Preparation And Performance Of Methanol Resistance Cation Membranes For Direct Methanol Fuel Cells

Fuel cell is a device that directly transforms chemical energy into electric energy.It has the advantages of high conversion efficiency and environmental friendliness,and has always been an important research direction.Direct methanol fuel cell(DMFC)is a kind of fuel cell.The use of methanol as fuel,without pre reformer,has some unique advantages,such as simple battery structure,higher theory specific energy density,wide fuel sources,low cost,fuel storage and transportation safety,fuel replenish convenience and so on.As a key component in DMFC,exchange membranes are playing the role of conducting proton and separating cathode and anode.It is very important to develop high performance,high stability and low methanol penetration membranes.Based on this,two kinds of cation exchange membranes have been prepared.The research work concerns the following aspects:1.Organic-inorganic hybrid membranes prepared through pre-irradiation grafting method based on ETFE.The based membranes ETFE subsequently monomers such as St,DTSi.Finally,chlorinated sulfonic acid was used for sulfonation,and NaOH hydrolysis.A series of membrane was prepared according to the amount of cross-linking agents.(1)At 30?,the conductivity of the membranes increases first and then decreases with the increase of the cross-linking dose.When the cross-linker was added to 4v%,the conductivity was maximum and reaches 0.15 S/cm.The conductivity of the membranes without cross-linked was 0.12 S/cm.(2)The conductivity increases with the increase of temperature in 30-80?.(3)It was found that the methanol permeability of the membrane decreased with the increase of cross-linking dose.The methanol permeability of the never cross-linked membrane was 8.15 × 10-7 cm2/s,and the methanol permeability of the membrane was reduced to 2.32 x 10-7 cm2/s when the cross-linking agent was added to 8v%.The methanol permeability of Nafionl 17 membrane was 5.79 × 10-6 cm2/s under the same test conditions.The methanol permeability of each membrane is about one order of magnitude lower than that of Nafionl 17,and the introduction of hybrid cross-linking can enhance the methanol permeability of the membrane.Finally,the stability of each series of membranes was investigated.(4)It was found that the membrane had high thermal stability at 280?.(5)The membrane was soaked with Fenton reagent.It was found that the cationic exchange membrane with hybrid cross-linking had better chemical stability.The above test results show that the membrane has good prospects in direct methanol fuel cells.2.ETFE was used as the base film to pre-irradiation.Then the styrene was grafted and cross-linked with isoprene.Finally,a cationic exchange membrane was prepared by sulfonation and hydrolysis.A series of membranes were prepared according to the amount of cross-linking agents.(1)With the increase of temperature,the conductivity of the membranes increases,and the conductivity of the membrane was 0.1-0.19 S/cm at 30-80?.(2)In terms of thermal stability,the membrane was excellent and stable under 400?.(3)The direct methanol fuel cell system containing the cross-linked membrane produced for this study exhibited an open circuit voltage(OCV)of 0.75 V and a maximum power density of 60 mW/cm2 at the operating temperature of 80?.These results indicate that the membrane has potential for direct methanol fuel cells.