ES2217957B1 - PROTONIC DRIVING MEMBERS BASED ON POLYMERS OF THE POLYBENCIMIDAZOL TYPE AND HYBRID MATERIALS AND NANOCOMPOSES DERIVED FROM THEM. - Google Patents

Abstract

Proton conductive membranes based on polybenzimidazole-type polymers and hybrid materials and nanocomposites derived therefrom. The materials and procedures described in this patent refer to protonic conductive materials for use at temperatures between room temperature and 200 ° C in electrochemical devices that require proton conductive membranes that include, but are not limited to, fuel cells, electrochemical capacitors, pumps hydrogen and other storage and energy conversion devices. The membranes are based on polybenzimidazoles and their derivatives, as well as on organic-inorganic hybrid materials composed of polybenzimidazoles or their derivatives and proton conductive inorganic compounds. To acquire a high proton conductivity, these membranes are doped with strong acids either during the casting process, or subsequently by immersion of the membrane in an acid bath.

Description

Proton conductive membranes based on polybenzimidazole polymers and hybrid materials and nanocomposites derived from them.

Technical sector

In relation to the manufacture of the materials described, this patent is addressed to the chemical sector and as a subsector polymers and composites

On the other hand, the application of membranes affects the energy sector and specifically fuel cells, electrochemical capacitors and other energy storage and conversion devices.

State of the art

Fuel cells are devices electrochemicals that convert the energy of a reaction electrochemistry directly in electric current. Piles of polymeric electrolyte fuel (PEMFC) are constituted basically by two electrodes (usually porous electrodes of platinum on carbon) separated by a polymeric membrane proton conductor but electron flow insulator, (this electrode and membrane assembly is called assembly electrode-membrane-electrode or MEA). The fuel, usually hydrogen, is circulated through the anode (negative electrode), while an oxidant, usually oxygen or air, is circulated through the cathode (electrode positive).

In a PEMFC, the reactions that take place are two. On the one hand, in the anode the dissociation of the hydrogen giving rise to two protons and two electrons. While the two electrons are circulated to the cathode by a external circuit generating electric current, the protons cross the membrane to reach the cathode, and combine with the two electrons and oxygen (pure or as air) to give rise to to water as the only "residue". The possibility of generating electricity from hydrogen, without generating any contaminants, and giving rise to water as the only byproduct makes the batteries of very attractive fuel from a scientific point of view, Technological, political, social, and economic.

Proton conductive membranes normally used as electrolyte in fuel cells and other cells electrochemical, are based on perfluorosulfonated polymers, among which Nafion® stands out. These membranes need to be strongly hydrated to maintain high conductivity proton, which limits its working temperature below 100 ° C and involves delicate moisture management in the gas inlet and outlet. On the other hand, in the stacks of polymer electrolyte fuel, catalysts are used of Pt / C. These catalysts are very sensitive to poisoning. even for the small amounts of CO present in the gases, especially when they come from hydrocarbon reforming. This effect can be reduced to higher temperatures, for which is necessary the development of polymeric membranes with Good conductivity and stability at high temperatures.

Polybenzimidazole (poly [2,2 '- (m-phenylene) -5,5'-bibencimidazole]) (which we will denote here as PBI) is the only commercial polymer of this type so far. It is a polymer with high thermal stability whose imidazole groups give it a basic nature, which allows when a membrane of this polymer is immersed in a phosphoric acid solution, the membrane absorbs up to 70% acid (Wainright, JS et al ., M. J. Electrochem. Soc . 1995, 142 , L121-L123). The different procedures for obtaining phosphoric acid doped PBI membranes that are described in the literature, both in scientific and technical journals and in patents, are summarized in the scheme shown in Figure 1. In these membranes, the conductivity is It derives precisely from the high proportion of acid absorbed by the polymer, while the GDP, while retaining the acid, confers mechanical stability to the whole. When working with PBI-H 3 PO 4 membranes, moisture management in gases becomes much less important, since proton conductivity is given by the high proportion of acid present in the membrane. This allows the GDP to work at temperatures up to 200 ° C. This higher working temperature of the GDP doped with phosphoric acid favors the kinetics of Pt catalysts, and decreases the effect of CO poisoning, which allows working with hydrogen of lower purity (Savadogo, O., Xing, B. J. New Mat. Electrochem. Systems 2000, 3, 345-349; Qingfeng, L. et al ., NJ J. Appl. Electrochem . 2001, 31,
773-779.)

These PBI-phosphoric acid membranes have been used mainly in fuel cells (generally using H2 as fuel, but also methanol, ethanol, propane, ..) (Savadogo, O. and Xing, B. J. New Mat Electrochem Systems 2000, 3, 345-349; Qingfeng, L. et al . J. Appl. Electrochem . 2001, 31, 773-779; Wang, JT et al . Electrochimica Acta 1996, 41, 193-197; Bjerrum , NJ and Li, Q .; Hjuler, HA, World Patent 0118894, 2001; Wang, JT et al . Electrochimica Acta 1998, 43, 3821-3828; Wang, JT et al . J. Electrochem. Soc . 1995, 142, 4218-4224; Weber, M. et al . J. Electrochem. Soc . 1996, 143, L158-L160; Xing, B. and Savadogo, O. Electrochem. Comm . 2000, 2, 697-702; Wang, JT et al . J. Appl. Electrochem . 1996, 26, 751-756; Savadogo, O. and Rodriguez Varela, FJ J. New Mat. Electrochem. Systems 2001, 4; Hasiotis, C. et al . J. Electrochem. Soc . 2001, 148, A513-A519.), In sensors (Bouchet, R. et al . J. Electrochem. Soc . 1997, 144, L95-L97; Bouchet, R. et al . J. Electroch em. Soc . 2000, 147, 3125-3130; Bouchet, R. et al . G. J. Electrochem. Soc . 2000, 147, 3548-3551; Bouchet, R. et al . Sensors and Actuators B: Chemical 2001, 76, 610-616), supercapacitors (Li, C., World Patent 9826466, 1998; Wu, H. et al . US Patent 5723231, 1998; Li, C. et al . World Patent 9738460, 1997), or electrochromic devices (Athenstaedt, W. et al . World Patent 0028374, 2000).

The most common way of preparing phosphorus-doped PBI membranes is the evaporation of PBI solutions in dimethylacetamide (DMAc) (Wainright, JS et al ., M. J. Electrochem. Soc . 1995, 142, L121-L123; Savinell , RF and Lift, M., US Patent 5525436, 1996; Moaddel, H., Ph. D. Thesis Case Western Reserve University, 1996). For this, a solution of PBI in DMAc (10-20%) is prepared and the solvent is allowed to evaporate by applying vacuum and / or temperature. Frequently, LiCl (1-2%) is added to avoid phase separation in the solution when it is stored (Trouw, NS and Gillette, NJ, US Patent 4693825, 1987). The membranes obtained are washed in boiling water to remove the remains of DMAc and LiCl, dried, and immersed for at least 16 hours in a phosphoric acid / water mixture, although it is possible to accelerate this process by increasing the temperature (Yamamoto, T ., World Patent 0039202, 2000). It has also been found that there is an immersion time of 10–11 hours after which the conductivity increases sharply up to two orders of magnitude (Glipa, X. et al . J. Mater. Chem . 1999, 9, 3045-3049 ). The membrane obtained is dried under vacuum or by heating.

The H 3 PO 4 molecules absorbed by the membrane form a salt protonating the imine nitrogen from the benzimidazole ring. This can be verified by the appearance of a very intense band in the FT-IR of films doped at 2500-3000 cm -1 (Bouchet, R. and Siebert, E. Solid State Ionics 1999, 118, 287- 299).

The mechanical properties of these membranes are improved by using higher molecular weight PBI, so prior polymer fractionation is recommended. This fractionation is carried out taking advantage of the solubility of GDP of different molecular weights in DMAc as a function of temperature (Moaddel, H., Ph. D. Thesis Case Western Reserve University, 1996; Buckley, A .; Stuez, ED; Serad , GA Polybenzimidazoles in Encyclopedia of Polymer Science and Engineering 2nd ed. Vol. 11 1988). Another way to improve the mechanical properties of evaporated DMAc membranes is to add ethylene glycol diglycidyl ether (Yamamoto, T., World Patent 0044816, 2000). This diepoxide reticulates the polymer when it is opened by reaction with the benzimidazole N. In this way the mechanical properties are improved, however, the amount of H 3 PO 4 that the membrane can absorb under the same conditions decreases.

An alternative method, which condenses all stages in one step, is direct acid casting (Savinell, RF and Litt, M., World Patent 9737396, 1997; Ameri, R., Ph. D. Thesis Case Western Reserve University, 1997; Ma, Y. et al . Conductivity of PBI Membranes for High Temperature Polymer Electrolyte Fuel Cells , Proceedings of the Meeting of the Electrochemical Society, San Francisco, 2001). These membranes are prepared from a solution of 20% PBI in trifluoroacetic acid (TFA) at reflux (Ameri, R., Ph. D. Thesis Case Western Reserve University, 1997.).

A patent of Celanese Ventures (sole manufacturer of PBI) (Sansone, MJ et al . Patent 6187231, 2001; Sansone, MJ et al World Patent 9814505, 1998) describes the preparation of polybenzimidazole membranes by solution coagulation.

In addition to PBI-phosphoric acid membranes, other materials are currently being tested as an alternative to Naphion membranes for the applications cited above. Among the most recent are the application of well-known inorganic protonic conductors, such as cesium acid sulfate (CsHSO4) whose application in fuel cells has been published recently (Haile, SM et al . Nature 2001, 410 , 910-913; Haile, SM, World Patent 0045447, 2000).

This patent affects the development of new polymeric and hybrid materials (organic-inorganic) with improved properties of conductivity and stability at high temperatures. The materials organic-inorganic hybrids are combinations to molecular level (nanocomposites) of organic polymers and species inorganic active and proton conductive. The development of These hybrid nanocomposite materials provide the opportunity to combine the best properties of both types of components optimizing its performance

Description brief description

The materials and procedures described in this patent refer to proton conductive materials for use at temperatures between room temperature and 200 ° C in electrochemical devices that require conductive membranes protonics that include, but are not limited to, batteries of fuel, electrochemical capacitors, sensors, pumps hydrogen and other storage and conversion devices of Energy.

The membranes are based on polybenzimidazoles and their derivatives, as well as on organic-inorganic hybrid materials composed of polybenzimidazoles or their derivatives and proton conductive inorganic compounds. To acquire a high proton conductivity, these membranes are doped with strong acids either during the casting process, or subsequently by immersion of the membrane in an acid bath.

An outline of the preparation techniques of these acid-doped membranes phosphoric.

Detailed description

The polymers used are basic polymers, preferably polybenzimidazoles or polymers with groups benzimidazole in its structure, polymers that include (although not limited to) poly (2,5-benzimidazole) (ABPBI), poly (m-phenylene-benzobisimidazole), poly (p-phenylene-benzobisimidazole), as well as sulphonated or phosphonated derivatives thereof, prepared from sulphonated or sulphonated monomers after polymerization. It is understood as polybenzimidazoles those polymers with benzimidazole or substituted benzimidazole groups length of the polymer chain (such as ABPBI, figure 2).

The polybenzimidazoles in particular can easily be obtained by condensation of aromatic tetraamines (such as 1,2,4,5-traaminobenzene, or diaminobenzidine) and alkyl or aromatic diacids. They can also be prepared from a single monomer containing two ortho-amines of a benzene ring, and a carboxylic group (such as 3,4-diaminobenzoic acid, Figure 2). To do this, the monomers are dissolved in polyphosphoric acid under a nitrogen atmosphere, and heated between 140 and 200 ° C for at least one hour, (Imai, Y. et al . Makromol. Chem . 1965, 83, 179-187).

1.- Acido-doped polybenzimidazole membranes phosphoric

The membranes can be prepared by dissolving the polybenzimidazoles, their sulphonated or phosphonated derivatives, mixtures of both or mixtures with other types of polymers in solvents appropriate such as methanesulfonic acid, acid chloromethanesulfonic acid, trifluoroacetic acid, or formic acid between others. The solution is deposited on a flat surface to evaporate the solvent at temperatures between room temperature and 300 ° C, and at atmospheric or lower atmospheric pressure (in air or in an inert atmosphere). The membranes obtained are doped with strong acids (phosphoric acid, sulfuric acid, or organic derivatives of these) submerging them in baths of said acids of concentrations greater than 5%, preferably between 50 and 75%, at room temperature, between 5 minutes and a week. To accelerate the doping process, you can heat the doping bath between room temperature and 90 ° C. The membrane will absorb a percentage of acid proportional to its concentration in the bath dopant

If the polybenzimidazoles dissolve in the solvents mentioned above, and the solution is added to desired amount of phosphoric or sulfuric acid or derivatives organic of these (between 5 and 80% with respect to the polymer), and evaporate the solvent at temperatures between room temperature and 300 ° C, and at atmospheric or lower atmospheric pressure (in air or in an inert atmosphere), a membrane with the proportion is obtained of desired acid, depending on the proportion of acid added.

2.- Membranes based on polybenzimidazoles sulphonated

The sulfonated polybenzimidazole membranes encompass polybenzimidazoles prepared from monomers sulphonates, or sulfonated polybenzimidazoles using an agent sulfonant For example sulfonating polybenzimidazoles in solution in concentrated sulfuric acid at a temperature between 50 and 300 ° C, or sulfuric acid doped membranes heat treated between 200 and 500 ° C for a time between 1 minute and several hours, in air, oxygen, or inert atmosphere. Sulfuric acid in excess it is removed by washing in boiling water between 1 hour and several days.

Subsequently, the membranes obtained can be dop with strong acids (phosphoric acid, sulfuric acid, or derivatives organic of these) as described above, submerging them in baths of said acids of concentrations greater than 5%, preferably between 50 and 75%, at room temperature, between 5 minutes and a week. To speed up the doping process, you can Heat the doping bath between room temperature and 90ºC. The membrane will absorb a percentage of acid proportional to the concentration of this in the doping bath.

3.- Membranes based on hybrid materials polybenzimidazoles-polyoxomethalates

The polyoxomethalates or heteropolyacids are molecular solid acids very good protonic conductors in their hydrated form, which makes them suitable for the manufacture of high temperature proton conductive membranes.

The polyoxomethalates comprise isopolyanions (IPA) and heteropolyanions (HPA), which in turn can be found in form of acid or salt and are represented by the general formulas [M_ {m} O_ {y}] {p-} and [X_ {x} M_ {m} O_ {y}] {q-} (x \ m) respectively. They are aggregates of metal ions surrounded by oxide ions shared The M atoms (called addenda) can be W, Mo mainly, but also V, Nb, Ta ... The heteroatoms X are generally H, P, Si, or a transition element primarily, but there is no limitation regarding its nature.

To give an idea of the wealth of this family of compounds, it is worth mentioning the Keggin and Dawson type structures. The Keggin type structure has a central heteroatom surrounded by 12 "addenda" atoms (general formula [X_ {M} {18} 0_ {62}] {q-}). Type structures Dawson have 2 central heteroatoms and 18 "addenda" atoms surrounding them (general formula [X 2 M 18 O 62] p-). Both structures can be described according to the general formula [X_ {X} M_ {m} O_ {y}] q-} where X = Al, As, B, Be, Bi, C, Ce, Co, Cr, Cu, Fe, Ga, Ge, H, Hf, I, In, Mn, Mo, Nb, Ni, P, Pt, Re, Rh, S, Se, Sb, Si, Sn, Ta, Te, Th, Ti, TI, V, W, Y, Zn, Zr, or Rare earth elements. M represents Mo, W, V, Nb, Ta, or their combinations with coefficients 0 \ leqx \ leq8, 1 \ leqm \ leq48, 4 \ leqy \ leq70.

Some of these polyoxomethalates have very Good properties of proton conduction in its acid form. By example phosphomolibic acid is one of the best conductors known protons. However, its use as a practical material is is limited by its molecular nature and water solubility and polar solvents Its incorporation into the polymer matrix that We describe here allows you to overcome those problems.

To prepare membranes based on polybenzimidazoles doped with polyoxomethalates, mix a polybenzimidazole, a derivative of polybenzimidazole, mixtures of both or mixtures with other types of polymers, and a polyoxomethalate (between 5 and 90% of the polyoxometalated, preferably between 45% and 60%, and between 95 and 10% of the polymer), in one of the solvents previously mentioned or in a mixture of them stirring at room temperature or heating if necessary, to form a solution or a homogeneous paste. This paste or solution is deposit on a glass, and the solvent is removed between ambient temperature and 300 ° C, and at atmospheric pressure or less than atmospheric, in air or inert atmosphere. You get a membrane with the desired acid ratio, according to the proportion of polyoxometalate added. If all the solvent is not removed, it is wash the membrane in boiling water between 1 hour and 2 days to Remove the remains.

Subsequently, as an additional treatment, these hybrid membranes can also be doped with strong acids (phosphoric acid, sulfuric acid, or organic derivatives thereof) immersing them in baths of said acids of concentrations greater than 5%, preferably between 50 and 75%, at temperature atmosphere, between 5 minutes and a week. To speed up the process of doping, you can heat the doping bath between room temperature and 90 ° C The membrane will absorb a percentage of acid proportional to its concentration in the doping bath.

If the polybenzimidazoles and polyoxomethalates (between 5 and 80% with respect to the polymer) are dissolved together with a desired amount of phosphoric or sulfuric acid or organic derivatives thereof (between 5 and 80% with respect to the polymer), in one of the solvents above or a mixture thereof, and the solvent is evaporated at temperatures between room temperature and 300 ° C, and at atmospheric or lower atmospheric pressure (in air or in inert atmosphere), a membrane is obtained with the proportion of desired acid and of polyoxometalates , according to the proportion added in a single step (" direct acid casting " method).

4.- Composite materials based on polybenzimidazoles and solid acids

Solid acids (such as MHSO4, MHSeO4, and MH2PO4 among others, with M = Cs, NH4, Rb, ..), are good protonic conductors under anhydrous conditions at temperatures higher than the transition to the high phase conductivity, which in the case of CsHSO4 occurs at 141 ° C. By This, like polyoxomethalates, is suitable for preparation of composite materials based on mixtures of these and polybenzimidazoles. Unlike polyoxomethalates, in the In the case of solid acids, it is necessary to have particles of these that maintain their crystalline structure within the polybenzimidazole, so that the transition to the phase occurs conductive at the right temperature.

For the preparation of membranes polybenzimidazoles-solid acids, a polybenzimidazole is mixed, a derivative of polybenzimidazole, mixtures of both or mixtures with other types of polymers, together with a solid acid or a mixture of  them (in a proportion between 10 and 90% of the acid, and preferably greater than 50% by weight), in one of the solvents mentioned above or in a mixture thereof. Then the solvent is evaporated at temperatures between temperature ambient and 300 ° C, and at atmospheric pressure or less than atmospheric in air or inert atmosphere. You get a membrane with the proportion of acid polymers and solid acids, according to the proportion added in a single step. By RX diffraction it is verified that during evaporation the crystallizes again solid acid (figure 3).

Description of the figures

Figure 1. Membrane preparation techniques GDP doped with phosphoric acid.

Figure 2. Synthesis of ABPBI.

Figure 3. RX diffractogram of CsHSO_ {4} and an ABPBI-CsHSO_4 50:50 membrane in weight.

Figure 4. Moles of acid and water absorbed by the membrane depending on the concentration of the doping bath, calculated by elementary analysis of the dry membrane, and from of weight loss when drying the doped membrane.

Figure 5. Conductivity of membranes based on ABPBI anhydrous. SABPBI x H_ {3} PO_ {4} (example 9) (squares solids), ABPBI 45% H 3 PoMo_ {12} 0_ {40} \ cdot x H_ {3} PO_ {4} (example 6) (hollow squares), ABPBI \ 2.7 H_ {3} PO_ {4} (example 3) (triangles), ABPBI \ cdot 3.0 H_ {3} PO_ {4} casting and simultaneous doping (example 4) (crosses).

Example (s) Example 1 Preparation of ABPBI membranes doped with H_ {PO} {4} a) Synthesis of Poly- (2,5-benzimidazole) (ABPBI)

3,040 g (20 mmol) of acid are dissolved 3,4-Diaminobenzoic acid 97% (DABA) in 50 g of acid polyphosphoric 85% P2O5 (PPA), under nitrogen atmosphere, at 150 ° C with magnetic stirring for ½ hour, (figure 2). Next, the mixture acquires a characteristic black color with violet glitters. The temperature is then increased to 200 ° C and It stays for 4½ hours. After ½ hour the increase in viscosity makes stirring impossible, but the temperature. To isolate the polymer, the reaction crude still hot is poured on water observing the rapid coagulation of this, forming a solid that still contains a large proportion of acid. The polymer is washed with deionized water until neutral of wash waters. An elementary analysis of C, H and N in this process point shows that the polymer still contains a large proportion of H 3 PO 4 (15-30%). For remove this acid, the polymer is stirred in 10% NaOH for a night, wash again until neutral, and boil in water deionized for 24 hours. Finally the ABPBI is dried at 100 ° C overnight and at 200ºC 24 hours. By elementary analysis of C, H and N are found to have all the acid removed. performance 2.32 g (100%). Inherent viscosity 2.3-2.4 dl • 1 for a solution 0.5 g • dl -1 in H 2 SO 4 concentrated at 30 ° C.

b) Development of ABPBI membranes

400 mg of ABPBI is dissolved in 6 ml of MSA and Shake 24 cold. If it does not dissolve completely, it is heated in a bathroom of water until a thick homogeneous solution of color is obtained black. A glass is coated with solution film that is evaporates on a heating plate until it is not observed evaporation of MSA (approximately 2 hours). The thickness of the membranes is a function of ABPBI / MSA film thickness deposited The elementary analysis reveals 5 - 6% of S (15 - 18% MSA), which indicates that there is still a large amount of MSA left in the membrane. This MSA is also detected by FT-IR of film (1200, 1050 cm -1). It is possible to remove it by washing the membrane in boiling water for 24 h.

c) ABPBI membrane doping with H 3 PO 4

ABPBI membranes prepared according to Example 2 are cut into fragments between 2 x 2 and 2 x 3 cm, and are immerse in baths of H 3 PO 4 (85%) / water in different proportions for 3 days. The membranes are removed from the bath of acid and dry on absorbent papers to remove the drops of surface acid, then dry at 100 ° C in an oven and thus eliminate the water absorbed by the membrane next to the acid. The composition is calculated from the elementary analysis of C, N e H, assuming that PO4 <3> is the residue other than C, N e H in the same way it was done for GDP doped with H_ {3} PO_ {4}. By elementary analysis it is found that% S < 0.1, so it is not necessary to wash the membranes before doping, since phosphoric acid displaces the MSA in the membrane. The amount of acid absorbed by the membrane is a function of the acid concentration in the bath (figure 4). The amount of Water molecules are calculated from the weight loss of the doped polymer when dried at 100 ° C, once the Dry membrane composition by elemental analysis. In the figure 5 you can find the curve that represents the conductivity depending on the temperature, under anhydrous conditions, of a ABPBI membrane 2.7 H 3 PO 4.

Example 2 Preparation of ABPBI? 3.0 H_ {3} PO4 {membranes per simultaneous membrane preparation and doping

To better control the proportion of acid, it prepared an ABPBI membrane doped with 3 acid molecules phosphoric per unit of ABPBI repetition, from one mixture of ABPBI / H 3 PO 4 85% / MSA. 400 mg dissolved of ABPBI and 1192 mg H 3 PO 4 85% in 6 ml of MSA. It was coated a glass with a film of this solution, and the solvent in a heating plate for 5 days. By analysis elementary is that the composition is the desired one, and that You have deleted the entire MSA. Figure 5 shows the conductivity in temperature function of an ABPBI membrane 3.0 H 3 PO 4 prepared by this procedure.

Example 3 ABPBI Membrane Preparation x H 3 PMo 12 O 40 doped with H 3 PO 4 a) Preparation of ABPBI membranes x H 3 PMo 12 O 40

200 mg of ABPBI is dissolved in MSA, a room temperature, with magnetic stirring obtaining a paste Brown with caramel appearance. Different are added amounts of H 3 PMo 12 O 40 (PMO 12) (16% H 2 O determined by TGA) and stir until a mixture is achieved homogeneous, obtaining a uniform paste of brown color dark and ocher according to the proportion of PMo12. They extend films of different thicknesses of the solution in a glass, and The MSA is evaporated in a heating pad. By elementary analysis it is detected that the membranes still contain a high percentage of MSA, which is removed by washing the membranes 24 hours in water boiling. The thermogravimetric analysis in air allows to determine the membrane composition of ABPBI-PMo12. In this way it is possible to prepare membranes with a content in PMo 12 of up to 60% by weight.

b) ABPBI membrane doping \ cdot x H 3 PMo 12 O 40 with H 3 PO 4

A membrane of ABPBI-45% PMo12 was doped for 3 days in a bath of H 3 PO 4 {85} / H 2 O 70:30 in volume, dried between filter papers, and subsequently dried at 100 ° C for several hours. The conductivity of this membrane under anhydrous conditions, depending on the temperature can  found in figure 5.

Example 4 ABPBI Membrane Preparation x H 3 PMo 12 O 40 doped with H 3 PO 4 by simultaneous membrane preparation and doping

To better control the acid ratio phosphoric, a membrane was prepared by dissolving 200 mg of ABPBI, 350 mg of PMo12 (16% H2O) and 596 mg of H3PO4 85% in 5 ml of MSA. A film of the solution was deposited on a glass, and the solvent was removed by heating on a plate Heated overnight.

Example 5 Sulfonation and doping of an ABPBI membrane

An 80 µm ABPBI membrane was immersed in an H 2 SO 4 bath of 10% volume concentration during one day. It was dried between blotting papers, and at 100 ° C to remove the surface acid and membrane water. To produce the sulfonation, the membrane was treated at 450 ° C for 5 minutes. For remove excess acid, washed in boiling water for 48 hours.

The membrane prepared according to example 8 was doped for 3 days in a bath of H 3 PO 4 {85} / H 2 O 70:30 by volume, after which it was dried between filter papers and at 100 ° C to remove surface acid and water from the membrane. The conductivity of this membrane under anhydrous conditions, depending on of temperature, can be found in figure 5.

Example 6 ABPBI Membrane Preparation - CsHSO4

For the previous preparation of CsHSO_ {4}, dissolve 5 g (13,817 mmol) of Cs 2 SO 4 and 2,6020 g of H 2 SO 4 concentrated (27,656 mmol) in 5 ml of water. He CsHSO4 (CHS) precipitates by adding 5 ml of acetone. Is left stirring for 2 hours and filter under reduced pressure. In the wash waters precipitate more CsHSO4, so more is added acetone, until precipitation ceases. Again it filters and it wash with acetone. A white crystalline powder is obtained that It is dried under vacuum for 3 days. Yield 5.66 g (89%). By DSC a phase transition at 141 ° C characteristic of the CsHSO4 confirming that this compound has been obtained.

For the preparation of the material membrane ABPBI-CHS compound, 200 mg of ABPBI was dissolved and 200 mg of CHS in 1.5 ml of MSA and 2 ml of TFA while stirring during a night. The solution was evaporated on a heating plate during approximately 2 hours, obtaining a homogeneous membrane without pores By diffraction of RX it can be verified that when the MSA and TFA form crystalline CHS.

Claims (9)

1. Material with proton conduction capacity characterized by being constituted by:

to)

a organic phase comprising polybenzimidazole polymers, their sulfonated or phosphonated derivatives, mixtures thereof, or mixtures of them with other polymers and doped with strong acids,

or

b)

a organic-inorganic hybrid composition where the organic phase comprises polybenzimidazole polymers, their derivatives, sulphonates and phosphonates, mixtures thereof, or mixtures of they with other polymers, and the inorganic phase comprises polyoxomethalates or solid acids in proportions between 95% and 10% of polymer and between 5% and 90% of inorganic component, doped with strong acids

2. Conductive material according to claim 1 characterized in that the organic phase of a) and b) comprises basic polymers, preferably polybenzimidazoles or polymers with benzimidazole groups in their structure, polymers that include (but are not limited to) poly (2,5-benzimidazole) ( ABPBI), poly (m-phenylene-benzobisimidazole), poly (p-phenylene-benzobisimidazole), as well as sulphonated or phosphonated derivatives thereof. 3. Organic-inorganic hybrid conductive material according to claim 1 characterized in that the inorganic phase (b) comprises:

to)

polyoxomethalates based on isopolyaniones (IPA) and heteropolianiones (HPA), which in turn can be in the form of acid or salt and that are represented by general formulas [M_ {m} O_ {y}] ^ p- and [X_ {X} M_ {m} O_ {y}] {q-} (x \ leqm) respectively,

or

b)

solid acids such as MHSO4, MHSeO4 and MH2PO4 where M can be Cs, NH4 and Rb.

4. Organic-inorganic hybrid conductive material according to claim 3 characterized in that in section a) the M atoms can be W, Mo, V, Nb and Ta or their combinations and the X heteroatoms can be Al, As, B, Be, Bi , C, Ce, Co, Cr, Cu, Fe, Ga, Ge, H, Hf, I, In, Mn, Mo, Nb, Ni, P, Pt, Re, Rh, S, Se, Sb, Si, Sn , Ta, Te, Th, Ti, TI, V, W, Y, Zn, Zr, or rare earth elements and whose coefficients are 0 \ leqx \ leq8, 1 \ leqm \ leq48, 4 \ leqy \ leq70. 5. Organic-inorganic hybrid conductive material according to claim 1, 2, 3 and 4 characterized in that the inorganic polyoxometalate phase is in a proportion between 5 and 90% in relation to the organic phase, preferably between 45% and 60%. 6. Organic-inorganic hybrid conductive material according to claim 1, 2, 3 and 4 characterized in that the inorganic phase of solid acid or mixture thereof is in a proportion between 10 and 90%, preferably greater than 50%, in relation to the organic phase 7. Method of obtaining conductive material according to claims 1 to 6 in the form of a membrane characterized in that it comprises the following phases:

to)

dissolution of polybenzimidazoles, their derivatives, mixtures of both or mixtures with other types of polymers, and where appropriate polyoxomethalates or solid acids, in solvents that include methanesulfonic acid, acid chloromethanesulfonic acid, trifluoroacetic acid, formic acid or mixture from them,

b)

placement / deposition of the solution on glass and solvent removal between room temperature and 300 ° C, at atmospheric or lower pressure, in air or atmosphere inert, which involves the formation of the membrane, and

C)

membrane doping with acids strong (phosphoric acid, sulfuric acid or organic derivatives thereof) of concentration greater than 5%, preferably between 50 and 75%, at room temperature, between 5 minutes and a week, by immersion of the membrane in a bath of any of the acids mentioned.

8. Method of obtaining the conductive material according to claims 1 to 6 in the form of a membrane characterized in that it comprises the following phases:

to)

dissolution of polybenzimidazoles, their derivatives, mixtures of both or mixtures with other types of polymers, phosphoric or sulfuric acid or organic derivatives of these (between 5 and 80% with respect to the polymer), and where appropriate polyoxomethalates or solid acids, in solvents that include acid methanesulfonic acid, chloromethanesulfonic acid, trifluoroacetic acid, formic acid or mixture thereof, and

b)

placement / deposition of the solution on glass and solvent removal between room temperature and 300 ° C, at atmospheric or lower pressure, in air or atmosphere inert that involves the formation of the membrane.

9. Use of conductive material according to claim 1 to 8 in developing devices electrochemicals that require proton conductive membranes that include, but are not limited to, fuel cells, electrochemical capacitors, sensors, hydrogen pumps and in other storage and energy conversion devices in the temperature range between room temperature and 200 ° C.