Issue 4, 2020

A new lithium diffusion model in layered oxides based on asymmetric but reversible transition metal migration

Abstract

Lithium-rich layered oxides (LLOs) are considered promising cathode materials for lithium-ion batteries because of their high reversible capacity, which is attributed to the exploitation of the novel anionic redox in addition to the conventional cationic redox process. Transition metal (TM) migration, which is known to be the main cause of the voltage decay in LLOs, is now understood to also be the critical factor triggering anionic redox, although this origin is still under debate. A better understanding of the specific TM migration behavior and its effect during charge/discharge would thus enable further development of this class of materials. Herein, we demonstrate that the unique TM migration during charge/discharge significantly alters the lithium diffusion mechanism/kinetics of LLO cathodes. We present clear evidence of the much more sluggish lithium diffusion occurring during discharge (lithiation) than during charge (de-lithiation), which contrasts with the traditional lithium diffusion model based on simple topotactic lithium intercalation/deintercalation in the layered framework. The reversible but asymmetric TM migration in the structure, which originates from the non-equivalent local environments around the TM during the charge and discharge processes, is shown to affect the lithium mobility. This correlation between TM migration and lithium mobility led us to propose a new lithium diffusion model for layered structures and suggests the importance of considering TM migration in designing new LLO cathode materials.

Graphical abstract: A new lithium diffusion model in layered oxides based on asymmetric but reversible transition metal migration

Supplementary files

Article information

Article type
Paper
Submitted
11 Mar 2019
Accepted
03 Mar 2020
First published
11 Mar 2020

Energy Environ. Sci., 2020,13, 1269-1278

A new lithium diffusion model in layered oxides based on asymmetric but reversible transition metal migration

K. Ku, B. Kim, S. Jung, Y. Gong, D. Eum, G. Yoon, K. Park, J. Hong, S. Cho, D. Kim, H. Kim, E. Jeong, L. Gu and K. Kang, Energy Environ. Sci., 2020, 13, 1269 DOI: 10.1039/C9EE04123K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements