Preparation and properties of high performance nano-composite bipolar plate for fuel cell

Fuel cells are expected to play a major role in the economy of this century and for the foreseeable future [1]. Recently, polymer electrolyte membrane fuel cells (PEMFC) exhibit the most promising power sources for various portable electronic devices and transportation applications. A significant part of the PEMFC fuel cell stack is the bipolar plates (BPs) [2], which account for about 80% of total weight and 45% of stack cost [3]. Bipolar plates electrically connect successive cells in a fuel-cell stack, and also provide the gas flow field [4, 5]. With the bipolar plate accounting for the bulk of the stack, it is desirable to fabricate bipolar plates which are as thin and lightweight as possible.This study aims at developing lightweight and high performance nano-composite bipolar plates for use in polymer electrolyte membrane fuel cells. The thin polymer nano-composite bipolar plates (the thickness < 3 mm) containing of epoxy resin (Eapon 828), graphite powder, triethylen eter amine, nano-composites as carbon nanotubes (CNTs) and polyaniline, have been fabricated by bulk molding compound (BMC) process. First the properties of electrodes with different content of carbon were investigated. Then the amount of carbon for the highest conductivity and thermal stability of bipolar plates were optimized. Finally bipolar plates were modified by adding polyaniline and CNTs. Thermal gravimetry, gas permability, conductivity, and flexural stability of fabricated bipolar plates were then investigated. We also earned important data from the polarization curves and Impedance spectroscopy about nano-composite bipolar corrosion in 1 M H2SO4 medium. The results show that the bipolar plates with % 50 amounts of carbon , 15%conductive polymer and 5%CNTs have good corrosion resistance and it may be a candidate material as bipolar plate of polymer electrolyte membrane fuel cells.

Keywords:

Nano-composite , Bipolar , Epoxy resin , Stack , Corrosion