Exfoliation of Layered Na-Ion Anode Material Na2Ti3O7 for Enhanced Capacity and Cyclability

Research output: Contribution to journalArticlepeer-review

Authors

  • Maria A. Tsiamtsouri
  • Andrew J. Pell
  • Joshua M. Stratford
  • Gunwoo Kim
  • Rachel N. Kerber
  • Pieter C.M.M. Magusin
  • David A. Jefferson
  • Clare P. Grey

Colleges, School and Institutes

External organisations

  • University of Cambridge
  • Stockholm University

Abstract

We report the exfoliation of layered Na2Ti3O7, a promising anode material for Na-ion batteries, and restacking using HNO3 and NaOH to form H-[Ti3O7] and Na(x)-[Ti3O7] compositions, respectively. The materials were characterized by a range of techniques (SEM, TEM, solid-state NMR, XRD, PDF). Although the formation of aggregated nanoparticles is favored under acidic restacking conditions, the use of basic conditions can lead to control over the adherence between the exfoliated layers. Pair distribution function (PDF) analysis confirms that the local TiO6 connectivity of the pristine material is maintained. The lowest sodium-containing phase Na(1)-[Ti3O7], which is the stable product upon Na+ leaching after consecutive washing steps, displays the best performance among the compositions studied, affording a stable reversible capacity of about 200 mAh·g-1 for 20 cycles at a C/20 rate. Washing removes the excess of "free/reactive" Na+, which otherwise forms inactive Na2CO3 in the insufficiently washed compositions.

Details

Original languageEnglish
Pages (from-to)1505-1516
Number of pages12
JournalChemistry of Materials
Volume30
Issue number5
Early online date6 Feb 2018
Publication statusPublished - 13 Mar 2018