CAREER: Membraneless Micro Fuel Cells

简介：Paul Kenis Institution：伊利诺伊大学香槟分校提议编号：0547617标题：Career：无膜微型燃料电池这项实验室研究将利用微尺度的一些特征物理性质，最显著的是层流，以获得无膜微流控燃料电池，PI和他的同事最近推出了无膜微流控燃料电池，作为便携式应用的有前途的电源。在这些基于层流的燃料电池(LFFC)中，含有燃料的气流(如甲醇、甲酸)和含有氧化剂的气流(如溶解氧、高锰酸盐)在单个微流体通道中合并，由于在这些小尺寸上没有湍流混合，因此继续进行层流平行流动。在这个通道内，这些燃料和氧化剂流分别流过相对侧壁的阳极和阴极并在其上反应。没有物理屏障消除了燃料交叉、水管理和介质组成限制等问题，这些问题在更常见的聚合物电解质膜(PEM，例如Nafion)燃料电池中通常会遇到。无膜LFFC的性能由众所周知的微尺度输运现象决定。电极耗尽边界层传质特性的工程化是本项目研究的具体课题之一。这项工作将集中于利用基于无膜层流的燃料电池在碱性和生物燃料电池的开发和性能优化方面的机会，因为缺乏膜克服了迄今为止严重限制其前景的许多技术问题。这将完成如下工作：a)建造无膜碱性燃料电池，利用在碱性介质中阳极和阴极的卓越电催化活性的优势，同时避免碳酸盐形成和膜堵塞问题，这些问题迄今阻碍了PEM型碱性燃料电池的发展，几乎没有例外。B)在无膜生物燃料电池中，使用多流层流可以调节单个燃料和氧化剂流中的pH，以最大限度地提高单个酶的稳定性和活性，而目前生物燃料电池使用的是某种折衷的pH。C)计划进行优化无膜燃料电池性能和燃料利用率的研究。设计规则将用于获取运行条件(流量、燃料/氧化剂流量比、燃料和氧化剂浓度等)。和设计参数(沟道长度、电极到电极距离等)。以最大化单个LFFC的性能。空气呼吸气体扩散电极的引入已经克服了阴极的传质限制。建议引入多个入口(或出口)来定期补充(或移除)耗尽的边界层，以解决目前出现的阳极限制。这一职业发展计划的教育部分将包括(1)为名为微型化学系统的课程开发模块；(2)多学科微型化学系统系列讲座；(3)非技术技能发展的研究生计划。后者是拟议教育计划的核心，将由四部分组成：(I)介绍非技术技能的基本原理和重要性的讲习班，以及提高这些技能的各种可用机会；(Ii)基于技能评估的个人发展计划，并在导师的帮助下实施该计划，导师通常从系校友中挑选；(Iii)项目管理研讨会，模拟公司环境中的典型情况；(Iv)由担任领导职务的著名校友举办的系列讲座。该计划的效果将通过学生反馈和第三方评估进行评估。PI将启动和协调这一方案的发展，并与该领域的专家密切合作，以确保方案的有效性。

ABSTRACTPI: Paul Kenis Institution: University of Illinois at Urbana-ChampaignProposal Number: 0547617Title: CAREER: Membraneless Micro Fuel CellsThis laboratory research will exploit some of the characteristic physical properties of the microscale, most notably laminar flow, to obtain membraneless microfluidic fuel cells that the PI and his coworkers recently introduced as a promising power source for portable applications. In these laminar flow-based fuel cells (LFFCs) a fuel containing stream (e.g. methanol, formic acid) and an oxidant containing stream (e.g. dissolved oxygen, permanganate) merge in a single microfluidic channel and proceed to flow laminarly in parallel due to lack of turbulent mixing at these small dimensions. Within this channel, these fuel and oxidant streams flow over and react at, respectively, the anode and cathode that line opposing sidewalls. The absence of a physical barrier eliminates issues such as fuel crossover, water management, and restrictions on media composition that are typically encountered in more common polymer electrolyte membrane (PEM, e.g. Nafion) based fuel cells. The performance of the membraneless LFFCs is dictated by well-understood microscale transport phenomena. Engineering of the mass transfer characteristics of the depletion boundary layers on the electrodes is one of the specific topics of study of this project. This work will focus on exploiting the opportunities of membraneless laminar flow-based fuel cells in the development and performance optimization of alkaline and bio-fuel cells, since the lack of a membrane overcomes many technical issues that to date have severely limited their promise. This will be accomplished as follows: a) Membraneless alkaline fuel cells are to be built that exploit the advantage of superior electrocatalytic activity at both the anode and the cathode in alkaline media while avoiding carbonate formation and membrane clogging issues that to date have hampered the development of PEM-type alkaline fuel cells with few exceptions. b) In membraneless biofuel cells the use of multistream laminar flow enables tailoring of the pH in the individual fuel and oxidant streams to maximize the stability and activity of the individual enzymes, whereas presently biofuel cells are operated using a certain compromise pH. c) Research to optimize the performance and fuel utilization of membraneless fuel cells is planned. Design rules will be derived to capture operation conditions (flow rates, fuel/oxidant flow rate ratio, fuel and oxidant concentrations, etc.) and design parameters (channel length, electrode to electrode distance, etc.) to maximize the performance of an individual LFFC. Introduction of an air-breathing gas diffusion electrode already overcomes mass transfer limitations at the cathode. The introduction of multiple inlets (or outlets) to periodically replenish (or remove) the depleted boundary layer is proposed to address the now arisen anode limitations. Broad ImpactThe educational component of this CAREER development program will consist of (1) the development of modules for a course entitled Microchemical Systems; (2) a multidisciplinary Microchemical Systems lecture series; (3) a graduate program for the development of non-technical skills. The latter non-technical skills program, the core of the proposed educational program, will consist of four components: (i) a Workshop presenting the fundamentals and importance of non-technical skills, as well as the wide variety of available opportunities to improve those skills; (ii) a Personal Development Plan based on a skills assessment and implementation of that plan with the aid of mentors, typically chosen from alumni of the department; (iii) a Project Management Seminar in which typical situations in a corporate environment are simulated; and (iv) a Lectures Series by prominent alumni in leadership positions. The effectiveness of the program will be assessed by student feedback and third party evaluation. The PI will initiate and coordinate the development of this program and work closely with experts in the field in order to ensure the programs efficacy.