EAGER: Continuous, Catalyzed Thermopower Wave Generators Powered by Renewable Biofuels: A New Fuel Cell Concept

便携式能量存储和输送是现代运输系统和便携式电子设备激增的基石，并且是一个快速增长的领域。此外，最新的自主和移动的传感器、机器人和离网无线网络（特别是在微米和纳米级）的开发如今常常受到缺乏类似尺寸的高功率密度能量系统的阻碍。今天的每一种便携式能源技术都有其明显的缺点。电池是最常见的电能存储形式，但与将能量存储在燃料的化学键中相比，电化学能量密度从根本上受到限制。此外，电池会随着时间的推移慢慢失去电量，这使得它们不太适合长期储能。超级电容器提供显著更高的功率密度（在重量和体积方面），但以能量密度为代价。此外，它们甚至不能像电池一样长时间充电。燃料电池和发动机可以利用化学燃料的大能量密度，但在小规模制造时更为复杂，因此迄今为止它们的功率密度受到限制。马萨诸塞州理工学院的Michael Strano教授已经对提供替代这些现有装置的可能性的替代能量装置进行了一些初步研究，基于热功率波的能量装置可以显著地增加便携式功率装置的能量密度超过10倍，具有其他优点，例如零存储损耗和电荷衰减。高导电性支架，如碳纳米管（CNT），引导热化学反应波沿着它们的长度;波也推动电荷载体产生高功率的电脉冲。根据Strano的说法，这种快速波意味着热功率波在功率密度方面通常可以优于使用静态热梯度的传统热电器件，并且可能没有相同的效率限制（通常约为1-5%）。要测试的概念是热动力燃料电池是否可以被创建，它可以被操作以连续发电;以前的设备只能使电脉冲短于一秒。该项目介绍了添加金属催化剂纳米颗粒的碳纳米管热电导管的新方面。通过专注于甲酸和甲醇等生物衍生燃料，这些发电机可以使用可再生能源。这是一个理想的EAGER项目，因为必须成功地证明几个高风险方面。首先，使用甲酸和甲醇的波传播必须使用低至中等活性的催化材料来证明，以使它们沿着热导管材料的长度分解，包括碳纳米管纤维、无机纳米线或石墨烯膜。对这些波的理论理解的进展将伴随着这一努力。催化剂的选择必须优化活化能;太低，燃料将自发反应而不受纳米管的控制，太高，所需的引发能量将太大，削弱效率。为了使液体燃料TWG实用，更常见的金属如Au、Fe或Cu必须是活性催化剂金属。除此之外，一个目标是制造一个工作装置，并证明延长工作寿命。这显然是EAGER奖项所设想的高风险高潜在回报项目。更广泛的影响对于这个项目，PI打算利用本科生和研究生的研究人员，作为促进工程多样性的一种手段。PI指出，组成这个项目的实验似乎非常适合本科生，他们适应并快速学习如何制备热动力波基板，并学习如何使用仪器。PI过去曾与大量本科生广泛合作，其中许多人是性别和种族少数群体。在一个短的EAGER项目中很难发展这些方面，因此PI在这方面的努力值得赞扬。

Abstract#1239073Strano, Michael S.Technical BasisPortable energy storage and delivery is the cornerstone of modern transportation systems and the of the proliferation of portable electronic devices and is a rapidly growing field. Additionally, the development of the newest autonomous and mobile sensors, robots, and off-grid wireless networks, particularly at the micro- and nanoscale, is often hampered today by the lack of high power density energy systems of similar size. Each of todays portable energy technologies has its distinct shortcomings. Batteries are the most familiar form of electrical energy storage, but electrochemical energy density is fundamentally limited compared to storing energy in the chemical bonds of fuels. In addition, batteries slowly lose their charge over years, making them less desirable for long-term energy storage. Supercapacitors offer substantially higher power density (in weight and volume terms), but at the expense of energy density. Moreover, they cannot hold their charge even as long as batteries. Fuel cells and engines can use the large energy density of chemical fuels but are more complicated to fabricate at the small scale, so their power density has been limited so far. Professor Michael Strano of the Massachusetts Institute of Technology has performed some initial studies on an alternative energy device that offers the possibility of supplanting these existing devices.Thermopower wave based energy devices may dramatically increase the energy density of portable power devices more than a factor of 10, with other advantages such as zero storage losses and charge decay. High-conductivity scaffolds, like carbon nanotubes (CNTs), direct a hot chemical reaction wave along their length; the wave also pushes charge carriers to create a high-power pulse of electricity. This fast wave means that thermopower waves can often outperform conventional thermoelectrics using static thermal gradients in terms of power density and may not have the same limits on efficiency (usually about 1-5%)according to Strano. The concept to be tested is whether thermopower fuel cells can be created, which could be operated to generate power continuously; previous devices could only make electrical pulses shorter than a second. This project introduces the new aspect of the addition of metal catalyst nanoparticles to the CNT thermoelectric conduits. By focusing on fuels like formic acid and methanol that can be biologically derived, these generators can use renewable energy sources. This is an ideal EAGER project in that several high risk aspects must be successfully demonstrated. First, wave propagation using formic acid and alternatively methanol must be demonstrated using low- to medium-activity catalytic materials for their decomposition along the length of thermal conduit materials, including carbon nanotube fibers, inorganic nanowires, or grapheme films. Advances in theoretical understanding of these waves will accompany this effort. The choice of catalyst(s) must optimize the activation energy; too low and the fuel will react spontaneously without being controlled by the nanotubes, too high and the required initiation energy will be too large, sapping the efficiency. For liquid-fueled-TWGs to be practical, more common metals like Au, Fe, or Cu must be the active catalyst metal. Beyond this, a target would be to fabricate a working device and demonstrate extended operating life. This is clearly the high risk-high potential return project envisioned for EAGER awards. Broader Impacts For this project, the PI intends to utilize undergraduate and graduate researchers, as a means of fostering diversity in Engineering. The PI notes that the experiments that make up this project seem to be well suited for undergraduates, who adapt and learn quickly how to prepare thermopower wave substrates, and learn how to use the instrumentation. The PI has extensively worked with a large body of undergraduate students in the past, many of whom are gender and racial minorities. It is difficult to develop these aspects in a short EAGER project, so the PI is to be commended for making this effort.