Understanding the Failure Mechanisims of Nanoelectrodes in Li-Ion Batteries: Integrating Multiscale Modeling with In-situ Experimental Studies

了解锂离子电池纳米电极的失效机制：将多尺度建模与原位实验研究相结合

• 批准号: 1201058
• 负责人: Sulin Zhang
• 金额: $ 38.83万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1201058&HistoricalAwards=false
• 关键词: Understanding; Failure; Mechanisims; Nanoelectrodes; Li

The research objective of this award is to elucidate the mechanisms of electro-chemically driven mechanical degradation in Si/C composite nanoelectrodes through an integrated experimental/computational approach. The nanoelectrodes consist of silicon nanocrystalline droplets deposited on the inner and outer surface of single-walled carbon nanotubes. This research has four tightly-integrated threads: i) develop first-principles based reactive force fields (ReaxFF) for Li-Si-C systems that enable large-scale atomistic simulations with quantum mechanical accuracy, ii) perform atomistic simulations with ReaxFF to extract basic thermodynamic properties of lithiated CNY and silicon nanodroplets as well as the kinetic parameters of lithium insertion, iii) develop an atomistically informed front-tracking finite element method to simulate and understand size-dependent morphological evolution, stress generation, and defect growth in nanoelectodes, and iv) perform in-situ electron microscopy studies of electrochemically driven deformation, defect nucleation, and growth at the nanoscale.This research will contribute both cutting edge numerical simulations and nanoscale in-situ experiments of the complex, coupled electrochemical-mechanical phenomena that occur in battery electrodes and lead to degradation and ultimately loss of battery capacity. The research is highly interdisciplinary and will involve interactions and visits with Sandia National Laboratories for the participating students; this will expose them to cutting-edge experimental facilities.

该奖项的研究目标是通过综合实验/计算方法阐明电化学驱动的Si/C复合纳米电极的机械降解机制。纳米电极由沉积在单壁碳纳米管内外表面的硅纳米晶液滴组成。这项研究有四个紧密结合的线索：i)为Li-Si-C系统开发基于第一性原理的反应力场（ReaxFF），实现具有量子力学精度的大规模原子模拟；ii)使用ReaxFF进行原子模拟，以提取锂化CNY和硅纳米液滴的基本热力学性质以及锂插入的动力学参数；iii)开发一种原子信息前沿跟踪有限元方法，以模拟和理解尺寸相关的形态演化。纳米电极中的应力产生和缺陷生长，以及iv)在纳米尺度上对电化学驱动的变形，缺陷成核和生长进行原位电子显微镜研究。这项研究将为电池电极中复杂的、耦合的电化学-机械现象提供前沿的数值模拟和纳米级的原位实验，这些现象会导致电池容量的退化和最终损失。这项研究是高度跨学科的，将包括参与学生与桑迪亚国家实验室的互动和访问；这将使他们接触到最先进的实验设备。