Multilayer Thin-Film Coatings for Titanium Electrolyzer Bipolar Plates Using Next-Generation Quasi-Conformal PVD with Precision Ion Energy Control

Green hydrogen is increasingly recognized as a clean industrial feedstock and primary energy carrier. Central to green hydrogen production is the water electrolyzer. Bipolar plates (BPPs) play an important role in proton exchange membrane (PEM) electrolyzer performance by serving product separation, water management, and electronic conductivity functions. Titanium plates have been the default electrolyzer material of choice with high conductivities; however, Ti is susceptible to oxidation, corrosion, and hydrogen embrittlement. There is a market opportunity for scalable manufacturing technology to apply durable high-conductivity thin-film films and protective surface coatings for BPPs utilizing low-cost substrates, such as aluminum, that are 10X less expensive and have world-wide supply chain access. BPPs represent a substantial fraction of the total cost of the stack and cost reductions in the BPP material with coatings could yield significant stack cost reductions. This Phase I SBIR will demonstrate using the IMPULSE® high-power impulse magnetron sputtering technology using a revolutionary technique called the Positive KickÖ for precision control of ion energies during quasi-conformal thin-film growth to control morphology. Controlling the ion energy allows selection of film properties, i.e. dense, hard, conductive Ti/TiN, Zr/ZrN coatings that are very resistant to corrosion, plus graded interface layers to inhibit hydrogen diffusion and embrittlement. The proposed technique is cost-effective and scalable with existing manufacturing process flow. A successful SBIR will path find a means to achieve >50% reduction in the cost of 316SS and >75% reduction in the cost of titanium bipolar plates for hydrogen production. Approximately 13% of the PEM electrolyzer stack cost is attributable to the BPP base material which is ~$30/kWEL. Transitioning from titanium to aluminum would result in over $100k savings per 5MW electrolyzer stackŚnearly 10% total cost reduction for local H2 generation. This incremental step will further the DOEĺs comprehensive energy portfolio goal to achieve net-zero emissionsŚparticularly local hydrogen generation.