Electrochemical and structural property of TiSiNb TFSOC on affordable interconnects in proton exchange membrane fuel cell applications

High cost and low electrochemical stability of the interconnection in Proton Exchange Membrane Fuel Cell (PEMFC) in the presence of H₂SO₄ are one of the main issues hindering the commercialization of these devices. This manuscript presents the utilization of cost-effective steel in an attempt to minimize the PEMFC interconnection costs with a thin-film solid oxide coating (TFSOC) providing sufficient corrosion resistance for efficient long-term operation. Novel Ti_0.50-y/2Si_0.50-y/2N_by1,2O₂ as TFSOC was deposited on the C45E steel as a metal interconnect utilizing a sol-gel process at various annealing temperatures. The analysis of the phase and surface morphology demonstrates that lower annealing temperatures developed nanometric crystallite size of 68 nm, more uniform structure and higher corrosion resistance. Under standard test conditions, the TFSOC demonstrated high polarization resistance (1.3 kQ cm²) even after 720 hours (h). Electrical conductivity of the TFSOC as low as 1.4 X 10^-2 (Q m)^-1 and activation energy of 0.20 eV were achieved, which helps to maintain the PEMFC output power.