Electrochemistry of Selenium with Sodium and Lithium: Kinetics and Reaction Mechanism

Qianqian Li, Heguang Liu, Zhenpeng Yao, Jipeng Cheng, Tiehu Li, Yuan Li, Chris Wolverton, Jinsong Wu*, Vinayak P. Dravid

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

There are economic and environmental advantages by replacing Li with Na in energy storage. However, sluggishness in the charge/discharge reaction and low capacity are among the major obstacles to development of high-power sodium-ion batteries. Among the electrode materials recently developed for sodium-ion batteries, selenium shows considerable promise because of its high capacity and good cycling ability. Herein, we have investigated the mechanism and kinetics of both sodiation and lithiation reactions with selenium nanotubes, using in situ transmission electron microscopy. Sodiation of a selenium nanotube exhibits a three-step reaction mechanism: (1) the selenium single crystal transforms into an amorphous phase Na0.5Se; (2) the Na0.5Se amorphous phase crystallizes to form a polycrystalline Na2Se2 phase; and (3) Na2Se2 transforms into the Na2Se phase. Under similar conditions, the lithiation of Se exhibits a one-step reaction mechanism, with phase transformation from single-crystalline Se to a Li2Se. Intriguingly, sodiation kinetics is generally about 4-5 times faster than that of lithiation, and the kinetics during the different stages of sodiation is different. Na-based intermediate phases are found to have improved electronic and ionic conductivity compared to those of Li compounds by first-principles density functional theory calculations.

Original languageEnglish (US)
Pages (from-to)8788-8795
Number of pages8
JournalACS nano
Volume10
Issue number9
DOIs
StatePublished - Sep 27 2016

Keywords

  • DFT calculation
  • alloying reaction
  • in situ electron diffraction
  • in situ transmission electron microscopy
  • lithium-ion battery
  • selenium cathodes
  • sodium-ion battery

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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