eScience (Oct 2023)

Boosting reversible anionic redox reaction with Li/Cu dual honeycomb centers

  • Xiaohui Rong,
  • Dongdong Xiao,
  • Qinghao Li,
  • Yaoshen Niu,
  • Feixiang Ding,
  • Xueyan Hou,
  • Qiyu Wang,
  • Juping Xu,
  • Chenglong Zhao,
  • Dong Zhou,
  • Ruijuan Xiao,
  • Xiqian Yu,
  • Wen Yin,
  • Lin Gu,
  • Hong Li,
  • Xuejie Huang,
  • Liquan Chen,
  • Yong-Sheng Hu

Journal volume & issue
Vol. 3, no. 5
p. 100159

Abstract

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The anionic redox reaction (ARR) is a promising charge contributor to improve the reversible capacity of layered-oxide cathodes for Na-ion batteries; however, some practical bottlenecks still need to be eliminated, including a low capacity retention, large voltage hysteresis, and low rate capability. Herein, we proposed a high-Na content honeycomb-ordered cathode, P2–Na5/6[Li1/6Cu1/6Mn2/3]O2 (P2-NLCMO), with combined cationic/anionic redox. Neutron powder diffraction and X-ray diffraction of P2-NLCMO suggested P2-type stacking with rarely found P6322 symmetry. In addition, advanced spectroscopy techniques and density functional theory calculations confirmed the synergistic stabilizing relationship between the Li/Cu dual honeycomb centers, achieving fully active Cu3+/Cu2+ redox and stabilized ARR with interactively suppressed local distortion. With a meticulously regulated charge/discharge protocol, both the cycling and rate capability of P2-NLCMO were significantly improved, demonstrating reasonable capacity and eliminating voltage hysteresis. Overall, this work contributes a well-defined layered oxide cathode with combined cationic/anionic redox towards rational designing advanced Na-ion batteries.

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