Suppressing the Dynamic Oxygen Evolution of Sodium Layered Cathodes through Synergistic Surface Dielectric Polarization and Bulk Site-Selective Co-Doping

Xiao Xia, Tong Liu, Chen Cheng, Hongtai Li, Tianran Yan, Haolv Hu, Yihao Shen, Huanxin Ju, Ting Shan Chan, Zhenwei Wu, Yuefeng Su, Yu Zhao*, Duanyun Cao*, Liang Zhang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)

Abstract

Utilizing anionic redox activity within layered oxide cathode materials represents a transformational avenue for enabling high-energy-density rechargeable batteries. However, the anionic oxygen redox reaction is often accompanied with irreversible dynamic oxygen evolution, leading to unfavorable structural distortion and thus severe voltage decay and rapid capacity fading. Herein, it is proposed and validated that the dynamic oxygen evolution can be effectively suppressed through the synergistic surface CaTiO3 dielectric coating and bulk site-selective Ca/Ti co-doping for layered Na2/3Ni1/3Mn2/3O2. The surface dielectric coating layer not only suppresses the surface oxygen release but more importantly inhibits the bulk oxygen migration by creating a reverse electric field through dielectric polarization. Meanwhile, the site-selective doping of oxygen-affinity Ca into Na layers and Ti into transition metal layers effectively stabilizes the bulk oxygen through modulating the O 2p band center and the oxygen migration barrier. Such a strategy also leads to a reversible structural evolution with a low volume change because of the enhanced structural integrality and improved oxygen rigidity. Because of these synergistic advantages, the designed electrode exhibits greatly suppressed voltage decay and capacity fading upon long-term cycling. This study affords a promising strategy for regulating the dynamic oxygen evolution to achieve high-capacity layered cathode materials.

Original languageEnglish
Article number2209556
JournalAdvanced Materials
Volume35
Issue number8
DOIs
Publication statusPublished - 23 Feb 2023

Keywords

  • dielectric polarization
  • layered oxide cathodes
  • oxygen redox
  • oxygen release
  • site-selective co-doping
  • sodium-ion batteries

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