Influence of graphite powder on the properties of carbon paper for proton-exchange membrane fuel cells
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摘要: 以干法成型技术所制备的聚丙烯腈基炭纤维纸作为炭纸坯体,添加有石墨粉的酚醛树脂溶液作为浸渍剂,通过浸渍、模压固化和热处理工艺制得PEMFC用炭纸。结果表明,随石墨含量的增加,炭纸的厚度、孔隙率逐渐增加,透气性、导电能力逐渐增强,密度和抗拉强度呈先增加后降低的变化规律,当石墨粉质量分数达到5%时炭纸的综合性能最佳,其基本性能参数为:厚度0.23 mm,密度0.53 g · cm-3,气透率2 080 mL · mm · cm-2 · h-1 · mmAq-1,孔隙率66%,平面电阻率2.6 mΩ · cm-1,拉伸强度19.4 MPa,符合质子交换膜燃料电池气体扩散层对炭纸的要求。采用Pt载量为0.5 mg · cm-2的MEA,在H2/Air=1.2/2.5、温度65 ℃、常压条件下进行单体电池性能测试,电流密度为800 mA · cm-2时输出电压为0.65 V,电池输出性能较好。Abstract: A PAN-based carbon fiber paper preform prepared by a dry casting method was impregnated with phenolic resin mixed with graphite powder, which was mold-pressed, cured, carbonized and graphitized to prepare carbon paper for proton-exchange membrane fuel cells (PEMFCs). The effect of graphite powder content on the properties of the carbon paper was investigated. Results showed that the thickness, porosity, permeability and conductivity of the carbon paper increased with increasing content of graphite powder while its density and tensile strength exhibited a maximum. The carbon paper has an optimum performance for PEMFCs with a graphite addition of 5 mass%. The optimized properties of the carbon paper are as follows: thickness 0.23 mm, density 0.53 g · cm-3, resistivity 2.6 mΩ · cm-1, tensile strength 19.4 MPa, porosity 66%, gas permeability 2 080 mm · cm-2 · h-1 · mmAq-1. The output voltage of a single cell with this paper loaded with 0.5 mg Pt/cm2 was 0.65 V with a current density of 800 mA · cm-2 under atmospheric pressure and 65 ℃ using a H2/air pair.
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Key words:
- Carbon fiber paper /
- Graphite powder /
- Resistivity /
- Tensile strength /
- Gas permeability
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