SOLID POLYMER ELECTROLYTE AND PROCESS FOR MAKING THE SAME

PROBLEM TO BE SOLVED: To provide a membrane material with high endurance, which can be utilized for a polymer electrolyte membrane fuel cell (PEMFC).SOLUTION: A solid polymer electrolyte membrane has a first surface and a second surface opposite the first surface. The solid polymer electrolyte membrane has a failure force of greater than about 115 g and comprises a composite membrane consisting essentially of (a) at least one expanded PTFE membrane having a porous microstructure of polymeric fibrils, and (b) at least one ion exchange material impregnated throughout the porous microstructure of the expanded PTFE membrane so as to render an interior volume of the expanded PTFE membrane substantially occlusive; (c) at least one substantially occlusive, electronically insulating first composite layer is interposed between the expanded PTFE membrane and the first surface, and the first composite layer comprises a plurality of first carbon particles supporting a catalyst comprising platinum and an ion exchange material, and the plurality of first carbon particles have a particle size less than about 75 nm, or less than about 50 nm, or less than about 25 nm.SELECTED DRAWING: Figure 1 【課題】高分子電解質膜燃料電池(PEMFC)に利用する耐久性の高い膜材料を提供する。【解決手段】第一表面およびその第一表面の反対側に第二表面を有する固体高分子電解質膜であって、破壊応力が約115gより大であり、かつ特に(a)高分子フィブリルの多孔質微細構造を有する少なくとも一つの延伸PTFE膜および(b)前記延伸PTFE膜の内部容積を実質的に閉塞するようにその延伸PTFE膜の多孔質微細構造全体に含浸させた少なくとも一種のイオン交換材料からなるコンポジット膜を含有し、(c)少なくとも一つの実質的に閉塞性で電子絶縁性の第一コンポジット層が、前記延伸PTFE膜と前記第一表面の間に挿置されかつ白金を含む触媒を担持する複数の第一カーボン粒子およびイオン交換材料を含有し、その複数の第一カーボン粒子は、粒子の大きさが約75nm未満、約50nm未満または約25nm未満である固体高分子電解質膜。【選択図】図１