Bipolar plate manufacturing and reconditioning using next-generation IMPULSE® HiPIMS etching, surface preparation, and pinhole-free deposition of corrosion-resistant, low-ICR coatings

Bipolar plates (BP) are a critical component in proton exchange membrane fuel cells (PEMFC) providing conducting paths for electrons between cells, distribute and provide a barrier for reactant gases, remove waste heat, and provide stack structural integrity. Metallic BP (such as 316SS) have attracted attention for automotive applications due to superior mechanical and physical properties for large stack sizes compared with non-porous graphite and composite materials that have difficulty supporting mediumduty and heavy-duty applications. Because BPs represent a major fraction the total PEMFC stack cost, it is imperative to have anti-corrosion coatings and scalable fabrication technologies to achieve low corrosion rates and low interface contact resistance with catalyst and gas diffusion layers for 25,000-hour PEMFC operation. Thin-film protective coatings using diamond-like carbon (DLC), metal nitrides/carbides, and noble coatings are leading candidates for metallic BPs using CVD and PVD processes. The opportunity presents for a thin-film surface modification technique that can provide both anticorrosion coating deposition and dry-plasma etching for reconditioning. This would enable a BP manufacturer to provide a solution over the entire lifecycle of the PEMFC stack. Through this SBIR/STTR we will demonstrate a technology to enable dry-plasma etching, metal/dopant implantation, and texture control that is ideal for coatings on BP metals, e.g. SS316, that is cost-effective and scalable with existing manufacturing process flow. A successful SBIR/STTR will pathfind means to apply superb anti-corrosion coatings with low interface contact resistance and enable recycling/reconditioning of used BPs at end of life. This incremental step will further the DOE’s comprehensive energy portfolio goal to achieve net-zero emissions—particularly in the transport sector. Enabling a cost-effective solution for metallic BPs leads to high-power density PEMFC with structural integrity. This will advance PEMFC adoption in the heavy-duty and medium-duty transport sectors, where access to H2 infrastructure and installation has lower costs and barriers to entry (vs. light-duty for example).