Proton exchange membrane used for direct methanol fuel cell and preparation method thereof

Abstract

The invention discloses a proton exchange membrane used for a direct methanol fuel cell and a preparation method thereof. The method comprises: first, polyether-ether-ketone is added into concentrated sulfuric acid for sulfonation reaction to obtain sulfonating polyether-ether-ketone; ball milling is carried out on the sulfonating polyether-ether-ketone, inorganic cross linker, silane coupling agent and organic solvent to obtain suspending liquid; the mass volume ratio between the sulfonating polyether-ether-ketone and the organic solvent is 1 / 5g / ml-1 / 15g / ml; the mass ratio between the silane coupling agent and the inorganic cross linker is 1:5-10; the mass ratio between the sulfonating polyether-ether-ketone and the inorganic cross linker is 5-20:1; finally, the mixture solution of the sulfonating polyether-ether-ketone, the inorganic cross linker and proton conductor are made into membrane which is then dried for demoulding, and the proton exchange membrane used for the direct methanol fuel cell can be obtained. The membrane features good methanol diffusion resistance, low cost, high proton conductivity and excellent water-resistant swelling capacity at the higher temperature. The preparation method is simpler as well as lower in raw material price and production cost.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, in particular to a proton exchange membrane for direct methanol fuel cells and a preparation method thereof. Background technique [0002] Direct methanol fuel cell (DMFC) is a kind of fuel cell that uses methanol as fuel and oxygen or air as oxidant. DMFC not only has the advantages of rich fuel resources, low cost, and high energy density, but also the fuel methanol used in DMFC does not have the problems of difficult preparation, storage, transportation, and unsafety of fuel hydrogen used in hydrogen / oxygen or hydrogen / air fuel cells; When working, the fuel is directly fed, without additional reforming and humidification treatment; the structure of the battery stack system is simple, the response time is short, and the operation is convenient. Therefore, DMFC is considered to be a kind of fuel cell with great development potential and application value in the application of low-power power...

AI Technical Summary

Problems solved by technology

[0005] 1. The SPEEK membrane with a higher sulfonation degree is not only easy to swell with water at a higher temperature, but the dimensional stability of the membrane is poor, and the membrane will become brittle, which will eventually reduce the mechanical strength of the membrane; while SPEEK with a lower sulfonation degree is not easy Soluble in organic solvents, it is difficult to process into a film, and the proton conductivity of the produced film is low, which cannot meet the requirements of DMFC

[0006] 2. In the process of research on the modification of SPEEK membrane, the methods adopted so far are relatively simple

Although the introduction of inorganic crosslinking structure into SPEEK can solve the swelling problem of the membrane and reduce the methanol permeability of the membrane, it also leads to the decline of the proton conductivity of the membrane; while only the introduction of heteropolyacid can improve the proton conductivity of the membrane, However, it will lead to a decline in the alcohol resistance of the membrane, and the heteropoly acid is also prone to seepage.

[0007] 3. Among the main methods of modification with inorganic cross-linking agents, gas-phase modification consumes a lot of energy and costs; sol-gel modification will cause large volume shrinkage of materials, long gel drying time, and organic impurities. Too much, the tetraethyl orthosilicate used is expensive; the inorganic particles modified by the precipitation method have a wide particle size distribution, and the shape and size of the particles are difficult to control

The research on the preparation process and comprehensive performance of the composite SPEEK proton exchange membrane is not perfect enough. How to improve the uniform dispersion of inorganic particles in the SPEEK matrix and how to effectively adjust and control the preparation conditions of the membrane material so that the proton conductivity of the membrane and the alcohol resistance To achieve the best balance between performance and so on needs to be further studied

[0008] 4. The proton exchange membranes developed so far for DMFC still have low proton conductivity, high methanol permeability, and high cost, so they cannot meet the requirements of DMFC.

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