膨胀石墨/聚酰亚胺-聚醚醚酮复合石墨双极板的制备及性能研究

Preparation and properties investigation of expanded graphite/polyimide-polyether ether ketone composite graphite bipolar plate

采用聚醚醚酮(PEEK)树脂对聚酰亚胺(PI)树脂进行改性,并以膨胀石墨作为第一导电填料,以模压成型方法制备了质子交换膜燃料电池用复合材料双极板,探究了PEEK和PI树脂比例,双极板树脂含量和石墨烯添加量对复合石墨双极板性能的影响。结果表明,当树脂质量分数固定为40%,PI∶PEEK质量比例为1∶1.25时所制得的膨胀石墨/PI-PEEK复合石墨双极板样品具有最佳的电导率(181.8 S/cm)和抗弯强度(43.49 MPa),较纯PI树脂样品电导率提高64.7%。对添加了PEEK的复合石墨双极板进行SEM、拉曼和红外光谱的表征,结果表明:PEEK树脂能较好地填入双极板孔隙之间,提高双极板致密性,红外光谱中O—H峰位变宽变长且向低频方向移动,说明添加PEEK树脂能引入大量柔性醚键和羟基从而在树脂之间形成分子间氢键。将PI与PEEK树脂的质量比固定为1∶1.25,调整树脂在双极板中的含量,当树脂含量从30%提高到50%时,膨胀石墨/PI-PEEK复合石墨双极板的电导率下降,力学性能提升。

The new composite bipolar plate for proton exchange membrane fuel cell was prepared by compression molding,using polyether ether ketone(PEEK)resin modified polyimide(PI)resins,and expanded graphite as a first conductive filler.By characterizing the properties of the bipolar plate,the effects of the ratio of PEEK and PI resin,the content of bipolar resin and the amount of graphene on the properties of the composite graphite bipolar plate were explored.The results show that,when the resin content is fixed at 40%and the PI∶PEEK ratio is 1∶1.25,the expanded graphite/PI-PEEK composite graphite bipolar plate samples have the best electrical conductivity of 181.8 S/cm and bending strength of 43.49 MPa.Compared with the sample without PEEK resin,the conductivity is increased by 64.7%,while the bending strength is not decreased significantly.The composite graphite bipolar plate with PEEK was characterized by SEM,Raman and FTIR spectra.The results show that PEEK resin can fill in the pores of the bipolar plates well and improve the density of the bipolar plates.The O—H peak in the infrared spectrum becomes wider and longer and moves to the low-frequency direction,indicating that the addition of PEEK resin can introduce a large number of flexible ether bonds and hydroxyl groups to form intermolecular hydrogen bonds between the resins.The ratio of PI to PEEK resin is fixed at 1∶1.25,and the content of resin in the bipolar plate is adjusted.When the content of resin is increased from 30%to 50%,the conductivity of expanded graphite/PI-PEEK composite graphite bipolar plate decreases and the mechanical properties improve.