物理化学学报

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碱性聚合物电解质膜的表面锥形阵列结构提升燃料电池性能

张婧雯1, 马华隆1, 马军1, 胡梅雪2, 李启浩2, 陈胜2, 宁添姝2, 葛创新3, 刘晰1, 肖丽2,4, 庄林2,3, 张熠霄1, 陈立桅1   

  1. 1 上海交通大学化学化工学院, 变革性分子前沿科学中心, 物质科学原位中心, 上海 200240;
    2 武汉大学化学与分子科学学院, 化学电源材料与技术湖北省重点实验室, 武汉 430072;
    3 武汉大学高等研究院, 武汉 430072;
    4 武汉大学索维奇国际分子科学研究中心, 武汉 430072
  • 收稿日期:2021-11-29 修回日期:2021-12-28 录用日期:2021-12-30 发布日期:2022-01-05
  • 通讯作者: 张熠霄, 陈立桅 E-mail:yxzhang2019@sjtu.edu.cn;lwchen2018@sjtu.edu.cn
  • 基金资助:
    国家自然科学基金（21991153，21991150）资助项目

Cone Shaped Surface Array Structure on an Alkaline Polymer Electrolyte Membrane Improves Fuel Cell Performance

Jingwen Zhang1, Hualong Ma1, Jun Ma1, Meixue Hu2, Qihao Li2, Sheng Chen2, Tianshu Ning2, Chuangxin Ge3, Xi Liu1, Li Xiao2,4, Lin Zhuang2,3, Yixiao Zhang1, Liwei Chen1   

  1. 1 School of Chemistry and Chemical Engineering, in-situ Center for Physical Sciences, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China;
    2 College of Chemistry and Molecular Sciences, Hubei Key Lab of Electrochemical Power Sources, Wuhan University, Wuhan 430072, China;
    3 The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China;
    4 Sauvage Center for Molecular Sciences, Wuhan University, Wuhan 430072, China
  • Received:2021-11-29 Revised:2021-12-28 Accepted:2021-12-30 Published:2022-01-05
  • Contact: Yixiao Zhang, Liwei Chen E-mail:yxzhang2019@sjtu.edu.cn;lwchen2018@sjtu.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China (21991153, 21991150).

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摘要： 燃料电池作为一种清洁高效的能量转换装置，被认为是构建未来社会可再生能源结构的关键一环。不同于质子交换膜燃料电池（PEMFC），碱性聚合物电解质燃料电池（APEFC）的出现使非贵金属催化剂的使用成为可能，因而受到了日益广泛的关注和研究。APEFC的关键结构是膜电极，主要由聚合物电解质膜和阴阳极（含催化层、气体扩散层）组成，膜电极是电化学反应发生的场所，其优劣直接决定着电池性能的好坏。因此，基于现有的碱性聚合物电解质及催化剂体系，如何构筑更加优化的膜电极结构，使APEFC发挥出更高的电池性能是亟待开展的研究。本文首先通过模板法在碱性聚合物电解质膜的表面构建出有序的锥形阵列，再将具有阵列结构的一侧作为阴极来构筑膜电极，同时，作为对比，制备了由无阵列结构的聚合物电解质膜构筑而成的膜电极，最后对基于两种不同膜电极的APEFC的电化学性能进行了对比研究。实验结果表明，锥形阵列结构可以将APEFC的峰值功率密度由1.04 W·cm-2显著提高到1.48 W·cm-2，这主要归因于在APEFC的阴极侧具有锥形阵列结构的聚合物电解质膜的亲水性的提升和催化剂电化学活性面积的增加。本工作为碱性聚合物电解质燃料电池的膜电极结构设计与优化提供了新思路。

关键词: 燃料电池, 碱性聚合物电解质膜, 膜电极, 阴极, 阵列结构

Abstract: Fuel cells are essential energy conversion devices for future renewable energy structures. Mainstream proton exchange membrane fuel cells (PEMFCs) generally exhibit satisfactory performance despite requiring noble metal catalysts to be stable in acidic environments. Alkaline polymer electrolyte fuel cells (APEFCs), in contrast, offer the benefit of employing nonnoble metal catalysts in fuel cells, but their overall performance and especially their long-term stability require further improvement. A critical component within APEFCs is the membrane electrode assembly (MEA), which comprises a hydroxide ion conductive polymer membrane, a cathode, and an anode (including a catalyst layer and a gas diffusion layer). MEA is where electrochemical reactions occur; thus, it plays a crucial role in determining fuel cell performance. Herein, the fabrication of a cone-shaped array on the surface of an alkaline polymer electrolyte membrane for improving the overall device performance is presented. The cone array was prepared using a sacrificial anodic aluminum oxide (AAO) template, and the array side of the polymer electrolyte was used as the cathode to construct the MEA, denoted as A-MEA. The control sample with no cone arrays on the polymer electrolyte surface is denoted as P-MEA. The Pt loadings on both the anode and cathode sides were approximately 0.2 mg·cm-2. APEFCs with A-MEA and P-MEA were separately assembled and tested in an 850e Fuel Cell Test System at a cell temperature of 80℃. Fully humidified hydrogen and oxygen were both supplied at a flow rate of 1000 mL·min-1. The back pressure for both the anode and the cathode was 0.2 MPa. As a result, the APEFC with A-MEA exhibited a higher peak power density than that of the APEFC with P-MEA (1.48 vs. 1.04 W·cm-2). The enhanced electrochemical performance of the APEFC with A-MEA was ascribed to the array-structured cathode, which improved the hydrophilicity of the polymer electrolyte membrane and increased the utilization efficiency of the catalyst. The hydrophilicity of the polymer electrolyte membrane with cone arrays was confirmed using contact angle measurements. The contact angles of the membranes with and without cone arrays were ~0° and 70.8°, respectively. The hydrophilic membrane promotes the electrode reaction at the cathode side. The electrochemically active surface area (ECSA) was also measured using cyclic voltammetry (CV) between 0.08 and 1 V (vs. reversible hydrogen electrode, RHE) at a scan rate of 20 mV·s-1, using fully humidified H2 and N2. A flow rate of 1000 mL·min-1 and back pressure of 0 MPa were employed. Results revealed that the ECSA of the cathode without the array was smaller than that of the array-structured cathode (21.17 vs. 24.89 m2·g-1), indicating that the array structure improved the catalyst utilization efficiency compared to that of the control sample. This study provides an effective strategy for the structural design and optimization of the MEAs in APEFCs.

Key words: Fuel cell, Alkaline polymer electrolyte membrane, Membrane electrode assembly, Cathode, Array structure

MSC2000: 

  • O646