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

这项教师早期职业发展（Career）基金支持力学及其与大容量电极及其界面的电化学过程耦合的基础研究。锂离子电池是一种高效的能量储存装置，它改变了个人电子产品，并使电动汽车进入市场。不断增长的储能行业对现有电池的需求急剧增加。开发下一代电池需要彻底了解复杂的材料行为和主要成分、电极及其接口的故障，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仿真能力，使人们对电极和界面在多个尺度上的电化学-机械行为有一个基本的了解。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，最终使高容量电极的发展成为可能，并使美国经济受益。赠款还支持将研究和创新教学方法结合起来的相关教育和外联活动。这些活动包括新电池和储能技术辅修课程的课程开发，高级顶点项目的设计，以及内华达大学里诺分校的多个K-12和未被充分代表的少数族裔外展活动。为了理解电极和界面的电化学力学，研究方法将实现三个具体目标：1)结合原子反应途径模型和反应力场的分子动力学模拟，识别和表征非均质性在电荷作用下应力介导（去）锂化动力学中的合作和竞争作用；2)通过计算非晶和开放材料系统的变形运动学以及有限应变弹塑性耦合相场建模，确定缺陷和机械应力如何影响电化学（去）锂化过程中的孔隙形成/消灭；3)评估电极-电解质界面的反应动力学与电极的化学力学和电池级电化学性能之间的相互作用；通过巴特勒-沃尔默式的方法，将反应动力学、离子传递和力学的影响结合起来。模型的验证将使用来自公开文献和合作者的实验数据进行。对潜在机制的探索将弥补单个电极的纳米级化学机械现象与电池单元级电化学性能之间缺失的联系。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。

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.