Mechanisms of sodiation in anatase TiO2 in terms of equilibrium thermodynamics and kinetics

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

1 Scopus Citations
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Author(s)

  • Zhongqiu Tong
  • Jianming Wu
  • Ruqian Lian
  • Hui Wang
  • Yongbing Tang

Detail(s)

Original languageEnglish
Pages (from-to)4702-4713
Journal / PublicationNanoscale Advances
Volume3
Issue number16
Online published25 Jun 2021
Publication statusPublished - 21 Aug 2021

Link(s)

Abstract

Anatase TiO2 is a promising anode material for sodium-ion batteries (SIBs). However, its sodium storage mechanisms in terms of crystal structure transformation during sodiation/de-sodiation processes are far from clear. Here, by analyzing the redox thermodynamics and kinetics under near-equilibrium states, we observe, for the first time, that upon Na-ion uptake, the anatase TiO2 undergoes a phase transition and then an irreversible crystal structure disintegration. Additionally, unlike previous theoretical studies which investigate only the two end points of the sodiation process (i.e., TiO2 and NaTiO2), we study the progressive crystal structure changes of anatase TiO2 upon step-by-step Na-ion uptake (NaxTiO2, x = 0.0625, 0.125, 0.25, 0.5, 0.75, and 1) for the first time. It is found that the anatase TiO2 goes through a thermodynamically unstable intermediate phase (Na0.25TiO2) before reaching crystalline NaTiO2, confirming the inevitable crystal structure disintegration during sodiation. These combined experimental and theoretical studies provide new insights into the sodium storage mechanisms of TiO2 and are expected to provide useful information for further improving the performance of TiO2-based anodes for SIB applications.

Research Area(s)

  • SODIUM-ION BATTERIES, HIGH-PERFORMANCE ANODE, DIFFUSION-COEFFICIENT, NANOTUBE ARRAYS, ELECTROCHEMICAL PERFORMANCES, STORAGE, LITHIUM, NANOSHEETS, INSERTION, PHASE

Citation Format(s)

Mechanisms of sodiation in anatase TiO2 in terms of equilibrium thermodynamics and kinetics. / Tong, Zhongqiu; Kang, Tianxing; Wu, Jianming; Yang, Rui; Wu, Yan; Lian, Ruqian; Wang, Hui; Tang, Yongbing; Lee, Chun Sing.

In: Nanoscale Advances, Vol. 3, No. 16, 21.08.2021, p. 4702-4713.

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