Electrochemical aspects of interconnect materials in PEMFCs

Proton Exchange Membrane Fuel Cell (PEMFC) is one of the promising technologies for generating electricity due to high energy density, environmental friendliness, and the absence of noise and pollution. However, under harsh acidic conditions, metal-based PEMFC interconnector (PEMFC_MI) may induce degradation and gradual deterioration of the PEMFC stack leading to a decreased output voltage. Literature review shows that several types of stainless steel interconnect can be promising materials for commercial PEMFCs. Various surface modification techniques and different types of protective coatings have been applied on PEMFC_MI. Although these surface modification methods and coatings improve resistance towards electrochemical degradation, still some weaknesses such as low electrical conductivity, stability, and high cost have limited their industrial viability. In this review, the PEMFC in general and the protective passive layers formed on interconnects in particular, have been discussed while keeping in view their electrochemical degradation mechanisms.