A new insight into the stability of nanofiber electrodes used in proton exchange membrane fuel cells

The nanofiber electrodes have been considered as promising candidates for commercial proton exchange membrane fuel cells due to their high catalyst utilization and enhanced mass transport efficiency. However, for the first time our research determined that the nanofiber electrodes were restricted by the poor chemical stability of the polymer carriers. To gain further insight into the durability of nanofiber electrodes, both cyclic voltammetry aging tests and Fenton's tests were conducted. Similar to previous reports, our research demonstrated that nanofiber electrodes showed remarkable stability in the cyclic voltammetry aging process. However, Fenton's tests indicated that nanofibers in the electrodes would decompose easily while being attacked by reactive oxygen species such as HO• or HOO•, which greatly limits their practicability and reliability. The different performances under the two tests also demonstrated that the cyclic voltammetry aging protocols, which have been applied extensively, cannot well mirror the real operating conditions of fuel cells.