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

非技术总结：在当今社会中，新的可再充电电池技术正被紧急开发以解决从移动的通信到电动和混合动力车辆的范围内的快速增长数量的无线设备的功率和能量需求。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NSF材料研究部的固态和材料化学计划资助，研究了Li 10 GeP 2S 12（LGPS）和Li 7 La 3 Zr 2 O 12（LLZO），这两种有前途的电解质材料负责传导用于为电池充电的离子。目前的问题是，这些材料可以捕获锂离子，并在电池运行期间发生显著变化，这反过来又会严重限制它们的寿命。因此，该研究项目直观地绘制了锂离子在电池使用过程中优先积累的位置。为了做到这一点，Leite和Wang的团队实施了互补的显微镜技术，并将获得的信息与设备性能的测量相关联。这项研究的外联/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，以丰富马里兰州大学材料科学与工程系和化学与生物分子工程系的课程，以及（iii）在马里兰州日（一个吸引了6万多人来到校园的开放日）期间，通过为K-12学生提供电池方面的实践经验，让他们参与STEM。技术总结：对全固态电池循环过程中发生的相关化学反应的理解和控制，将有助于设计基于Li、Na和Mg的改变游戏规则的储能材料。本研究阐明了两种具有高锂离子导电电解质的全固态电池模型系统中固体电解质界面（SEI）形成的基本机制：Li 10 GeP 2S 12（LGPS）和Li 7 La 3 Zr 2 O 12（LLZO）。该项目由NSF材料研究部的固态和材料化学项目资助，促进了对目前限制锂离子全固态电池性能的材料化学的理解。通过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）原位探测SEI的形成。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，从而影响这些能量存储模型系统的性能。在循环期间确定Li优先空间分布可以潜在地改变具有受控SEI的全固态电池的未来设计。虽然多个原位实验已经验证了纳米级电池中SEI的形成，但是没有证明锂化/脱锂后电池的所有活性层内的中尺度Li空间分布的动态。因此，这项研究在材料化学和其他领域具有科学影响。这项研究的推广/教育部分包括指导各级学生;将科学研究结果纳入马里兰州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;并在马里兰州日期间为K-12学生提供电池实践经验，这是一个开放日活动，吸引了超过60，000人到校园。这个奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

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.