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A New Approach to Stable Cationic and Anionic Redox Activity in O3‐Layered Cathode for Sodium‐Ion Batteries
Author(s) -
Voronitalia,
Yaqoob Najma,
Kim Hee Jae,
Lee KugSeung,
Lim HeeDae,
Jung HunGi,
Guillon Olivier,
Kaghazchi Payam,
Myung SeungTaek
Publication year - 2021
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.202100901
Subject(s) - redox , electrochemistry , density functional theory , valence (chemistry) , delocalized electron , materials science , transition metal , cathode , cationic polymerization , inorganic chemistry , oxidation state , metal , crystallography , chemistry , electrode , catalysis , computational chemistry , biochemistry , organic chemistry , polymer chemistry , metallurgy
Herein, stable cationic and anionic redox in an O3‐type layered Na[Ni 2/3 Ru 1/3 ]O 2 cathode for sodium‐ion batteries (SIBs) is revealed. Density functional theory (DFT) calculation shows that the electron density features change in density of state with mixing of delocalized valence states as well as localized deeper energy states of O( p ), Ni( d ), and Ru( d ) for the highly desodiated Na 1− x [Ni 2/3 Ru 1/3 ]O 2 electrode, revealing the covalent characteristic of the transition metal (TM)O and TMTM bonds in the charged system. These properties lead to cycling stability for 200 cycles, with ≈79% of the capacity retained at a rate of 1C (210 mA g −1 ). Operando X‐ray diffraction, X‐ray absorption spectroscopy, and DFT calculations reveal the reversible electrochemical activity of the Ni 2+ /Ni 3+ and O 2− /O 1− redox reactions, which are sustainable throughout the cycles. In addition, no loss of oxygen from the crystal structure of Na[Ni 2/3 Ru 1/3 ]O 2 occurs according to differential electrochemical mass spectrometry. The findings provide additional insight into the complex mechanism of the oxygen redox activity of high‐capacity O3‐type cathode materials for SIBs, encouraging further studies on their development.