Proton exchange membrane fuel cells (PEMFCs) are hydrogen fuel cells that can convert chemical energy into electric energy while only producing pure water, thereby completely eliminating CO, NO_X, SO_X and dust pollution. Bipolar plates are important components of PEMFCs and undertake the important role of conduct current, transport reaction gases (oxidant and hydrogen), and discharge the heat of reaction and water. Hence excellent electrical conductivity, hydrophobicity and corrosion resistance is necessary for bipolar plates. In this work, N-doped graphite-like carbon coatings are deposited on titanium bipolar plates which are used in proton exchange membrane fuel cells (PEMFCs) by high power pulsed magnetron sputtering (HiPIMS). The nitrogen content was contraled by nitrogen flow rate to optimize the performance of the N-doped graphite-like carbon coatings in PEMFCs. The dense amorphous carbon with a large content of sp2 hybrid bonds leads to an excellent conductivity at 1.4 MPa which is considered to be the conventional compaction pressure in the PEMFCs and improves the corrosion resistance in the acidic environment of 0.5 mol/L H₂SO₄+5×10^-6 mol/L F^-. In addition, the hydrophobicity of the N-doped graphite-like carbon coatings is improved obviously compared with the titanium bipolar plates. The N-doped graphite-like carbon coatings prepared in this work significantly improved the hydrophobicity, corrosion resistance and interfacial conductivity of titanium bipolar plates, showing a great potential for applications in PEMFCs.
Proton exchange membrane fuel cells (PEMFCs) are hydrogen fuel cells that can convert chemical energy into electric energy while only producing pure water, thereby completely eliminating CO, NO_X, SO_X and dust pollution. Bipolar plates are important components of PEMFCs and undertake the important role of conduct current, transport reaction gases (oxidant and hydrogen), and discharge the heat of reaction and water. Hence excellent electrical conductivity, hydrophobicity and corrosion resistance is necessary for bipolar plates. In this work, N-doped graphite-like carbon coatings are deposited on titanium bipolar plates which are used in proton exchange membrane fuel cells (PEMFCs) by high power pulsed magnetron sputtering (HiPIMS). The nitrogen content was contraled by nitrogen flow rate to optimize the performance of the N-doped graphite-like carbon coatings in PEMFCs. The dense amorphous carbon with a large content of sp2 hybrid bonds leads to an excellent conductivity at 1.4 MPa which is considered to be the conventional compaction pressure in the PEMFCs and improves the corrosion resistance in the acidic environment of 0.5 mol/L H₂SO₄+5×10^-6 mol/L F^-. In addition, the hydrophobicity of the N-doped graphite-like carbon coatings is improved obviously compared with the titanium bipolar plates. The N-doped graphite-like carbon coatings prepared in this work significantly improved the hydrophobicity, corrosion resistance and interfacial conductivity of titanium bipolar plates, showing a great potential for applications in PEMFCs.
 

N-doped graphite-like carbon,proton exchange membrane fuel cells,corrosion resistance