Development of Inorganic-organic Membranes Consisting of ZrO2·nH2O and Sulfonated-PES for Direct Methanol Fuel Cells
OPEN ACCESS
We investigated inorganic-organic membranes consisting of sulfonated-poly(ether sulfone) (S-PES) and ZrO2·nH2O with the aim of improving proton conductivity and blocking methanol. We prepared excellent uniform membranes by the method using ZrOCl28H2O as a precursor. The proton conductivity of the ZrO2·nH2O/S-PES (EW=850) composite membrane with 50wt% ZrO2·nH2O content was about four times higher than that of S-PES (EW=850). On the other hand, the methanol permeability of the ZrO2·nH2O/S-PES (EW=850) composite membrane with 50wt% ZrO2·nH2O content was almost the same as that of S-PES (EW=850). These results mean in the composite membranes, the trade-off relationship between proton conductivity and methanol permeability found in S-PES was improved. The initial I-V performance of an MEA consisting of the ZrO2·nH2O/S-PES (EW=850) composite membrane with 50wt% ZrO2·nH2O content showed a maximum power density of 65 mW cm-2 at 260 mA cm-2.
We have prepared inorganic-organic membranes consisting of SPES and ZrO2·nH2O. A preparation method using ZrOCl28H2O as a precursor gave excellent uniformity. In the ZrO2·nH2O/S-PES composite membranes, the trade-off relationship between the proton conductivity and methanol permeability found in S-PES single polymer membranes was improved. The maximum power density of an MEA using the ZrO2·nH2O/S-PES composite membrane was 65 mW cm-2. The MEA consisting of the composite membrane shows good performance stability up to 600 hours, investigated by galvanostatic operation.
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