Dealloying Under Conditions of Significant Solid-State Mass Transport

大量固态传质条件下的脱合金

• 批准号: 1306224
• 负责人: Karl Sieradzki
• 金额: $ 50.69万
• 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: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1306224&HistoricalAwards=false
• 关键词: Dealloying; Under; Conditions; Significant; Solid

TECHNICAL SUMMARY:This research program examines the kinetics of dealloying and morphology evolution in alloy systems for which the solid-state mass transport processes of lattice and grain-boundary diffusion are significant at ambient temperature. The major control parameters in the work will be the alloy composition, grain size of the polycrystalline hosts, particle size in the particulate hosts and temperature. The electrochemical parameters to be varied include dissolution under conditions of fixed voltage (chronoamperometry) and fixed current (chronopotentiometry). This will allow for the separate determination of the dependence of morphology on the applied electrochemical potential and dealloying rate. In order to examine these issues a combined experimental and computational approach is used. The alloy systems under study are Li-Sn, Li-Pb and Li-Cd. These host metals and similar ones are currently being considered as anode reservoirs in future lithium-ion batteries and have been chosen for study since they represent variations in the host crystal structures, tetragonal, face-centered cubic and hexagonal close-packed, respectively, and have a rich history with abundant thermodynamic and kinetic data available. Electrochemical methods are used to produce the alloys, measure dealloying rates and determine associated solid-state mass transport rates. Dealloying morphologies are examined using focused ion-beam machining and scanning electron microscopy. Kinetic Monte Carlo simulations are used to model morphology evolution in dealloying as a function of the electrochemical potential and dealloying rate.NON-TECHNICAL SUMMARY:This research examines morphology evolution during dealloying of low melting point lithium alloys. Such alloys are currently being considered for use in advanced lithium-ion batteries in which the dealloying process corresponds to that occurring during discharge of these battery systems. The findings likely to emerge from this research will significantly impact research in energy storage and particularly the development of new materials for future batteries. As this country considers its energy options, it will need people with combined expertise in electrochemistry and materials science to address current and future energy technologies. The scope of research in this program will afford undergraduate and graduate students the opportunity for fundamental training in an integrated materials electrochemistry laboratory environment. More generally in the area of education and training, the PI will be developing a new undergraduate course in the "materials science of electrochemical energy storage and production," and the course together with all materials will be available for colleagues to use via the worldwide web.

技术概述：本研究项目考察了合金体系的脱合金化动力学和形态演变，其中晶格和晶界扩散的固态质量传递过程在室温下是重要的。工作中的主要控制参数是合金成分、多晶基体的晶粒尺寸、颗粒基体中的颗粒尺寸和温度。需要改变的电化学参数包括在固定电压（计时安培法）和固定电流（计时电势法）条件下的溶解。这将允许单独测定形貌对应用的电化学电位和脱合金速率的依赖性。为了检验这些问题，采用了实验和计算相结合的方法。研究的合金体系为Li-Sn、Li-Pb和Li-Cd。这些主金属和类似金属目前被认为是未来锂离子电池的阳极储层，之所以选择它们进行研究，是因为它们分别代表了主晶体结构的变化，分别是四方、面心立方和六边形的紧密排列，并且具有丰富的历史和丰富的热力学和动力学数据。使用电化学方法生产合金，测量脱合金速率并确定相关的固态质量输运速率。使用聚焦离子束加工和扫描电子显微镜检查脱合金的形貌。动力学蒙特卡罗模拟被用来模拟作为电化学电位和脱合金速率函数的脱合金过程中的形态演变。非技术总结：本研究考察了低熔点锂合金脱合金过程中的形貌演变。这种合金目前正在考虑用于先进的锂离子电池，其中的脱合金过程对应于这些电池系统放电时发生的过程。这项研究可能产生的发现将对能源存储的研究产生重大影响，特别是未来电池新材料的开发。当这个国家考虑其能源选择时，它将需要兼具电化学和材料科学专业知识的人才来解决当前和未来的能源技术问题。该项目的研究范围将为本科生和研究生提供在综合材料电化学实验室环境中进行基础训练的机会。更广泛地说，在教育和培训领域，PI将开发一门新的本科课程“电化学能量储存和生产的材料科学”，该课程连同所有材料将通过全球网络提供给同事使用。