An ion-exchange promoted phase transition in a li-excess layered cathode material for high-performance lithium ion batteries

Jianqing Zhao, Ruiming Huang, Wenpei Gao, Jian Min Zuo, Xiao Feng Zhang, Scott T. Misture, Yuan Chen, Jenny V. Lockard, Boliang Zhang, Shengmin Guo, Mohammad Reza Khoshi, Kerry Dooley, Huixin He, Ying Wang

Research output: Contribution to journalArticle

Abstract

A new approach to intentionally induce phase transition of Li-excess layered cathode materials for high-performance lithium ion batteries is reported. In high contrast to the limited layered-to-spinel phase transformation that occurred during in situ electrochemical cycles, a Li-excess layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is completely converted to a Li4Mn5O12-type spinel product via ex situ ion-exchanges and a post-annealing process. Such a layered-to-spinel phase conversion is examined using in situ X-ray diffraction and in situ high-resolution transmission electron microscopy. It is found that generation of sufficient lithium ion vacancies within the Li-excess layered oxide plays a critical role for realizing a complete phase transition. The newly formed spinel material exhibits initial discharge capacities of 313.6, 267.2, 204.0, and 126.3 mAh g-1 when cycled at 0.1, 0.5, 1, and 5 C (1 C = 250 mA g-1), respectively, and can retain a specific capacity of 197.5 mAh g-1 at 1 C after 100 electrochemical cycles, demonstrating remarkably improved rate capability and cycling stability in comparison with the original Li-excess layered cathode materials. This work sheds light on fundamental understanding of phase transitions within Li-excess layered oxides. It also provides a novel route for tailoring electrochemical performance of Li-excess layered cathode materials for high-capacity lithium ion batteries. A Li-excess layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 is completely converted to a Li4Mn5O12-type spinel product via ex situ ion exchanges and a post-annealing process. This sheds light on the fundamental understanding of phase transitions within Li-excess layered oxides and provides a novel route for tailoring electrochemical performance of Li-excess layered cathode materials for high-capacity lithium ion batteries.

Original languageEnglish (US)
Article number1401937
JournalAdvanced Energy Materials
Volume5
Issue number9
DOIs
StatePublished - May 1 2015

    Fingerprint

Keywords

  • Li-excess layered cathodes
  • in situ characterization
  • ion exchange
  • lithium ion batteries
  • phase transitions

ASJC Scopus subject areas

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

Cite this

Zhao, J., Huang, R., Gao, W., Zuo, J. M., Zhang, X. F., Misture, S. T., Chen, Y., Lockard, J. V., Zhang, B., Guo, S., Khoshi, M. R., Dooley, K., He, H., & Wang, Y. (2015). An ion-exchange promoted phase transition in a li-excess layered cathode material for high-performance lithium ion batteries. Advanced Energy Materials, 5(9), [1401937]. https://doi.org/10.1002/aenm.201401937