Research On The Preparation And Properties Of Novel Polysulfone-based Organic-Inorganic Composite Anion Exchange Membrane

Fuel cells are green power sources, which can convert the chemical energy into the electrical energy directly with high energy efficiency and low environmental pollution. As one important type of fuel cells, alkaline membrane fuel cell is more attractive than proton exchange membrane fuel cell recently due to its advantages in alkaline conditions, e.g. the use of non-precious metal catalysts and enhanced electrode reaction kinetics. As a crucial component of alkaline membrane fuel cell,anion exchange membrane plays an important role in anion transportation, fuel and oxidant separation, and catalyst-supporting. Among the various types of the anion exchange membranes, organic-inorganic composite membranes possess good mechanical properties, enhanced thermal properties and stability because of the combination of advantages of organic phase and inorganic phase, thus have broad research prospects. This thesis is based on the preparation of the organic-inorganic composite alkaline anion membranes for fuel cells, various detail characterizations and researches are shown together. Herein, the thesis includes the following two parts:In the first part, we prepared highly dispersed quaternized graphenes(QGs) and then incorporated QGs into the chloromethylated polysulfone(CMPSU) to prepare a series of composite anion exchange membranes with different weight proportions of QGs. The influences of the content of QGs on the properties of the composite membranes were studied in detail. The results indicated that the QPSU-0.5%-QGs membrane showed a 4-fold improvement in the bicarbonate conductivity than that of pristine QPSU membrane at 80 o C, and the QPSU-0.25%-QGs membrane showed a3-fold increase in Young’s modules and Tensile strength. The improvements in the properties of the composite membranes could be attributed to the formation of the interconnected transfer channels within the composite membrane and the excellent compatibility between QPSU matrix and QGs fillers. In addition, the good morphologies without phase separation were observed by SEM, acceptable thermal properties, alkaline resistances and oxide stabilities were also presented in the obtained composite membranes.In the second part, quaternized mesoporous silica nanoparticles(QMSNs) were prepared, and then different proportions of QMSNs were incorporated intochloromethylated polysulfone(CMPSU) to fabricate a series of organic-inorganic composite alkaline anion exchange membranes by a simple blending method. The incorporation of QMSNs greatly improved the properties of the composite membranes,and the QPSU-15%-QMSNs membrane showed the highest bicarbonate conductivity,which was nearly twofold compared with the bicarbonate conductivity of the pristine QPSU membrane. The WU and IEC values of composite membranes also increased with the increasing content of QMSNs, the swelling ratio was suppressed at the same time. The acceptable mechanical properties, alkaline resistance and oxide stability were presented in the composite membranes.