The effects of different dimensional carbon additives on performance of PEMFC with low-Pt loading cathode catalytic layers

The addition of carbon additives to the catalytic layers (CLs) with low-Pt loadings significantly improves the cell performance of proton exchange membrane fuel cells. However, the structure-activity relationship between the different dimensional carbon materials in CLs and the cell performance is still unknown. In the present work, three different dimensional carbon materials have been added into the cathode CLs with low Pt loading. The addition of one-dimensional carbon nanotubes and zero-dimensional XC-72R significantly enhanced the power density of the fuel cell because of the improved Pt dispersion and porous structures of the CL. This resulted in enhanced gas transfer and water removal accessibility. Nevertheless, the tortuous transfer path of gas and water after the presence of graphene nanosheet in the CL results in increased mass transfer resistance, although it reduces the charge transfer of the CL due to the improved catalyst utilization at low current density regions of polarization curves.