CAREER: Regulating the Interface Chemistry of Sodium Ceramic Electrolytes for Solid-State Sodium Metal Batteries

除锂离子电池外，钠离子电池因其相似的电池化学特性、高含量的钠源、低成本的钠原料和可及性，在交通电气化和大规模储能方面显示出巨大的潜力。与此同时，固态电池采用不易燃的固体电解质代替易燃的液体电解质，为减少阻碍电池技术进步的火灾隐患提供了一种革命性的解决方案。开发高性能固态钠电池的主要挑战之一是钠陶瓷固体电解质与电极材料之间存在较大的界面电阻。该职业奖项目由材料研究部的陶瓷项目和刺激竞争研究的既定计划（EPSCoR）共同支持，通过调节电解质表面特性来解决钠金属电极和钠陶瓷固体电解质之间面临的关键界面挑战。PI和她的研究小组寻求对钠陶瓷固体电解质的界面结构-组成-性能关系的基本理解。这项研究所带来的科学知识的进步将刺激具有优异热稳定性和化学稳定性的固态钠电池的发展。这种电池可以作为多种能源存储应用的新的替代低成本电源。通过这个项目，PI将促进当地小学、初中和高中学生、本科生和研究生在科学话语中的参与，特别是在能源材料领域。PI将把这项研究整合到高中AP课程中，并将开发一个以电池为主题的暑期讲习班，特别是为小学和初中女生提供科学和工程项目的实践经验。该项目的科学和教育价值将推动储能技术的前沿，促进科学和工程研究的多样性，并解决STEM领域的性别差距。在已知的钠电池系统固体电解质中，钠离子超离子导体（即NASICON）由于其高钠离子电导率和优异的电化学和热稳定性，是最有前途的钠离子导电陶瓷固体电解质之一。同时，金属钠因其电化学电位低、理论比容量高而被认为是钠电池的“圣杯”负极材料。然而，将NASICON电解质与金属钠阳极配对用于固态钠电池，会导致电化学循环过程中出现较大的NASICON/钠界面电阻和不均匀的枝状钠沉积。在这个CAREER项目中，NASICON的界面化学将由各种超薄金属氧化物涂层通过原子层沉积来调节。本研究将探讨NASICON表面氧化膜的组成、结晶度、形貌和微观结构对金属钠的早期电化学润湿性和钠离子在界面上的传输起关键作用，从而影响界面阻抗、钠的成核/生长过程和电化学特性。这项研究可以超越锂技术，利用更可持续、自然丰富和低成本的钠资源。与锂电池系统相比，钠电池的低成本将使其非常适合大规模储能应用。项目将把这项研究计划整合到各种教育和外展活动中，以广泛传播知识/研究成果，促进工程研究的多样性，并解决STEM领域的性别差距问题。教育组成部分主要包括以下几个方面：(1)通过为本科生和研究生开发新的课程课程和研究项目，将本研究纳入教学；(2)将本研究融入当地高中AP课程；(3)为中小女生举办“电池仙境”暑期工作坊，让她们亲身体验科学与工程项目。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。

NON-TECHNICAL SUMMARYBeyond lithium-ion batteries, sodium-ion batteries show great potential for transportation electrification and large-scale energy storage owing to their analogous battery chemistry, high abundance of sodium sources, low cost of sodium raw materials, and accessibility. Meanwhile, solid-state batteries, which employ nonflammable solid electrolytes to replace the flammable liquid ones, offer a revolutionary solution to mitigate fire hazards that have hobbled the advances of battery technology. One of the major challenges in the development of high-performance solid-state sodium batteries lies in the large interfacial resistance between the sodium ceramic solid electrolyte and the electrode material. This CAREER award project, jointly supported by the Ceramics program in the Division of Materials Research, and the the Established Program to Stimulate Competitive Research (EPSCoR), addresses the critical interfacial challenges facing between a sodium metal electrode and the sodium ceramic solid electrolyte through regulating the electrolyte surface properties. The PI and her research group seek fundamental understanding on the interfacial structure-composition-property relationship of the sodium ceramic solid electrolyte. The advancement of scientific knowledge enabled by this research will stimulate the development of solid-state sodium batteries with superior thermal and chemical stability. Such batteries can serve as new alterative low-cost power sources for diverse energy storage applications. Through this project the PI will promote engagement between local elementary, middle and high school students, undergraduate and graduate students in scientific discourse, particularly in the field of energy materials. The PI will integrate this research into high school AP curriculum and will develop a battery-themed summer workshop, especially for elementary and middle school girls to get hands-on experience for science and engineering projects. The scientific and educational merits of this project will advance the frontiers of energy storage technologies, promote the diversity in science and engineering research, and tackle the gender gap in STEM fields.TECHNICAL SUMMARYAmong the known solid electrolytes for sodium battery systems, sodium-ion superionic conductor, namely NASICON, is one of the most promising sodium-ion conducting ceramic solid electrolytes owing to its high sodium-ion conductivity and excellent electrochemical and thermal stabilities. Meanwhile, sodium metal is considered as the “holy grail” anode material for sodium batteries because of its low electrochemical potential and high theoretical specific capacity. However, the pairing of NASICON electrolyte with metallic sodium anode for solid-state sodium batteries gives large NASICON/sodium interfacial resistance and nonuniform dendritic sodium deposition over electrochemical cycling. In this CAREER project, the interface chemistry of NASICON will be regulated by a variety of ultrathin metal oxide coatings via atomic layer deposition. This research will investigate the hypothesis that the composition, crystallinity, morphology, and microstructure of the oxide coating on NASICON play critical roles in the early-stage electrochemical wettability of sodium metal and the sodium-ion transport across the interface, which affect the interfacial impedance, the sodium nucleation/growth process, and the electrochemical characteristics. This research can take a leap beyond the lithium technology by utilizing the much more sustainable, natural abundant and low-cost sodium resources. The reduced cost of sodium batteries compared to the lithium systems will make them highly desirable for large-scale energy storage application. The PI will integrate this research program into a variety of educational and outreach activities to broadly disseminate the knowledge/research findings, to promote the diversity in engineering research, and to tackle the gender gap in STEM fields. The education components mainly include the following aspects: (1) incorporating this research into teaching by developing new course curriculums and research projects for undergraduate and graduate students; (2) integrating this research into local high school AP curriculum; (3) developing summer workshop “Battery Wonderland” for elementary and middle school girls to get hands-on experience for science and engineering projects.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.