KTi2(PO4)3 Electrode with a Long Cycling Stability for Potassium-Ion Batteries

Natalia Voronina, Jae Hyeon Jo, Aishuak Konarov, Jongsoon Kim, Seung Taek Myung

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

In this work, rhombohedral KTi2(PO4)3 is introduced to investigate the related theoretical, structural, and electrochemical properties in K cells. The suggested KTi2(PO4)3 modified by electro-conducting carbon brings about a flat voltage profile at ≈1.6 V, providing a large capacity of 126 mAh (g-phosphate)−1, corresponding to 98.5% of the theoretical capacity, with 89% capacity retention for 500 cycles. Structural analyses using electrochemical performance measurements, first-principles calculations, ex situ X-ray absorption spectroscopy, and operando X-ray diffraction provide new insights into the reaction mechanism controlling the (de)intercalation of potassium ions into the host KTi2(PO4)3 structure. It is observed that a biphasic redox process by Ti4+/3+ occurs upon discharge, whereas a single-phase reaction followed by a biphasic process occurs upon charge. Along with the structural refinement of the electrochemically reduced K3Ti2(PO4)3 phase, these new findings provide insight into the reaction mechanism in Na superionic conductor (NASICON)-type KTi2(PO4)3. The present approach can also be extended to the investigation of other NASICON-type materials for potassium-ion batteries.

Original languageEnglish
Article number2001090
JournalSmall
Volume16
Issue number20
DOIs
Publication statusAccepted/In press - Jan 1 2020

Keywords

  • first-principles calculations
  • insertion
  • KTi(PO)
  • potassium-ion batteries

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

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    Voronina, N., Jo, J. H., Konarov, A., Kim, J., & Myung, S. T. (Accepted/In press). KTi2(PO4)3 Electrode with a Long Cycling Stability for Potassium-Ion Batteries. Small, 16(20), [2001090]. https://doi.org/10.1002/smll.202001090