CAREER: The Role of Heterogeneities in Electro-Chemo-Mechanics of Electrodes and Interfaces

这笔学院早期职业发展(CALEAR)补助金支持高容量电极及其界面中的机理及其与电化学过程的耦合的基础研究。锂离子电池是一种高效的能量存储设备，它改变了个人电子产品，并使电动汽车的市场引入成为可能。不断增长的储能行业大幅增加了对现有电池无法满足的需求。开发下一代电池需要深入了解主要部件、电极及其界面的复杂材料行为和故障，以确保设备的安全性和耐用性。这项研究将通过开发建模和模拟能力，从根本上理解电极和界面在多个尺度上的电化学-机械行为。这一努力将导致发现电极中的电化学降解机制，并指导其设计，最终使大容量电极的发展成为可能，并使美国经济受益。赠款还支持相互关联的教育和外展活动，将研究和创新的教学方法结合起来。这些活动包括为新的电池和储能技术次要项目制定课程，设计高级Capstone项目，以及在里诺州内华达大学举办多个K-12和代表性较低的少数族裔外联活动。为了了解电极和界面的电化学力学，该研究方法将实现三个具体目标：1)通过将原子反应路径建模和分子动力学模拟与反应力场相结合，识别和表征异质在具有电荷影响的应力中介(De)锂化动力学中的合作和竞争作用，2)通过考虑非晶态和开放材料体系的变形运动学，并将相场模拟与有限应变弹塑性相结合，确定缺陷和机械应力对电化学(脱锂)过程中孔的形成/湮灭的影响；3)通过集反应动力学、离子传输和力学影响于一体的Butler-Volmer方法，评估电极-电解液界面的反应动力学与电极的化学力学和电池水平的电化学性能之间的相互作用。模型的验证将使用开放文献和合作者(S)的实验数据进行。对潜在机制的追求将弥合单个电极中的纳米级化学机械现象与电池单元水平的电化学性能之间缺失的联系。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Faculty Early Career Development (CAREER) grant supports fundamental research on the mechanics and its coupling with electrochemical processes in high-capacity electrodes and their interfaces. Lithium-ion batteries are highly efficient energy storage devices that have transformed personal electronics and enabled the market introduction of electric vehicles. The ever-growing energy storage industry has imposed dramatically increased demands that the current batteries are unable to meet. Developing next-generation batteries requires a thorough understanding of complex material behavior and failures of the primary constituents, electrodes and their interfaces, to ensure the safety and durability of devices. This research will enable a fundamental understanding of the electro-chemo-mechanical behavior of electrodes and interfaces at multiple scales by developing modeling and simulation capabilities. The effort will lead to the discovery of electrochemical degradation mechanisms in electrodes and guide their design, ultimately enabling the development of high-capacity electrodes and benefitting the US economy. The grant also supports interrelated education and outreach activities that integrate research and innovative teaching approaches. These activities include curriculum development for a new Batteries and Energy Storage Technologies minor program, design of senior capstone projects, and multiple K-12 and underrepresented minority outreach events at the University of Nevada, Reno.To understand the electro-chemo-mechanics of electrodes and interfaces, the research approach will achieve three specific objectives: 1) identify and characterize the cooperative and competitive roles of heterogeneities in stress-mediated (de)lithiation kinetics with the effect of charge by combining atomistic reaction pathway modeling and molecular dynamics simulations with a reactive force field, 2) identify how defects and mechanical stress affect pore formation/annihilation during electrochemical (de)lithiation by accounting for deformation kinematics in amorphous and open material systems and by coupling phase field modeling with finite strain elastoplasticity, 3) evaluate the interaction between the reaction kinetics at electrode-electrolyte interfaces with the chemo-mechanics of electrodes and electrochemical performance at the battery cell level, via a Butler-Volmer type approach that integrates reaction kinetics, ion transport, and the influence of mechanics. The validation of the models will be performed with experimental data from open literature and collaborator(s). The pursuit of the underlying mechanisms will bridge the missing links between nanoscale chemo-mechanical phenomena in individual electrodes and the electrochemical performance at the battery cell level.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.