Electronic Structure Engineering of Honeycomb Layered Cathode Material for Sodium-Ion Batteries

Natalia Voronina, Hee Jae Kim, Aishuak Konarov, Najma Yaqoob, Kug Seung Lee, Payam Kaghazchi, Olivier Guillon, Seung Taek Myung

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

In this work, the rational design of O′3-type Na[Ni2/3−xCoxSb1/3]O2, a solid solution of Na[Ni2/3Sb1/3]O2–Na[Co2/3Sb1/3]O2, is introduced. Because of the difficulty of the Co3+/2+ redox reaction, the electronic structures of Na[Ni2/3−xCoxSb1/3]O2 compounds are engineered to build electroconducting networks in the oxide matrix through electrochemical oxidation of Co2+ to Co3+, after which the formed Co3+ does not participate in the electrochemical reaction but improves the electrical conductivity in the structure. Density functional theory calculations reveal a reduced bandgap energy after the formation of Co3+ during desodiation of Na1−y[Ni2/3−xCoxSb1/3]O2. Using the oxidized Co3+ species while improving the electrical conductivity, the Na[Ni2/3−xCoxSb1/3]O2 (x = 1/6) electrode exhibits excellent cyclability for 1000 cycles with ≈72.5% capacity retention at 2C (400 mA g−1) and activity even at 50C (10 A g−1) in Na cells. Operando X-ray diffraction and ex situ X-ray absorption near-edge structure investigations reveal suppressed lattice variations upon charge and discharge compared with those of Na[Ni2/3Sb1/3]O2 achieved by the presence of the electrochemical-driven Co3+ in the structure. These findings offer a new strategy for the development of cathode materials for sodium-ion batteries, providing important insight into their structural transformations and the electronic nature of advanced cathode materials.

Original languageEnglish
Article number2003399
JournalAdvanced Energy Materials
Volume11
Issue number14
DOIs
Publication statusPublished - Apr 15 2021

Keywords

  • batteries
  • cathodes
  • electronic structure
  • layered
  • sodium

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

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