Electrical and Thermal Conductivities of Novel Metal Mesh Hybrid Polymer Composite Bipolar Plates for Proton Exchange Membrane Fuel Cells

Novel metal mesh hybrid polymer composite bipolar plates for proton exchange membrane fuel cells (PEMFCs) have been prepared via inserting a copper or alumina mesh in polymer composites. The composition of polymer composites consisted of 70 wt% graphite powder and 0–2 wt% modified multi-walled carbon nanotubes (m-MWCNTs). Results indicated that the inplane electrical conductivity of m-MWCNTs/polymer composite bipolar plates increased from 156 S cm⁻¹ (0 wt% MWCNT) to 643 Scm⁻¹ (with 1 wt% MWCNT) (D.O.E target > 100 S cm⁻¹). The bulk thermal conductivities of the copper and aluminum mesh hybrid polymer composite bipolar plates increased from 27.2 W m⁻¹ K⁻¹ to 30.0 W m⁻¹ K⁻¹ and 30.4 W m⁻¹ K⁻¹, respectively. Furthermore, the current and power densities of a single fuel cell using copper or alumina mesh hybrid polymer composite bipolar plates are more stable than that of using neat polymer composite bipolar plates, especially in the ohmic overpotential region of the polarization curves of single fuel cell tests. The overall performance confirms that the metal mesh hybrid polymer composite bipolar plates prepared in this study are promising for PEMFC application.