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.

化学制造业是美国经济的重要贡献者，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，但与碳足迹和化学制造业的集中有关的问题仍然存在。许多化学过程都是在大规模的集中工厂中进行的，因为较小的产能在经济上是不可行的。一个例子是Haber-Bosch工艺，它生产了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，Haber-Bosch工艺占全球二氧化碳排放量的1 - 2%。电化学合成氨可以在低碳足迹和较小的生产能力的竞争制造。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下进行，规模更小，更接近最终用户，例如以分布式方式进行。这个CAREER项目将侧重于基础研究，研究如何利用锂基电化学系统提高氨生产电化学过程的选择性和生产率。该项目开发的方法将推进如何在高活性的电极-电解质界面上选择性地合成一种化学物质（氨）。这些研究知识将被用于一个外展项目，重点是向中学生教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和生产方式，将有助于对其对社会和环境的影响进行批判性评估。目前，电化学氮还原合成方法在水溶液中存在选择性差、反应速率低的问题，主要是由于析氢反应存在竞争性。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，因为质子活性可以很好地控制，锂金属介导的化学反应允许在环境条件下固氮。采用原位和非原位光谱方法研究了电解质成分对锂覆盖电极上固体-电解质间相（SEI）物质的影响。假设SEI的结构和组成控制了氮还原和竞争性析氢的选择性。该项目将解决传输限制的性质及其对耦合传输动力学的影响。作为这项工作的结果，将获得对非水溶剂中高效电化学氨生产的必要界面步骤的基本理解。这一认识将转化为在非水电解质中发生的其他电合成反应。该项目分为三个目标。目的1解决工程固体电解质界面相，以促进所需的界面反应。目的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，Aim 3将重点关注阳极和电解质设计的质量和能量平衡。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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