at the center of the membrane electrode assembly 200, and an anode catalyst layer 220 And the cathode catalyst layer 230 are bonded to each other. Although not shown in the figure, the membrane 210 is bonded to the anode catalyst layer 220 and the cathode catalyst layer 230, which include a polymeric binder and a catalyst of the same material as the base material of the membrane. The gas diffusion layer 240 is stacked on the opposite surfaces of the electrode layers 220 and 230 that are not in contact with the membrane 210 and a bipolar plate 250 is disposed around the gas diffusion layer 240. During operation of the fuel cell, H ₂ O generated at the anode 220 side passes through the pores of the pore filling membrane 210 and moves toward the cathode 230, and OH ^- generated at the cathode 230 side flows through the pore filling membrane 210 And moves to the anode 220 side.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only illustrative and not intended to limit the scope of the present invention.

EXAMPLE 1 Preparation of Membrane Electrode Assembly

Catalyst HiSPEC 4000 (40 wt% Pt, Vulcan-XC72) from Johnson Matthey using Acta's carbon-based non-platinum catalyst Hypermec 4020 (Cu-Fe / C, 3.5 wt% metal, Vulcan- Was used as an anode, and a commercially available AMFC ionomer was used to prepare a catalyst slurry. PE emulsion (REXAMINE 9159, Prolaxkorea, 35 wt%) or PTFE dispersion (PTFE 30, DuPont, 60 wt%) was added to the catalyst slurry as a binder. These were well dispersed by ultrasonication (Ultra TURRAX, IKA Labortechnik, 10,000 rpm) and dispersed well. Anion-conducting membrane (self-made pore filling membrane using a porous polyethylene base, ionic conductivity 0.043 S / cm, To form a membrane electrode assembly (MEA) (active area: 25 cm < ² >). FIG. 1 shows photographs of the catalytic layer transferred to the pore-filling membrane by the decal method and then observed (FIG. 1A: before transfer; FIG. 1B: after transfer, the catalyst layer was transferred to the membrane electrode (Right side)).

Example 2: Production of a unit cell

A unit cell was assembled using a stainless steel bipolar plate, a Teflon seal, and a gas diffusion layer (10BA, SGL, containing a microporous layer). FIG. 2 is a schematic view of an AMFC unit cell showing a simplified reaction process.

Example 3. Cell performance and durability test

The performance of the MEA was measured at a unit cell test station (Osun Tech.) Under conditions of 100% RH, atmospheric pressure, and 50 캜 while providing H ₂ and CO ₂ -free air. Reaction gases were blown through distilled water and humidified and sent to the test station. The gas flow rate was fixed with 200 sccm H ₂ and 600 sccm CO ₂ -free air. Also, electrochemical impedance spectra were analyzed by high current potentiostat / galvanostat with EIS (/ Z) (HCP-803, Biologic). The durability of the MEA was checked by a continuous constant voltage mode at 0.6 V for 12 hours.

Example 4. Bond strength test

Prior to comparison of the binding effect by the polymer binder, the surface of the cathode catalyst layer was optically irradiated after 12 hours of constant voltage operation as shown in Fig. 3A. Next, the cathode surface was morphologically analyzed in a field emission scanning electron microscope (FE-SEM, S4800, Hitachi) as shown in Fig. 3B. In order to evaluate the binding force between the binder and the pore-filling membrane, a cathode catalyst slurry with or without a 20 wt% binder (PE or PTFE) was coated on PET (polyethylene terephthalate) using a doctor-blade type table coater (Comate 3000 VH, Kibae) (RS21G, SKC Corporation, 100 占 퐉). To confirm the possibility of a hot-compression temperature near the glass temperature, the pore-filled membrane was hot compacted at 130 ° C and 30 bar / cm ² for 5 minutes (2699 benchtop press, Carver). The ionic conductivity of the membrane was measured in a conductivity cell (BT-112, Bekktech). Got a sudden decrease in the hot pressing after ion from 0.03S / cm to 0.0055S / cm conductivity up and hot pressing condition for the fuel cell performance gain was set to ^{50 ℃, 30bar / cm 2,} 5 min. The transfer rates of the cathode layer delivered to the pore-filled membrane were compared with each other.

Evaluation Example 1. H ₂ / air cell performance

As a result of the ionomer content from 20 wt% to 60 wt%, the binderless AMFC MEA showed the best performance at 50 wt% ionomer content as shown in Fig. In order to minimize the influence of the ionomer in the MEA durability test, all the tests were carried out using an MEA in which the ionomer content was kept constant at 50% by weight. The I-V performance of MEAs with different PE or PTFE polymeric binder contents was compared.

As shown in Fig. 5, as the binder content in the catalyst slurry increased, the cell performance continued to decrease. The MEA without PE binder showed the best performance of 118 mA / cm ² at 0.6V. At 10 wt.% And 20 wt.% Binder content the performance was nearly the same (i.e., 70 mA / cm ² at 0.6 V), down to 59% of the initial value. When the 30 wt% binder content was used, the performance drastically decreased from 0.6 V to 39 mA / cm ² , which was 33% of the initial value.

Figure 6 shows the effect of PTFE polymeric binder content in the cathode catalyst layer on unit cell performance. When the PTFE binder was used, the cell performance continued to decrease as the binder content in the catalyst slurry increased. The MEA without binder showed the best performance of 113 mA / cm ² at 0.6V. Unlike in the case of PE binders, the current density of the MEA with 20 wt% binder was significantly reduced from 0.6 V to 42 mA / cm < ² >, which was 35% of the initial value. This is similar to the performance of an MEA containing 30 wt% PE binder. The performance of the MEA containing 30 wt.% PTFE binder sharply decreased from 0.6 V to 15 mA / cm ² , which was 13% of the initial value.

Evaluation example 2. Impedance spectroscopic analysis of MEA

Electrochemical impedance spectra (EIS) are the most widely used techniques for investigating complex electrochemical processes in fuel cells (S. Lee, S. Pyun. Effect of annealing temperature on mixed proton transport and charge transfer -controlled oxygen reduction in gas diffusion electrode, Electrochim. Acta 2007; 52 (23): 6525-6533). The impedance spectrum of an MEA containing or without a binder (e.g., PE or PTFE) was measured at E _app = 0.6 V _SHE . Figure 7 shows the Nyquist plot of the impedance spectrum at E _app = 0.6 V _SHE obtained from the unit cell by adding different binders of different contents. In Fig. 7A, the size of the total arc is substantially the same, except that a 30 wt% PE binder is used. In the case of an MEA using a 20 wt% binder, the first arc representing the contact resistance is smaller than the other cases, and the second arc representing the charge transfer resistance is larger than the other cases. This shows the effect of the PE binder attached to the interface between the pore-filled membrane and the cathode catalyst layer. The third call for diffusion resistance occurred only in the impedance spectrum of the MEA using a 30 wt% PE binder. In this case, the size of the third arc is much larger than the first and second arcs. The added polymeric binder fills the voids in the catalyst bed, thereby negating the positive effect.

Figure 7b shows the Nyquist plot of the impedance spectrum at E _app = 0.6V _SHE obtained from the MEA according to the addition of PTFE binder. Unlike PE binders, the addition of PTFE binders showed little effect in reducing contact resistance, and the overall impedance increased sharply. This is consistent with the performance results of the MEA using PE binders.

Evaluation example 3. Durability test by the constant voltage method

In Figure 8, the relative durability enhancement with the degree of binder addition was compared according to various PE or PTFE binder contents. Durability test was carried out by constant voltage method at 0.6 V for 12 hours.

Figure 8a shows the effect of PE binder in enhancing the durability of the MEA. Without the binder, the performance after constant voltage operation decreased to 85% of the initial value. The addition of 10 wt.% Or 30 wt.% PE binder has little effect on the durability improvement of the MEA, but the best durability results are achieved with a binder content of 20 wt.%. The initial performance was 2/3 of the binderless MEA, but only for the MEA with 20 wt% binder, the current density was only reduced by 47% after 12 hours of the experiment. Also, when 30 wt% PE binder was used, the durability of the MEA was much lower than expected. This result was also consistent with the impedance spectrum of FIG. 7A. Therefore, the optimum PE binder content can be determined from the effects of contact resistance and diffusion resistance. This shows the effect of bonding force between the cathode catalyst layer and the membrane of the PE binder, which is the same material as the base material of the pore-filling membrane. However, in the AMFC using the polymer binder as the additive, a certain performance loss is required. On the other hand, the durability of the MEA does not change with the increase of the PTFE binder content from 0 wt% to 30 wt% as shown in Fig. 8B. Whether with or without PTFE binders, all performance of the MEA has been reduced to more than 80% of its initial value after operation.

Evaluation Example 4. Effect of Binder on Bonding Force Between Cathode and Membrane

Three kinds of catalyst slurries (i.e., binder-free, 20 wt% PE binder and 20 wt% PTFE binder) were coated on the PET film and hot compacted to evaluate the interfacial bonding strength between the cathode layer and the pore-filling membrane. To confirm the possibility of hot compression temperature near the glass temperature, the pore filling membrane was hot compacted at 130 ° C and 30 bar / cm ² for 5 minutes. Due to the rapid decrease in ionic conductivity from 0.03 S / cm to 0.0055 S / cm, only low hot compression temperatures should be used. Therefore, the hot compression temperature was set at 50 占 폚, which is the unit cell operating temperature.

Figure 9 shows the surface state of the coated catalyst layer before and after the hot compacting process when different binders are used. All catalyst layers were uniformly coated by a table coater and transferred via hot compression. It can be seen in Figures 9a and 9b that the interfacial bonding force between the catalyst layer and the electrolyte is highly dependent on the properties of the polymeric binder material. The transfer rate of the cathode layer using a 20 wt% PTFE binder is insufficient to employ a hot pressing process in producing the MEA. On the other hand, the catalyst layer using the PE binder was completely transferred to the pore-filling membrane. This means that the same material as the substrate of the pore-filled membrane is more effective as a binder capable of enhancing the interfacial bonding force than other binders such as PTFE.

As can be seen from the results of the examples and the evaluation examples, the durability of the alkaline membrane fuel cell using the pore-filled membrane can be improved by adding the polymer binder to the non-platinum cathode layer.

As a result of evaluating the polymer binder solution of two kinds of PE emulsion and PTFE dispersion, the AMFC MEA without the polymer binder showed the best performance at an ionomer content of 50% by weight. As the binder content in the catalyst slurry increased, Battery performance was significantly reduced, especially for PTFE binders.

In the case of the MEA using the binder (PE or PTFE) and the MEA without the binder, the impedance spectroscopy was measured at E _app = 0.6 V _SHE . As a result, in the case of the MEA using the 20 wt% PE binder, Arcs were less than other cases. This is due to the effect of the PE binder attached to the interface between the pore-filled membrane and the cathode catalyst layer. Unlike PE binders, the addition of PTFE binders showed little effect on the reduction of contact resistance, and the overall impedance increased sharply.

On the other hand, when the durability test was carried out at 0.6 V for 12 hours by the constant-voltage method, the initial performance was 2/3 of the binder-free MEA, but the best durability results were achieved at 20 wt% binder content. The optimum PE binder content can be determined from the effects of contact resistance and charge transfer resistance. This shows the bonding effect between the cathode catalyst and the membrane of the PE binder, which is the same material as the base material of the pore-filling membrane, but the loss of certain partial performance in the AMFC using the polymer binder as an additive should be avoided. On the other hand, the durability of the MEA did not change with the increase of PTFE binder content from 0 wt% to 30 wt%.

In addition, the effect of the binder on the bondability between the cathode and the membrane was evaluated through the hot compression test. Unlike the case of using the PTFE binder, the catalyst layer using the PE binder was completely packed with the pore- .

Claims (11)

delete delete delete delete delete delete A cathode catalyst layer;
An anode catalyst layer; And
And a pore-filling membrane disposed between the cathode catalyst layer and the anode catalyst layer, wherein the catalyst layer comprises a polymer binder having the same material as that of the base of the pore-filling membrane, in an amount of 5 to 40 parts by weight A membrane electrode assembly including a membrane electrode assembly
An alkaline membrane fuel cell comprising a gas diffusion layer and a bipolar plate. The alkaline membrane fuel cell of claim 7, wherein the polymeric binder is a polyolefin material. The alkaline membrane fuel cell according to claim 7, wherein the polymer binder is at least one material selected from the group consisting of polyethylene, polytetrafluoroethylene, polyimide, polyamideimide, polypropylene and polyfluorinated vinylidene. . The alkaline membrane fuel cell according to claim 7, wherein the catalyst comprises 30 to 70 parts by weight of catalyst based on 100 parts by weight of the catalyst layer. 11. The alkaline membrane fuel cell of claim 10, wherein the catalyst is at least one material selected from the group consisting of platinum, palladium, silver and a copper-iron alloy.

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