Improving the sodium storage capacity of tunnel structured NaxFexTi2-xO4 (x = 1, 0.9 & 0.8) anode materials by tuning sodium deficiency

Deu S. Bhange, Ghulam Ali, Ji Young Kim, Kyung Yoon Chung, Kyung Wan Nam

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Due to their abundance and environmentally benign nature, iron and titanium present as the most attractive potential elements for use in rechargeable sodium-ion batteries (SIBs). Accordingly, two structurally different Fe and Ti based compounds, stoichiometric NaFeTiO4 and sodium deficient NaxFexTi2-xO4 (where x = 0.9, and 0.8), are explored as anode materials for SIBs. Their structure and sodium storage capacity are systematically investigated by using combined structural and electrochemical analysis. Rietveld refinement analysis reveals that the sodium deficiency leads to the structural transformation from a single-tunnel structure (NaFeTiO4) to a zigzag-type double-tunnel structure (Na0.9Fe0.9Ti1.1O4 and Na0.8Fe0.8Ti1.2O4). The series of sodium deficient compounds bears systematic sodium ion vacancies in their structure up to 20%. Sodium deficiency in the NaxFexTi2-xO4 logically provides additional space for accommodating the excess sodium ions as such the NaxFexTi2-xO4 compounds with higher level of sodium deficiency show higher specific capacities than the stoichiometric NaFeTiO4. All the compounds exhibited very good electrochemical cycling stability, with minimal capacity loss during cycling. The present approach is a model example of improvement in the sodium storage capacity of the anode materials by tuning the chemical composition, and could facilitate the performance improvement of known or new electrode materials for SIBs.

Original languageEnglish
Pages (from-to)115-122
Number of pages8
JournalJournal of Power Sources
Volume366
DOIs
StatePublished - 2017

Keywords

  • Anode
  • NaFeTiO
  • Sodium ion battery
  • Synchrotron X-rays
  • Tunnel structure

Fingerprint

Dive into the research topics of 'Improving the sodium storage capacity of tunnel structured NaxFexTi2-xO4 (x = 1, 0.9 & 0.8) anode materials by tuning sodium deficiency'. Together they form a unique fingerprint.

Cite this