Effect Of Mixed Solvent And Ferricyanide Coordination Group On The Structure And Performance Of Proton Exchange Membrane

Proton exchange membrane fuel cell(PEMFC)is an electrochemical device that can directly convert chemical energy into electrical energy.It has the characteristics of cleanliness,rapid response,and high efficiency.Among them,the proton exchange membrane(PEM)as the core component in the fuel cell,its working performance and applicable durability have a great impact on the performance and life of the PEMFC.Generally,the durability of PEM is related to the relative humidity environment and thermal,mechanical and chemical stability,and the working performance depends on the effective proton transport in PEM and the effective water management in PEMFC.In order to obtain a sufficiently high proton conductivity,the proton conducting component is one of the primary considerations in proton exchange membrane design.It can be seen that in order to improve the practical durability of proton exchange membrane fuel cells and reduce their performance loss during use,the selection of the proton conductive components is very important.In this study,we first explore the effect of solvents on the structure and properties of proton exchange membranes prepared by solvent casting.We have prepared two kinds of SPEEK membranes with different sulfonation degrees.We prepared them by using solution casting method with different mixed solvents.It was proved that the addition of two non-solvents,ethylene glycol and tetramethylbenzene,can promote the phase separation of the membrane and make the membrane have a larger hydrophilic phase,thereby further improving the performance of PEM.According to the conclusions of the above research,we used a ferricyanide coordination group to coordinate with the commercially available fluoroelastomer FC-2178 to design a new type of PEM.The membrane utilizes the free radical scavenging ability of the ferricyanide coordination group and the excellent proton conduction ability,while ensuring the membrane with high performance,and also improving the stability and durability of the membrane.By tested the proton conductivity,power output and chemical stability under low humidity,the results showed obvious advantages compared with Nafion 212 membrane,which shows that the new PEM has great prospects in the application of PEMFC.Since the excellent proton conductivity and durability of the ferricyanide coordination group were discovered in the above experiment,in order to further study the free radical scavenging ability of the ferricyanide coordination group,we have incorporated potassium ferrocyanide and potassium ferricyanide stabilizer materials into perfluorinated and hydrocarbon matrix proton conductive PEM by physical means.According to the results of PEMFC evaluation,for two polymer substrates with different molecular compositions,the durability of PEMFC based on composite membranes of potassium ferrocyanide and potassium ferricyanide is significantly higher than the original membrane and the composite membranes based on Ce³⁺additives approved by the US Department of Energy.Moreover,compared with Ce³⁺composite membrane,two additional advantages of the Fc(II)\Fc(III)composite membranes,the increased cell output due to extra protons and the enhanced additive retention established by hydrogen bondings,further pronounce the advancements of this strategy.Therefore,ferrocyanide and ferricyanide species have demonstrated considerable potential with high universality in improving the chemical stability of various types of PEMs.