Development of polystyrene sulfonate/glycol chitosan hybrid membrane for direct methanol fuel cell

The direct methanol fuel cell (DMFC) is the battery of the system, which directly supplies methanol to the cell containing a polyelectrolyte membrane. As for DMFC, a miniaturization and weight saving in the whole system are possible, because device does not have to constitute reformer. Therefore, DMFC is expected as a power source of a mobile device. Polyelectrolyte membranes for DMFC need a characteristic of the proton conductivity and the reduction of methanol crossover (MCO). In this research, hybrid membrane comprising a polystyrene sulfonate (PSS) and a glycol chitosan (G-Ch) was investigated. PSS/G-Ch hybrid membranes were prepared by cast method and were cross-linked with glutaraldehyde (GA) to reduce the water content. From the Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) measurement, the amino group of the G-Ch origin and the sulfonate group of the PSS origin in hybrid membranes generated ionic bond. On the other hand, the proton conductivity of the hybrid membranes increased with increasing amount of PSS and/or concentration of GA, and maximum value was 0.013 S/cm in case of composition of 4/2/2 (PSS/G-Ch/GA).