Resolving Interphases in Solid Electrolyte Batteries through Time-of-Flight Secondary Ion Mass Spectroscopy

非技术总结：在当今社会，新的可充电电池技术迫切需要开发，以满足快速增长的无线设备的电力和能源需求，从移动通信到电动和混合动力汽车。特别是，迫切需要开发安全、高性能、稳定的全固态电池组件。该项目由美国国家科学基金会材料研究部固态与材料化学项目资助，研究了Li10GeP2S12 （LGPS）和Li7La3Zr2O12 （LLZO）这两种有前途的电解质材料，它们负责传导用于给电池充电的离子。目前的问题是，这些材料会捕获锂离子，并在电池运行过程中发生显著变化，这反过来又会严重限制电池的使用寿命。因此，这个研究项目可以直观地绘制出锂离子在电池使用过程中优先积聚的位置。为了做到这一点，Leite和Wang的团队实施了互补显微镜技术，并将获得的信息与设备性能的测量相关联。本研究的外展/教育部分包括：(i)指导研究生、本科生和高中生；（ii）将科学发现纳入讲座，以丰富马里兰大学材料科学与工程系、化学与生物分子工程系的课程；（iii）在马里兰日期间，通过为K-12学生提供电池的实践经验，让他们参与STEM，这是一个吸引6万多人来到校园的开放活动。技术总结：理解和控制全固态电池循环过程中发生的相关化学反应，将使基于Li， Na和Mg的储能材料的设计改变游戏规则。本研究阐明了两种具有高锂离子导电性电解质的全固态电池模型体系：Li10GeP2S12 （LGPS）和Li7La3Zr2O12 （LLZO）中固体-电解质界面（SEIs）形成的潜在机制。该项目由美国国家科学基金会材料研究部固态和材料化学项目资助，促进了对材料化学的理解，这些化学目前限制了锂离子全固态电池的性能。利用飞行时间二次离子质谱（ToF-SIMS），结合非原位x射线光电子能谱（XPS）和透射电子显微镜（TEM），对SEIs的形成进行了原位探测。电化学阻抗和Li分布图之间的相关性揭示了sei如何影响界面电阻，从而影响这些储能模型系统的性能。确定循环过程中Li的优先空间分布可能会改变未来全固态电池的设计，并控制sei。虽然多个原位实验已经证实了纳米级电池中SEI的形成，但没有证据表明锂化/衰减过程中电池所有活性层内中尺度Li空间分布的动力学。因此，本研究在材料化学及其他领域具有科学影响。本研究的外展/教育部分包括在不同层次上指导学生；将科学发现纳入马里兰大学材料科学与工程系以及化学与生物分子工程系的课程；在马里兰日期间，通过为K-12学生提供电池的实践经验，吸引他们参与STEM，这是一个吸引6万多人来到校园的开放活动。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。

Non-Technical Summary: In today's society, new rechargeable battery technologies are urgently being developed to address the power and energy demands of the rapidly growing number of wireless devices, ranging from mobile communication to electric and hybrid vehicles. In particular, there is a pressing need for the development of safe, high performance, stable components for all-solid-state batteries. This project, funded by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, investigates Li10GeP2S12 (LGPS) and Li7La3Zr2O12 (LLZO), two promising electrolyte materials, which are responsible for conducting the ions used to charge the batteries. The current problem is that these materials can trap Li ions and significantly change during battery operation, which, in turn, can severely limit their lifetime. Thus, this research project visually maps where the Li ions preferentially accumulate while the batteries are being used. To do this, Leite's and Wang's groups implement complementary microscopy techniques and correlate the acquired information with measurements of device performance. The outreach/education components of this research encompass: (i) mentoring graduate, undergraduate, and high school students, (ii) incorporating the scientific findings into lectures to enrich the curriculum of the Departments of Materials Science and Engineering and Chemical and Biomolecular Engineering at the University of Maryland, and (iii) engaging K-12 students in STEM by providing them with hands-on experiences on batteries during the Maryland Day, an open house event that attracts more than 60,000 people to campus. Technical Summary: The understanding and control of the relevant chemical reactions taking place during all-solid-state batteries cycling will enable the design of game-changing materials for energy storage based on Li, Na and Mg. This research elucidates the underlying mechanisms for the formation of solid-electrolyte interphases (SEIs) in two all-solid-state battery model systems with highly Li-ion conductive electrolytes: Li10GeP2S12 (LGPS) and Li7La3Zr2O12 (LLZO). This project, funded by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, advances the understanding of the materials chemistry that currently limits the performance of Li-ion all-solid-state batteries. The formation of SEIs is probed in situ by time-of-flight secondary ion mass spectroscopy (ToF-SIMS), combined with ex situ X-Ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). A correlation between the electrochemical impedance and the Li distribution maps reveals how the SEIs affect the interfacial resistance and, thus, the performance of these energy storage model systems. Determining Li preferential spatial distribution during cycling can potentially transform the future design of all-solid-state batteries, with controlled SEIs. While multiple in situ experiments have validated the formation of SEI in nanoscale batteries, there are no demonstrations of the dynamics of the mesoscale Li spatial distribution within all active layers of the batteries upon lithiation/delithiation. Thus, this research has scientific impacts in the field of materials chemistry and beyond. The outreach/education components of this research encompass mentoring students at various levels; incorporating the scientific findings into the curriculum of the Departments of Materials Science and Engineering as well as Chemical and Biomolecular Engineering at the University of Maryland; and engaging K-12 students in STEM by providing them with hands-on experiences on batteries during the Maryland Day, an open house event that attracts more than 60,000 people to campus.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.