磁场对PBI/磷酸燃料电池阴极传质-反应过程影响规律研究

It is well known that magnetism and electricity are closely linked in nature. The development of electromagnetism resultsed in the electromechanical and electronic industry. A magnetic field could change the rate of the electron transfer,thus, it is no doubt that combination of the magnetism and electrochemistry is a promising discipline.There is an increasing numbers of paper reporting the magnetic enhancement of the oxygen reduction reaction during the last decade. However, the influence of the magnetic on the structure of the electric double layer and the dissolution-diffusion behavior of oxygen are still unclear. In this project, we will investigate the magnetic effects on the PBI/H3PO4 based fuel cell. The research works are focus on: 1)investigating the magnetic effects on the potential distribution and particle adsorption in the electric double layer in order to understand the changes in the structure of electric double layer under magnetic field; 2)measuring the physical properties of oxygen in the electrolyte under magnetic field and providing a mathematical description of the oxygen mass transfer process; 3)developing a model for coupled mass transfer and kinetic process of oxygen reduction under magnetic field. The research will provide theoretical guidance for the magnetic enhancement of the oxygen reduction reaction and enrich the content of magnetochemistry.

众所周知，电磁学的发展奠定了现代机电工业和电子工业的理论基础。磁场可影响电子的转移过程，不无理由期望磁学与电化学相结合有巨大的发展潜力。近十年来，关于磁场对氧还原反应促进作用的报导不断。然而磁场对双电层的结构影响及磁场作用下氧气的溶解扩散行为尚未阐清。本项目针对PBI/磷酸为电解质膜的燃料电池体系，研究外加磁场对双电层电位分布、粒子吸附的影响，认识和揭示磁场作用下双电层结构变化规律；测量外磁场作用下氧气在电解质中的物性参数，定量描述氧气的传递行为；整理归纳上述实验结果，建立磁场作用下阴极传质-反应过程模型。为利用磁场促进氧还原反应提供理论指导，并丰富磁化学的应用体系。

高温质子交换膜燃料电池，工作温度在150-180°C，因其（1）耐CO能力强（可直接使用甲醇重整气无需净化）；（2）余热品质高；（3）系统结构简单（工作温度>120℃，水热管理简单）而在携行、动力电源领域具有广阔的应用前景。然而它也面临着阴极氧还原过电位高的难题。本项目针对氧传质损失大问题，开展了磁场对氧传输迁移行为的影响研究。围绕耐磷酸催化剂开展了化学修饰分子研究和PtAu催化剂研究，通过在Pt基催化剂表面预吸附一些小分子，改变双电层结构，从而抑制磷酸吸附，经胺基小分子修饰后的Pt/C催化剂在磷酸中ORR活性提高1.6倍；采用表面Au修饰Pt替代体相合金，在提升耐磷酸能力的同时抑制表面晶格膨胀；围绕提高电池效率，开展了传质关联式的建立和燃料效率优化工作，所建立传质关联式拟合效果优于化工经典传质关联式。此外还开展了温差电池研究。