阅读说明：本技术 有机硅烷基质子交换膜的制备方法 (Preparation method of organic silane base proton exchange membrane ) 是由 姜孝武 徐成鹏 马瑶 张思琦 袁晓芬 惠佳柯 倪伶俐 于 2019-10-17 设计创作，主要内容包括：本发明涉及燃料电池技术领域,公开了一种有机硅烷基质子交换膜的制备方法,包括以下步骤：将膦酸酯功能化的硅烷、光致碱引发剂混合均匀后涂覆在基底上形成液膜；将该液膜置于LED灯下辐照聚合后,得到含膦酸酯基团的薄膜；将该薄膜置于三氟醋酸中煮沸水解后,得到高膦酸根密度的质子交换膜。本发明创造性的将光致碱引发有机硅烷聚合方法引入到质子交换膜的制备中去,具备操作简便、制备周期短且无溶剂等优点,是一种绿色高效的质子交换膜制备方法；另外,质子传递介质膦酸基团通过稳定的C-P键键合在质子交换膜中,且膦酸基团密度高,是一种适用于中高温的高效质子交换膜,在燃料电池中具有显著的应用价值。(The invention relates to the technical field of fuel cells, and discloses a preparation method of an organic silane base proton exchange membrane, which comprises the following steps: uniformly mixing phosphonate functionalized silane and a photobase initiator, and coating the mixture on a substrate to form a liquid film; placing the liquid film under an LED lamp for irradiation polymerization to obtain a film containing phosphonate groups; the membrane is placed in trifluoroacetic acid to be boiled and hydrolyzed to obtain the proton exchange membrane with high phosphonate density. The invention creatively introduces the photoinduced alkali-initiated organosilane polymerization method into the preparation of the proton exchange membrane, has the advantages of simple and convenient operation, short preparation period, no solvent and the like, and is a green and efficient preparation method of the proton exchange membrane; in addition, phosphonic acid groups of the proton transfer medium are bonded in the proton exchange membrane through stable C-P bonds, and the phosphonic acid groups have high density, so that the proton transfer medium is a high-efficiency proton exchange membrane suitable for medium and high temperature, and has obvious application value in fuel cells.)

1. A preparation method of an organic silane base proton exchange membrane is characterized by comprising the following steps:

s1: uniformly mixing organic silane functionalized by phosphonate ester and a photobase initiator, and coating the mixture on a substrate to form a liquid film;

s2: placing the liquid film under an LED lamp for irradiation polymerization for 30-60 minutes to obtain a film containing phosphonate groups;

s3: and (3) boiling the film in trifluoroacetic acid for 2-5 h to obtain the organic silane-based proton exchange membrane with high phosphonic acid group density.

2. The method of claim 1, wherein the phosphonate functionalized organosilane is any one of the following:

diethyl (trimethoxysilane) nonyl) phosphonate, dimethyl (trimethoxysilane) heptyl) phosphonate, dimethyl (triethoxysilane) hexyl) phosphonate.

3. The method of claim 1, wherein the photobase initiator is any one of the following:

α -benzoylbenzyl carbamate, bis 4-acetamidophenylmethane, 9-fluorenylmethyl carbamate.

4. The preparation method of the organo-silane based proton exchange membrane according to claim 1, wherein the mass percentage of the photobase in the photobase initiator is 2-8%.

5. The method of claim 1, wherein the LED lamp has a wavelength of 365nm, 395 nm or 425nm and an illumination intensity of 20 mw/cm²。

6. The method of claim 1, wherein the concentration of trifluoroacetic acid is 0.2-1 mol/L.

7. The process for the preparation of an organosilyl proton exchange membrane according to any one of claims 1 to 6, characterized in that the substrate is polytetrafluoroethylene.

Technical Field

The invention relates to the technical field of fuel cells, in particular to a preparation method of an organic silane-based proton exchange membrane with high-density phosphonic acid groups as proton conduction elements.

Background

Proton exchange membrane fuel cells are a type of fuel cell system that uses a proton exchange membrane as a solid electrolyte. Among them, the proton exchange membrane is a core component of the fuel cell, which directly affects the performance and life of the cell. At present, the most widely used perfluorosulfonic acid proton exchange membrane has high proton conductivity only in the presence of water molecules, and when the temperature is higher than 80 ℃, the conductivity of the proton exchange membrane is greatly reduced due to the large volatilization of water, so that the proton exchange membrane loses use value. However, higher temperature (>80^oC) The catalyst activity in the fuel cell can be activated, the CO poisoning of the catalyst can be prevented, and the service performance of the cell can be effectively improved. Therefore, the development of the proton exchange membrane suitable for medium and high temperature has remarkable application value.

The phosphonic acid group has high proton conductivity and can conduct electricity under non-aqueous conditions, so that the phosphonic acid group attracts great attention. However, phosphonic acid is often directly doped in the proton exchange membrane at the present stage, the doping amount is small, the density of phosphonic acid groups is low, and the loss of phosphonic acid is easily caused in the use process, so that the use safety and the long-term use stability of the fuel cell are influenced. In addition, the polyorganosiloxane is used as an organic-inorganic hybrid material, has excellent performances of high and low temperature resistance, weather aging resistance, flame resistance, no toxicity, no corrosion and the like, and has the characteristic of easy processing of organic high polymer materials, so that the preparation of the proton exchange membrane by using the polyorganosiloxane as a proton exchange membrane substrate and adding phosphonic acid type proton conduction elements is a good choice. Moreover, the traditional sol-gel method for preparing the organosilane hybrid material has the defects of long synthesis period, large amount of organic solvent and the like.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides a preparation method of an organic silane base proton exchange membrane, the proton exchange membrane prepared by the method contains phosphonic acid groups with higher density, can keep higher proton conductivity at higher temperature, and has green and high-efficiency preparation process.

The technical scheme is as follows: the invention provides a preparation method of an organic silane base proton exchange membrane, which comprises the following steps: s1: uniformly mixing organic silane functionalized by phosphonate ester and a photobase initiator, and coating the mixture on a substrate to form a liquid film; s2: placing the liquid film under an LED lamp for irradiation polymerization for 30-60 minutes to obtain a film containing phosphonate groups; s3: and (3) boiling the film in trifluoroacetic acid for 2-5 h to obtain the organic silane-based proton exchange membrane with high phosphonic acid group density.

Preferably, the phosphonate functionalized organosilane is any one of: diethyl (trimethoxysilane) nonyl) phosphonate, dimethyl (trimethoxysilane) heptyl) phosphonate, dimethyl (triethoxysilane) hexyl) phosphonate. More preferably diethyl (trimethoxysilane) nonyl) phosphonate.

Preferably, the photobase initiator is any one of α -benzoylbenzyl carbamate, bis 4-acetamidophenylmethane, and 9-fluorenylmethyl carbamate, more preferably α -benzoylbenzyl carbamate.

Preferably, the mass percentage of the photobase in the photobase initiator is 2% -8%. Preferably, the percentage content of the photobase is 4%, the irradiation polymerization time is preferably 40 minutes, and the boiling hydrolysis time in trifluoroacetic acid is preferably 3 hours.

Has the advantages that: compared with the prior art, the invention has the following advantages:

(1) according to the invention, phosphonate functionalized organosilane is used as a precursor, a phosphonate functionalized organic silicon film is obtained through polymerization, then the phosphonate functionalized organic silicon film is subjected to boiling in trifluoroacetic acid and in-situ hydrolysis to obtain the phosphonate proton exchange membrane, and the phosphonate group is bonded in the proton exchange membrane through a stable C-P bond and has higher density. Because the preparation process of the method does not involve solvent (water), the polyorganosiloxane hybrid proton exchange membrane prepared by the method can not reduce the proton transmission capability caused by the evaporation of water under the medium-high temperature condition; in addition, the phosphonic acid group has high proton conductivity and can conduct electricity under a non-aqueous condition, and the polyorganosiloxane hybrid proton exchange membrane prepared by the method contains the phosphonic acid group with higher density, so that the polyorganosiloxane hybrid proton exchange membrane prepared by the method can still keep good conductivity under medium-high temperature conditions.

(2) The method has the advantages of high curing speed, high silane crosslinking density, short preparation period, no solvent and the like by initiating organosilane polymerization through photobase, and is a green and efficient preparation method of the proton exchange membrane.

(3) The phosphonic acid group of the proton transfer medium is bonded in the proton exchange membrane through a stable C-P bond, and the phosphonic acid group has high density, so that the proton transfer medium is a high-efficiency proton exchange membrane suitable for medium and high temperature, and has obvious application value in a fuel cell.

Detailed Description

The present invention will be described in detail with reference to specific examples.