Interfaces and Related Losses in PEM Fuel Cells: Theoretical and Experimental Studies

[66623] PI kumburr本工作的目的是定义一个科学框架，以详细评估聚合物电解质燃料电池（PEFCs）的界面形态和界面传输机制。pi假设当前模型的许多缺点的主要原因是将界面处理为无限薄层，具有完美的接触和均匀性。pi的初步工作表明，微孔层（MPL）和催化剂层（CL）表面不光滑；相反，它们表现出表面不规则，如细长的表面裂缝、孔洞和凹痕。这些表面特征导致了不完美的接口，从而导致性能损失和缺陷。令人信服的证据表明，界面区域对燃料电池的性能很重要，但对这些关键区域的作用仍然缺乏基本的理解。pi将解决这个问题，并验证接口对pefc性能和耐用性的影响。为了实现这一目标，pi将执行一个结合实验和计算的计划，包括：1)利用先进的诊断工具和中子成像技术对界面输运性质和保水特性进行了广泛的原位和原位测量；2)通过结合光学轮廓术和双束聚焦离子束扫描电子显微镜研究对键合界面结构进行了数字表征；3)开发一个有效的界面接触模型（适应摩擦学中成熟的框架），以创建一组克隆的虚拟MPL/CL界面结构。4)使用这些虚拟界面，开发多尺度传输和性能模型，以描述这些界面区域对pefc的质量、热和电传输特性的影响。智力优势：这种方法将使具有真实界面形态和界面传输的更高保真度建模能力成为可能。该项目不仅将对高性能新材料工程产生重大影响，而且将为耐久性研究提供重要指导。所提出的方法也具有很强的变革性，因为它将为处理pefc和其他类型燃料电池的接口相关性能和耐久性问题带来新的视角。所提出的表征界面的方法将转化为其他领域，因为它可以进一步扩展到其他电化学系统（例如，锂离子电池和其他电池），以帮助我们解决类似的基本差距。更广泛的影响：具体活动将包括：i)在多学科工程领域培养研究生和本科生，ii)在德雷塞尔大学和卡内基梅隆大学（CMU）的实验室之间形成每年一次的研究生交换，iii)为德雷塞尔大学和卡内基梅隆大学教授的燃料电池课程开发新的教学材料，iv)通过利用德雷塞尔大学和CMU的既定项目（REU， IGERT， GAANN， LSAMP）积极招募和培训女性和未被充分代表的少数族裔工程师，v)通过德雷塞尔导师计划培训当地高中生；vi)通过德雷塞尔-宾夕法尼亚大学NanoRET计划接待当地高中教师，开发与替代能源相关的教育模块；vii)每半年为高中教师举办一次研讨会，作为“？什么是工程？8)在出版物和pi中展示结果。网站进行更广泛的传播。

1066623 PI KumburThe objective of this work is to define a scientific framework that enables detailed assessment of the interfacial morphology and interfacial transport mechanisms on the of the polymer electrolyte fuel cell (PEFCs). The PIs hypothesize that a major reason for many shortcomings of current model is the treatment of the interface as an infinitely thin layer, having perfect contact and homogenous properties. Preliminary work by PIs demonstrates that the micro-porous layer (MPL) and catalyst layer (CL) surfaces are not smooth; instead they exhibit surface irregularities, such as elongated surface cracks, holes, and dents. These surface features result in imperfect interfaces, which promote performance loss an. Compelling evidence suggests that interfacial regions are of importance in fuel-cell performance, but a fundamental understanding of the role of these critical regions is still lacking. The PIs will address this issue and perform a verification of the impact of the interface on the performance and durability of PEFCs. To achieve this, the PIs will carry out a combined experimental and computational plan, including: 1) ex-situ and in-situ measurements of a broad range of interfacial transport properties and water retention characteristics using advanced diagnostic tools and neutron imaging, 2) digital characterization of the bonded interface structure through a combined optical profilometry and dual-beam focused ion-beam scanning electron microscope study, 3) development of a validated interfacial contact model ( adapting well-established frameworks from tribology) to create a set of cloned virtual MPL/CL interface structures under compression, and 4) using these virtual interfaces, develop multi-scale transport and performance models to describe the impact of these interface regions on the mass, thermal and electrical transport characteristics of PEFCs.Intellectual Merit: This approach will enable higher fidelity modeling capability with realistic interfacial morphology and interfacial transport. This project will not only have a substantial impact on the engineering of novel materials for high performance, but also will provide significant guidance for durability studies. The proposed methodology also has a strong transformative nature as it will bring a new perspective to approach the interface related performance and durability issues in PEFCs and other types of fuel cells. The proposed methodology for characterizing the interface will be transformable to other fields, as it can be further extended into other electrochemical systems (e.g., Li-ion and other batteries) to help us address similar fundamental gaps.Broader Impact: Specific activities will include: i) training of graduate and undergraduate students in multidisciplinary engineering fields, ii) formation of a yearly graduate student exchange between labs at Drexel and Carnegie Mellon (CMU), iii) development of new instructional materials for fuel cell courses taught at Drexel and CMU, iv) active recruitment and training of women and underrepresented minority engineers by leveraging the established programs (REU, IGERT, GAANN, LSAMP) at Drexel and CMU, v) training of local high school students through Drexel Mentorship Program, vi) hosting local high school teachers through Drexel-Penn NanoRET program to develop educational modules related to alternative energy, vii) semi-annual workshops for high school teachers as a part of the ?What is Engineering? program at CMU, and viii) presentation of results in publications and PIs? websites for broader dissemination.