燃料电池金属双极板涂层综述

A Review of Metal Bipolar Plate Coatings for Fuel Cells

质子交换膜燃料电池(PEMFC)是一种新型的能源装置,双极板是其主要的部件之一。金属双极板在成本和力学性能方面都具有优势,因此逐渐占据市场主流,但是其易腐蚀的特点也影响了燃料电池的性能。从后镀金属双极板、预镀金属双极板和免镀金属双极板3种不同的工艺路线出发,系统总结了相关研究进展。对于不同工艺路线下的不同涂层,通过接触电阻、腐蚀电流和表面形貌等指标进行了评价。发现后镀金属双极板的性能好于预镀金属双极板和免镀金属双极板,但是其工艺路线最复杂,成本最高,而免镀金属双极板工艺最简单,但是其防腐导电性能不能满足DOE2025标准,预镀涂层介于两者之间,是一种过渡的工艺路线。最后,从涂层结构和元素掺杂角度对后镀涂层进行了展望,从涂层晶体结构和涂层材料选择角度对预镀涂层进行了展望,从箔材元素比例、预处理工艺角度对免镀金属双极板进行了展望。综述了燃料电池金属双极板防腐导电性的发展方向,对金属双极板朝着更低的成本和更好的性能方向发展有着重要意义。

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.