Electromechanical and electrochemical properties of highly filled Titanium composites for PEM bipolar plates

Abstract

Titanium polymer composites are evaluated concerning their suitability as bipolar plates in acid water electrolysis as a replacement of milled Titanium bipolar plates. It turns out that our highly filled polymer composites with 80 wt.-% Titanium powder meet all criteria given by US Department of Energy concerning electric conductivity and mechanical stability. Concerning the electrochemical corrosion test, an improved behavior is obtained by coating the composites by a 0.5 μm thin Titanium layer. The coated Titanium composite bipolar plate has been successfully integrated in a PEM fuel cell. The polarization curves show good electrolysis performances for short time, but further improvements on the coating and the surface roughness need to be made for long-time stability.