| 초록 |
Water management in electrolytes is one of the complicated problems to be overcome.So far, water content in PEMs has been managed indirectly by humidifying reactant gas.External humidification of the reactant gas is a burden for the fuel cell system.It requires a gas humidification subsystem that adds to the weight.For examples, commercial stacks with stack integrated gas humidification systems,the humidification section accounts for about 20% of the stack weight.Furthermore, the humidifiedreactant gas transports latent heat caused by water vaporization into the cell, which has to be removed by the cooling system.Therefore, this method makes the system complicate and lower the cell's energy efficiency because of the large latent heat.This also has difficulty responding to a quick start-up due to a large heat capacity of water reservoir.In this study, we report on PEMFC, which do not require external humidification.Pt-Nafion composite membrane was fabricated for self-humidifying PEMFCs by equilibrium impregnation reduction method. Water is produced by the crossover of hydrogen and oxygen on Pt particles in the membrane. The generated water can fully hydrate the membrane, resulting in stable operation of PEMFCs without any external humidification.But there is a decrease of fuel cell performance due to poor proton conductivity as the cell temperature was increased. Zirconium phosphate hydrate (ZrP, Zr(HPO4)H2O for form and Zr(PO4)(H2PO4)32H2O for form) have features of increasing conductivity using high proton mobility on the surface of ZrP particles and good water retention. So we fabricate Pt-Zirconium phosphate Nafion composite membrane in order to improve water retention properties at increased cell temperature. |
