磺化聚醚醚酮立体化树脂胶束溶液的可控制备及在质子交换膜燃料电池中的应用研究

The incompatibility problem between C-H aromatic proton exchange membrane and Nafion ionomer in the interface between catalyst layer and membrane leads to substituting C-H aromatic ionomer for Nafion. However, the transportation of H2O and gas is blocked and the proton conductivity is low. This proposal will focus on the synthesis of rod-coil block SPEEK copolymer and comb SPEEK polymer in order to make the ionomer self assemble in the selective solvent. The influence of molecular structure of ionomer, relative length and ratio of the two-phase on the dispersion state of ionomer will be studied, and the effect of the morphology of ionomer on the micropore structure of catalyst layer will be investigated. A series of membrane electrode assemblies featured by identical molecular structure are prepared and cross-linked by thermal initiation. The influence of the morphology of ionomer and hot-press technology on the properties of membrane electrode assemblies will be explored. The relation between the molecular structure of ionomer, the morphology of ionomer and the properties of membrane electrode assemblies will be systematically studied. The successful implementation of present project will establish theoretical foundation for C-H aromatic ionomer in proton exchange membrane fuel cell.

基于碳氢芳香型质子交换膜与Nafion立体化树脂存在催化层与膜界面相容性差的问题，而用碳氢芳香型立体化树脂替代Nafion树脂，存在催化层水气传输受阻，质子传导差等问题，制约其在燃料电池催化层中的应用。本项目提出设计合成分子结构规整的刚柔链交替的嵌段型、柔性脂肪链为侧链的梳型磺化聚醚醚酮（SPEEK），实现立体化树脂在选择性溶剂中自组装，形成亲水磺酸基团为壳，疏水脂肪链为核的胶束溶液。研究分子结构、溶剂性质对树脂在溶液中分散状态的影响规律，阐明胶束结构对催化层微孔结构、质子通道的影响，进而实现立体化树脂对催化层水气传输、质子传导等性质的调控。同时提出在构筑同质材料膜电极时，利用热引发实现立体化树脂原位交联，探索立体化树脂胶束结构、热压工艺等对膜电极性能的影响规律，阐明树脂分子结构-胶束溶液微观形态-电池性能之间的关系，为碳氢芳香型立体化树脂在质子交换膜燃料电池的应用奠定理论基础。

碳氢芳香型聚合物电解质作为催化层树脂应用于质子交换膜燃料电池时，存在电池性能差，膜与催化层界面不稳定等问题。本课题从分子设计的角度出发，合成了不同分子链结构的可热引发交联的磺化聚醚醚酮（SPEEK），讨论了分子链形式、所含基团极性、盐形式等对SPEEK在选择性溶剂中的溶解性影响。筛选了水醇可溶的羟基化SPEEK作为催化层树脂，讨论了热压条件即交联条件、溶剂性质、固含量等对催化层孔结构及膜电极电池性能的影响。结果表明，羟基化SPEEK作为阴极立体化树脂及质子交换膜，水-异丙醇作为树脂分散溶剂，制备的膜电极在25 °C，4M甲醇为燃料的直接甲醇燃料工况下，最大功率密度达到了29.0 mW cm-2，与目前商业化的Nafion基膜电极的最大功率密度相当（31.8 mW cm-2），是在树脂溶液中引入35wt%二甲基亚砜所制备的膜电极最大功率密度（6.5 mW cm-2）的4.5倍。综上所述，合成水醇可溶可交联型碳氢芳香型聚合物电解质，在催化层制备过程中避免引入高沸点溶剂，是提高碳氢基膜电极电池性能的有效方法。本研究为碳氢芳香型立体化树脂在质子交换膜燃料电池的应用奠定了工作基础。项目资助发表核心论文3篇，专利1项。培养研究生一名，在读硕博连读生一名。项目投入经费24万元，支出21.7618万元，各项支出基本与预算相符。剩余经费2.2382万元，剩余经费计划用于本项目研究后续支出。