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

该学院早期职业发展（CAREER）资助支持力学及其与高容量电极及其界面中电化学过程耦合的基础研究。锂离子电池是一种高效的储能设备，它改变了个人电子产品，并使电动汽车能够进入市场。不断增长的储能行业对现有电池的需求急剧增加，无法满足。开发下一代电池需要全面了解主要成分、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，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。这项工作将导致电极中电化学降解机制的发现，并指导其设计，最终实现高容量电极的开发，并使美国经济受益。该赠款还支持整合研究和创新教学方法的相互关联的教育和外展活动。这些活动包括一个新的电池和能源存储技术小程序的课程开发，高级顶点项目的设计，以及多个K-12和代表性不足的少数民族外展活动在内华达州，里诺的大学。为了了解电极和接口的电化学力学，研究方法将实现三个具体目标：1）通过将原子反应途径建模和分子动力学模拟与反应力场相结合，识别和表征具有电荷效应的应力介导的（脱）锂动力学中的异质性的合作和竞争作用，2）通过解释无定形和开放材料系统中的变形运动学并通过将相场建模与有限应变弹塑性耦合来识别缺陷和机械应力如何影响电化学（脱）锂期间的孔形成/湮灭，3）评估电极-电解质界面处的反应动力学与化学反应之间的相互作用。通过Butler-Volmer类型的方法，整合了反应动力学，离子传输和力学的影响，在电池单元水平上研究了电极的力学和电化学性能。将使用来自公开文献和合作者的实验数据对模型进行验证。对潜在机制的追求将弥合单个电极中纳米级化学机械现象与电池单元水平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.