Proton exchange membrane fuel cell (PEMFC) is a new type of energy device, and bipolar plate is one of its main components. Metal bipolar plates have advantages in terms of cost and mechanical properties, and gradually occupy the mainstream of the market, but their easy corrosion characteristics also affect the performance of fuel cells. This paper systematically summarized the relevant research progress from three different process routes: post-coated metal bipolar plates, pre-coated metal bipolar plates and no-coated metal bipolar plates. Different coatings under different process routes were evaluated by contact resistance, corrosion current and surface morphology. It was found that the performance of post-coated metal bipolar plates was better than that of pre-coated metal bipolar plates and no-coated metal bipolar plates, but its process route was the most complicated and its cost was the most expensive; while the process of no-coated metal bipolar plates was the simplest, but its anticorrosive and conductive performance could not meet the DOE2025 standard; and the pre-coating was a transitional process route between the two. Finally, the outlook of post-coating from coating structure and element doping, the outlook of pre-coating from coating crystal structure and coating material selection, and the outlook of no-coated metal bipolar plate from foil element ratio and pretreatment process were presented. This paper reviewed the development direction of the anti-corrosion conductivity of metal bipolar plates for fuel cells, which was of great significance for the development of metal bipolar plates toward lower cost and better performance. The process route for post-coated metal bipolar plates was to prepare a single plate by micro-stamping and forming in the first step, and in the second step to prepare a coating on the surface of the plate to improve its corrosion resistance and electrical conductivity under cathodic and anodic conditions. The advantage of this process was that it facilitated the fabrication of specimens and the high quality of the coating. There were many post-plating process routes and a wide range of coatings. Common coatings included precious metal coatings, carbon-based coatings, ceramic coatings, etc. The generation cost of the post-plating process route was high and could not adapt to the rapid development requirements of the new industry. In order to overcome the shortcomings of the post-plating process, some researchers envisaged the plating process in advance. Using the roll to roll method on the steel strip of the stainless steel substrate to first deposit corrosion-resistant conductive coating, and then micro-stamping forming flow channel study, eliminating the post-plating process while also simplifying the production process of bipolar plates was a cost-effective solution. The coating deposited on the surface of metal bipolar plates is difficult to avoid defects in the deposition process, resulting in a reduced lifetime, and the coating itself increases the cost and production time of the bipolar plates. The no-coated metal bipolar plate solves the above problems perfectly. The advantages of post-coating are the wide variety of coating options and the sequence of processing and then coating ensures the integrity and quality of the coating, but the highest production cost and the slow and difficult deposition rate of the coating make it difficult to achieve large scale, batch and high standard production. Pre-coating has the advantage of producing coated strips on a large, fast, batch basis, greatly saving the cost and time of production, but the coated strips are prone to cracking and failure when processing the flow field. The advantage of no-coating is the elimination of the coating process, its cost is the lowest among the three routes, but the anticorrosive conductivity of no-coating is poor, its research data are few, and has not yet been widely used in a large area. The anticorrosive conductivity and mechanical properties of no-coated metal bipolar plates need to be further verified. © 2024 Chongqing Wujiu Periodicals Press. All rights reserved.
