JPH1126005A - Direct type methanol fuel cell with solid polyelectrolyte - Google Patents
Direct type methanol fuel cell with solid polyelectrolyteInfo
- Publication number
- JPH1126005A JPH1126005A JP9190625A JP19062597A JPH1126005A JP H1126005 A JPH1126005 A JP H1126005A JP 9190625 A JP9190625 A JP 9190625A JP 19062597 A JP19062597 A JP 19062597A JP H1126005 A JPH1126005 A JP H1126005A
- Authority
- JP
- Japan
- Prior art keywords
- water
- fuel cell
- methanol
- intermediate layer
- positive electrode
- 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.)
- Granted
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Classifications
-
- 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
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- Fuel Cell (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、メタノールを負極
に供給し、負極で直接電気化学反応させて電力を得る、
直接型メタノール燃料電池に関するものである。BACKGROUND OF THE INVENTION The present invention relates to a method for supplying methanol to a negative electrode and performing an electrochemical reaction directly at the negative electrode to obtain electric power.
The present invention relates to a direct methanol fuel cell.
【０００２】[0002]
【従来の技術】燃料電池は、イオン導電体である電解質
の両側に２つの電極を備え、一方の電極に酸素や空気な
どの酸化ガス（酸化剤）を供給し、他方の電極に水素や
炭化水素などの燃料（還元剤）を供給し、電気化学反応
を起こさせて電気を発生させる電池である。2. Description of the Related Art A fuel cell has two electrodes on both sides of an electrolyte which is an ion conductor, supplies an oxidizing gas (oxidizing agent) such as oxygen or air to one electrode, and supplies hydrogen or carbonized gas to the other electrode. A battery that supplies fuel (reducing agent) such as hydrogen and causes an electrochemical reaction to generate electricity.
【０００３】燃料電池にはいくつもの種類があるが、直
接型メタノール燃料電池（ＤＭＦＣと略す）は、燃料で
あるメタノールを直接負極に供給するもので、多くの燃
料電池が燃料としては水素、あるいは炭化水素を改質し
た水素を使用しているのと比較して、装置が簡単なだけ
でなく、燃料そのものの輸送や貯蔵も容易であり、しか
も１００℃以下の温度で作動できる可能性があるため
に、小型・可搬用に最も適していると考えられており、
将来の自動車用動力源として有力視されている。There are many types of fuel cells. A direct methanol fuel cell (abbreviated as DMFC) directly supplies methanol, which is a fuel, to a negative electrode. Many fuel cells use hydrogen or hydrogen as a fuel. Compared to using hydrocarbon reformed hydrogen, the equipment is not only simpler, but also easier to transport and store the fuel itself, and may be able to operate at temperatures below 100 ° C Therefore, it is considered to be most suitable for small size and portable use,
It is regarded as a promising power source for future vehicles.
【０００４】直接型メタノール燃料電池の電解質として
は、初期のアルカリ型から酸型へと変化し、最近では多
くの場合固体高分子電解質が使用されている。固体高分
子電解質を使用することにより、作動温度を液体電解質
の場合よりも高くすることができ、直接型メタノール燃
料電池の性能は初期のものよりかなり改善された。[0004] As an electrolyte of a direct methanol fuel cell, an alkaline type is changed from an initial type to an acid type, and in recent years, a solid polymer electrolyte is often used. By using solid polymer electrolytes, the operating temperature could be higher than with liquid electrolytes, and the performance of direct methanol fuel cells was significantly improved over the earlier ones.
【０００５】固体高分子電解質を使用した直接型メタノ
ール燃料電池（ＰＥＭ−ＤＭＦＣ）は、ＤＵ ＰＯＮＴ
社製のナフィオンのようなプロトン導電性固体高分子電
解質膜の両側を、触媒をとりつけた２つの多孔性電極で
はさんだ構造を持ち、負極にメタノールを直接供給し、
正極に酸素または空気を供給するものである。負極で
は、メタノールと水が反応して二酸化炭素とプロトンと
電子が発生し、電子は外部回路を通って仕事をした後正
極に達する。また、プロトンは高分子固体電解質中を通
って正極に達する。正極では、酸素とプロトンと電子が
反応して水が生成する。したがって、直接型メタノール
燃料電池の全反応は、メタノールと酸素とから水と二酸
化炭素が生成する反応である。これらの反応は電極中の
触媒の助けを借りて進行する。この反応の理論電圧は
１．１８Ｖであるが、実際の電池においては、ＩＲドロ
ップなどのために、この値よりも低い電圧となる。A direct methanol fuel cell (PEM-DMFC) using a solid polymer electrolyte is a DU PONT
It has a structure in which both sides of a proton conductive solid polymer electrolyte membrane such as Nafion manufactured by the company are sandwiched between two porous electrodes with a catalyst attached, and methanol is directly supplied to the negative electrode,
It supplies oxygen or air to the positive electrode. At the negative electrode, methanol and water react to generate carbon dioxide, protons, and electrons, and the electrons reach the positive electrode after working through an external circuit. Further, protons reach the positive electrode through the solid polymer electrolyte. At the positive electrode, oxygen, protons, and electrons react to generate water. Therefore, the entire reaction of the direct methanol fuel cell is a reaction in which water and carbon dioxide are generated from methanol and oxygen. These reactions proceed with the aid of a catalyst in the electrode. The theoretical voltage of this reaction is 1.18 V, but in an actual battery, the voltage is lower than this value due to IR drop and the like.
【０００６】直接型メタノール燃料電池はその特性はか
なり改善されたとはいえ、その他の燃料電池と比較して
電池の出力と効率が低い、という欠点をもっている。そ
の原因は、メタノールを酸化する触媒の活性が低いこと
と、メタノールが電解質中を拡散して陽極に達し、そこ
で正極の触媒上で酸化剤と直接反応するという短絡現象
（この現象は「クロスオーバー」と呼ばれている）の２
つであることが明らかになっている［Ｍ．Ｐ．Ｈｏｇａ
ｒｔｈ ａｎｄ Ｈ．Ａ．Ｈａｒｄｓ Ｐｌａｔｉｎｕ
ｍ Ｍｅｔａｌｓ Ｒｅｖ．，４０ （４） １５０
（１９９６）］。[0006] Although the characteristics of direct methanol fuel cells have been considerably improved, they have the disadvantage that the output and efficiency of the cells are lower than those of other fuel cells. This is due to the low activity of the catalyst that oxidizes methanol, and the short-circuit phenomenon in which methanol diffuses through the electrolyte to reach the anode, where it reacts directly with the oxidant on the catalyst of the cathode (this phenomenon is called “crossover” 2)
[M. P. Hoga
rth and H.R. A. Hards Platinu
m Metals Rev. , 40 (4) 150
(1996)].
【０００７】直接型メタノール燃料電池においては、正
極・負極とも触媒が必要であるが、特に負極の触媒が問
題である。すなわち、メタノールが白金触媒上で酸化さ
れる時、白金に吸着した一酸化炭素が生じ、これが白金
を被毒して触媒活性を低下させる［Ｒ．Ｐａｒｓｏｎｓ
ａｎｄ Ｔ．Ｖａｎｄｅｒｎｏｏｔ Ｊ．Ｅｌｅｃｔ
ｒｏａｎａｌ．Ｃｈｅｍ．，２５７ ９（１９８８）］
と考えられている。白金の表面から一酸化炭素をすみや
かに除去するために、二次金属の添加が検討され、現在
では白金−ルテニウム系が最も高活性触媒であることが
知られている。[0007] In the direct methanol fuel cell, a catalyst is required for both the positive electrode and the negative electrode, and the catalyst of the negative electrode is particularly problematic. That is, when methanol is oxidized on a platinum catalyst, carbon monoxide adsorbed on the platinum is generated, which poisons the platinum and reduces the catalytic activity [R. Parsons
and T. Vandernote J .; Elect
roanal. Chem. , 257 9 (1988)]
It is believed that. In order to quickly remove carbon monoxide from the surface of platinum, the addition of a secondary metal has been studied. At present, it is known that a platinum-ruthenium system is the most highly active catalyst.
【０００８】固体高分子電解質としてのイオン交換樹脂
膜は、乾燥状態では全く導電性を示さないが、通常は水
で膨潤させることによって高い導電性を示すようにな
る。The ion exchange resin membrane as a solid polymer electrolyte does not show any conductivity in a dry state, but usually shows high conductivity by swelling with water.
【０００９】固体高分子電解質膜として最も良く知られ
ているＤｕ Ｐｏｎｔ社のナフィオン膜の構造は、主鎖
である撥水性のポリフルオロエチレン［−（ＣＦ2 ）n
−］骨格部分と、側鎖に結合した親水性のイオン交換基
であるスルフォン酸基（−ＳＯ3 Ｈ）の部分からなる。
この膜が水を吸収した場合、親水性のイオン交換基の部
分が集合し、球状のクラスターを形成し、このクラスタ
ーがポリフルオロエチレンのマトリックス中に分散して
いるというモデルが有力であり、このモデルでは、水は
クラスター部分に含有され、これらのクラスターが細い
通路で結ばれている、と考えられている［竹中 大工試
季報 ３６ ８１（１９８５）］。その他の固体高分子
電解質の場合も、同じような構造をしているものと推定
される。The structure of the Nafion membrane of Du Pont, which is best known as a solid polymer electrolyte membrane, has a water-repellent polyfluoroethylene [-(CF 2 ) n as a main chain.
-] and skeletal portion, consisting of the portion of the sulfonic acid group is a hydrophilic ion exchange groups attached to side chains (-SO 3 H).
When this membrane absorbs water, the model in which hydrophilic ion exchange groups are aggregated to form spherical clusters, and the clusters are dispersed in a polyfluoroethylene matrix, is a powerful model. in the model, the water is contained in the cluster portion, these clusters are connected by a narrow passage, believed to [Takenaka carpenter試季report 36 81 (1985)]. It is presumed that other solid polymer electrolytes have a similar structure.
【００１０】[0010]
【発明が解決しようとする課題】水を吸収した高分子固
体電解質膜にメタノールが接触すると、メタノールは水
に溶けやすいため、高分子固体電解質膜内のクラスター
中の水に溶解し、その中を通って正極に達し、正極の触
媒上で酸化されることになる。When methanol comes into contact with a polymer solid electrolyte membrane that has absorbed water, methanol is easily dissolved in water, and is dissolved in water in clusters in the polymer solid electrolyte membrane. Through the anode and oxidized on the catalyst of the cathode.
【００１１】一方、正極においては、触媒としての貴金
属が、負極から電解質膜中を通ってきたメタノールを電
気化学的に酸化するために、正極の特性が著しく悪くな
る。メタノールが電解質膜中を通って正極に達する現
象、いわゆるクロスオーバーを少しでも減少させる方法
として、酸素あるいは空気の圧力を高くする方法と、電
池の作動温度を１００℃以上まで上げる方法が検討さ
れ、特性はかなり改善されてきたが、実用的に十分な特
性は得られていない。また、酸素または空気の圧力を高
くするためおよび電池の作動温度を上げるためには、そ
のための装置が必要になり、電池全体としては複雑にな
る。On the other hand, in the positive electrode, the noble metal as a catalyst electrochemically oxidizes methanol passing through the electrolyte membrane from the negative electrode, so that the characteristics of the positive electrode are significantly deteriorated. As a method of reducing the phenomenon that methanol reaches the positive electrode through the electrolyte membrane, so-called crossover, a method of increasing the pressure of oxygen or air and a method of increasing the operating temperature of the battery to 100 ° C. or higher are studied. Although the characteristics have been considerably improved, practically sufficient characteristics have not been obtained. Further, in order to increase the pressure of oxygen or air and to raise the operating temperature of the battery, a device for that is required, and the whole battery becomes complicated.
【００１２】直接型メタノール燃料電池の特性を改善す
るためには、燃料であるメタノールが固体高分子電解質
膜を通って正極側に達すること、すなわち、メタノール
のクロスオーバーをできるだけ小さくするかなくす必要
があり、そのための具体的な手段が求められていた。In order to improve the characteristics of the direct methanol fuel cell, it is necessary that methanol as a fuel reaches the positive electrode side through the solid polymer electrolyte membrane, that is, it is necessary to minimize or eliminate the methanol crossover. There was a need for specific means for that.
【００１３】[0013]
【課題を解決するための手段】本発明は、固体高分子電
解質膜を備えた直接型メタノール燃料電池において、二
枚の固体高分子電解質膜の間にプロトン型イオン交換樹
脂粉末と水を含む中間層を備え、中間層の水を流動させ
るものである。また、水が電池の外部から供給され、中
間層を通った後、電池外部に放出されるようにする。あ
るいは、中間層と、電池外部に備えた水中に含まれるメ
タノールの含有量を減少させる装置との間を、水が循環
するようにする。SUMMARY OF THE INVENTION The present invention relates to a direct methanol fuel cell provided with a solid polymer electrolyte membrane, comprising an intermediate membrane containing a proton-type ion exchange resin powder and water between two solid polymer electrolyte membranes. A layer is provided for flowing water of the intermediate layer. Water is supplied from the outside of the battery, passes through the intermediate layer, and is then discharged to the outside of the battery. Alternatively, water is circulated between the intermediate layer and a device provided outside the battery for reducing the content of methanol contained in water.
【００１４】[0014]
【発明の実施の形態】本発明になる固体高分子電解質膜
を使用した直接型メタノール燃料電池には、従来の固体
高分子電解質膜を使用した直接型メタノール燃料電池に
使用されているプロトン導電性固体高分子電解質膜、貴
金属触媒、多孔性電極などが使用でき、負極にメタノー
ルと水の混合物を、正極には酸素あるいは空気を供給
し、電気を取り出すものである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A direct methanol fuel cell using a solid polymer electrolyte membrane according to the present invention includes a proton conductive membrane used in a direct methanol fuel cell using a conventional solid polymer electrolyte membrane. A solid polymer electrolyte membrane, a noble metal catalyst, a porous electrode, or the like can be used. A mixture of methanol and water is supplied to the negative electrode, and oxygen or air is supplied to the positive electrode to extract electricity.
【００１５】多孔性電極の基体としては、正・負極と
も、カーボンペーパー、カーボンの成形体、カーボンの
焼結体、焼結金属、発泡金属などの多孔性基体を撥水処
理して使用することができ、撥水剤としてはポリテトラ
フルオロエチレン等を使用することができる。As the substrate of the porous electrode, for both the positive and negative electrodes, a porous substrate such as carbon paper, a molded carbon article, a sintered carbon article, a sintered metal, or a foamed metal is used after being subjected to a water-repellent treatment. Polytetrafluoroethylene or the like can be used as the water repellent.
【００１６】貴金属触媒としては、正極用には白金、白
金合金、金、金合金、パラジウム、パラジウム合金な
ど、負極用には白金あるいは白金とルテニウム、金、レ
ニウムなどの合金が使用でき、これら貴金属の微粉末あ
るいは貴金属を担持したカーボン粉末を使用することが
できる。As the noble metal catalyst, platinum, platinum alloy, gold, gold alloy, palladium, palladium alloy and the like can be used for the positive electrode, and platinum or an alloy of platinum and ruthenium, gold and rhenium can be used for the negative electrode. Fine powder or a carbon powder supporting a noble metal can be used.
【００１７】本発明になる多孔性電極は、撥水処理をし
た電極の表面に、触媒分散溶液を塗布して作製される。
触媒分散溶液は、白金ブラックなどの触媒の微粒子ある
いは触媒を担持したカーボン粉末と、ポリテトラフルオ
ロエチレン等の撥水剤と、アルコールなどに溶解した固
体高分子電解質を、適当な溶媒中で均一に混合すること
によって作製する。The porous electrode according to the present invention is produced by applying a catalyst dispersion solution to the surface of a water-repellent electrode.
The catalyst dispersion solution is obtained by uniformly mixing fine particles of a catalyst such as platinum black or a carbon powder carrying the catalyst, a water repellent such as polytetrafluoroethylene, and a solid polymer electrolyte dissolved in an alcohol or the like in an appropriate solvent. It is prepared by mixing.
【００１８】本発明になる直接型メタノール燃料電池の
電解質層は、二枚の固体高分子電解質膜の間にプロトン
型イオン交換樹脂粉末と水を含む中間層を備えた三層か
らなっており、中間層の水を流動させるものである。中
間層の水を流動させる方法としては、次に二つが考えら
れる。The electrolyte layer of the direct methanol fuel cell according to the present invention comprises three layers including an intermediate layer containing a proton-type ion exchange resin powder and water between two solid polymer electrolyte membranes. This is to make the water in the middle layer flow. The following two methods can be considered for flowing the water in the intermediate layer.
【００１９】第一は、直接型メタノール燃料電池が小型
で、自動車などの移動体に搭載する場合には、水はあら
かじめタンクに貯蔵しておき、これを燃料電池に供給し
て二枚の固体高分子電解質膜の間のプロトン型イオン交
換樹脂粉末を含む中間層を通した後、電池外部に取り出
す。中間層を通ってきた水には、負極側固体高分子電解
質膜の中に含まれるメタノールを少量含むことになる。
このメタノールを含んだ水溶液を、２枚の固体高分子電
解質膜の間の中間層に循環させると、水溶液中のメタノ
ールの濃度が高くなり、中間層を通る時に、メタノール
は正極側固体高分子電解質膜に移動し、さらに正極に達
して、正極触媒上でメタノールが電気化学的に酸化され
て、クロスオーバーの原因となる。そのため、中間層を
通ったメタノールを含む水は別のタンクに貯蔵してお
き、移動体が停止後、取り出して、別の装置で酸性水溶
液とメタノールを分離すればよい。First, when the direct methanol fuel cell is small and is mounted on a moving body such as an automobile, water is stored in a tank in advance and supplied to the fuel cell to supply two solid fuel cells. After passing through the intermediate layer containing the proton-type ion exchange resin powder between the polymer electrolyte membranes, it is taken out of the battery. The water that has passed through the intermediate layer contains a small amount of methanol contained in the anode-side solid polymer electrolyte membrane.
When the aqueous solution containing methanol is circulated to the intermediate layer between the two solid polymer electrolyte membranes, the concentration of methanol in the aqueous solution increases, and when the aqueous solution passes through the intermediate layer, the methanol is removed from the solid polymer electrolyte on the positive electrode side. It moves to the membrane and further reaches the positive electrode, where methanol is electrochemically oxidized on the positive electrode catalyst, causing crossover. Therefore, the water containing methanol that has passed through the intermediate layer may be stored in another tank, taken out after the moving body is stopped, and separated from the acidic aqueous solution and methanol by another device.
【００２０】第二の方法は、直接型メタノール燃料電池
が大型で、据え置き型として使用する場合、燃料電池の
二枚の固体高分子電解質膜の間の中間層を通ってきたメ
タノールを少量含んだ水溶液を、燃料電池に併設した水
とメタノールを分離する装置で処理して、メタノールを
除去した後、水を循環すればよい。The second method is that when the direct methanol fuel cell is large and used as a stationary type, it contains a small amount of methanol that has passed through the intermediate layer between the two solid polymer electrolyte membranes of the fuel cell. The aqueous solution may be treated with an apparatus provided in the fuel cell that separates water and methanol to remove methanol and then circulate the water.
【００２１】なお、直接型メタノール燃料電池に使用す
る固体高分子電解質膜としては、パーフルオロカーボン
スルフォン酸系樹脂やスチレン−ジビニルベンゼン共重
合体系樹脂等の、各種プロトン型イオン交換膜樹脂膜を
使用することができる。As the solid polymer electrolyte membrane used in the direct methanol fuel cell, various proton-type ion exchange membrane resin membranes such as a perfluorocarbonsulfonic acid-based resin and a styrene-divinylbenzene copolymer-based resin are used. be able to.
【００２２】[0022]
【実施例】本発明になる直接型メタノール燃料電池の構
造と特性を、好適な実施例を用いて詳述する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and characteristics of a direct methanol fuel cell according to the present invention will be described in detail using preferred embodiments.
【００２３】［実施例１］二枚の固体高分子電解質膜の
間に、イオン交換樹脂の粉末と水からなる中間層を備
え、中間層の水を流動させた、直接型メタノール燃料電
池を作製した。[Example 1] A direct methanol fuel cell was prepared in which an intermediate layer composed of ion exchange resin powder and water was provided between two solid polymer electrolyte membranes, and the water in the intermediate layer was allowed to flow. did.
【００２４】まず、空隙率７５％、厚み０．４０ｍｍの
カーボンペーパーを５０ｍｍ×５０ｍｍの大きさに切
り、２−プロパノールで洗浄し、乾燥したものを、ポリ
テトラフルオロエチレンを５重量パーセント含むディス
パージョンポリテトラフルオロエチレン水溶液中に数秒
間浸漬し、取り出して自然乾燥した後、アルゴンガス雰
囲気下で３００℃、１０分間焼成する。得られた撥水処
理済みカーボンペーパーには約０．５ｍｇ／ｃｍ2 のポ
リテトラフルオロエチレンがとりつけられている。First, carbon paper having a porosity of 75% and a thickness of 0.40 mm is cut into a size of 50 mm × 50 mm, washed with 2-propanol, and dried to obtain a dispersion containing 5 wt% of polytetrafluoroethylene. It is immersed in a polytetrafluoroethylene aqueous solution for several seconds, taken out and air-dried, and then fired at 300 ° C. for 10 minutes in an argon gas atmosphere. About 0.5 mg / cm 2 of polytetrafluoroethylene is attached to the obtained water-repellent carbon paper.
【００２５】つぎに、触媒分散溶液を作製した。まず、
ステンレス製ビーカーに、白金を１０重量％含む白金担
持カーボンを５ｇ入れ、水８０ｍｌを加えて撹拌し、さ
らに２−プロパノール８０ｍｌを加えて１時間撹拌す
る。つぎに、ポリテトラフルオロエチレンを２０重量パ
ーセント含むディスパージョンポリテトラフルオロエチ
レン水溶液２ｍｌ加え、撹拌し、さらに市販のナフィオ
ン溶液（ナフィオン５重量％含む、アルドリッチケミカ
ル製）１０ｍｌ加え、超音波を照射しながら撹拌機で１
時間撹拌して、正極用触媒分散溶液を作製した。Next, a catalyst dispersion solution was prepared. First,
5 g of platinum-supported carbon containing 10% by weight of platinum is put into a stainless steel beaker, 80 ml of water is added and stirred, and 80 ml of 2-propanol is further added and stirred for 1 hour. Next, 2 ml of an aqueous dispersion of polytetrafluoroethylene containing 20% by weight of polytetrafluoroethylene was added, stirred, and 10 ml of a commercially available Nafion solution (containing 5% by weight of Nafion, manufactured by Aldrich Chemical) was added. 1 with a stirrer
After stirring for an hour, a catalyst dispersion solution for a positive electrode was prepared.
【００２６】別に、白金１０重量％とルテニウム１０重
量％を含む白金−ルテニウム担持カーボンを１０ｇを使
用し、その他は正極用と同様の手順で、負極用触媒分散
溶液を作製した。Separately, a negative electrode catalyst dispersion solution was prepared in the same procedure as for the positive electrode except that 10 g of platinum-ruthenium-supported carbon containing 10% by weight of platinum and 10% by weight of ruthenium was used.
【００２７】正極および負極とも、撥水処理済みのカー
ボンペーパーの表面に、それぞれ触媒分散溶液を塗布
し、自然乾燥した。さらに、再度塗布、自然乾燥の後、
１１０℃で１時間乾燥して、片面に触媒層が取り付けら
れた、直接型メタノール燃料電池用電極を得た。なお、
正極用電極の触媒層の厚みは約０．０５ｍｍ、電極表面
の白金重量は約１．０ｍｇ／ｃｍ2 とし、負極用電極の
触媒層の厚みは約０．０８ｍｍ、電極表面の白金とルテ
ニウムの合計重量は約２．０ｍｇ／ｃｍ2 とた。For both the positive electrode and the negative electrode, a catalyst dispersion solution was applied to the surface of the water-repellent carbon paper and air-dried. Furthermore, after applying again and drying naturally,
After drying at 110 ° C. for 1 hour, an electrode for a direct methanol fuel cell having a catalyst layer attached to one surface was obtained. In addition,
The thickness of the catalyst layer of the positive electrode is about 0.05 mm, the platinum weight of the electrode surface is about 1.0 mg / cm 2 , the thickness of the catalyst layer of the negative electrode is about 0.08 mm, and the platinum and ruthenium on the electrode surface are The total weight was about 2.0 mg / cm 2 .
【００２８】このようにして得られた正極用電極と固体
高分子電解質膜としてのナフィオン１１５膜を、電極の
触媒を取り付けた面がナフィオン側になるようにして挟
み、１４０℃、３分間ホットプレスして接合し、正極用
電極／電解質膜接合体を作製した。同様にして、負極用
電極と固体高分子電解質膜としてのナフィオン１１５膜
をホットプレスして接合し、負極用電極／電解質膜接合
体を作製した。The positive electrode thus obtained and the Nafion 115 membrane as a solid polymer electrolyte membrane are sandwiched so that the surface of the electrode on which the catalyst is attached is on the Nafion side, and hot pressed at 140 ° C. for 3 minutes. To form a positive electrode / electrolyte membrane assembly. Similarly, a negative electrode and a Nafion 115 film as a solid polymer electrolyte membrane were hot-pressed and joined to produce a negative electrode / electrolyte membrane assembly.
【００２９】つぎに、正極用電極／電解質膜接合体と負
極用電極／電解質膜接合体とを、固体高分子電解質膜を
互いに向かい合わせ、その間に厚み約１．０ｍｍのイオ
ン交換樹脂粉末層をとりつける。イオン交換樹脂粉末と
しては、プロトン型強酸性陽イオン交換樹脂であるオル
ガノ社製−ＳＯ3 Ｈ型アンバーライト２００Ｃを使用し
た。水は燃料電池の外部から供給し、燃料電池内の二枚
の固体高分子電解質膜の間のイオン交換樹脂粉末を含む
中間層を通って、燃料電池の外部に流出するようになっ
ている。なお、水は、燃料電池の上部から下部へ自然に
流れるようにしてもよいし、ポンプを使用して強制的に
流してもよい。Next, the positive electrode / electrolyte membrane assembly and the negative electrode / electrolyte membrane assembly were placed with the solid polymer electrolyte membranes facing each other, and an ion exchange resin powder layer having a thickness of about 1.0 mm was interposed therebetween. Attach The ion-exchange resin powder was used Organo Co. -SO 3 H type Amberlite 200C is a proton type strong acidic cation exchange resin. Water is supplied from outside the fuel cell, and flows out of the fuel cell through an intermediate layer containing ion exchange resin powder between two solid polymer electrolyte membranes in the fuel cell. Water may flow naturally from the upper part to the lower part of the fuel cell, or may be forced to flow using a pump.
【００３０】図１は、本発明になる直接型メタノール燃
料電池の断面構造を示したもので、図１において、１は
負極側固体高分子電解質膜としてのナフィオン１１５
膜、２は正極側固体高分子電解質膜としてのナフィオン
１１５膜、３はイオン交換樹脂粉末と水を含む中間層、
４は水入口、５は水出口であり、水は水入口４から電池
に供給され、中間層を通って水出口５から電池外部に流
出する。６は負極触媒層、７は負極用多孔性集電体とし
てのカーボンペーパーであり、８は燃料であるメタノー
ル水溶液の供給口、９は負極の反応生成物の二酸化炭素
と未反応のメタノールおよび溶媒としての水の排出口で
ある。１０は正極触媒層、１１は正極用多孔性集電体と
してのカーボンペーパーであり、１２は空気あるいは酸
素の供給口、１３は余分の空気あるいは酸素および反応
生成物の水の排出口である。１４は負極端子、１５は正
極端子、１６は燃料電池の枠体である。FIG. 1 shows a cross-sectional structure of a direct methanol fuel cell according to the present invention. In FIG. 1, reference numeral 1 denotes Nafion 115 as a solid polymer electrolyte membrane on the negative electrode side.
Membrane 2, a Nafion 115 membrane as a solid polymer electrolyte membrane on the positive electrode side, 3 an intermediate layer containing ion exchange resin powder and water,
Reference numeral 4 denotes a water inlet, and 5 denotes a water outlet. Water is supplied to the battery from the water inlet 4 and flows out of the battery from the water outlet 5 through the intermediate layer. Reference numeral 6 denotes a negative electrode catalyst layer, 7 denotes carbon paper as a porous current collector for the negative electrode, 8 denotes a supply port of an aqueous methanol solution as a fuel, 9 denotes methanol and a solvent which have not reacted with carbon dioxide as a reaction product of the negative electrode. As a water outlet. Reference numeral 10 denotes a positive electrode catalyst layer, 11 denotes carbon paper as a porous current collector for the positive electrode, 12 denotes a supply port for air or oxygen, and 13 denotes a discharge port for excess air or oxygen and water for reaction products. Reference numeral 14 denotes a negative terminal, 15 denotes a positive terminal, and 16 denotes a fuel cell frame.
【００３１】本発明になる直接型メタノール燃料電池
（電池Ａとする）では、あらかじめ二枚のナフィオン膜
の間に設けたイオン交換樹脂粉末層に、水を３０ｍｌ／
ｍｉｎの速度で流しておく。一方、比較用の直接型メタ
ノール燃料電池（電池Ｂとする）は、負極側のナフィオ
ン膜と正極側ナフィオン膜の間に、イオン交換樹脂粉末
とからなる層を設け、水は流動させなかった。In the direct methanol fuel cell according to the present invention (referred to as a battery A), 30 ml of water is added to the ion exchange resin powder layer previously provided between the two Nafion membranes.
Flow at a speed of min. On the other hand, in a direct methanol fuel cell for comparison (referred to as battery B), a layer composed of an ion-exchange resin powder was provided between the Nafion membrane on the negative electrode side and the Nafion membrane on the positive electrode side, and water was not allowed to flow.
【００３２】次に、正極に６０℃の水蒸気で加湿した空
気を２ｌ／ｍｉｎの速度で供給し、負極にメタノールを
ｌｍｏｌ／ｌ含む７０℃の水溶液を供給して、直接型メ
タノール燃料電池の特性を測定した。図２はｉ−Ｖ特性
を示したもので、水を流動しない比較電池Ｂにくらべ、
本発明になる電池Ａの特性はかなり優れたものとなっ
た。Next, air humidified with steam at 60 ° C. was supplied to the positive electrode at a rate of 2 l / min, and an aqueous solution at 70 ° C. containing 1 mol / l of methanol was supplied to the negative electrode. Was measured. FIG. 2 shows the i-V characteristic, and is compared with the comparative battery B which does not flow water.
The characteristics of the battery A according to the present invention were considerably excellent.
【００３３】［実施例２］二枚の固体高分子電解質の間
に設けた中間層のイオン交換樹脂粉末として、プロトン
型弱酸性陽イオン交換樹脂であるオルガノ社製−ＣＯＯ
Ｈ型アンバーライトＩＲＣ−５０を使用し、その他の条
件は実施例１と同様の直接型メタノール燃料電池（電池
Ｃとする）を作製した。電池Ｃの特性を実施例１と同様
の条件で測定した結果、そののｉ−Ｖ曲線は電池Ａの特
性とほぼ同じであった。Example 2 As an ion-exchange resin powder of an intermediate layer provided between two solid polymer electrolytes, a proton-type weakly acidic cation-exchange resin, -COO manufactured by Organo Corporation was used.
A direct methanol fuel cell (referred to as cell C) was prepared using H-type Amberlite IRC-50 under the same conditions as in Example 1 except for the above conditions. As a result of measuring the characteristics of Battery C under the same conditions as in Example 1, the i-V curve thereof was almost the same as the characteristics of Battery A.
【００３４】[0034]
【発明の効果】従来の直接型メタノール燃料電池におい
ては、負極に燃料としてのメタノールを溶かした水溶液
を供給するが、メタノールが水を吸収した高分子固体電
解質膜と接触した場合、メタノールは速やかに高分子固
体電解質膜中の水に溶解し、高分子固体電解質膜中に含
まれる水の中を拡散して正極に達し、正極の触媒上で反
応することになる。その結果、正極の触媒活性が低下
し、電池の特性が悪化する。In the conventional direct methanol fuel cell, an aqueous solution in which methanol as a fuel is dissolved is supplied to the negative electrode. However, when the methanol comes into contact with the solid polymer electrolyte membrane that has absorbed water, the methanol is quickly removed. It is dissolved in the water in the polymer solid electrolyte membrane, diffuses in the water contained in the polymer solid electrolyte membrane, reaches the positive electrode, and reacts on the catalyst of the positive electrode. As a result, the catalytic activity of the positive electrode decreases, and the characteristics of the battery deteriorate.
【００３５】しかし、本発明の直接型メタノール燃料電
池では、電解質層が二枚の固体高分子電解質膜の間にプ
ロトン型イオン交換樹脂粉末と水を含む中間層を備えた
三層となっており、しかも中間層の水を流動させている
ため、メタノールが負極から負極側固体高分子電解質膜
を通ってイオン交換樹脂粉末と水を含む中間層に拡散し
た場合、中間層の水は流動しており、メタノールを含ん
だ水は燃料電池の外部に取り出され、メタノールは正極
側固体高分子電解質膜へはほとんど移動しない。その結
果、正極の触媒活性は元の状態に保たれ、電池特性の劣
化を防ぐことができる。また、本発明においては、燃料
電池の反応に使われなかったメタノールは、回収して再
使用することができる。However, in the direct methanol fuel cell of the present invention, the electrolyte layer is a three-layer structure including an intermediate layer containing a proton-type ion exchange resin powder and water between two solid polymer electrolyte membranes. In addition, since the water in the intermediate layer is flowing, when the methanol diffuses from the negative electrode through the solid polymer electrolyte membrane on the negative electrode side to the intermediate layer containing the ion exchange resin powder and water, the water in the intermediate layer flows. In this case, water containing methanol is taken out of the fuel cell, and methanol hardly moves to the solid polymer electrolyte membrane on the positive electrode side. As a result, the catalytic activity of the positive electrode is maintained in the original state, and deterioration of battery characteristics can be prevented. Further, in the present invention, methanol not used in the reaction of the fuel cell can be recovered and reused.
【００３６】なお、中間層にはイオン交換樹脂粉末が含
まれているため、中間層のイオン電導度は通常は固体高
分子電解質膜よりやや小さいが、そのために燃料電池の
放電特性が特に悪くなることはない。なお、実施例で
は、中間層に使用するイオン交換樹脂粉末としてアンバ
ーライト２００ＣやＩＲＣ−５０を使用したが、本発明
において使用するイオン交換樹脂粉末としては、その他
のあらゆるプロトン型イオン交換樹脂粉末を使用した場
合も同様の効果が得られるものである。Since the intermediate layer contains the ion exchange resin powder, the ion conductivity of the intermediate layer is usually slightly lower than that of the solid polymer electrolyte membrane, but the discharge characteristics of the fuel cell are particularly deteriorated. Never. In the examples, Amberlite 200C or IRC-50 was used as the ion exchange resin powder used for the intermediate layer. However, as the ion exchange resin powder used in the present invention, any other proton-type ion exchange resin powder was used. Similar effects can be obtained when used.
【図１】本発明になる直接型メタノール燃料電池の断面
構造を示す図FIG. 1 is a diagram showing a cross-sectional structure of a direct methanol fuel cell according to the present invention.
【図２】本発明になる直接型メタノール燃料電池Ａと比
較電池Ｂの特性を比較した図FIG. 2 is a diagram comparing the characteristics of a direct methanol fuel cell A according to the present invention and a comparative cell B.
１ 負極側固体高分子電解質膜 ２ 正極側固体高分子電解質膜 ３ 中間層 ４ 水入口 ５ 水出口 ６ 負極触媒層 ８ メタノール水溶液供給口 １０ 正極触媒層 １２ 空気あるいは酸素供給口 Reference Signs List 1 negative electrode side solid polymer electrolyte membrane 2 positive electrode side solid polymer electrolyte membrane 3 intermediate layer 4 water inlet 5 water outlet 6 negative electrode catalyst layer 8 methanol aqueous solution supply port 10 positive electrode catalyst layer 12 air or oxygen supply port
Claims (3)
ン型イオン交換樹脂粉末と水を含む中間層を備え、該中
間層の水を流動させることを特徴とする、固体高分子電
解質を備えた直接型メタノール燃料電池。1. A solid polymer electrolyte comprising: an intermediate layer containing a proton-type ion exchange resin powder and water between two solid polymer electrolyte membranes; and allowing the water in the intermediate layer to flow. Equipped direct methanol fuel cell.
通った後、電池外部に放出されることを特徴とする、請
求項１記載の固体高分子電解質を備えた直接型メタノー
ル燃料電池。2. The direct methanol fuel cell equipped with a solid polymer electrolyte according to claim 1, wherein water is supplied from outside the cell, passes through the intermediate layer, and is discharged outside the cell. .
るメタノールの含有量を減少させる装置との間を、水が
循環することを特徴とする、請求項１記載の固体高分子
電解質を備えた直接型メタノール燃料電池。3. The solid polymer electrolyte according to claim 1, wherein water circulates between the intermediate layer and a device provided outside the battery for reducing the content of methanol contained in the water. Direct methanol fuel cell equipped with
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19062597A JP3774898B2 (en) | 1997-06-30 | 1997-06-30 | Direct methanol fuel cell with solid polymer electrolyte |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19062597A JP3774898B2 (en) | 1997-06-30 | 1997-06-30 | Direct methanol fuel cell with solid polymer electrolyte |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1126005A true JPH1126005A (en) | 1999-01-29 |
| JP3774898B2 JP3774898B2 (en) | 2006-05-17 |
Family
ID=16261192
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19062597A Expired - Lifetime JP3774898B2 (en) | 1997-06-30 | 1997-06-30 | Direct methanol fuel cell with solid polymer electrolyte |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002014212A1 (en) * | 2000-08-16 | 2002-02-21 | Siemens Aktiengesellschaft | Method for mixing a fuel with water, a corresponding device and the use thereof |
| JP2006260909A (en) * | 2005-03-16 | 2006-09-28 | Nissan Motor Co Ltd | Membrane electrode assembly and polymer electrolyte fuel cell using the same |
| US7175929B2 (en) | 2002-11-25 | 2007-02-13 | Fujitsu Component Limited | Fuel cell, method of manufacturing the same, and fuel cell stack including the same |
| US7749625B2 (en) | 2003-12-18 | 2010-07-06 | Kurita Water Industries Ltd. | Fuel for fuel cell, fuel cell and application thereof |
| JP4768261B2 (en) * | 2002-04-23 | 2011-09-07 | コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ | Basic fuel cell element to limit methanol passing through the electrolyte layer |
-
1997
- 1997-06-30 JP JP19062597A patent/JP3774898B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002014212A1 (en) * | 2000-08-16 | 2002-02-21 | Siemens Aktiengesellschaft | Method for mixing a fuel with water, a corresponding device and the use thereof |
| JP4768261B2 (en) * | 2002-04-23 | 2011-09-07 | コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ | Basic fuel cell element to limit methanol passing through the electrolyte layer |
| US7175929B2 (en) | 2002-11-25 | 2007-02-13 | Fujitsu Component Limited | Fuel cell, method of manufacturing the same, and fuel cell stack including the same |
| US7749625B2 (en) | 2003-12-18 | 2010-07-06 | Kurita Water Industries Ltd. | Fuel for fuel cell, fuel cell and application thereof |
| JP2006260909A (en) * | 2005-03-16 | 2006-09-28 | Nissan Motor Co Ltd | Membrane electrode assembly and polymer electrolyte fuel cell using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3774898B2 (en) | 2006-05-17 |
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