Synthesis And Properties Of Acid-base Copolymer Proton Exchange Membranes For Fuel Cell

Fuel cell is a device which converts chemical energy into electrical energy through the reactions on the electrode. Proton exchange membrane fuel cells (PEMFC) use hydrogen or methanol as fuel. PEMFC has been considered as a recognized energy source because of that fastest startup, the highest specific energy and environment friendly. Proton exchange membrane (PEM) is the core component of PEMFC which directly influences the PEMFC’s performance. It is very important that the study of PEM in the development of PEMFC. The commercially available proton exchange membranes is Nafion membrane that produced by DuPont company. However, there are many weakness that expensive cost, high methanol permeability and restricted working temperature make them impossible for wider application. A lot of advantages for PEMFC to be operated at high temperature(120～200℃), such as improved CO tolerance of the platinum electrode, simplified water and heating system and increased the energy efficiency. Therefore develop of new PEMs which providing a good performance at high temperature and low relative humidity has become a serious problem of fuel cell technologies.Due to its good mechanical properties, high thermal stability, chemical stability and low cost, sulfonated poly(aryl ethers) have been widely employed as PEM materials. However, high exchange capacity (IEC) of sulfonated poly (aryl ether) membrane has poor dimensional stability, low mechanical properties and high methanol permeability. The proton conductivity will be reduced when the temperature higher than100℃. It is difficult to directly application in DMFC and the PEMFC in the temperature (>100℃) operation. So we have synthesized a contain amino bisphenol monomer. Sulfonated poly(aryle ether ketone sulfone) and contain amino poly(aryle ether ketone) have been synthesized. Cross-linked composite membranes are obtained by a heating reaction at160℃. The Am-PAEK/SPAEKS-C-3membrane exhibits excellent proton conductivity up to0.0892S/cm at120℃, which is superior to that of Nafion(?) membrane and SPAEKS membrane at the same test conditions. The methanol diffusion coefficient (0.14×10-6m2/s) of Am-PAEK/SPAEKS-C-3is lower than that of pure SPAEKS membranes (0.85×10-6m2/s) and the Nafion(?) membrane(2×10-6m2/s).Contain amino sulfonated poly(aryle ether keton sulfone) has been synthesized. By acid-base cross-linked in the same polymer to build a new way of selective ion channel that solve the conflict of methanol permeability and proton conductivity. The PEM has low methanol permeability and high proton conductivity when low relative humidity. The Am-SPAEKS-3membrane exhibits high proton conductivity up to0.0798S/cm at120℃. The methanol diffusion coefficient of Am-SPAEKS-3is0.08×10-6cm2/s. Meet the requirements of the middle-high temperature PEMFC for PEMs.