PECASE: Nanoscale Assembly Approaches Toward High Performance Micro Fuel Cells

0954985 Taylor Fuel电池曾被认为是现有电池技术的可行储能替代品。然而，由于催化剂界面组装不佳，导致这些设备的性能不佳，这种希望尚未实现。这里提出的研究将使用一种新的综合方法，结合自上而下(微制造)和自下而上(静电组装)的优点来获得高性能燃料电池。这项工作将把高性能纳米材料集成到CMOS微制造燃料电池体系结构中，通过集成到硅基微结构燃料电池体系结构中的水基处理方法，产生自组装纳米材料/聚电解质复合材料。由于乙醇等可再生液体燃料的高功率密度，直接酒精燃料电池(DAFC)特别受关注。拟议的燃料电池架构将通过在硅基衬底上蚀刻微流控通道来实现，该衬底带有集成的电极、加热器和温度传感器。该衬底将作为催化剂纳米材料(例如，装饰碳纳米管、聚合物)在整体式开放式燃料电池架构上分层的平台。对组装方法的探索以及对适合这种方法的材料的全面评估将通过创造易于与电子设备集成的下一代电源来改变这一领域。智慧价值这项研究是新颖的，因为它结合了自上而下的微制造和自下而上的静电组装的优点，获得了独特的燃料电池装置结构。此外，这项研究具有潜在的变革性，因为这种新的制造方法及其产生的设备架构具有巨大的潜力，可以实现高性能碱性燃料电池所需的突破，将乙醇(一种可再生液体燃料)直接转化为车辆使用的电力。尽管具体工作将集中在碱性直接乙醇燃料电池上，但所产生的系统应该被证明适用于氢和生物燃料电池系统。该研究计划包括自上而下、自下而上和综合的方法。首先，在自上而下的方法中，集成的单片微结构燃料电池设计将最大限度地提高最初为集成电路和MEMS设备开发的体微机械加工能力和表面微机械加工能力。将导出设计规则以获取操作条件(例如，流速和温度)和设计参数(例如，通道长度、电极设计和有源面积)，以最大化单个微结构燃料电池的性能。其次，在自下而上的方法中，将使用在阳极和阴极上都具有优异电催化活性的纳米材料，使用带有过渡金属催化剂的碳纳米管。第三，在一体化方法中，将通过改变聚阳离子和阴离子聚合物/纳米材料体系，使用静电逐层(LBL)组装方法来制备(在整体式燃料电池顶部)超薄膜。这一改变将使薄膜成分的纳米级操纵成为可能，并创造出使用传统燃料电池组装方法难以生产的分子级混合物。除了研究生和本科生的传统跨学科培训外，还将使用基于网络的远程学习方法，通过两个阶段的合作渠道，接触到更多、更广泛的来自代表性不足群体的学生。第一阶段是使用YouTube为底特律高中的化学课堂开发电化学模块，第二阶段是让阿姆斯特朗大西洋州立大学的本科生领导设计和开发一种喷涂层逐层沉积机，旨在减少研究中使用的功能薄膜的制造时间。其他活动包括为一门名为“微电化学系统”的课程开发模块。

0954985TaylorFuel cells were once championed as viable alternatives to existing battery technology for energy storage. However, such hopes have not been realized due to poor assembly of the catalyst interface contributing to the meager performance of these devices. The research proposed here will use a new, integrated approach, combining the advantages of top down (microfabrication) with bottom up (electrostatic assembly) to obtain high-performance fuel cells. The work will integrate high-performance nanomaterials into a CMOS microfabricated fuel cell architecture, resulting in self-assembled nanomaterial/polyelectrolyte composites through water-based processing methods integrated into a silicon-based, microstructured fuel cell architecture. Direct alcohol fuel cells (DAFCs) are of particular interest because of the high power density of renewable liquid fuels such as ethanol. The proposed fuel cell architecture will be achieved by etching microfluidic channels into a silicon-based substrate with integrated electrodes, heaters, and temperature sensors. The substrate will serve as a platform for the layering of the catalyst nanomaterials (e.g. decorated carbon nanotubes, polymers) on top of a monolithic, open face, fuel cell architecture. Exploration of the assembly methods as well as a comprehensive assessment of materials suitable for this approach would transform this field by creating next-generation power sources that can readily be integrated with electronic devices. Intellectual MeritThe research is novel because it combines the advantages of top-down microfabrication with bottom-up electrostatic assembly to obtain unique fuel cell device structures. Furthermore, this research is potentially transformative because this new fabrication approach and its resulting device architectures have significant potential to make the breakthroughs needed to achieve high-performance alkaline fuel cells that convert ethanol, a renewable liquid fuel, directly to electricity for use in vehicles. Although the specific work will focus on alkaline direct ethanol fuel cells, the systems generated should prove to be applicable to hydrogen and bio-fuel cell systems. The research plan incorporates top-down, bottom-up, and integrative approaches. First, in the top-down approach, an integrated monolithic microstructured fuel cell design will maximize bulk and surface micromachining processing capabilities originally developed for integrated circuits and MEMs devices. Design rules will be derived to capture operating conditions (e.g., flow rates and temperatures) and design parameters (e.g., channel length, electrode design, and active area) to maximize the performance of an individual microstructured fuel cell. Second, in the bottom-up approach, nanomaterials that exploit the advantage of superior electrocatalytic activity at both the anode and cathode will be employed, using carbon nanotubes decorated with transition metal catalysts. Third, in the integrative approach, the electrostatic layer-by-layer (LBL) assembly method will be used to generate ultrathin films (on top of the monolithic fuel cell) through the alteration of polycationic and anionic polymer/nanomaterial systems. This alteration will enable the nanoscale manipulation of thin film composition and the creation of molecular level blends that would be difficult to produce using conventional fuel cell assembly methods. Parameters (e.g. ionic strength and polyion composition) will be varied to generate a highly tuned membrane electrode assembly interface built directly on top of the integrated silicon based platform.Broader Impact In addition to the traditional interdisciplinary training of graduate and undergraduate students, web-based distance learning approaches will be used to reach a larger, broader audience of students from under-represented groups through a two-stage collaborative pipeline. The first stage is the development of electrochemistry modules for a Detroit High School chemistry class using YouTube, and the second is to have undergraduates at Armstrong Atlantic State University lead the design and development of a spray coat layer-by-layer deposition machine aimed to decrease the fabrication time of functional thin films used in the research. Other activities include development of modules for a course entitled Microelectrochemical Systems.