Proton Exchange Membranes From Side-chain Type Sulfonated Poly(arylene Ether Sulfone)s For Fuel Cell Applications

Fuel cell technology can realize the efficient and green conversion of chemical energy,which will alleviate the environmental pollution caused by traditional fossil fuel combustion.Proton exchange membrane(PEM),as the core component of polymer electrolyte membrane fuel cell,is one of the decisive factors affecting the comprehensive performance of fuel cell.In this thesis,sulfonated poly(arylene ether sulfone)s-based PEMs with low cost and good comprehensive performance were selected and investigated.In order to improve the proton conductivity and stability of this type of PEMs,several kinds of sulfonated poly(arylene ether sulfone)PEMs were prepared by introducing flexible sulfonated grafts through molecular structure design and subsequent compositing modification.Their physicochemical properties and fuel cell performance were investigated.Aminated and side-chain type sulfonated poly(arylene ether sulfone)(s SPAES)were synthesized by nucleophilic polycondensation and ring-opening substitution reactions,respectively.A series of s SPAES films with ion exchange capacities of 1.47~2.32 mmol/g were prepared by solution casting.The results show that the flexible sulfonated side chain structure is beneficial to the construction of proton transfer channels in PEM.Proton conductivity of the s SPAES-40 membrane reaches 261.5 m S/cm@80oC,and the maximum power output in a H2/O2 fuel cell achieves 678.5 m W/cm2@80oC,which is higher than that of Nafion 112(633.4m W/cm2).Sulfonated graphene oxide(SGO)was prepared from graphene oxide and 1,4-butylenesulfone.A series of s SPAES/SGO composite membranes were prepared by solution casting with s SPAES-25 by physical blending.The results show that the prepared s SPAES/SGO composite membranes have good dimensional stability and high mechanical strength.The inplane and through-plane swelling ratios of the s SPAES/SGO-2 membrane are 13.5% and15.7%@90oC,respectively,at SGO loading of 2 wt%,which is nearly half of those of the s SPAES-25 membrane.Proton conductivity of the s SPAES/SGO-0.5 membrane reaches 232.1m S/cm@90oC,and the maximum output power output in a H2/O2 fuel cell achieves 634.9m W/cm2.CeO2 particles with cubic fluorite structure were synthesized by hydrothermal method.After physical blending with s SPAES-25,a series of s SPAES/Ce O2 composite membranes were prepared by solution casting with s SPAES-25 via physical blending.The results show that the free radical capture ability of Ce O2 particles greatly enhances the antioxidant activity of the s SPAES/Ce O2 composite membranes.After Fenton reagent treatment,weight loss of s SPAES/Ce O2-10 membrane with 10 wt% Ce O2 loading is only 5.4%,which is much lower than that of the control s SPAES membrane(14.2%).All the s SPAES/Ce O2 composite membranes exhibit good dimensional stability and high mechanical strength.In a H2/O2 fuel cell test,the maximum power output of the s SPAES/Ce O2-2.5 membrane reaches 504 m W/cm2,which is similar to that of the control s SPAES membrane(523.2 m W/cm2).