Study On Barriers In The Industrialization Of Proton Exchange Membrane Fuel Cell

Proton exchange membrane fuel cell (PEMFC) is a device converting the chemical energy of the fuel to electrical energy through electrochemical reaction. The characteristics of fast start-up, high efficiency and low emission make it the promising candidate for the mobile and stationary power.The major hurdles for the commercialization of fuel cell are durability and cost issues of the fuel cell. Proton exchange membrane is the key component of PEMFC. It is believed that the fast degradation of the proton exchange membrane would lead to the early failure of the PEMFC. Extensive researches have demonstrated the durability of the membrane could be enhanced by reinforcing the membrane by annealing. Although the durability of the membranes could be improved through annealing, the origin of the improvement in durability is still unknown. Besides, the annealed membranes may show a lower conductivity compared to the as-received membranes. In this thesis, we carefully investigated the effect of annealing on Nafion 211 membrane. Furthermore, we investigate the impact of several key materials used in catalyst, bipolar plate and proton exchange membrane on PEMFC industrialization by commercialization modeling. The conclusions have been drawn as followed:(1) Annealing Nafion 211 membrane between 120℃-160℃would help to increase the membrane crystallinity and the mechanical properties of the membrane could be enhanced as a result. But the annealing procedure may disturb the cluster structure in the membrane. Therefore, the conductivity of the membrane is lower after annealing. Annealing the Nafion 211 membrane in Na-form also improves the mechanical properties of the membrane. At the same time, the conductivity of the membrane is also improved because annealing with the introduction of Na +ion could reform the membrane to a structure with lower constrain to the side chain of the membrane. Annealing the Na-form membrane (i.e. at 240℃) could balance the mechanical properties and conductivity of the membrane. Besides, The durability of the membrane could be expected to be enhanced because the decrease of the humidity induced stress after annealing.(2) We investigate the impact of several key materials used in catalyst, bipolar plate and proton exchange membrane on PEMFC industrialization by commercialization modeling. The results indicate in order to satisfy the demand of long-term industrialization, it is strongly recommended to lower platinum loading of PEMFC to 0.15mg/cm2 with 1100mA at 0.7V along with high efficient recycling. Titanium, nickel, chromium and fluorite would have no apparent influence on FCV industrialization.