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

PI：Shawn E. Litster机构：卡内基梅隆大学提案编号：1053752标题：职业：用于贯穿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替代车辆的燃料电池和电池的成本和耐用性。制造和装置模型预测，质子交换膜燃料电池（PEMFC）和锂离子（Li离子）电池的成本可以通过具有上级反应物传输特性的新电极结构而从根本上降低。目前，确定最佳架构受到缺乏原位测量的阻碍，限制了对电化学和传输现象的微米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计划使用微结构电极支架（MES）诊断建立多孔电极的微米级原位分析，并将其应用于推进燃料电池和电池电极的科学和工程。MES是多层平面基板，其围绕电极的垂直列并且包含薄膜感测材料（例如，铂超微电极），相交的电极？并延伸到外部仪器。PI有一些初步的结果，包括第一个空间分辨的测量质子交换膜燃料电池阴极内的离子电位和氧气。计划中的教育和外联计划旨在招募代表性不足的群体进入工程领域，并为扩大电化学技术与车辆电气化做好准备。智力优点：MES诊断是变革性的，因为它们打开了以前无法访问的电极内部，以直接进行原位测量。现有的诊断不能非侵入性地探测多孔电极的厚度，因为活性层难以接近并且非常薄。原位MES诊断允许代表性的通过平面传输;测量电势、电流和浓度的通过平面的空间分布;可以实现1微米的分辨率;并且具有广泛的适用性。通过MES诊断，PI将解决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电极中不同的传输阻力和降解机制，测试几种假设;（2）使用功能通过平面分级和MES数据，识别改善传输的成分和结构分布;（3）验证和推进领先的团聚体和孔隙尺度模型;（4）确定新的无铂电极结构，克服当前版本的严重传输损失（如果它们变得可行，无铂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，以阐明并最大限度地减少其成本决定的传输阻力。更广泛的影响：凭借其新的测量能力和广泛的适用性（例如，到超级电容器），MES方法将对多孔电极的研究产生影响。燃料电池和电池研究解决了支持广泛的未来替代车辆的挑战，以减少对石油的依赖和排放，以及支持其他关键应用（例如，可再生能源存储）。教育和推广计划？的主要影响是：（1）准备工程专业的学生在卡内基梅隆大学及以后的未来过渡到电化学电源与新的？面包板？教育方法和设备（BESA），通过实践和项目强化学习来加强能源系统和电化学设备的教育。一个关键的重点是可转移到其他机构。(2)招募代表性不足的群体进入工程与互动推广活动与便携式BESA在社区活动和服务不足的学校，并通过？什么是工程学？教师研讨会。

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.