Gradient Li-rich oxide cathode particles immunized against oxygen release by a molten salt treatment

Zhi Zhu, Daiwei Yu, Yang Yang, Cong Su, Yimeng Huang, Yanhao Dong, Iradwikanari Waluyo, Baoming Wang, Adrian Hunt, Xiahui Yao, Jinhyuk Lee, Weijiang Xue, Ju Li

Research output: Contribution to journalArticlepeer-review

102 Scopus citations

Abstract

Lithium-rich transition metal oxide (Li1+XM1−XO2) cathodes have high energy density above 900 Wh kg−1 due to hybrid anion- and cation-redox (HACR) contributions, but critical issues such as oxygen release and voltage decay during cycling have prevented their application for years. Here we show that a molten molybdate-assisted LiO extraction at 700 °C creates lattice-coherent but depth (r)-dependent Li1+X(r)M1−X(r)O2 particles with a Li-rich (X ≈ 0.2) interior, a Li-poor (X ≈ −0.05) surface and a continuous gradient in between. The gradient Li-rich single crystals eliminate the oxygen release to the electrolyte and, importantly, still allow stable oxygen redox contributions within. Both the metal valence states and the crystal structure are well maintained during cycling. The gradient HACR cathode displays a specific density of 843 Wh kg−1 after 200 cycles at 0.2C and 808 Wh kg−1 after 100 cycles at 1C, with very little oxygen release and consumption of electrolyte. This high-temperature immunization treatment can be generalized to leach other elements to avoid unexpected surface reactions in batteries.

Original languageEnglish (US)
Pages (from-to)1049-1058
Number of pages10
JournalNature Energy
Volume4
Issue number12
DOIs
StatePublished - Dec 1 2019

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology

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