UNS: Mechanical/Chemical Failure of Solid Electrolyte Interphase in Lithium-ion Batteries: Understanding Its Mechanisms and Suppressing Its Onset

PI: Jonghyun Park提案号：1510085锂离子电池通过存储风能和太阳能等可再生资源产生的电力，或为使用可再生资源充电的零排放电动汽车提供动力，支持可持续能源系统的发展。然而，目前的可充电锂离子电池只能容纳其理论能量含量的10%左右，需要新的概念来提高储能容量和放电率。将金属锗添加到锂离子电池电极中，有可能提高存储容量和功率。然而，锗在充放电过程中会明显膨胀，这会使电池破裂，使电池失效。该项目的目标是确定失效过程的机制，然后利用这一基本认识来开发锗粒子的涂层材料和工艺，以控制膨胀行为。与此项目相关的教育活动包括努力扩大参与，包括密苏里州林肯大学的本科生参与拟议的研究。在锂离子电池正极的固体界面层中使用锗金属，具有较高的理论电化学储能容量和放电倍率的潜力。然而，在重复的充放电循环中，阳极的固体电解质界面层被击穿。固体电解质层的损坏是由于锂离子插入（充电）和提取（放电）过程中Ge金属的机械体积变化，导致该层出现裂纹和粉碎，从而导致电极失去接触，固体电解质层溶解到电解质中。本研究的目标是表征锗阳极的失效机制，然后利用这一基本认识来开发制造策略，通过控制含有锗纳米颗粒的固体电解质层的内部结构，以及它与活性材料的界面来抑制这些损伤过程。通过表征固体界面层组分的机械强度和化学溶解速率来阐明其破坏机制。固体界面层的内部结构将通过使用原子层沉积（ALD）来控制，将添加剂（例如金属氧化物）涂覆在Ge纳米颗粒上，以减少锂离子插入和提取时的应力。将开发一个多尺度模型，将固体界面层中的纳米颗粒水平行为与电化学电池操作耦合，以预测触发固体界面层失效的条件及其对电池性能的后续影响。然后，该模型将用于确定优化ALD材料和工艺的策略，以提高机械稳定性和电池性能。为了将研究与教育联系起来，PI将在顶点机械工程顶点设计课程中介绍能源材料和电池设计概念，并将为密苏里科技大学的本科生和K-12学生演示锂离子电池硬币电池组装。

PI: Jonghyun Park Proposal Number: 1510085Lithium ion batteries support the development of sustainable energy systems by storing electricity generated by renewable resources such as wind and solar energy, or by powering zero-emission electric vehicles charged by electricity from renewable resources. However, current rechargeable lithium ion batteries can hold only about 10% of their theoretical energy content, and new concepts are needed to improve energy storage capacity and power discharge rate. The addition of the metal germanium to lithium ion battery electrodes offers the potential to improve both storage capacity and power. However, the germanium swells significantly upon charging and discharging, which cracks the battery and renders it useless. The goals of this project are to determine the mechanisms of the failure process, and then to use this fundamental understanding to develop coating materials and processes for the germanium particles that will control the swelling behavior. The educational activities associated with this project include efforts to broaden participation by involving undergraduates from nearly Lincoln University of Missouri in the proposed research.The use of geranium (Ge) metal in the solid interface layer of the anode of lithium ion batteries offers the potential for high theoretical electrochemical energy storage capacity and power discharge rate. However, upon repeated charge/discharge cycles, the solid electrolyte interface layer of the anode breaks down. The damage to the solid electrolyte layer is due to the mechanical volume change in Ge metal during lithium-ion insertion (charging) and extraction (discharge), which causes cracks and pulverization of this layer that lead to loss of electrode contact and dissolution of the solid electrolyte layer into the electrolyte. The goals of the research are to characterize the mechanisms of failure in the Ge anode, and then use this fundamental understanding to develop fabrication strategies for suppressing these damage processes by controlling internal structure of the solid electrolyte layer containing Ge nanoparticles, as well as its interface with active materials. The mechanisms of failure will be elucidated by characterizing mechanical strength and chemical dissolution rate of the solid interface layer components. The internal structure of the solid interface layer will be controlled by using Atomic Layer Deposition (ALD) to coat additive materials, for example metal oxides, onto Ge nanoparticles in the attempt to reduce stress upon lithium ion insertion and extraction. A multiscale model will be developed that couples the nanoparticle level behavior in the solid interface layer to electrochemical cell operation to predict the conditions that trigger solid interface layer failure and its subsequent effect on battery performance. This model will then be used to identify strategies to optimize the ALD materials and process for improved mechanical stability and battery performance. To connect the research to education, the PI will introduce energy materials and battery design concepts in a capstone mechanical engineering capstone design course, and will give demonstrations on lithium-ion battery coin cell assembly for undergraduate and K-12 students at the Missouri University of Science and Technology.