Collaborative Research: Promoting or Suppressing Solid-State Phase Transformation via Interface Control

非技术描述：从电动汽车到可充电个人设备，可再生能源的未来在很大程度上取决于锂离子储能技术。该项目的重点是了解和控制电极材料中的过程，这些过程可以实现更大的存储容量，但通常会因其固态结构的变化而严重退化。大多数研究，其中涉及实验和计算方法，旨在促进或抑制固态相变的电极通过沉积涂层施加化学和机械约束。该项目的具体发现，特别是在抑制相变方面的发现，将使低成本、丰富、无钴、高容量的转换电极具有长循环寿命，适用于各种应用的锂基电池。这一科学进步将刺激更广泛的材料研究界探索界面控制对许多材料系统相竞争的影响。知识转移是通过公共传播和通过PI的研究网络与工业和国家实验室合作伙伴的直接互动进行的。此外，这些研究活动作为一个教育平台，为各级学生和来自不同背景的发展跨学科的专业知识，通过直接体验计算和实验方法，通过这种合作研究。技术规格：追求高锂存储容量和可逆性是一个两难选择，但也是一个至关重要的需求，因为可再生能源的未来，从电动汽车到可再生能源，强烈依赖于锂离子储能技术。 该项目将探索一种新的设计原理，通过使用表面改性和保形涂层来抑制不可逆的固态相变，将可逆嵌入反应扩展到更高的锂容量。密歇根州立大学致力于开发基于密度泛函理论（DFT）的多尺度建模方法，以准确预测涂层电极中的相演变。马里兰州大学的努力将通过原子层沉积（ALD）精确控制表面层，以改变其化学性质、模量和厚度，并进行电化学表征。这些合作努力将确定在转换阴极材料的锂化期间转换和嵌入反应之间的竞争的原子起源，并确定纳米级涂层对两种反应的竞争的耦合化学机械效应。该项目的科学影响超越了转换型材料的寿命和性能的改善，为了解如何通过精心设计的界面控制层调节材料的本体反应提供了基本机会。 来自两所大学的教师正在与来自不同背景的各级学生合作，将教育成果扩展到更广泛的研究社区。该奖项反映了NSF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 DESCRIPTION: The renewable energy future, from electric vehicles to rechargeable personal devices, strongly depends on Li-ion energy storage technology. This project focuses on understanding and controlling processes in electrode materials that can allow for greater storage capacities but typically suffer from severe degradation due to changes in their solid-state structures. Most of the research, which involves both experimental and computational approaches, is designed to promote or suppress the solid-state phase change of the electrode by depositing a coating layer to impose chemical and mechanical constraints. The specific findings from this project, especially on suppressing the phase change, will enable low-cost, abundant, cobalt-free, high-capacity conversion electrodes with long cycle life for lithium-based batteries that are used in a variety of applications. The scientific advancement will stimulate the broader materials research community to explore the influence of interfacial controls on phase competition for many materials systems. Knowledge transfer is occurring through both public dissemination and direct interactions with industrial and national lab partners through the PIs’ research network. Furthermore, these research activities serve as an educational platform for students at all levels and from different backgrounds to develop interdisciplinary expertise by directly experiencing both computational and experimental methods through this collaborative research. TECHNICAL DETAILS: Pursuing both high lithium storage capacity and reversibility is a dilemma but also a crucial need as the renewable energy future, from electric vehicles to renewable power, strongly depends on Li-ion energy storage technology. This project will explore a new design principle to extend reversible intercalation reactions to higher lithium capacity by using surface modification and conformal coatings to suppress the irreversible solid-state phase transformations. Efforts at Michigan State University focus on developing a Density Functional Theory (DFT)-based multiscale modeling method to accurately predict phase evolution in the coated electrode. Efforts at University of Maryland will precisely control the surface layer with atomic layer deposition (ALD) to vary its chemistry, modulus, and thickness and perform electrochemical characterization. The collaborative efforts will determine atomistic origins of the competition between conversion and intercalation reactions during lithiation of conversion cathode materials and determine the coupled chemical-mechanical effect of the nanoscale coating layer on the competition of the two reactions. The scientific impact of this project goes beyond improved life and performance of conversion-type materials to the fundamental opportunity to understand how a material’s bulk reactions can be modulated through carefully designed interfacial control layers. Faculty from both Universities are working with students at all levels and from different backgrounds to expand educational outcomes to a broader research community.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.