CAREER: Engineering Structure and Ionic Conductivity in Li7La3Zr2O12 Nanowire-Based Solid Electrolytes

职业：Li7La3Zr2O12 纳米线固体电解质的工程结构和离子电导率

基本信息

批准号：
1553519
负责人：
Candace Chan
金额：
$ 55万
依托单位：
Arizona State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-06-01 至 2022-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1553519&HistoricalAwards=false
关键词：
CAREER Engineering Structure Ionic Conductivity

项目摘要

NON-TECHNICAL DESCRIPTION: Lithium ion batteries are ubiquitous in laptops and cell phones and may gain more use in transportation applications in the near future. However, these batteries suffer from safety issues originating from the flammable liquid electrolyte that is used to transport lithium ions within the battery. One of the most promising candidates for a safer, replacement electrolyte is the ceramic lithium lanthanum zirconate (LLZO), which has good thermal/chemical stability and ionic transport properties. Nonetheless, there is still much fundamental research needed in order to improve understanding of several critical issues in LLZO and how to improve its performance. This project investigates novel LLZO nanowire structures and composites with unique nanoscale properties that can improve their conductivity for lithium ions and integration into safer, all-solid-state batteries. This project also supports education and outreach activities that focus on improving the pipeline and retention of female students in science and engineering through hands-on experiences that will increase understanding and retention of engineering concepts and stimulate the students' interests in research. Outreach to local middle school girls through a battery-related challenge to provide context on issues related to electric cars and research opportunities to high school, undergraduate, and graduate students are example activities. Educational efforts include international exchange of teaching methodologies with faculty in South Korea to understand strategies that promote female student achievement, as well as how to best engage students from diverse backgrounds in student-centered learning environments.TECHNICAL DETAILS: This research project aims to correlate composition, grain boundary structure, and crystal phase with ionic conductivity in LLZO nanowire materials prepared using electrospinning. Nanowire solid electrolytes can offer characteristics that are beneficial and advantageous compared to bulk materials - namely milder calcination conditions for crystallization, stabilization of metastable phases, and opportunities for unique structures such as core-shell composites. These characteristics can lead to properties that improve the ionic conductivity, sintering ability, and integration of the electrolytes into all-solid-state batteries. The nanowires are used to understand the LLZO phase stability, crystallization, and sintering processes. Core-shell nanowire structures are used to investigate interfacial properties and transport in composites to understand how to maximize highly conducting pathways for lithium ions and uniformly modify grain boundaries. Additionally, detailed in situ and aberration-corrected transmission electron microscopy is used to understand processes such as crystallization of electrospun nanowires, impurity segregation to grain boundaries, sintering in networks of nanowires, and interdiffusion at the electrolyte/cathode interface. This information is being correlated with ionic conductivity and electrochemical cycling tests on the nanowire solid electrolyte materials and compared to bulk materials. The insights gained from this work are enabling better control of composition, stabilization of metastable phases, sintering processes, and Li ion transport, which can ultimately lead to higher ionic conductivity ceramic electrolytes.

非技术描述：锂离子电池在笔记本电脑和手机中无处不在，在不久的将来可能会在运输应用中获得更多用途。但是，这些电池遭受了源自用于在电池内运输锂离子的易燃液体电解质的安全问题。更安全，替代电解质的最有前途的候选者之一是陶瓷锂锆酸锂（LLZO），其具有良好的热/化学稳定性和离子传输性能。但是，为了提高对LLZO中几个关键问题的理解以及如何提高其绩效，仍然需要许多基础研究。该项目研究了具有独特的纳米级特性的新型LLZO纳米线结构和复合材料，可以提高其用于锂离子的电导率并集成到更安全的全稳态电池中。该项目还支持教育和推广活动，这些活动专注于通过动手经验来改善女学生在科学和工程领域的管道和保留，这将提高对工程概念的理解和保留，并刺激学生对研究的兴趣。通过与电池相关的挑战向当地中学女孩推广，以提供有关电动汽车和研究机会的问题的背景，这是示例活动。教育努力包括与韩国教师的国际教学方法交流，以了解促进女学生成就的策略，以及如何最好地吸引来自以学生为中心的学习环境的不同背景的学生。技术详细信息：该研究项目旨在将组成，粒度边界结构和晶体相关联与使用llzo Nanawire Nanawire Materess prectrealssnning的组成，晶粒边界结构和水晶相关。与散装材料相比，纳米线固体电解质可以提供有益且有利的特性 - 即结晶的钙化条件，亚稳态相位的稳定性以及诸如核心壳复合材料等独特结构的机会。这些特征可以导致提高离子电导率，烧结能力以及将电解质整合到全稳态电池中的特性。纳米线用于了解LLZO相稳定性，结晶和烧结过程。核壳纳米线结构用于研究复合材料中的界面特性和运输，以了解如何最大程度地提高锂离子高度传导途径并均匀地修改晶界。此外，使用详细的原位和被像差校正的透射电子显微镜用于了解诸如电纺纳米线结晶的过程，杂质隔离到晶界，纳米线网络中的烧结以及电解质/阴极界面处的互化。该信息与纳米固体固体电解质材料上的离子电导率和电化学循环测试相关，并与大量材料进行了比较。从这项工作中获得的见解是可以更好地控制组成，亚稳态相，烧结过程和运输的稳定，最终可以导致更高的离子电导率陶瓷电解质。