燃料电池复合石墨双极板基材的研究进展:材料、结构与性能

Graphite-Filled Composite Bipolar Plates for Fuel Cells:Material,Structure,and Performance

双极板是燃料电池的重要组成部件,需要满足导电、抗弯强度、耐腐蚀等方面性能的要求。复合石墨双极板具有成本低、耐腐蚀性好、易成型等优势,是双极板的一个重要研究方向。复合石墨双极板的导电功能是由以石墨为代表的导电填料相互连接形成传导网络实现的,抗弯强度及气密等性能则主要依靠树脂固化形成的基体。因此,复合石墨双极板性能不仅受到导电填料以及树脂性能的影响,同时导电填料、树脂固化形成的结构对于极板性能也有着不可忽视的影响。本文总结了导电填料及树脂的性质、改性方法等对于复合石墨极板性能的影响,并分析了分子结构以及制备工艺对于极板结构以及实用性能的影响规律。导电填料与树脂的相容性受到原料表面官能团的影响,并直接影响了导电填料的离散均匀度以及导电填料/树脂的界面性能。通过填料诱导工艺优化导电网络,能够有效提升极板的导电性能。基于对研究现状的总结,本文对复合石墨极板开发的未来发展方向进行了展望。

Bipolar plates(BPs)are one of the key components of proton exchange membrane fuel cell(PEMFC)stacks.To ensure that such a stack operates stably,a BP needs to meet exhibit electrical conductivity,heat conduction,H2 airtight,flexural strength,and durability.Based on these requirements,the BP should also be as thin as possible to reduce the overall cost of PEMFCs,while improving their volumetric energy density.A composite bipolar plate(CBP)exhibits the advantages of a low production cost,low processing difficulty,and corrosion resistance;it is produced using polymers and graphite as the main materials.Moreover,channel structures can be formed directly after a compression molding process.However,the trade-off that exists between electrical conductivity and flexural strength is a major challenge.The electrical conductivity of a CBP is realized through the network formed by graphite materials.Therefore,it not only depends on the filler concentration,but also on the network structure.At the same time,microstructures such as accumulation polymers and graphite/resin interface are directly related to the gas tightness and flexural strength of CBP.This review summarizes the conductive fillers and polymers that are commonly used for fabricating CBPs.The universal modification methods for both(fillers and polymers)are discussed,and a brief description of the conductive theoretical model has also been included.In addition,the advanced production technology of CBP is summarized,which includes the organization of the conductive network,elimination of the polymer on the plate surface,and preparation technology of the layered plates.The relationship between the production process and the performance of the plate was also analyzed.Some studies indicate that the conductive network can be optimized by combining kinds of carbon-based filler or electric field inducing,which could significantly promote the electrical conductivity of CBP.Flexural strength and H2 permeation rates were increased by introducing carbon-based materials such as carbon fabric and graphite foil.The modification of the filler and polymer could facilitate their bonding with each other,which reduces agglomeration and increases the performance.It is worth noting that the structure had a notable influence on the performance of CBP,which was reflected in the filler/polymer interface or the hybrid layer structure.Based on this results,some ideas have been provided as the next steps that can be taken for the optimization and production of a CBP.We believe that the optimization of the CBP structure will be the key point for its future research.