Stabilizing the oxygen lattice and reversible oxygen redox in Na-deficient cathode oxides

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Wei Zheng
  • Qiong Liu
  • Zhenyu Wang
  • Zhibin Yi
  • Yingzhi Li
  • Lujie Cao
  • Zhouguang Lu

Detail(s)

Original languageEnglish
Article number227086
Journal / PublicationJournal of Power Sources
Volume439
Online published5 Sep 2019
Publication statusPublished - 1 Nov 2019

Abstract

To overcome the limitation of capacity from traditional oxide-based intercalation cathodes, oxygen redox reaction garners intense interest in Li-rich/Na-rich cathodes for rechargeable batteries. However, cycle degradation and voltage drop caused by the irreversible structural changes and O2 release upon electrochemical cycling hinder their commercial applications. Herein, a Na-deficient layered compound Na0.67Mn0.72Zn0.28O2 is employed to study the relationship between the oxygen redox reaction and the (O2)n− stabilization mechanism by using a combined experimental and computational approach. Our results indicate that Na0.67Mn0.72Zn0.28O2 has a long plateau of approximately 4.1 V with a total capacity of 157 mAh g−1, majorly stemming from the oxygen redox reactions of O2−/(O2)n−. The O-2p nonbonding states originating from the weak Zn–O interaction and the shortened O–O bonds induced by the absence of Na atoms in the alkali layers catalyze the formation of peroxo-like O–O dimer between the Mn–Mn atoms. The honeycomb TM layer of the Na-deficient materials remains stable with a small O–O bond length evolution from 2.55 Å to 2.48 Å during the oxygen redox process, which stabilizes the lattice oxygen in electrochemical cycles. This finding is important for further understanding the mechanism underlying the oxygen redox chemistry of high energy Na-deficient cathode materials.

Research Area(s)

  • Cathode material, Lattice oxygen stabilization, Oxygen redox reaction, O–O shortening, Sodium ion battery

Citation Format(s)

Stabilizing the oxygen lattice and reversible oxygen redox in Na-deficient cathode oxides. / Zheng, Wei; Liu, Qiong; Wang, Zhenyu; Yi, Zhibin; Li, Yingzhi; Cao, Lujie; Zhang, Kaili; Lu, Zhouguang.

In: Journal of Power Sources, Vol. 439, 227086, 01.11.2019.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review