Cr-doped lithium titanate nanocrystals as Mg ion insertion materials for Mg batteries

Boeun Lee, Eunmi Jo, Jihwan Choi, Jong Hak Kim, Wonyoung Chang, Seungho Yu, Hyung Seok Kim, Si Hyoung Oh

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Magnesium metal anodes offer significant economic, capacitive, and safety advantages over their lithium counterparts. However, developing viable magnesium batteries remains challenging because of the lack of efficient insertion cathode materials; the presently used materials suffer from lethargic reaction kinetics caused by strong electrostatic interactions between the divalent intercalant ions and the host. Herein, we present a technique integrating physical and chemical approaches toward achieving high intercalation kinetics utilizing lithium titanate (LTO). We demonstrate that reducing the particle size of LTO to 8 nm drastically enhances the utilization of redox-active centers, leading to a 300% higher reversible capacity than the bulk-sized material. Moreover, aliovalent doping of Cr into the LTO structure not only increases the electrical conductivity, facilitating fast charge redistribution at redox centers, but also causes a favorable structural disordering that can enhance the local ion mobility, ensuring good high-rate performance, long-term cycle stability, and rapid completion of initial activation compared to that offered by the undoped LTO. These findings agree with the computational study reporting that the diffusion barriers for Mg2+ and Li+ ions can be reduced significantly upon Cr doping. This study provides an interesting and novel opportunity to improve conventional insertion materials with poor reaction kinetics to unlock excellent electrochemical activity for practical application in magnesium battery cathodes.

Original languageEnglish
Pages (from-to)25619-25627
Number of pages9
JournalJournal of Materials Chemistry A
Volume7
Issue number44
DOIs
Publication statusPublished - 2019 Jan 1
Externally publishedYes

    Fingerprint

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

Cite this

Lee, B., Jo, E., Choi, J., Kim, J. H., Chang, W., Yu, S., Kim, H. S., & Oh, S. H. (2019). Cr-doped lithium titanate nanocrystals as Mg ion insertion materials for Mg batteries. Journal of Materials Chemistry A, 7(44), 25619-25627. https://doi.org/10.1039/c9ta08362f