CAREER:Engineering Interphases for Li-Mediated Nitrogen Reduction at Ambient Conditions

职业：常温条件下锂介导氮还原的工程中间相

• 批准号: 1944007
• 负责人: Karthish Manthiram
• 金额: $ 62.5万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1944007&HistoricalAwards=false
• 关键词: CAREER; Engineering; Interphases; Li; Mediated

Chemical manufacturing is a key contributor to the Nation's economy, producing everything from fertilizers and pharmaceuticals to plastics and fuels. Despite the successes of the chemical industry to produce chemicals and materials critical to everyday living, there are issues associated with the carbon-footprint and centralization of chemical manufacturing. Many chemical processes are run in centralized plants at large scale because smaller capacities are not economically viable. An example is the Haber-Bosch process that produces a large portion of the ammonia needed for nitrogen-containing fertilizers. The process is run at high temperatures and pressures and at large scale in a centralized fashion. Furthermore, the Haber-Bosch process contributes to 1 - 2% of global carbon dioxide emissions. Electrochemical synthesis of ammonia could enable competitive manufacture at a lower carbon footprint and with a smaller production capacity. By applying an electrical potential to drive reactions instead of using temperature and pressure, chemical processes can be run at milder conditions, at smaller scales, and closer to the end user, e.g. in a distributed fashion. This CAREER project will focus on fundamental research to study ways to improve selectivity and production rates of an electrochemical process for ammonia production using a lithium based electrochemical system. Methods developed in the project will advance how to selectively synthesize one chemical (ammonia) over another at the highly reactive electrode-electrolyte interface. The research knowledge will be adapted to be used in an outreach program focused on teaching the importance of mass and energy balances to middle school students. Understanding where everyday chemicals and materials come from and how they are produced will allow for critical evaluation of their impact on society and the environment. To date, synthesis methods using electrochemical nitrogen reduction suffer from poor selectivity and low reaction rates in aqueous electrolytes due to the competing hydrogen evolution reaction. In order to improve selectivity for nitrogen reduction, this project will investigate ammonia synthesis in nonaqueous electrolytes, as the proton activity can be well-controlled, with a lithium metal-mediated chemistry, which allows for nitrogen fixation at ambient conditions. The effect of the electrolyte composition on the solid-electrolyte interphase (SEI) species present on the lithium-covered electrode will be studied with both in situ and ex situ spectroscopic methods. The SEI structure and composition is hypothesized to control the selectivity for nitrogen reduction versus competing hydrogen evolution. The project will address the nature of the transport limitations and its impact on the coupled transport-kinetics. As a result of this work, fundamental understanding of the necessary interfacial steps for efficient electrochemical ammonia production in a nonaqueous solvent will be obtained. This understanding will translate to other electrosynthetic reactions in nonaqueous electrolytes that take place at SEIs. The project is structured into three aims. Aim 1 addresses engineering the solid electrolyte interphase to promote desired interfacial reactions. Aim 2 will study the design of omniphobic electrodes for non-aqueous solvents to achieve fast nitrogen transport to the active sites. Finally, Aim 3 will focus on the mass and energy balances for anode and electrolyte design.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

化学制造业是国家经济的关键贡献者，生产从化肥、药品到塑料和燃料的各种产品。尽管化学工业在生产对日常生活至关重要的化学品和材料方面取得了成功，但仍存在与碳足迹和化学制造集中化相关的问题。许多化学工艺都是在大规模的集中工厂中运行，因为较小的产能在经济上不可行。哈伯-博世工艺就是一个例子，该工艺生产含氮肥料所需的大部分氨。该过程在高温高压下以集中方式大规模运行。此外，哈伯-博世工艺占全球二氧化碳排放量的 1 - 2%。氨的电化学合成可以以较低的碳足迹和较小的产能实现具有竞争力的制造。通过施加电势来驱动反应而不是使用温度和压力，化学过程可以在更温和的条件、更小的规模和更接近最终用户的情况下运行。以分布式方式。该职业项目将侧重于基础研究，研究提高使用锂基电化学系统生产氨的电化学过程的选择性和生产率的方法。该项目开发的方法将推进如何在高反应性电极-电解质界面选择性合成一种化学物质（氨）而不是另一种化学物质。研究知识将用于一项外展计划，该计划的重点是向中学生传授质量和能量平衡的重要性。了解日常化学品和材料的来源以及它们的生产方式将有助于对其对社会和环境的影响进行批判性评估。迄今为止，由于竞争性析氢反应，使用电化学氮还原的合成方法在水性电解质中选择性差且反应速率低。为了提高氮还原的选择性，该项目将研究非水电解质中的氨合成，因为质子活性可以通过锂金属介导的化学反应得到很好的控制，从而可以在环境条件下进行固氮。将通过原位和非原位光谱方法研究电解质组合物对锂覆盖电极上存在的固体电解质界面（SEI）物质的影响。假设 SEI 结构和组成可以控制氮还原与竞争氢析出的选择性。该项目将解决运输限制的性质及其对耦合运输动力学的影响。这项工作的结果是，我们将获得对在非水溶剂中高效电化学氨生产所需的界面步骤的基本了解。这种理解将转化为 SEI 中发生的非水电解质中的其他电合成反应。该项目分为三个目标。目标 1 致力于设计固体电解质界面以促进所需的界面反应。目标 2 将研究非水溶剂的全疏电极设计，以实现氮快速传输到活性位点。最后，目标 3 将重点关注阳极和电解质设计的质量和能量平衡。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Thermodynamic Discrimination between Energy Sources for Chemical Reactions

• DOI: 10.1016/j.joule.2020.12.014
• 发表时间: 2021-01-20
• 期刊: JOULE
• 影响因子: 39.8
• 作者: Schiffer, Zachary J.;Limaye, Aditya M.;Manthiram, Karthish
• 通讯作者: Manthiram, Karthish

Non-aqueous gas diffusion electrodes for rapid ammonia synthesis from nitrogen and water-splitting-derived hydrogen

• DOI: 10.1038/s41929-020-0455-8
• 发表时间: 2020-05-04
• 期刊: NATURE CATALYSIS
• 影响因子: 37.8
• 作者: Lazouski, Nikifar;Chung, Minju;Manthiram, Karthish
• 通讯作者: Manthiram, Karthish