Preparation And Application Of Inorganic Nanoparticles Compositing-modified Polymer Electrolyte Membranes

Proton exchange membrane is an important part of polymer electrolyte membrane fuel cell.In this dissertation,sulfonated aromatic polymers,including sulfonated poly(aryl ether sulfone)(SPAES)and sulfonated poly(ether ketone)(SPAEK),with mature production process,low cost and excellent comprehensive performance,were selected as the raw materials,and three kinds of inorganic nanomaterials dual-compositing modified proton exchange membranes were prepared.The basic physical and chemical properties of the membranes were studied and evaluated.The SPAES polymer was prepared by nucleophilic condensation polymerization.Phosphotungstic acid(HPW)was anchored on the surface of mesoporous graphitic carbon nitride nanosheets(mg-C₃N₄)and then blended with SPAES by solution casting to prepare a series of SPAES/HPW/mg-C₃N₄ nanocomposite membrane(1.62?1.70 mmol/g).The results showed that the prepared nanocomposite membranes had a dense structure,improved mechanical strength,high water uptake,good dimensional stability and excellent oxidative stability,besides,the leaching of HPW was largely suppressed by the incorporation of mg-C₃N₄.The SPAES/HPW/mg-C₃N₄-1.5 nanocomposite membrane exhibited a water absorption of 50%,dimensional change less than 7.2%,and proton conductivity of 203m S/cm at 80°C.At 80°C,the maximum power density(MPD)of hydrogen/oxygen fuel cell reached 582 m W/cm².Using P25 as the raw material,titanium dioxide nanotubes grafted with butyl sulfonic acid(s-TNT)were prepared and then blended with mg-C₃N₄ and SPAES.A series of SPAES/s-TNT/mg-C₃N₄ nanocomposite membranes(1.53?1.69 mmol/g)were prepared by solution casting.The results indicated that the prepared nanocomposite membranes were dense in structure,excellent in mechanical strength,good in dimensional and oxidative stability.The SPAES/s-TNT/mg-C₃N₄(1/3)membrane had a proton conductivity of 202mS/cm at 90?.The weight losses after ex-situ oxidative Fenton tests were less than 5%,and the ion exchange capacity and proton conductivity still maintained above 90%.The MPD of the hydrogen/oxygen fuel cell reached 512 mW/cm² at 80?.The SPAEK was prepared by nucleophilic condensation polymerization and then blended with graphene oxide(GO)nanosheets and graphitic carbon nitride(g-C₃N₄)nanoparticles,SPAEK/GO/g-C₃N₄ nanocomposite membranes(1.44?1.61 mmol/g)were prepared by solution casting.The results indicated that the prepared nanocomposite membranes were dense,dimensional and oxidative stable,with tensile strain of 113.5?238%,tensile strength of 28.6?40.5 MPa and Young's modulus of 1.49?1.8 GPa.The dual-compositing system effectively improved the proton conductivity and fuel cell performance of the membrane.The SPAEK/GO/g-C₃N₄(2/2)membrane exhibited a proton conductivity of 228 mS/cm at 90?,and a MPD of 669.5 m W/cm² at 80? in a hydrogen/oxygen fuel cell.