Kim Hyunwoo, Choi Woosung, Yoon Jaesang, Um Ji Hyun, Lee Wontae, Kim Jaeyoung, Cabana Jordi, Yoon Won-Sub
Department of Energy Science, Sungkyunkwan University (SKKU), Natural Sciences Campus, 2066, Seobu-ro, Jangan-gu, Suwon, Gyeonggi 16419, South Korea.
Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, United States.
Chem Rev. 2020 Jul 22;120(14):6934-6976. doi: 10.1021/acs.chemrev.9b00618. Epub 2020 Feb 26.
To advance current Li rechargeable batteries further, tremendous emphasis has been made on the development of anode materials with higher capacities than the widely commercialized graphite. Some of these anode materials exhibit capacities above the theoretical value predicted based on conventional mechanisms of Li storage, namely insertion, alloying, and conversion. In addition, in contrast to conventional observations of loss upon cycling, the capacity has been found to increase during repeated cycling in a significant number of cases. As the internal environment in the battery is very complicated and continuously changing, these abnormal charge storage behaviors are caused by diverse reactions. In this review, we will introduce our current understanding of reported reactions accounting for the extra capacity. It includes formation/decomposition of electrolyte-derived surface layer, the possibility of additional charge storage at sharp interfaces between electronic and ionic sinks, redox reactions of Li-containing species, unconventional activity of structural defects, and metallic-cluster like Li storage. We will also discuss how the changes in the anode can induce capacity increase upon cycling. With this knowledge, new insights into possible strategies to effectively and sustainably utilize these abnormal charge storage mechanisms to produce vertical leaps in performance of anode materials will be laid out.
为了进一步推动当前的锂可充电电池发展，人们极大地重视开发比广泛商业化的石墨具有更高容量的负极材料。其中一些负极材料展现出的容量高于基于传统锂存储机制（即嵌入、合金化和转化）预测的理论值。此外，与传统的循环过程中容量损失的观察结果相反，在大量情况下，人们发现容量在反复循环过程中会增加。由于电池内部环境非常复杂且不断变化，这些异常的电荷存储行为是由多种反应引起的。在本综述中，我们将介绍目前对报道的导致额外容量的反应的理解。这包括电解质衍生表面层的形成/分解、电子和离子汇之间尖锐界面处额外电荷存储的可能性、含锂物种的氧化还原反应、结构缺陷的非常规活性以及类似金属簇的锂存储。我们还将讨论负极的变化如何在循环过程中导致容量增加。有了这些知识，将阐述对有效且可持续利用这些异常电荷存储机制以实现负极材料性能大幅提升的可能策略的新见解。
