Lithium Metal Anodes: Toward an Improved Understanding of Coupled Morphological, Electrochemical, and Mechanical Behavior
Lithium Metal Anodes: Toward an Improved Understanding of Coupled Morphological, Electrochemical, and Mechanical Behavior
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DOI：
10.1021/acsenergylett.6b00650
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发表时间：
2017-03-01
影响因子：
22
通讯作者：
Dasgupta, Neil P.
中科院分区：
文献类型：
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作者：
Wood, Kevin N.;Noked, Malachi;Dasgupta, Neil P.
在充电电池领域，锂金属负极常被认为是一座“圣杯”。因此，研究界不断寻求新的战略，以改善其循环性和减少界面退化。然而，最近的许多报告侧重于缓解由于树枝状组织而导致的性能不良症状的方法，而没有解决树枝状组织形成和演变的根本原因。我们认为，对纯粹基于绩效的指标的强调已经冲淡了社区对为什么某一方法是(不)成功的理解。此外，缺乏报告电池性能的一致协议，以及描述发生在锂阳极上的物理现象的不一致术语，使得定量比较变得困难。这一视角的目标是激发对锂金属阳极界面电化学的更一致和更基础的研究的需要。本文综述了：1)研究锂金属基本行为的最新进展；2)循环过程中经常观察到的不同“树枝晶”形态(针状、苔藓状、分形状)；3)循环过程中不同树枝晶对应的电化学和力学特征；4)锂金属阳极的各种失效模式；5)这些失效模式与电极/电解液界面相互作用的关系。作为这些讨论的结果，提出了五个应通过基础研究解决的主要问题，以制定减轻锂金属阳极有害性能的设计规则，并提出了在报告新的锂稳定策略时应考虑的标准实验条件。
Li metal anodes are often considered a "holy grail" in the field of rechargeable batteries. Accordingly, the research community continuously seeks new strategies to improve their cyclability and reduce interfacial degradation. However, many recent reports focus on approaches that mitigate the symptoms of poor performance due to dendrites without addressing the underlying root cause of why they form and how they evolve. We propose that an emphasis on purely performance-based metrics has diluted the community's understanding of why a certain methodology is (un)successful. Furthermore, the lack of consistent protocols for reporting cell performance and inconsistent terminology for describing physical phenomena that occur at the Li anode make quantitative comparison difficult. The goal of this Perspective is to motivate the need for more consistent and fundamental research on the interfacial electrochemistry on Li metal anodes. Herein we provide an overview of: 1) recent advances in understanding the fundamental behavior of Li metal 2) the different "dendrite" morphologies (needle, mossy, fractal) often observed during cycling 3) the corresponding electrochemical and mechanical signatures of these various dendrites during cycling 4) the various failure modes of Li metal anodes and 5) how these failure modes are related to interactions at the electrode/electrolyte interface. As a result of these discussion points, five major questions are proposed that should be addressed through fundamental research in order to formulate design rules for mitigating deleterious performance of Li metal anodes, and standard experimental conditions are proposed that should be taken into account when reporting new strategies for Li stabilization.