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

主要研究者：Jonghyun Park提案编号：1510085锂离子电池通过储存风能和太阳能等可再生资源产生的电力，或为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保持其理论能量含量的10%左右，需要新的概念来提高储能容量和功率放电速率。 将金属锗添加到锂离子电池电极中提供了提高存储容量和功率的潜力。 然而，锗在充电和放电时会显著膨胀，这会使电池破裂并使其无用。 该项目的目标是确定失效过程的机制，然后使用这种基本的理解来开发用于控制膨胀行为的锗颗粒的涂层材料和工艺。 与该项目相关的教育活动包括努力扩大参与，让来自密苏里州近林肯大学的本科生参与拟议的研究。在锂离子电池阳极固体界面层中使用锗（Ge）金属提供了获得高理论电化学储能容量和功率放电速率的潜力。 然而，在重复充电/放电循环时，阳极的固体电解质界面层破裂。对固体电解质层的损坏是由于在锂离子插入（充电）和抽出（放电）期间Ge金属中的机械体积变化，这导致该层的破裂和粉碎，这导致电极接触的损失和固体电解质层溶解到电解质中。该研究的目标是表征Ge阳极中的失效机制，然后使用这种基本理解来开发通过控制含有Ge纳米颗粒的固体电解质层的内部结构以及其与活性材料的界面来抑制这些损伤过程的制造策略。故障的机制将阐明表征的机械强度和化学溶解速率的固体界面层组件。 固体界面层的内部结构将通过使用原子层沉积（ALD）将添加剂材料（例如金属氧化物）涂覆到Ge纳米颗粒上来控制，以试图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相结合，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，并将在密苏里州科技大学为本科生和K-12学生演示锂离子电池纽扣电池组装。

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.