一维炭材料一体式气体扩散层的制备及其在直接甲醇燃料电池中的应用  

A novel gas diffusion layer and its application to direct methanol fuel cells

作　　者：舒清柱 夏章讯[2] 魏伟[2] 许新龙[2] 王素力[2] 赵红[1] 孙公权[2] SHU Qing-zhu;XIA Zhang-xun;WEI Wei;XU Xin-long;WANG Su-li;ZHAO Hong;SUN Gong-quan(The College of Materials Science and Engineering,Dalian Jiaotong University,Dalian 116028,China;Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian 116023,China)

机构地区：[1]大连交通大学材料科学与工程学院,辽宁大连116028 [2]中国科学院大连化学物理研究所,辽宁大连116023

出　　处：《新型炭材料》2021年第2期409-419,共11页New Carbon Materials

基　　金：国家自然科学基金(No.21506212,2150060681,21776027).

摘　　要：气体扩散层(GDL)是燃料电池(FCs)膜电极组件(MEA)的重要组成部分,起到支撑催化层、收集电流、对物料进行传输及再分配的作用。传统的扩散层一般以炭纸或炭布为基底,但炭纸价格昂贵、缺乏柔韧性、孔结构单一,为了更好地进行气液相管理,需再涂覆上一层微孔层(MPL)。本文以炭纤维(CF)为骨架,复合多壁碳纳米管(MWCNT),并添加一定量的聚四氟乙烯(PTFE)作为粘结剂和憎水剂,通过减压抽滤成型法一步制成新型一体式气体扩散层(GDL/CNT-CF)。扫描电子显微镜(SEM)结合导电性、气体渗透性及孔隙率等表征表明,一体式扩散层中高导电性的碳纳米管在炭纤维中呈梯度分布,亦利于电子传输,形成的多级孔隙结构,亦利于物料分配,均匀分布的PTFE有助于水分排除,从而取代了由炭纸和微孔层构成的传统扩散层。将其应用于直接甲醇燃料电池(DMFC)的阴极或同时作为阴阳极扩散层时,具有优异的传质性能,单电池的最大功率密度相比商品扩散层分别提高了20%和35%。The gas diffusion layer(GDL)is an important component of the membrane electrode assembly of fuel cells(FCs).Its roles include supporting the catalyst layer,collecting current,and transferring and redistributing materials.A conventional GDL consists of a backing layer,typically of commercial carbon paper or carbon cloth,but it suffers from its high cost,narrow pore-size distribution,lack of flexibility and poor conductivity,and a micro-porous layer(MPL)is necessary for better gas/liquid management.A novel flexible gas diffusion layer(GDL)was prepared by vacuum filtration of a suspension of carbon fibers(CFs)and highly-dispersed multi-wall carbon nanotubes(MWCNTs)in a polytetrafluoroethylene(PTFE)binder and water repellent.SEM observations,gas permeability and porosity tests indicate that there is a gradient in the concentration of highly-conductive MWCNTs in the CNTCF GDL network that facilitates electron transport.A multi-level pore structure is formed,which is beneficial to mass transport.The PTFE is distributed uniformly,which is favorable for the discharge of condensed water from the FCs.When the GDL/CNT-CF is used in the cathode,or in both the cathode and anode in direct methanol FCs,the maximum power densities of single cells are increased by 20%and 35%,respectively,compared with those using a commercial GDL consisting of carbon paper with a MPL due to its excellent mass transfer performance.

关 键 词：气体扩散层 炭纤维 碳纳米管 多孔结构 直接甲醇燃料电池 

分 类 号：TQ127.11[化学工程—无机化工]