膨胀石墨/酚醛树脂-聚乙烯醇缩丁醛复合双极板的制备与性能

Preparation and properties of expanded graphite/phenolic resin-polyvinyl butyral composite bipolar plates

采用聚乙烯醇缩丁醛(PVB)对酚醛树脂(PF)进行改性,并以膨胀石墨为第一导电填料,用模压成型法制备了新型质子交换膜燃料电池用膨胀石墨/PF-PVB复合材料双极板。研究了PVB与PF质量比、改性树脂含量及炭黑的添加对膨胀石墨/PF-PVB复合材料双极板电导率、抗弯强度等性能的影响。结果表明,当改性树脂质量分数固定为30wt%时,膨胀石墨/PF-PVB复合材料双极板在PVB∶PF=0.5时表现出最佳的电导率及抗弯强度,分别为192.3S/cm、47.25MPa,与不添加PVB的膨胀石墨/PF复合材料双极板相比,平面内电导率和抗弯强度分别提高了12.3%、14.2%。在PVB含量固定的条件下(PVB∶PF=0.5),当改性树脂的质量分数由25wt%增加至45wt%时,膨胀石墨/PF-PVB复合材料双极板的电导率下降,而抗弯强度增加。进一步添加炭黑提高膨胀石墨/PF-PVB复合材料双极板的导电性能,当改性树脂质量分数固定为45wt%时,炭黑添加量为4wt%的试样表现出最佳的平面电导率和面比电阻,分别为137S/cm、14.4mΩ·cm^2。

A new kind of bipolar plate for proton exchange membrane fuel cell was prepared by compression molding method,using polyvinyl butyral（PVB）modified phenolic resin（PF）as binder and expanded graphite as the first conductive filler.The effects of PVB to PF mass ratio,the modified resin content and addition of carbon black on the conductivity,flexural strength of the expanded graphite/PF-PVB composite bipolar plate were also investigated.The results show that,when the mass fraction of resin is fixed at 30 wt%,the expanded graphite/PF-PVB composite bipolar plate posses the highest in-plane conductivity（192.3 S/cm）and flexural strength（47.25 MPa）with the PVB∶PF=0.5,which is increased by 12.3% and 14.2% respectively compared to the expanded graphite/PF composite bipolar plate samples without PVB addition.When PVB∶PF=0.5,with the mass fraction of resin increase from 25 wt% to 45 wt%,the conductivity of the expanded graphite/PF-PVB composite bipolar plate declines while flexural strength increases.Further add carbon black to improve the conductivity of the expanded graphite/PF-PVB composite bipolar plate,when resin mass fraction at 45 wt%,the sample with 4 wt%carbon black shows the best in-plane conductivity（137 S/cm）and best area specific resistance（14.4 mΩ·cm^2）.