CAREER: Elucidation and Development of Electrolyte and Interface Mechanisms Governing Calcium Redox in Nonaqueous Environments

职业：阐明和开发非水环境中控制钙氧化还原的电解质和界面机制

• 批准号: 2045868
• 负责人: Betar Gallant
• 金额: $ 54.86万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2045868&HistoricalAwards=false
• 关键词: CAREER; Elucidation; Development; Electrolyte; Interface

Electrochemical energy storage plays a critical role in storing energy from intermittent renewable sources, such as solar and wind energy, and making these sources suitable for electrified transportation. Today’s lithium (Li)-ion and emerging Li metal-based batteries have high energy densities, but they suffer from safety and performance issues along with increasing concerns about scarcity of Li resources. Calcium (Ca) presents a compelling alternative as the basis for next-generation batteries: it is the 5th most abundant element in the earth’s crust, and batteries utilizing Ca metal anodes are projected to have energy storage capabilities comparable to Li counterparts with potential for improved safety. However, development of Ca batteries has been hindered by numerous challenges, including formation of blocking interfaces on Ca metal anodes that impede reversibility, and the need to design electrolytes specifically optimized for divalent Ca ion electrochemistry. This research will build the fundamental understanding of Ca-based electrochemical reactions and the resulting interfaces on Ca metal. To achieve these aims, this research will create tools to conduct novel experimental, quantitative analysis of Ca electrolyte and interface thermochemistry that will guide design of improved Ca batteries. As an additional outcome of the work, middle-school students will engage in active virtual teaching modules that use outcomes of this research while fulfilling a Massachusetts state education standard, bringing exposure to scientists and engineers and motivating pursuit of STEM careers.This research effort will conduct a targeted experimental study of the chemical, thermodynamic and interface parameters that govern Ca ion redox behavior and elucidate Ca solid electrolyte interphase (SEI) chemistry and properties. The central hypothesis guiding this work is that the heightened degrees of freedom in Ca2+ ion solvation present new opportunities to intervene in electrochemical pathways, which can allow reversibility and reaction selectivity to be unlocked if better understood. The tools to be developed to test this hypothesis include a new thermodynamic framework for measuring the solvated Ca state using reaction calorimetry; metal deposition methodologies to prepare high-quality Ca metal interfaces for fundamental study; an operando approach to probe the chemical dynamics of Ca SEI formation; and a cathode conversion reaction involving Ca and CO2 to test and strengthen understanding of how Ca2+ solvation affects reactivity. The results will be integrated to identify the fundamental origins that determine electrochemical parameters: redox potential, Coulombic efficiency, cycle life, and rate capability, and therein identify strategies to improve them. Collectively, this work will yield progress in anode, cathode, and electrolyte aspects of Ca batteries.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.

电化学储能在存储间歇性可再生能源（如太阳能和风能）的能量，并使这些能源适用于电气化运输方面发挥着关键作用。今天的锂离子电池和新兴的锂金属电池具有高能量密度，但它们受到安全和性能问题的困扰，同时人们越来越担心锂资源的稀缺。作为下一代电池的基础，钙（Ca）是一个令人信服的选择：它是地壳中含量第五丰富的元素，使用Ca金属阳极的电池预计具有与锂电池相当的储能能力，并且具有提高安全性的潜力。然而，钙离子电池的发展一直受到许多挑战的阻碍，包括在钙金属阳极上形成阻塞界面，阻碍可逆性，以及需要设计专门针对二价钙离子电化学优化的电解质。本研究将建立对基于Ca的电化学反应及其在Ca金属上产生的界面的基本理解。为了实现这些目标，本研究将创造工具来进行新颖的实验，定量分析钙电解质和界面热化学，这将指导改进的钙电池的设计。作为这项工作的额外成果，中学生将参与积极的虚拟教学模块，这些模块使用这项研究的成果，同时满足马萨诸塞州的教育标准，为科学家和工程师带来机会，并激励他们追求STEM职业。本研究将对控制Ca离子氧化还原行为的化学、热力学和界面参数进行有针对性的实验研究，并阐明Ca固体电解质界面相（SEI）的化学和性质。指导这项工作的中心假设是，Ca2+离子溶剂化的高度自由度为干预电化学途径提供了新的机会，如果更好地理解，这可以允许可逆性和反应选择性被解锁。为验证这一假设而开发的工具包括一个新的热力学框架，用于使用反应量热法测量溶剂化Ca状态；制备高质量Ca金属界面的金属沉积方法；用operando方法探测Ca - SEI地层的化学动力学；以及涉及Ca和CO2的阴极转化反应，以测试和加强对Ca2+溶剂化如何影响反应性的理解。结果将被整合，以确定决定电化学参数的基本来源：氧化还原电位、库仑效率、循环寿命和速率能力，并在此基础上确定改进策略。总的来说，这项工作将在钙电池的阳极、阴极和电解质方面取得进展。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。