膨胀石墨作为质子交换膜燃料电池双极板材料研究

Study on Expanded Graphite as Bipolar Plate Material of PEMFC

以膨胀石墨、T90密封剂为原料,采用真空加压注密和高温焙烧方法,制备得到膨胀石墨复合材料,并应用于质子交换膜燃料电池双极板.此方法有利于低成本化的模压生产,推动膨胀石墨作为质子交换膜燃料电池双极板材料的商业化发展.结果表明,在真空负压8 h后注入密封剂,加压0.7 MPa下维持12 h.然后先在120℃时焙烧4 h,在200℃时焙烧4 h固化密封剂,制备得到改性后的注密膨胀石墨,并对其进行物理表征和化学表征.结果表明:在压力1.4 MPa下,注密膨胀石墨的接触电阻为4.4 mΩ·cm^(2),小于美国DOE标准(10 mΩ·cm^(2));相比较原始膨胀石墨,注密后的膨胀石墨比表面减小了48.594 m^(2)/g、孔体积减小了0.14 cm^(3)/g;腐蚀电位增加了0.409 V,经过拟合后腐蚀电流密度从0.957 9μA/cm^(2)降到0.0008μA/cm^(2),耐腐蚀性良好,达到质子交换膜燃料电池双极板的要求.

Expanded graphite and T90 sealant are used as raw materials, and vacuum expanded injection compaction and high-temperature firing are used to prepare expanded graphite composites, which are applied to the bipolar plates of proton exchange membrane fuel cells. This method is conducive to low-cost molded production and promotes the commercial development of expanded graphite as a material for bipolar plates of proton exchange membrane fuel cells. The results show that a sealant is injected after eight hours of vacuum negative pressure maintained at 0.7 MPa for 12 hours. Then it is calcined at 120 oC and 200℃ for 4 h to cure the sealant. The physical test and chemical characterization results show that the contact resistance of the compacted expanded graphite at a pressure of 1.4 MPa is 4.4 mΩcm^(2), which is less than the US DOE standard(10 mΩcm^(2)). Compared with the original expanded graphite, the expanded graphite has a reduced surface area of 48.594 m^(2)/g with a pore volume of 0.14 cm^(3)/g. The corrosion potential is increased by 0.409 V, and the corrosion current density is reduced from 0.9579 A/cm^(2) to 0.0008 A/cm^(2) after fitting, which meets the requirements of the proton exchange membrane fuel cell plates.