CAREER: Synthesis of Novel Two-Dimensional Materials from Metastable Layered Materials

非技术描述：原子-和几个原子-薄的二维（2D）材料是在纳米材料研究的最前沿，由于其独特的性能和形态相比，他们的散装同行。它们通常是通过剥离层状材料而产生的，所述层状材料通过弱键和力（例如货车德瓦尔（vdW）力）保持在一起。控制2D材料的成分可以调整它们的特性，从而调整它们在电化学能量存储等应用中的性能。该项目的目标是利用块体层状陶瓷材料的亚稳态来合成具有独特组成的新型2D材料和异质结构，并研究它们作为电化学能量存储电极材料的行为。该项目中生产的新型2D材料的重要性超出了电化学能量存储的范围，扩展到许多其他领域，包括电子、复合材料、电磁干扰屏蔽、催化等。研究目标与为广泛学生服务的教育计划相结合。不同水平（博士，本科，K-12）加强材料科学和工程教育，通过教育和培训下一代材料科学家和工程师，使科学和工程劳动力多样化，技术优势：通过将不同性质的2D材料堆叠成vdW异质结构，可以实现不寻常的性质和现象。在这样的异质结构中，理解和设计固体/固体界面是具有挑战性的。填充2D材料属性空间中这一未占领领域的另一种方法是剥离新的大块分层材料以产生新型2D材料。大多数已知的热稳定的vdW结合的层状材料已经被剥离成2D材料。因此，需要新的方法来合成可以剥离的新的块状层状材料。在这个项目中，拓扑化学反应被用来呈现强有力的结合陶瓷材料成亚稳态可剥离的VDW层状材料。为实现这一项目的目标，要实现三个具体目标。第一个目的是发展理解的亚稳VDW层状材料的形成反应机制。二是了解这些亚稳态vdW层状材料的剥离机制。第三个重点是二维材料的异质结构，旨在揭示二维异质结构之间的界面在电化学储能中的作用。除了开发一种新的2D材料家族外，该项目的理解和知识还可以用于其他组成和结构材料空间。在这个项目的教育计划的一部分，涉及到材料科学与工程本科课程整合一个新的服务学习部分。本科生开发新的动手材料活动，以吸引和教育中学生在材料科学和工程。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

NON-TECHNICAL DESCRIPTION: Atomically -and few atomically- thin two-dimensional (2D) materials are at the forefront of nanomaterials research due to their unique properties and morphology compared to their bulk counterparts. They are usually produced by exfoliating layered materials that are held together with weak bonds and forces (such as van der Waal (vdW) forces). Controlling the 2D materials composition tunes their properties and therefore their performance in applications such as electrochemical energy storage. The goal of this project is to exploit metastability in bulk layered ceramic materials to synthesize novel 2D materials and heterostructures with unique compositions and study their behavior as electrode materials for electrochemical energy storage. The importance of the new 2D materials that are produced in this project extends beyond electrochemical energy storage to many other fields including electronics, composites, electromagnetic interference shielding, catalysis, etc. The research goal is integrated with an educational plan that serves a broad spectrum of students at different levels (doctoral, undergraduate, K-12) to strengthen the materials science and engineering education and diversify the science and engineering workforce by educating and training the next generation of materials scientists and engineers through hands-on learning approach.TECHNICAL DETAILS: Unusual properties and phenomena can be realized by stacking 2D materials of different properties into vdW heterostructures. In such heterostructures, understanding and engineering the solid/solid interface is challenging. Another approach to populate this unoccupied territory in the 2D materials properties space, is to exfoliate new bulk layered materials to produce novel 2D materials. Most of the known thermodynamically stable vdW bonded layered materials have been exfoliated already into the 2D materials. Therefore, novel approaches are necessary to synthesize new bulk layered materials that can be exfoliated. In this project, topochemical reactions are utilized to render strongly bonded ceramic materials into metastable exfoliateable vdW layered materials. To achieve the goal of this project, three specific aims are pursued. The first aim is to develop understanding for the formation reaction mechanism of metastable vdW layered materials. The second is to understand the exfoliation mechanism of these metastable vdW layered materials. The third focuses on heterostructures of 2D materials with aim to unveil the role of interfaces between 2D heterostructures in electrochemical energy storage. In addition to developing a novel family of 2D materials, the understanding and knowledge in this project can be employed to other compositional and structural materials spaces. Part of the educational plan in this project involves integrating a new service-learning section into the Materials Science and Engineering undergraduate course. Undergraduate students develop new hands-on materials activities to engage and educate middle school students in materials science and engineering.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.