Fluorine gradient-doped LiNi0.5Mn1.5O4 spinel with improved high voltage stability for Li-ion batteries

Ying Luo, Haiyan Li, Taolin Lu, Yixiao Zhang, Samuel S. Mao, Zhi Liu, Wen Wen, Jingying Xie, Liqin Yan

Research output: Contribution to journalArticlepeer-review

51 Scopus citations

Abstract

The fluorine gradient-doped LiNi0.5Mn1.5O4 spinels are synthesized by a facile one-step method and the effect of heat treatment on their structure, morphology, and electrochemical performance are investigated. The results show that introduction of fluorine leads to a larger lattice parameter and particle size, and the formation of F-enriched surface. Whereas at 400 °C, the fluorine gradient-doped LiNi0.5Mn1.5O4 sample exhibits an improved long-term cycling stability and high rate performance, due to the suppression of the reaction between electrolyte and cathode, resulting in a decrease in the total resistance and the formation of a thin, uniform and smooth film on the surface. As a result of in situ XRD with charged pristine and the fluorine gradient-doped samples, the similar thermal-decomposition pathways from the charged spinel to the final NiMn2O4-type spinel structure with a small amount of NiMnO3 and α-Mn2O3 are observed. In addition, the disappearance temperature of the charged spinel structures is at about 280 °C for the fluorine gradient-doped sample, exhibiting an improved thermal stability of high voltage cathode material. These results show that fluorine gradient-doped LiNi0.5Mn1.5O4 sample is a promising positive electrode material for high performance lithium ion batteries.

Original languageBritish English
Pages (from-to)237-245
Number of pages9
JournalElectrochimica Acta
Volume238
DOIs
StatePublished - 1 Jun 2017

Keywords

  • Fluorine gradient-doped
  • High voltage stability
  • LiNiMnO cathodes
  • Lithium ion battery

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