POROUS MEMBRANE, PROCESS FOR PRODUCING POROUS MEMBRANE, SOLID POLYMER ELECTROLYTE MEMBRANE, AND FUEL CELL

摘要

This invention provides a porous membrane formed of a film or sheet comprising a polymer or an inorganic material. The porous membrane is characterized by having a number of pores formed by applying an ultra-short pulse laser having a pulse width of not more than 10-9 sec at a focal point output of 0.001 to 10 W, the diameter of the pores being 0.1 to 100 .mu.m. There is also provided a polymer electrolyte membrane comprising a polymer electrolyte filled into the pore. The polymer electrolyte membrane may be brought to a thickness reduced form, has high strength, causes no significant cross-leakage of fuel gas, and is highly durable. When this porous membrane is used as a solid polymer electrolyte membrane, a fuel cell having improved output voltage and current density can be provided.