Using Electrodeposition to Understand the Effects of Composition and Element Segregation on the Physical Properties of Anodes for High Energy-Density Rechargeable Batteries

第1部分：非技术概述能源转换和存储技术对现代社会的运行、维护和发展至关重要。美国现在每年生产超过25太瓦时的电力，其中绝大多数是由煤炭、天然气和石油等不可再生燃料提供的。因此，开发比现有技术更高效的新技术，或帮助现有技术更有效地利用能源的技术，对我们的未来至关重要。在过去的几十年里，很明显，能量存储设备是一系列拟议技术的关键组成部分。技术要求根据每个期望应用的具体限制而有很大差异，因此需要广泛的功能材料、化学物质和体系结构，这些材料、化学物质和体系结构可用于构建目标和特定的能量存储设备。这项研究由固态和材料化学项目资助，重点是开发无毒，廉价的制造方法，用于三种潜在的阳极材料，可用于锂和钠可充电电池。这些材料是已知的，但他们如何降解（以及为什么）是未知的。了解这些材料的工作原理以及它们的主要局限性是本研究的主要目标。这是找出如何延长这些材料的寿命从而延长电池寿命的关键的第一步。该固态和材料化学奖进一步使主要研究者能够开展与她的研究相关的外展活动，涉及所有年级的学生以及公众和政策制定者。例如，科罗拉多州立大学的“化学俱乐部”招收小学生，高中学生由首席研究员和她的学生在研究实验室指导，首席研究员在当地俱乐部邀请科学演讲，她是科罗拉多清洁能源集群的董事会成员，直接影响科罗拉多州的政策。第2部分：技术概述存储大量锂并在电解质电化学电位范围的极端末端可逆运行的电池材料使高电压和高能量密度电池成为可能。在可用的候选材料中，元素合金材料如锑和相关的锑化物具有极高的体积容量，并且在接近锂金属电镀的电位下工作，从而允许高理论能量密度。然而，由于在循环过程中体积的巨大变化，它们的可逆性很低，并且表面钝化不良，导致阳极表面电解质的显著降解和随后的电池阻抗上升。本研究开发了直接电沉积方法，用于生产低成本、高性能的碱金属离子（锂和钠）可充电电池阳极。电沉积的优点是可以控制材料的组成和形态，并且完全消除了非活性粘结剂（这极大地有助于功能材料的表征）。研究工作涉及直接合成三种关键锑化物（镍、铜、锌和锑）的电沉积薄膜和纳米结构的策略，并充分表征它们，以更深入地了解作为组成函数发生的锂化和衰减反应，以及这些反应如何导致降解和最终细胞衰竭。观察循环过程中膜上的相形成和元素组成进一步有助于建立一个清晰的模型，了解这些材料是如何工作的，它们是如何降解的，并最终为如何延长循环寿命和效用提出假设。有了这笔拨款，首席研究员还将开展各种教育和推广活动。除了让所有年级的学生参与与stem相关的活动外，她还通过邀请当地俱乐部的科学讲座，以及作为科罗拉多州清洁能源集群的董事会成员，直接向公众传达她的发现，该集群旨在影响科罗拉多州与清洁技术公司经济发展相关的政策。

PART 1:  NON-TECHNICAL SUMMARYEnergy conversion and storage technology is critical to the operation, maintenance, and development of modern society. The United States now produces over 25 terawatt hours of electricity per year, with the vast majority being provided by non-renewable fuels such as coal, natural gas, and oil. Developing new technologies that are more efficient than existing ones, or technologies that help existing technologies use energy more efficiently, is therefore critical to our future. Over the last few decades, it has become clear that energy storage devices are a key component in a wide range of proposed technologies. The technical requirements vary dramatically based on the specific constraints of each desired application, and as such there is need for a wide range of functional materials, chemistries, and architectures that can be used to build targeted and specific energy storage devices. The research, funded by the Solid State and Materials Chemistry program, focuses on developing non-toxic, inexpensive manufacturing methods for three potential anode materials that could be used in lithium and sodium rechargeable batteries. These materials are known, but how they degrade (and why) is not. Understanding how these materials work and what their key limitations are is the main goal of this study. This is the critical first step toward finding out how to extend the life of these materials and thereby the life of batteries. This Solid State and Materials Chemistry award furthermore enables the principle investigator to conduct outreach activities related to her research involving students at all grade levels as well as the general public and policymakers. For example, the CSU 'Chemistry Club' engages elementary school students, high school students are mentored by the principle investigator and her students in the research lab, the principle investigator gives invited talks about science at local clubs, and she is a board member of the Colorado Clean Energy Cluster, which impacts policy in Colorado directly.PART 2:  TECHNICAL SUMMARYBattery materials that store large amounts of lithium and operate reversibly at the extreme ends of the electrochemical potential range of electrolytes enable high voltage and high energy density battery cells. Among available candidates, elemental alloying materials such antimony and related antimonides possess exceptionally high volumetric capacities and operate at potentials close to the plating of lithium metal, allowing for high theoretical energy density. Nevertheless, they suffer from low reversibility as a result of large changes in their volume during cycling, and poor surface passivation that causes significant degradation of the electrolyte at the anode surface and a subsequent rise in the cell impedance. This work develops direct electrodeposition methods for producing low-cost, high-performance anodes for alkali metal ion (lithium and sodium) rechargeable batteries. The advantage of using electrodeposition is that the composition and morphology of the material can be controlled, and inactive binders are completely eliminated (which greatly aides in the characterization of the functional materials). The research endeavor involves a strategy of synthesizing directly electrodeposited thin films and nanostructures of three key antimonides (nickel, copper, and zinc and animonide) and characterizing them fully to develop a deeper understanding of the lithiation and delithiation reactions that occur as a function of composition, and how these reactions may lead to degradation and ultimately cell failure. Observing the phase formation and elemental composition across films during cycling further aids in the development of a clear model of how these materials work, how they degrade, and ultimately, the development of hypotheses for how to extend cycle life and utility. With this grant the principle investigator also conducts a variety of educational and outreach activities. Besides engaging students at all grade levels in STEM-related activities, she also communicates her findings directly to the general public through invited talks about science at local clubs and as a board member of the Colorado Clean Energy Cluster, which serves to impact policy in Colorado related to the economic development of clean tech companies.