CAREER: Electro-Chemo-Mechanics of Polymer/Active Material Interface Fracture

该学院早期职业发展（CAREER）计划研究项目旨在提供对聚合物/活性材料界面断裂行为的基本和定量理解，这些界面几乎存在于所有现有和许多新兴的可充电电池化学中。这些界面的机械完整性对于维持电池系统中的电化学反应至关重要;因此，它决定了电池的长期性能（或耐久性）。聚合物/活性颗粒界面的断裂电隔离活性颗粒，并且是电池中发生容量衰减的主要机制之一，然而这种界面失效的机理是最不了解的问题。此外，电池中的界面更加复杂，并且它们的特性不断变化。本文开发的新型原位技术和断裂标准将有助于验证多物理电池模型，并为新兴电池技术开发新的电极材料设计，这些技术可以改变汽车，生物医学，航空航天和军事应用，其中耐用性是一个重要要求。综合教育计划包括为NJIT的学生开发一个实验室模块，演示电化学循环过程中的应力产生过程（机械损伤的原因）。该模块将被修改和调整为K-12学生和教师的推广计划。该奖项还使纽瓦克学校系统的小学教师受训人员能够参与研究。聚合物/活性材料界面断裂一直是下一代电池电极（例如Si、Sn、Al和其他大体积变化材料）快速发展的主要障碍。为了解决这些挑战，新的原位断裂实验和支持模型的组合将提供一个基本的了解如何在电池运行过程中的界面特性的演变，并了解影响界面断裂行为的化学机械因素。为了使工作更加集中，锂离子电池中的接口系统被认为是一个模型系统。一个断裂力学框架与界面本构模型，可以结合在现场观察，将开发用于预测在电化学反应过程中的界面失效。这项研究将使用断裂力学模型在同时的机械和电化学负载下进行界面失效预测;因此，它为开发用于各种应用的长循环寿命，低成本和耐用电池奠定了基础。

This Faculty Early Career Development (CAREER) Program research project aims to provide a fundamental and quantitative understanding of the fracture behavior of polymer/active material interfaces that are found in almost all existing and many emerging rechargeable battery chemistries. The mechanical integrity of these interfaces is critical for sustaining electrochemical reactions in the battery systems; consequently, it dictates the long-term performance (or durability) of batteries. Fracture of the polymer/active particle interface electrically isolates active particles and is one of the predominant mechanisms by which capacity fade occurs in batteries, yet the mechanics of this interface failure is the least understood problem. Also, the interfaces in batteries are more complex and their properties change continuously. The novel in situ techniques and fracture criterion developed here will be useful in the validation of multi-physics battery models and development of new electrode material designs for emerging battery technologies that can transform automotive, biomedical, aerospace, and military applications where durability is an important requirement. The integrated education plan includes development of a lab module for students at NJIT that demonstrates the process of stress generation (cause of mechanical damage) during electrochemical cycling processes. This module will be modified and adapted into outreach programs for K-12 students and teachers. This award also enables elementary teacher trainees from the Newark school system to participate in the research. The polymer/active material interface fracture has been a major roadblock for the rapid advancement of next generation battery electrodes such as Si, Sn, Al, and other large volume change materials. To address these challenges, a combination of novel in situ fracture experiments and supporting models will provide a fundamental understanding of how the interface properties evolve during battery operation and to understand the chemo-mechanical factors that influence the interface fracture behavior. To keep the effort more focused, the interface system in lithium-ion batteries is considered as a model system. A fracture mechanics framework with an interface constitutive model that can incorporate in situ observations, will be developed for prediction of interface failure during an electrochemical reaction. This research will enable interface failure prediction under concurrent mechanical and electrochemical loading using the fracture mechanics models; hence, it lays the groundwork for the essential fundamental understanding to develop long cyclic life, low-cost, and durable batteries for a diverse range of applications.