CAREER: Micro-structured scaffolds for through-plane porous electrode diagnostics and design

项目负责人：Shawn E. LitsterInstitution: Carnegie Mellon University提案号：1053752题目：职业：用于通平面多孔电极诊断和设计的微结构支架解决石油安全和温室气体排放的障碍之一是燃料电池和替代汽车电池的成本和耐用性。制造和器件模型预测，质子交换膜燃料电池（PEMFC）和锂离子（Li-ion）电池的成本可以从根本上降低，因为新型电极结构具有优越的反应物传输性能。目前，由于缺乏原位测量，确定最佳结构受到阻碍，限制了对电化学和输运现象的微观和纳米尺度耦合的科学理解。为了推进替代车辆和多孔电极科学，需要原位电极诊断来揭示限制机制，测试理论模型，并指导未来的设计。PI计划利用微结构电极支架（MES）诊断技术建立微米尺度的多孔电极原位分析，并将其应用于推进燃料电池和电池电极的科学和工程。MES是一种多层平面衬底，围绕着垂直的电极柱，并包含与电极相交的空间分离的薄膜传感材料层（例如，Pt超微电极）。S侧并扩展到外部仪器。PI有一些初步结果，包括首次在PEMFC阴极内进行离子电位和氧的空间分辨测量。计划中的教育和推广计划旨在招募代表性不足的群体进入工程领域，并为在汽车电气化方面扩大电化学技术培养工程师。知识优势：MES诊断具有变革性，因为它们打开了以前无法进入的电极内部，以直接进行原位测量。现有的诊断方法无法在多孔电极的厚度上进行非侵入性探测，因为活性层很难进入，而且非常薄。原位MES诊断允许代表性的平面传输；测量平面内电位、电流和浓度的空间分布；可实现1微米分辨率；并且是广泛适用的。通过MES诊断，PI将解决有关传输和电化学耦合以及最佳电极结构的关键科学和工程问题，包括：(1)识别和量化PEMFC电极中的不同传输阻力和降解机制，测试几个假设；(2)利用功能通平面分级和MES数据，识别改善交通的成分和结构分布；(3)验证和推进领先的团块和孔隙尺度模型；(4)确定新的无pt电极结构，克服当前版本的严重传输损失（如果它们成为可行的，无pt电极将从根本上改变燃料电池的经济性）；(5)将MES方法扩展到锂离子电池，以阐明并最小化其成本决定的运输阻力。更广泛的影响：MES方法具有新的测量能力和广泛的适用性（例如，超级电容器），将对多孔电极研究产生影响。燃料电池和电池的研究解决了这些挑战，这些挑战支持未来广泛的替代汽车，以减少对石油的依赖和排放，以及支持其他关键应用（如可再生能源存储）。教育和推广计划？它的主要影响是：(1)用新的面包板为卡内基梅隆大学及以后的工程专业学生准备好未来向电化学电源的过渡。教学方法和设备（BESA），通过实践和项目强化学习，加强能源系统和电化学装置的教育。一个关键的重点是可转移到其他机构。(2)通过与便携式BESA在社区活动和服务不足的学校开展互动外展活动，招募代表性不足的群体进入工程领域。什么是工程？为教师举办的讲习班。

PI: Shawn E. LitsterInstitution: Carnegie Mellon University Proposal Number: 1053752Title: CAREER: Micro-structured scaffolds for through-plane porous electrode diagnostics and design Among the barriers to addressing oil security and greenhouse gas emissions are the cost and durability of fuel cells and batteries for alternative vehicles. Manufacturing and device models forecast that proton exchange membrane fuel cell (PEMFC) and lithium-ion (Li-ion) battery costs can be radically reduced with new electrode architectures having superior reactant transport properties. Presently, identifying optimal architectures is hampered by a lack of in situ measurements, limiting scientific understanding of the micro- and nano-scale coupling of electrochemistry and transport phenomena. To advance alternative vehicles and porous electrode science, in situ electrode diagnostics are needed to reveal limiting mechanisms, test theoretical models, and guide future designs. The PI plans to establish micron-scale in situ analysis of porous electrodes using micro-structured electrode scaffold (MES) diagnostics and to apply them in advancing the science and engineering of fuel cell and battery electrodes. An MES is a multi-layer, planar substrate that surrounds a perpendicular column of electrode and contains spatially separated layers of thin-film sensing materials (e.g., Pt ultra-microelectrodes) that intersect the electrode?s side and extend to external instrumentation. The PI has some preliminary results, including the first spatially resolved measurements of ionic potential and oxygen within a PEMFC cathode. The planned education and outreach plan aims to recruit underrepresented groups into engineering and to prepare engineers for the expansion of electrochemical technology with vehicle electrification. Intellectual merit: MES diagnostics are transformative in that they open the previously inaccessible electrode internals to direct in situ measurements. Existing diagnostics are not able to probe non-intrusively across the thickness of porous electrodes because the active layers are difficult to access and are very thin. In situ MES diagnostics allow representative through-plane transport; measure through-plane spatial distributions of potentials, currents, and concentrations; can achieve 1 micrometer resolution; and are broadly applicable. With MES diagnostics, the PI will address key scientific and engineering questions on coupling of transport and electrochemistry and the architecture of optimal electrodes, including: (1) identify and quantify the distinct transport resistances and degradation mechanisms in PEMFC electrodes, testing several hypotheses; (2) using functional through-plane grading and MES data, identify distributions of composition and structure that improve transport; (3) validate and advance leading agglomerate and pore-scale models; (4) identify new Pt-free electrode architectures that overcome the severe transport losses of current versions (if they become viable, Pt-free electrodes will radically alter fuel cell economics); (5) extend MES methods to Li-ion batteries to elucidate and minimize their cost-dictating transport resistances. Broader impact: With their new measurement capabilities and broad applicability (e.g., to ultra-capacitors), MES methods will have impact on porous electrode research. The fuel cell and battery research addresses those challenges that support a wide range of future alternative vehicles to reduce oil reliance and emissions as well as supporting other key applications (e.g., renewable energy storage). The education and outreach plan?s key impacts are: (1) Preparing engineering students at Carnegie Mellon and beyond for future transitions to electrochemical power with a new ?breadboard? pedagogical approach and apparatus (BESA) that enhances education on energy systems and electrochemical devices with hands-on and project enhanced learning. A key emphasis is transferability to other institutions. (2) Recruiting underrepresented groups into engineering with interactive outreach activities with the portable BESA at community events and underserved schools and by ?What is Engineering?? workshops for teachers.