Collaborative Research: Engineering the Chemistry at Solid-Solid Interfaces of Li-O2 Battery Cathodes

锂氧电池可能具有与汽油燃料相媲美的储能能力，但在该技术商业化之前，仍有许多基础科学知识需要了解。特别是，在电池运行期间形成的一些化学产物会缓慢降解并使材料中毒，导致长时间运行后的性能损失。该研究项目旨在通过探索一类廉价的混合金属氧化物电催化剂来克服这些问题，这些催化剂可能会改变锂氧电池的化学性质。该项目旨在开发一个框架来设计锂氧电池的化学，这是一种潜在的下一代储能设备，并提高其性能。这些研究结合了联合收割机先进的表征方法和理论计算，以确定氧化物表面的性质如何影响锂氧电极上产生的产物。这些见解将被用来开发设计原则，这些原则将有助于确定提高电池性能的氧化物电催化剂。参与该项目的研究人员将与当地K-12学校合作，通过暑期实习和学生交流，让经济上处于不利地位的学生参与拟议的研究。 他们的目标是激励学生追求科学和工程事业。对发生在固-固界面的反应的基本理解对于下一代能量存储设备（例如锂氧电池）的开发至关重要。 近年来，锂氧电池由于其极高的理论能量密度而引起了人们的极大兴趣。如果能达到这种能量密度的15%，那么它将相当于汽油的价值，使每次充电行驶里程高达500英里的锂氧电池在商业上可行。虽然这项技术非常有吸引力，但在其广泛采用之前需要克服许多技术挑战。这些挑战中的一些包括：（i）固体放电反应产物的不溶性，导致阴极堵塞并最终导致电池单元死亡;（ii）由于高充电过电位而解离主要放电反应产物过氧化锂的低往返（放电-充电循环）效率;以及（iii）电解质在高过电位下的不稳定性。该研究项目旨在通过在锂氧电池阴极设计固-固界面来缓解这些问题，这些界面选择性地稳定不绝缘的缺锂放电产物，并且可以在合理的过电位下解离。研究人员将采用实验和理论相结合的方法来研究这些固-固界面的化学性质，目的是设计能够选择性调节放电产物分布的材料，从而提高电池性能。特别是，这项工作将涉及先进的表征研究和理论计算相结合，以确定氧化物表面的元素组成，电子性质和对称性如何影响锂氧阴极中的放电产物分布。 这些研究将阐明全球氧化物晶体结构对放电产物形成的影响，并导致开发用于识别对锂形成具有高度选择性的氧化物电催化剂的设计原则。该奖项反映了NSF的法定使命，并通过使用基金会的知识产权进行评估，被认为值得支持。优点和更广泛的影响审查标准。

Lithium-oxygen batteries potentially could have energy storage capacities that rival gasoline fuel, but there remains much fundamental scientific knowledge to learn about these batteries before the technology can be commercialized. In particular, some of the chemical products formed during the operation of the batteries can slowly degrade and poison the materials, leading to performance losses over extended periods of operation. This research project seeks to overcome these problems by exploring a class of inexpensive, mixed metal oxide electrocatalysts that may alter the chemistry of lithium-oxygen batteries. This project aims to develop a framework to engineer the chemistry of lithium-oxygen batteries, which are a potential next-generation energy storage device, and to improve their performance. The studies combine advanced characterization methods and theoretical calculations to determine how the properties of the oxide surfaces influence the products that are produced on lithium-oxygen electrodes. These insights will be leveraged to develop design principles that will aide in identifying oxide electrocatalysts that improve battery cell performance. The researchers involved in this project will partner with local K-12 schools to involve economically disadvantaged students with the proposed research through summer internships and student exchanges. They aim to inspire the students to pursue careers in science and engineering. A fundamental understanding of the reactions occurring at solid-solid interfaces is critical for the development of next-generation energy storage devices, such as lithium-oxygen batteries. Lithium-oxygen batteries have attracted significant interest in recent years due to their exceptionally high theoretical energy density. If even 15% of this energy density is achieved, then it would equal the value of gasoline, making lithium-oxygen batteries with driving ranges of up to 500 miles per charge commercially viable. While this technology is very attractive, numerous technical challenges need to be overcome before its widespread adoption is possible. Some of these challenges include: (i) insolubility of the solid discharge reaction products, leading to clogging of the cathode and eventually resulting battery cell death; (ii) low roundtrip (discharge-charge cycle) efficiency due to high charge overpotentials to dissociate the main discharge reaction product, lithium peroxide; and (iii) instability of electrolytes at high overpotentials. This research project seeks to alleviate these issues by designing solid-solid interfaces at the cathode of lithium-oxygen batteries that selectively stabilize lithium-deficient discharge products that are not insulating and can be dissociated at reasonable overpotentials. The researchers will apply a combined experimental and theoretical approach to study the chemistry at these solid-solid interfaces with the aim of designing materials that can selectivity tune the discharge product distribution such that it leads to improved battery performance. In particular, the work will involve a combination of advanced characterization studies and theoretical calculations to determine how the elemental composition, electronic properties, and symmetry of the oxide surface influence the discharge product distribution in lithium-oxygen cathodes. The studies will elucidate the effect of the global oxide crystal structure on the discharge product formation and lead to the development of design principles for identifying oxide electrocatalysts that are highly selective towards the formation of lithium-deficient oxide discharge products and therefore exhibit low charge overpotentials.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.