Polymer electrolyte fuel cell (PEFC) directly converts chemical energy into electrical energy with a high efficiency and low emission of pollutants, and is one of the most promising power sources for portable, stationary, and automotive applications. The properties of proton exchange membrane (PEM) significantly attribute PEMFC performance, so PEM is a key component in fuel cell systems. In our group, we develop novel and unique PEMs, which are composed of functional nanofibers.