JP2013089404A - Passive type fuel cell and liquid fuel supply member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a passive type fuel cell capable of improving power generation characteristics and power generation characteristics when liquid fuel is recharged, and a liquid fuel supply member.SOLUTION: A passive type fuel cell 100 includes: a membrane electrode assembly 110 in which an electrolyte membrane 113 is held between an anode 111 and a cathode 112; and a liquid fuel supply tank 140 for supplying liquid fuel F to the anode 111. The liquid fuel supply tank 140 has a porous membrane 141 provided so as to face the anode 111. The liquid fuel F includes a fuel component and an ionic micro gel, and the ionic micro gel has a constitutional unit derived from an ionic monomer and a constitutional unit derived from a nonionic monomer.

Description

  The present invention relates to a passive fuel cell and a liquid fuel supply member.

  In recent years, fuel cells have attracted attention as energy generators with high power generation efficiency and low environmental load. The basic principle of a fuel cell is the reverse reaction of water electrolysis, which does not involve combustion. For this reason, no harmful substances such as nitrogen oxides are generated, and carbon dioxide is generated when energy is extracted from fuel other than hydrogen, but the generation amount is suppressed as compared with an internal combustion engine. In addition, since chemical energy is directly converted into electrical energy, energy loss in the conversion process is small and power generation efficiency is high. Since the fuel cell has a simple device configuration by combining the anode, cathode and electrolyte membrane, it does not require a special power source and can be made compact. It can be used not only for stationary distributed power sources but also for power sources for vehicles, etc. Recently, research on practical application has been widely conducted as a power source for mobile devices.

A direct methanol fuel cell (DMFC) is known as a fuel cell in which liquid fuel such as aqueous methanol solution is supplied to the anode for oxidation and oxygen is supplied to the cathode for reduction. The direct methanol fuel cell has an anode, reaction formula CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻ (1)
As shown, the methanol reacts with water to give hydrogen ions and electrons. On the other hand, at the cathode, the reaction formula O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O (2)
As shown, protons and electrons are consumed. At this time, protons permeate the electrolyte membrane, and electrons move through the external circuit, whereby electric energy can be obtained.

  However, the direct methanol fuel cell has a problem that methanol crossover occurs in which methanol permeates the electrolyte membrane and moves to the cathode.

  Patent Document 1 discloses a liquid fuel for a fuel cell containing a fuel component and an ionic microgel. At this time, the ionic microgel has a structural unit derived from an ionic monomer and a structural unit derived from a nonionic monomer.

  However, it is desired to further improve the power generation characteristics when liquid fuel is applied to a passive fuel cell and the power generation characteristics when liquid fuel is refilled in a passive fuel cell.

Japanese Patent No. 4541277

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide a passive fuel cell and a liquid fuel supply member capable of improving power generation characteristics and power generation characteristics when liquid fuel is refilled. To do.

  The passive fuel cell of the present invention includes a membrane electrode assembly in which an electrolyte membrane is sandwiched between an anode and a cathode, and a liquid fuel supply member that supplies liquid fuel to the anode. The liquid fuel includes a fuel component and an ionic microgel, and the ionic microgel includes a structural unit derived from an ionic monomer and a nonionic monomer. It has a structural unit.

  The liquid fuel supply member of the present invention is a liquid fuel supply member that supplies liquid fuel to an anode of a passive fuel cell, and has a porous membrane provided to face the anode, and the liquid fuel Includes a fuel component and an ionic microgel, and the ionic microgel has a structural unit derived from an ionic monomer and a structural unit derived from a nonionic monomer.

  According to the present invention, it is possible to provide a passive fuel cell and a liquid fuel supply member that can improve power generation characteristics and power generation characteristics when liquid fuel is refilled.

It is a figure which shows an example of the passive type fuel cell of this invention. It is a figure which shows the electric power generation characteristic of the passive type fuel cell of an Example. It is a figure which shows the electric power generation characteristic of the passive fuel cell which refilled methanol of the Example. It is a figure which shows the evaluation result of the methanol crossover of the passive type fuel cell of an Example.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of a passive fuel cell of the present invention. The passive fuel cell 100 includes a membrane electrode assembly 110 in which an electrolyte membrane 113 is sandwiched between an anode 111 that oxidizes a fuel component contained in a liquid fuel F and a cathode 112 that reduces an oxidizing agent (not shown) such as oxygen. Have. At this time, the anode 111 has the catalyst layer 111b formed on the diffusion layer 111a, and the cathode 112 has the catalyst layer 112b formed on the diffusion layer 112a. A separator 120 is installed on the anode 111, and the separator 120 has a flow path 121 through which a fuel component contained in the liquid fuel F flows. Furthermore, the separator 130 is installed on the cathode 112, and the separator 130 has the flow path 131 through which an oxidizing agent flows.

  Although it does not specifically limit as a material which comprises the diffused layers 111a and 112a, A carbon fiber nonwoven fabric etc. are mentioned.

  Although it does not specifically limit as a catalyst contained in the catalyst layer 111b, A platinum-ruthenium catalyst etc. are mentioned.

  Although it does not specifically limit as a catalyst contained in the catalyst layer 112b, A platinum catalyst etc. are mentioned.

  The material constituting the electrolyte membrane 113 is not particularly limited, and examples thereof include Nafion (registered trademark).

  Although it does not specifically limit as a material which comprises the separators 120 and 130, Metals, such as stainless steel, carbon, etc. are mentioned.

  Further, a liquid fuel supply tank 140 for supplying the liquid fuel F to the anode 111 is detachably installed on the separator 120. At this time, the liquid fuel F further includes an ionic microgel having a structural unit derived from an ionic monomer and a structural unit derived from a nonionic monomer. For this reason, the liquid fuel F stored in the liquid fuel supply tank 140 holds the fuel component by the ionic microgel and suppresses the fuel component from passing through the electrolyte membrane 113 and moving to the cathode 112. be able to. As a result, the occurrence of fuel component crossover can be suppressed. The liquid fuel supply tank 140 has a porous membrane 141 installed on the separator 120 so as to face the anode 111. For this reason, adhesion of the ionic microgel to the diffusion layer 111a can be suppressed. As a result, the power generation characteristics of the passive fuel cell 100 can be improved.

  Although it does not specifically limit as a material which comprises the main body of the liquid fuel supply tank 140, A fluororesin, a vinyl resin, etc. are mentioned.

  The average pore diameter of the porous membrane 141 is usually 0.01 to 10 μm, preferably 0.05 to 0.2 μm. When the average pore diameter of the porous membrane 141 is less than 0.01 μm, the power generation characteristics when the liquid fuel of the passive fuel cell 100 is refilled may deteriorate, and when it exceeds 10 μm, the passive fuel cell 100 The power generation characteristics may deteriorate.

  Although it does not specifically limit as a material which comprises the porous film | membrane 141, A fluororesin, a polyimide, a phenol resin, glass, carbon etc. are mentioned. Of these, fluororesins are preferred because ionic microgels are difficult to adhere.

  The content of the ionic microgel in the liquid fuel F is usually 0.1 to 50% by mass, preferably 0.1 to 10% by mass, and more preferably 0.1 to 5% by mass. If the content of the ionic microgel in the liquid fuel F is less than 0.1% by mass, a crossover of the fuel component may occur. If the content exceeds 50% by mass, the liquid fuel of the passive fuel cell 100 may be reused. When it is filled, the power generation characteristics may deteriorate.

  The content of the fuel component in the liquid fuel F is usually 10 to 99.9% by mass, but preferably 64% by mass or more. When the content of the fuel component in the liquid fuel F is less than 64% by mass, the power generation efficiency of the passive fuel cell 100 may be lowered.

  Although it does not specifically limit as a fuel component, Methanol, ethanol, a dimethyl ether etc. are mentioned. Of these, methanol is preferable.

  The liquid fuel F may further contain water.

  Although it does not specifically limit as a method to manufacture ionic microgel, The reverse phase emulsion polymerization method etc. are mentioned. At this time, the reverse phase emulsion polymerization method is a method in which an ionic monomer and a nonionic monomer are radically polymerized in a state where an aqueous phase containing an ionic monomer and a nonionic monomer is dispersed in an oil phase. Thereby, powdery ionic microgel can be separated without crushing. Furthermore, since the ionic microgel swells when dispersed in a fuel component such as methanol, ethanol, dimethyl ether, etc., crossover of the fuel component can be suppressed.

  The oil phase is not particularly limited, but alkanes such as pentane, hexane, heptane, octane, nonane, decane, undecane; cycloalkanes such as cyclopentane, cyclohexane, cycloheptane, cyclooctane; benzene, toluene, xylene, Aromatic hydrocarbons such as decalin and naphthalene and cyclic hydrocarbons; Nonpolar oils such as paraffin oil and the like.

  In dispersing the aqueous phase in the oil phase, it is preferable to use a surfactant.

  The surfactant is not particularly limited, but polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene hexyl decyl ether, polyoxyethylene Oxyethylene isostearyl ether, polyoxyethylene octyldodecyl ether, polyoxyethylene behenyl ether, polyoxyethylene cholesteryl ether, polyoxyethylene hydrogenated castor oil, sorbitan fatty acid ester, glycerin monofatty acid ester, glycerin trifatty acid ester, polyglycerin fatty acid ester, Polyoxyethylene glycerin isostearate, polyoxyethylene glycerin trii Stearic acid esters, polyoxyethylene glycerin monostearate, polyoxyethylene glycerin distearate, polyoxyethylene glycerin stearic acid ester and the like, may be used in combination.

  At this time, a one-phase microemulsion or a fine W / O emulsion can be formed by appropriately adjusting the hydrophilic / hydrophobic balance (HLB) of the surfactant.

  A one-phase microemulsion is a state in which an oil phase and an aqueous phase coexist thermodynamically and the interfacial tension between the oil phase and the aqueous phase is minimized. A fine W / O emulsion is a state in which an oil phase and a water phase exist stably in terms of kinetics, although unstable in thermodynamics. Generally, the particle diameter of the aqueous phase of the fine W / O emulsion is about several tens to 100 nm.

  Hereinafter, the manufacturing method of an ionic microgel is demonstrated concretely. First, an ionic monomer and a nonionic monomer are dissolved in water to prepare an aqueous phase, and then mixed with an oil phase. Next, after raising the temperature to a predetermined temperature, a polymerization initiator is added to the aqueous phase for polymerization. At this time, polymerization is performed in a state where a thermodynamically stable one-phase microemulsion or a kinetically stable fine W / O emulsion is formed. Specifically, after forming a one-phase microemulsion or fine W / O emulsion in the vicinity of the optimum polymerization temperature of a polymerization initiator for thermal polymerization or redox polymerization, the ionic monomer and the nonionic monomer are polymerized. Thus, the ionic microgel can be stably produced.

  At this time, the hydrophilic / hydrophobic balance (HLB) of the surfactant is adjusted so as to show a cloud point in the vicinity of the optimum polymerization temperature of the polymerization initiator for thermal polymerization or redox polymerization. In the vicinity, a one-phase microemulsion or a fine W / O emulsion can be formed.

  The nonionic monomer is not particularly limited, but the general formula

（式中、Ｒ_１は、水素原子又はメチル基であり、Ｒ_２及びＲ_３は、それぞれ独立に、メチル基、エチル基、プロピル基又はイソプロピル基である。）
で表されるＮ，Ｎ−ジアルキル（メタ）アクリルアミド等が挙げられる。中でも、Ｎ，Ｎ−ジメチル（メタ）アクリルアミド、Ｎ，Ｎ−ジエチル（メタ）アクリルアミドが好ましい。

(In the formula, R ₁ is a hydrogen atom or a methyl group, and R ₂ and R ₃ are each independently a methyl group, an ethyl group, a propyl group, or an isopropyl group.)
N, N-dialkyl (meth) acrylamide represented by Among these, N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide are preferable.

  The ionic monomer is not particularly limited, but the general formula

（式中、Ｒ_４及びＲ_５は、それぞれ独立に、水素原子又はメチル基であり、Ｒ_６は、炭素原子数が１〜６の直鎖又は分岐のアルキレン基であり、Ｘ^＋は、プロトン、１価の金属カチオン又はアンモニウムイオンである。）
で表されるアニオン性（メタ）アクリルアミド誘導体、一般式

(Wherein R ₄ and R ₅ are each independently a hydrogen atom or a methyl group, R ₆ is a linear or branched alkylene group having 1 to 6 carbon atoms, and X ⁺ is a proton. Monovalent metal cation or ammonium ion.)
Anionic (meth) acrylamide derivatives represented by the general formula

（式中、Ｒ_７は、水素原子又はメチル基であり、Ｒ_８は、水素原子又は炭素原子数が１〜６の直鎖又は分岐のアルキル基であり、Ｒ_９は、炭素原子数が１〜６の直鎖又は分岐のアルキレン基であり、Ｒ_１０、Ｒ_１１及びＲ_１２は、それぞれ独立に、メチル基又はエチル基であり、Ｙ⁻は、ハロゲン化物イオンである。）
で表されるカチオン性アクリルアミド誘導体等が挙げられる。中でも、アニオン性（メタ）アクリルアミド誘導体が好ましく、２−アクリルアミド−２−メチルプロパンスルホン酸及びその塩がさらに好ましい。

(In the formula, R ₇ is a hydrogen atom or a methyl group, R ₈ is a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and R ₉ has 1 carbon atom. -6 linear or branched alkylene groups, R ₁₀ , R ₁₁ and R ₁₂ are each independently a methyl group or an ethyl group, and Y ⁻ is a halide ion.)
And the like, and the like. Among these, an anionic (meth) acrylamide derivative is preferable, and 2-acrylamido-2-methylpropanesulfonic acid and a salt thereof are more preferable.

  The mass ratio of the nonionic monomer to the ionic monomer is usually 0.5 / 9.5 to 9.5 / 0.5, preferably 1/9 to 9/1, and 7/3 to 9/1. Is more preferable, and 8/2 is particularly preferable.

  The ionic microgel preferably contains a copolymer of N, N-dimethylacrylamide and 2-acrylamido-2-methylpropanesulfonic acid. Thereby, crossover can be further suppressed.

  The aqueous phase may further contain a crosslinking agent.

  Although it does not specifically limit as a crosslinking agent, General formula

（Ｒ_１３及びＲ_１７は、それぞれ独立に、水素原子又はメチル基であり、Ｒ_１４及びＲ_１６は、それぞれ独立に、オキシ基又はイミノ基であり、Ｒ_１５は、炭素原子数が１〜６の直鎖若しくは分岐のアルキレン基又は炭素原子数が８〜２００のポリオキシエチレン基である。）
で表される（メタ）アクリルアミド誘導体又は（メタ）アクリル酸誘導体が挙げられる。

(R ₁₃ and R ₁₇ are each independently a hydrogen atom or a methyl group, R ₁₄ and R ₁₆ are each independently an oxy group or an imino group, and R ₁₅ has 1 to 6 carbon atoms. A linear or branched alkylene group or a polyoxyethylene group having 8 to 200 carbon atoms.)
(Meth) acrylamide derivatives or (meth) acrylic acid derivatives represented by:

  In addition, the crosslinking agent may have 3 or more polymerizable functional groups.

  Specific examples of the crosslinking agent include ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyoxyethylene diacrylate, polyoxyethylene dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane triacrylate, N, N′-methylenebisacrylamide, N , N′-ethylenebisacrylamide, triallyl isocyanurate, pentaerythritol dimethacrylate, etc., may be used in combination. Among these, N, N′-methylenebisacrylamide is preferable.

The ratio of the amount of the crosslinking agent to the total amount of the nonionic monomer and the ionic monomer is usually 1 × 10 ⁻⁴ to 2%. When the ratio of the amount of the crosslinking agent to the total amount of the nonionic monomer and the ionic monomer is less than 1 × 10 ⁻⁴ %, it may be difficult to produce the ionic microgel. It may be difficult to suppress the occurrence of crossover.

  When an aqueous phase containing N, N-dialkylacrylamide and an ionic acrylamide derivative is used, an ionic microgel can be produced without using a crosslinking agent.

The weight average molecular weight of the ionic microgel is usually 1 × 10 ^{5 to} 5 × 10 ⁶ .

  In addition, the weight average molecular weight of ionic microgel is a molecular weight of PEG conversion, and can be measured using GPC.

  The average particle diameter of the ionic microgel is usually 0.01 to 10 μm, preferably 0.01 to 1 μm.

The apparent viscosity of an aqueous dispersion of 0.5% by mass of ionic microgel is usually 1 × 10 ⁴ mPa · s or more at a shear rate of 1.0 s ⁻¹ . The apparent viscosity of the 0.5% by mass ethanol dispersion of the ionic microgel is usually 5 × 10 ³ mPa · s or more at a shear rate of 1.0 s ⁻¹ . Furthermore, the dynamic elastic modulus of the ionic microgel in an aqueous dispersion or ethanol dispersion of 0.5% by mass has a strain of 1% or less and a frequency in the range of 0.01 to 10 Hz. G ′> loss elastic modulus G ″.

  The apparent viscosity and dynamic elastic modulus can be measured at 25 ° C. using a cone plate rheometer MCR-300 (manufactured by Paar Physica).

  Further, examples of the present invention will be described.

(Preparation of membrane electrode assembly 110)
As the diffusion layers 111a and 112a, 2.4 cm × 2.4 cm × 0.018 cm PTFE-treated carbon paper EC-TP1-060T (manufactured by Toyo Corporation) was used.

  4 parts by mass of carbon carrying a platinum-ruthenium catalyst, 5 parts by mass of Nafion (registered trademark) solution 44 parts by mass of EC-NS-05-AQ (manufactured by Toyo Technica) and 52 parts of ethanol are mixed to form a catalyst layer. A coating solution for 111b was obtained. At this time, the carbon carrying the platinum-ruthenium catalyst has a platinum loading of 29.9 mass% and a ruthenium loading of 23.1 mass%.

Using a spray coating method, a coating solution for the catalyst layer 111b was applied on the diffusion layer 111a to form the catalyst layer 111b, whereby an anode 111 was obtained. At this time, the coating solution for the catalyst layer 111b was applied so that the platinum content in the catalyst layer 111b was 1.00 mg / cm ² .

  For catalyst layer 112b, 4 parts by mass of carbon carrying platinum catalyst, 5 parts by mass of Nafion (registered trademark) solution EC-NS-05-AQ (made by Toyo Technica) 27 parts by mass and 69 parts of ethanol are mixed. A coating solution was obtained. At this time, the carbon carrying the platinum catalyst has a platinum loading of 45.7% by mass.

Using a spray coating method, a coating solution for the catalyst layer 112b was applied on the diffusion layer 112a to form the catalyst layer 112b, whereby the cathode 112 was obtained. At this time, the coating solution for the catalyst layer 112b was applied so that the platinum content in the catalyst layer 112b was 1.00 mg / cm ² .

  As the electrolyte membrane 113, 3.4 cm × 3.4 cm × 0.0051 cm of Nafion 212 (manufactured by DuPont) was used.

  The electrolyte membrane 113 was sandwiched between the anode 111 and the cathode 112 and hot pressed at 135 ° C. and 11.5 MPa for 180 seconds to obtain a membrane electrode assembly 110.

(Production of ionic microgel)
After dissolving 35 g of N, N-dimethylacrylamide, 17.5 g of 2-acrylamido-2-methylpropanesulfonic acid and 70 mg of methylenebisacrylamide in 260 g of ion-exchanged water, the pH is adjusted to 7.0 using sodium hydroxide. To obtain a monomer aqueous solution.

  In a 1 L three-necked flask equipped with a reflux apparatus, 260 g of n-hexane, 8.7 g of polyoxyethylene (3) oleyl ether Emalex 503 (manufactured by Nippon Emulsion Co., Ltd.) and polyoxyethylene (6) oleyl ether emma 17.6 g of Rex 506 (manufactured by Nippon Emulsion Co., Ltd.) was added and mixed, and then replaced with nitrogen. Next, an aqueous monomer solution was added, and the temperature of the polymerization system was raised to 65 to 70 ° C. using an oil bath while stirring in a nitrogen atmosphere. At this time, it was confirmed that a translucent one-phase microemulsion was formed. Further, after adding 2 g of ammonium persulfate, the mixture was stirred for 3 hours while maintaining the temperature of the polymerization system at 65 to 70 ° C. to obtain an ionic microgel. Next, acetone was added to precipitate the ionic microgel, followed by washing with acetone three times. Further, the ionic microgel was filtered and then dried under reduced pressure to obtain a white powdery ionic microgel.

Example 1
Liquid fuel F was obtained by mixing 0.5 parts by mass of ionic microgel and 99.5 parts by mass of a 99.8% by mass aqueous methanol solution.

  After the separators 120 and 130 were installed on the membrane electrode assembly 110, the liquid fuel supply tank 140 in which 2 mL of liquid fuel F was stored was installed, and the passive fuel cell 100 was obtained. At this time, as the porous membrane 141, an omnipore membrane JGWP04700 (manufactured by Micropore) made of polytetrafluoroethylene (PTFE) having a thickness of 10 μm and an average pore diameter of 0.2 μm was used.

(Example 2)
A passive fuel cell 100 was obtained in the same manner as in Example 1 except that 1.0 part by mass of ionic microgel and 99.0 parts by mass of a 99.8% by mass methanol aqueous solution were mixed.

(Example 3)
A passive fuel cell 100 was obtained in the same manner as in Example 1 except that 2.0 parts by mass of ionic microgel and 98.0 parts by mass of a 99.8% by mass aqueous methanol solution were mixed.

(Power generation characteristics)
Using a fuel cell evaluation device 890B-100W / 10A (manufactured by Toyo Technica Co., Ltd.), the power generation characteristics at a current density of 50 mA / cm ² of the passive fuel cell 100 were measured in an environment of 25 ° C. and 50% RH.

  FIG. 2 shows the power generation characteristics of the passive fuel cell 100.

  FIG. 2 shows that the passive fuel cells 100 of Examples 1 to 3 have excellent power generation characteristics.

  After the methanol consumed in the liquid fuel supply tank 140 of the passive fuel cell 100 was refilled, it was left for 100 minutes. Next, the power generation characteristics of the passive fuel cell 100 were measured using an electronic loader PLZ70UA (manufactured by KIKUSUI) in an environment of 25 ° C. and 50% RH.

  FIG. 3 shows the power generation characteristics of the passive fuel cell 100 refilled with methanol. 3A, 3B, and 3C show the power generation characteristics of the passive fuel cells 100 of Examples 1, 2, and 3, respectively.

  FIG. 3 shows that the passive fuel cells 100 of Examples 1 to 3 have excellent power generation characteristics even after refilling with methanol.

(Methanol crossover)
Before and after the power generation characteristics at a current density of 50 mA / cm ² were measured, the liquid fuel supply tank 140 of the passive fuel cell 100 was filled with a 10% by mass methanol aqueous solution instead of the 99.8% by mass methanol aqueous solution. Next, methanol crossover of the passive fuel cell 100 was evaluated in an environment of 25 ° C. and 50% RH using a fuel cell evaluation device 890B-100W / 10A (manufactured by Toyo Technica Co., Ltd.).

  In FIG. 4, the evaluation result of the methanol crossover of the passive fuel cell 100 is shown. 4A, 4B, and 4C show the evaluation results of the passive fuel cells 100 of Examples 1, 2, and 3, respectively.

FIG. 4 shows that the passive fuel cells 100 of Examples 1 to 3 have substantially the same power generation characteristics before and after measuring the power generation characteristics at a current density of 50 mA / cm ² and can suppress the occurrence of methanol crossover.

DESCRIPTION OF SYMBOLS 100 Passive type fuel cell 110 Membrane electrode assembly 111 Anode 111a Diffusion layer 111b Catalyst layer 112 Cathode 112a Diffusion layer 112b Catalyst layer 113 Electrolyte membrane 120, 130 Separator 121, 131 Channel 140 Liquid fuel supply tank 141 Porous membrane F Liquid fuel

Claims (8)

A membrane electrode assembly in which an electrolyte membrane is sandwiched between an anode and a cathode, and a liquid fuel supply member that supplies liquid fuel to the anode,
The liquid fuel supply member has a porous membrane provided to face the anode,
The liquid fuel includes a fuel component and an ionic microgel,
The ionic microgel has a structural unit derived from an ionic monomer and a structural unit derived from a nonionic monomer.   2. The passive fuel cell according to claim 1, wherein the porous membrane has an average pore diameter of 0.01 μm or more and 10 μm or less.   The passive fuel cell according to claim 1, wherein the porous membrane contains a fluororesin.   4. The passive fuel cell according to claim 1, wherein the liquid fuel has a content of the ionic microgel of 0.1% by mass or more and 50% by mass or less.   5. The passive fuel cell according to claim 1, wherein the liquid fuel has a content of the fuel component of 10% by mass or more and 99.9% by mass or less.   The passive fuel cell according to any one of claims 1 to 5, wherein the ionic monomer is an anionic monomer.   The passive fuel cell according to any one of claims 1 to 6, wherein the fuel component is methanol. A liquid fuel supply member for supplying liquid fuel to an anode of a passive fuel cell,
A porous membrane provided to face the anode;
The liquid fuel includes a fuel component and an ionic microgel,
The ionic microgel has a structural unit derived from an ionic monomer and a structural unit derived from a nonionic monomer.

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