乙烯基酯树脂/膨胀石墨燃料电池复合双极板

Study on vinyl ester resin/expanded graphite composite bipolar plates for proton exchange membrane fuel cells

采用真空浸渍结合模压的方法,选取乙烯基酯树脂(VE)和膨胀石墨(EG)板材为原料制备复合双极板。考察了微观结构以及成型压力对双极板材料的导电性能、密封性能、机械性能以及表面亲/憎水性的影响。结果表明:随着成型压力的增加,双极板的电阻下降;双极板的气体密封性优异,其渗透率低于2×10-6cm^3/(S·cm^2),相对于原始EG板材降低了3个数量级;复合双极板有很高的表面能,与水的接触角均大于90°,这有利于电池内部液态水的排出。此外还研究了双极板在模拟燃料电池环境下的腐蚀行为,并利用性能最优的复合双极板组装成单电池,进行性能测试,当电流密度达到1500 mA/cm^2时,其功率密度可达到最大值670 mW/cm^2。并且经200h运行后,电池性能仍然稳定。因此,乙烯基酯树脂/膨胀石墨复合材料是一种有前景的双极板材料。

In this paper,composite bipolar plates were prepared with vinyl ester resin（VE） and expanded graphite（EG） sheets by the method of resin vacuum impregnation and compression molding.The effects of microstructure and molding pressure on the electrical property,gas permeability,mechanical property and hydrophobicity/hydrophilicity were investigated.The results show that with the increase of molding pressure,the resistance of composite bipolar plate was reduced.Compared with the raw EG sheets,its gas impermeability is lower than 2×10-6 cm^3/（S·cm^2）,which is reduced by three orders of magnitude.Composite bipolar plate has high surface energy and its contact angle with water is greater than 90°,which makes the liquid water in the cell easily to be swept away.In addition,the corrosion behavior of the bipolar plate in a simulated fuel cell environment was also studied.And the optimum composite bipolar plates were assembled in single cell to test its performance.When the current density was 1 500 mA/cm^2,the power density could reach 670 mW/cm^2.The performance of the cell showed no significant degradation after 200 h fuel cell testing.Therefore,the VE/EG composite is a promising candidate for bipolar plate materials in PEMFCs.