Non-equilibrium insertion of lithium ions into graphite. Issue 20 (17th May 2021)

• Record Type: Journal Article
• Authors: Li, Na; Sun, Ming-Zi; Hwang, Sooyeon; Li, Shuang; Zhao, Hong-Yang; Du, Ya-Ping; Huang, Bo-Long; Su, Dong
• Is Part Of: Journal of materials chemistry. Volume 9:Issue 20(2021)
• Page Start: 12080
• Page End: 12086
• Publication Date: 2021-05-17
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d1ta02836g
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Atomic-level in situ exploration unravels a non-equilibrium process on the insertion of lithium ions into graphite. This finding reports a non-equilibrium scenario different from classic Rüdorff–Hofmann (R–H) and Daumas–Hérold (D–H) models. Abstract : Graphite has been regarded as the most important anode material for currently used lithium-ion batteries due to its two-dimensional (2D) nature hosting ionic intercalations. However, the kinetic insertion of Li ions is still not well known microscopically. In this work, we investigate the real-time intercalation process of Li ions using in situ transmission electron microscopy. We observe the lithium insertion process at the atomic scale, in which the graphite layers undergo expansion, forming wrinkles and finally inhomogeneous cracks as the Li ions accumulate, different from the proposed models. Leveraging on theoretical simulations, Li-ion migration driven by an external electrical field is suggested to be induced into the irreversible wrinkled structures. This non-equilibrium behavior that occur in lithium-ion batteries can be more pronounced at a high charging rate, which will practically degrade the capacity of graphite. This work unveils the reaction scenario of the non-equilibrium Li-ion insertion, which benefits the understanding of the performance of graphite-based energy-storage devices.