High-Performance Titanium Nitride Structural Coatings for Corrosion Protection of Aluminum-Based Proton Exchange Membrane Fuel Cells

Electrification of vehicles is the key to reduce greenhouse gas emissions to meet new energy policies. New energy sources such as proton exchange membrane fuel cells (PEMFCs) have arisen as one of the most sustainable solutions. Their performance depends on the choice of materials, such as bipolar plates (BPPs). Reduction in weight, volume, and costs are of paramount importance to enable commercialization and popularization of PEMFCs. In this context, aluminum emerges as a promising candidate for BPPs, although its corrosion resistance is inadequate for the harsh environment of PEMFCs. Recently, titanium nitride (TiN) coatings have shown potential to increase the corrosion resistance of aluminum BPPs. Herein, we discovered that the performance of the aluminum-TiN functional system in a simulated PEMFC environment can be tailored by synthesis parameters. Electrochemical tests in combination with transmission electron microscopy indicate that optimal deposition settings can significantly improve the corrosion resistance by creating denser and defect-free film microstructures.