JPS5946104A - Composite membrane selectively permeable for gaseous oxygen - Google Patents

Abstract

PURPOSE:To provide a selectively permeable membrane for oxygen capable of heavy load discharge over a long period of time, excellent in preservability and suitable for preparing a thin air electrode, obtained by integrally adhering a thin layer of metal oxide having a rutile type crystal structure on one surface of a porous membrane. CONSTITUTION:As a porous membrane, a porous fluorine membrane, a porous polycarbonate membrane or a porous cellulose ester membrane can be recommended. Metal oxide having a rutile type crystal structure has such a structure that a coordinate polyhedron shown by a chemical formula AO2 is a regular octahedron and aggregates each arranged unidimensionally in relation holding an edge thereof in common are combined and, concretely, titamium dioxide, vanadium dioxide or molybdenum dioxide alone or a composite in an arbitrary combination comprising two kinds or more of them can be mentioned. In the case of a composite membrane having a two-layered structure, a thin layer of metal oxide with a rutile type crystal structure is directly adhered on one surface of the porous membrane by a vapor deposition method on a sputtering method.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a hydrogen/oxygen battery, a metal/air tank,
Regarding the oxygen gas selectively permeable composite membrane, which is effective in manufacturing air electrodes for oxygen sensors, we have detailed information about it.Even though it is thin, it can be subjected to heavy loads for a long time, and has excellent storage performance. 15jl is applied to a composite membrane selectively permeable to He and 9 gases for air electrodes.

[Technical background of the invention' and its points of interest]

Conventionally, force diffusion electrodes have been used for air electrodes in various fuel cells, air metal batteries, galvanic oxygen sensors, etc. As the diffusion 1 electrode, the original porous TFC electrode with a uniform pore size distribution in the % and Q periods has been used, but recently, electrochemical reduction ability (to ionize oxygen) for oxygen gas has been used. It consists of a porous ?lZ L& system body which also has a current collector (J) function, and a four-film water-repellent layer that is integrally attached to the gas side surface of the 'FIX electrode body. Two-layer 1'H electrodes are often used.

In this case, the electrode body mainly consists of h.? The sum is refunded.

Nickel tungstic acid with low overvoltage; ] and radium.
Tungsten carbide coated with cobalt; nickel; silver; platinum; , which is integrated with a porous metal body, a porous carbon body, a nonwoven fabric of carbine fiber, etc., is used.

In addition, the water-repellent layer attached to the gas side surface of the electrode body is mainly made of fluororesins such as polytetrafluoroethylene, polytetrafluoroethylene-hegizafluoropropylene copolymer, and polyethylene-tetrafluoroethylene copolymer. , or a thin film made of resin such as polypropylene
For example, these particles with a particle size of 0.2 to 40 μm (
A sintered body of T, 4 fat powder; a paper-like material made by heating the fibers of these resins and making it into a non-woven fabric; a fibrous cloth-like object;
These (a part of the τrl fat powder is replaced with fluorinated graphite; these fine powders are roll-pressed together with pore-forming agent, lubricating oil, etc. and then heat-treated to form a film, or roll-pressed and then heated. It is a multifloral thin film with a distribution of vyta pores, such as a film-like film that does not undergo any processing.

However, in the above-mentioned conventional air 1°C electrode, the cold water layer attached to the gas side surface of the electrode body is impermeable to the electrolyte, but air or air It is impermeable to the water vapor inside.

Therefore, for example, water vapor in the air can pass through the outer aqueous layer and enter the polar body at '1', diluting the liquid 'r(f, Water in the solution may dissipate as water vapor from the aqueous layer, concentrating the electrolyte.As a result, the concentration of the electrolyte fluctuates, making it difficult to maintain a stable discharge for a long time. This may result in a situation where it becomes impossible to do so.

When carbon dioxide gas in the air passes through the water-repellent layer, enters the electrode body, and is adsorbed on the active layer, the electrochemical reduction ability for oxygen gas at that location decreases, and heavy load discharge is inhibited. Also, the electrolyte is Alka! When the J If solution is 0, it causes deterioration of the electrolyte, a decrease in concentration, or, when the cathode is zinc, a phenomenon such as inversion (quaternization) of the zinc cathode. In the porous parts of the system body, heavy-load discharges are 1) impeded because carbonates form and block the pores, reducing the area in which chemical evacuation takes place.

This kind of thing happens when the pond is stored for a long time or used for a long time. In this case, the performance of the battery deteriorates from the design standard.

For this reason, the gas side (air side) of the water repellent layer sponsored by Ritoki i
In addition, one proposed fli pond is provided with a layer of a moisture absorbent such as calcium chloride, an absorbent, or a carbon 1.1 ammonium gas absorbent such as an alkaline earth metal hydroxide.

This can prevent the above-mentioned inconveniences to some extent, but if these absorbents reach a saturated state and lose their absorption capacity after a certain period of time, the effect disappears, so there is no essential effect. It couldn't have been Ai's fault.

Further, attempts have been made to further integrally form a thin film selectively permeable to oxygen gas, such as a polysiloxane film, on the water-repellent layer described above. However, to date, no sufficiently effective f',27 gas-selective membrane has been developed.

[Purpose of the invention]

Mizumoto 19 has a selective permeability for oxygen gas, and therefore, when applied to an air electrode, water vapor or carbon dioxide in the air can be absorbed into the main body without infiltration.
Therefore, it is possible to discharge the charge over a long period of time, and the storage performance is also improved.
・The purpose is to provide a composite membrane that can be selected from phosphorus gas.

(Required for Jnj Ming's I1) The 19th membrane of the present invention has a first fAjJ with a pore diameter of 1 μm.
One side of a porous membrane having the following micropores is a two-layer structure characterized by a rutile structure, and the second aspect is a combination of the porous membrane and a thin layer of the metal oxide. It is a composite membrane with a three-layer structure that is entirely integrated with 11 aqueous layers interposed between them.

In the composite membrane of the present invention, the porous membrane has a pore diameter of 0.
The material may be any material as long as it has micropores of 1 μm or less, but it is preferable to use a material with high flexibility in consideration of attachment to the electrode body. Further, the porous membrane is preferably one in which the above-mentioned micropores are uniformly distributed,
The pore volume of the small 111 holes is 0.1 to 0.1 to the cash conversion volume.
Those within the scope of Article 90 are suitable.

Such porous membranes include, for example, porous fluororesin membranes (trade name, Fluoropore; manufactured by Sumitomo Electric Corporation), porous polycarbonate membranes (trade name, -Nucrypore; manufactured by Nucripore Corporation), porous Cellulose ester membrane (trade name, Milin Amenplan Filter; manufactured by Milin 1? Accorporation), porous polypropylene
An example of this product is Celguard (trade name, Celguard; manufactured by Celanese Φ Zorasbutuk). In these porous membranes, when the pore diameter exceeds 1 μm, when a thin layer of metal oxide or a water-repellent layer, which will be described later, is formed on the porous membrane, a large amount of vinyl sol will be generated in the thin layer or water-repellent layer. This results in a loss of the effect of preventing the intrusion of water vapor or carbon dioxide gas, as well as a decrease in mechanical strength, making it more likely to break.

Next, the metal oxide of the rutile-type crystal 11V structure according to the present invention (#'i, represented by the chemical formula AO2, the coordination polyhedron is a regular octahedron, and the edges of this octahedron are sputum-shaped and one-dimensionally It refers to a substance having a 4,'4 structure in which 11 and 3iS combinations are combined, and specifically, tin dioxide (Sn02).

2jV-Titanium oxide (T102) l Vanadium dioxide (VO2).

Molybdenum dioxide (Mo02) -21, nominal tungsten <vjo2), 21', rubidium Q ide (Ru0
2), Niobium diH47ide (NbOz), 211:2
Chromium chloride (Cr'-)2), rhenium dioxide (α
-ReO7), Osmiu A ((-) s
02) rdioxide (RhO2), dil+
Iridium +9 (I rO?) r21'1 cultured platinum (
P-tox) may be used alone or in combination of two or more of them.

Of these, 5nOz + Tilt is particularly useful.

The composite membrane of the present invention can be manufactured as follows. First, in the case of composite 11q having a two-layer structure, 9 layers of metal oxide F having a rutile type crystal structure are directly attached to one side of the above-mentioned porous membrane.

As a method of attachment, a vapor deposition method and a sputtering method, which are frequently used as a r'='J IIA forming method, are suitable.

At this time, the thickness of the thin layer is preferably 0.01 to 1.0 μm, and the thickness is less than 0.01 μm. ') If the formed thin layer has many pinholes, it is necessary to remove the water vapor or carbon 112 gas from the charcoal gas.
1-At the same time as the effectiveness is reduced, the mechanical strength of the 9 layer is reduced and it becomes easy to break. On the other hand, if the thickness exceeds 1 μm, the amount of permeation of oxygen gas decreases, which deteriorates the heavy-load discharge characteristics of the prepared battery.

Next, in the case of a composite membrane with a three-layer structure, water-blocking M is first formed on one side of the porous membrane, and then vaporized A is applied as in the case of a two-layer structure composite membrane. A layer of gold having a rutile type crystal structure is formed on the water-repellent layer by a sputtering method or a sputtering method.

Here, the material Jj5 forming the water-repellent layer may be any material having water resistance and electrolyte resistance,
-1'.

Soil, such as polytetrafluoroethylene (PTli'E)
), fluoroethylene propylene (I”El)), , l
? IJ phenylene oxide (PPO), polyphenylene sulfide (PPS), polyethylene (P, Fl:
), polypropylene (pp), copolymers thereof, or mixtures thereof.

7k Jr. At this time, the material of the aqueous layer q'' and [-te7j゛? Reflow mouth ethylene propylene (FE, P) 1.
je IJ ethylene (PfiE), ethylene-tetrafluoroethylene co-T1r combination:
By using the power, (・V,・1゛1), it is possible to use the complex meditator 'l'().
It is possible to increase the degree.

The water-repellent layer used in the present invention is SU! For each (1st generation of (T-organic compounds,
I
Hydrocarbon compounds, C0-C12 unsaturated hydrocarbon compounds, C8-CI4 alkylbenzene compounds, styrene,
(An example is a thin layer formed on a porous layer by plasma polymerizing a hydrocarbon compound such as χ-methylstyrene or a mixture thereof. All of these γ layers have no pinholes. In particular, the above-mentioned fluorinated organic compound has an excellent permeability to oxygen gas.In particular, the above-mentioned fluorinated organic compound has a thin layer formed by subjecting its single molecule to 70° plasma polymerization [7]. It is useful because it has the effect of preventing the intrusion of rii2 gas for 5 hours.

The thickness of the thin film to be formed is preferably in the range of 01 to 1.0 μm, and when the Iλ value is less than 0.01 μm, the formed layer becomes island-like. Therefore, the surface of the porous membrane cannot be uniformly coated, and the effect of stopping carbon dioxide gas or water vapor from entering is reduced. Furthermore, ``, False; i of the whole 4 ;: J + ・(12 intensity is lowered to 1〇 Conversely, if the j-J difference exceeds 1.0 μm, ′
I: 7 (hi:li is supplied to the electrode body when it is erected)
Ru II? The discharge characteristics of 1.4 poles deteriorate due to lack of 1d of elementary gas (heavy (Ll"::n' is 12 +'?,'lf
become).

Also mentioned above:! The y layer may be formed as a single layer, but a polymeric thin film made of an organic compound of f:H may also be separately formed on this layer.

On top of the aqueous layer thus formed, 1((
What about the rutile crystal structure? kJ41”!Evening light
・? j・;−] is changed to (?suj・;4. Its thickness is
Same as in the case of 4jt aqueous 1.゛.te ([, it is clever that it is 0.01 to 1.0 μm for the reason of Q.

Gold 11. has a rutile crystal structure, whether it is a two-layer structure or a 3-layer structure. i (1 ~ Monster Ngin layer //)
, When it comes to 1 sugina, its source or spa °
Gold 1. that can be collected as a source of ivy? The 41-oxide itself can be used as a storage or as a source of sulfur, reacting with the 12-element to form these gold 1y+i.
(+Using various simple metals that generate trapped compounds, and
Oxygen 9. If j is the surrounding air J″, the metal r′i,″
The rate of formation of a thin layer of debris increases, creating a trench.1. : is preferable because it also facilitates the layer formation operation.

(Example of '+ij Akira) Jitinoiri 1 row 1 to 13 A porous polycarbonate membrane (trade name,
Nucleipore; Nucleipore corporation, thickness 5
μm) on one side of Sn, Ti + V + Mo, WRu
, Nb, Cr, R, e, Os, Rh+ Ir, Pt as a snokkuta source, a mixed gas of argon and oxygen (Ar 90 vol 1%) at a pressure of 2 X 10-3 Torr.
*0210 voe %) +High frequency'+ power 10
Sputtering was carried out under the condition of 0 W to form thin layers of various metal chlorides having rutile type crystal structures. Thickness 0.2μm
□ Examples 14 to 26 Argon gas pressure of 1 x 102 Torr was applied to one side of a porous polycarbonate membrane with the same specifications as used in Examples 1 to 13.
A water-repellent layer having a thickness of 0.2 μm was formed by sputtering fluoroethylenezolopyrene (FEP) under conditions of a high frequency output of 200 W. Next, various rutile molds were added on top of this in the same manner as in Examples 1 to 13! Examples 27 to 39 A porous polycarbonate membrane having the same specifications as those used in Examples 1 to 13 was 13. Load the plasma reactor and remove it from the outside.
56 MI (high frequency 'u force of z was applied, 600 ml/rtm of argon and 600 ml/+nin of pentafluorostyrene monomer gas were introduced into the chamber, and the PF output was 0°4 W/Nada. A plasma reaction was carried out to form an R layer of pentafluorostyrene polymer having a thickness of 2 μm on one side of the 71?recarbonate film.

Then, on top of this, an i'f layer (0.2 μm
) was formed.

For the above 39 types of composite membranes, the sum) oxygen i to 1
i, i(l speed (JO2: cc/5ee-cri
c+aHg) by normal washing using a gas chromatograph as a detection means, i ta, water vapor permeability 3fjii i degrees (
Jn2o: ”/sec-d-mHz)
208 (cup method), and detected as the ratio of the two (JO2/, rH2o) f: gas η excess ratio.

For comparison, a 50 μm thick polypropylene film (Comparative Example 1), a 20 μm thick medium density polyethylene film (
Comparative Example 2), 20 μm thick biaxially oriented polypropylene film (Comparative Example 3), 20 μm thick polytetrafluoroethylene film (Comparative Example 4), 20/1 m thick commercially available I・'E
P film (Comparative Example 5), 0.2 μm thick I” EPj film (1
Regarding upper axis example 6), Jo, , Jit2o were similarly determined, and JO2/Jn,o was calculated.

The above results are summarized in the table.

〔Effect of the invention〕

As is clear from the above explanation, although the composite membrane of the present invention is extremely thin, it does not allow the permeation of water vapor in the air, and has a large selective permeability with oxygen gas. 4) The air electrode combined with the main body is
′! 7. It is possible to perform load discharge over a long period of time, and its storage performance is also improved. Also, leakage resistance is improved.

Therefore, the engineering value of the composite membrane of the present invention is extremely significant.

Claims (1)

[Scope of Claims] 1. A thin layer of gold kRf4' having a rutile crystal structure is integrally attached to one side of a porous membrane having micropores with a pore diameter of 0.1 μm rLμ, elementary gas i
1 selectively permeable composite membrane. 2. The metal oxide is tin dioxide, titanium nitride, vanadium dioxide, molybdenum dihydride, tungsten dioxide, rubidium dioxide, niobium dioxide, chromium dioxide, rhenium dinitride, osmium dioxide, rhodium dioxide, iridium dioxide, or An oxygen gas selectively permeable composite membrane as described in item 1 of the scope of patent RI'r, which is made of at least one metal oxide selected from the group of platinum. 3. The gas-selective permselective composite membrane according to claim 1, wherein the thin layer has a thickness of 0.01 to 1.011 m. 4 Porous membrane having micropores with a pore diameter of 0.1 μm or less 3
An oxygen gas permselective composite membrane characterized in that a water-repellent layer and a thin layer of a rutile-type, crystalline metal oxide are integrally laminated on one side of the 1] in the direct order of the above. 5 The metal oxide is tin dioxide, titanium dioxide, vanadium dioxide, molybdenum dioxide, tungsten dioxide, rubidium diyride, niobium dioxide, chromium dioxide,
Patent M, which is at least one metal oxide selected from the group consisting of di-alpha-z dihydride, osmium dioxide, di-i' (rhodium dioxide, iridium dioxide, and platinum dioxide); Oxygen gas selective permeation] Comb composite blade. 6. The oxygen gas selective permeation composite membrane according to item 4 of the scope of Patent M1, wherein the water-repellent layer is a thin layer of a monomolecular plasma polymer of a fluorinated finite compound. 7. The thickness of the water-repellent layer and the metal oxide thin layer are 0.01 to 1.0 μm, respectively! 1 month of oxygen according to any one of items 4 to 6, within the range of blue water. Gas-selective permeable composite membrane.