Origin of high Coulombic loss during sodiation in Na-Sn battery

Young Woon Byeon, Yong Seok Choi, Jae Pyoung Ahn, Jae-chul Lee

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Electrochemical sodiation is performed in crystalline Sn foil using in situ scanning electron microscopy (SEM) to simultaneously measure the changes in the electrical resistivity and volume of the Sn anode in a Na-Sn battery. We observe that sodiation causes an increase in the Sn anode resistivity by six orders of magnitude. Ab initio molecular dynamics simulations of the Na-Sn alloy system demonstrate that the increased resistivity of the anode is caused by the formation of an electrically resistive amorphous NaSn phase (a-NaSn) with a pseudogap. It is also observed that the formation of a-NaSn is always accompanied by a large volume expansion of ∼200%, causing the development of residual tensile stress. The residual stress in turn alters the electronic structure of the a-NaSn phase, further increasing the resistivity of a-NaSn and thus decreasing the energy efficiency of the Na-Sn battery.

Original languageEnglish
Pages (from-to)513-519
Number of pages7
JournalJournal of Power Sources
Volume343
DOIs
Publication statusPublished - 2017 Mar 1

Keywords

  • Ab initio calculation
  • Electrical resistivity
  • Phase transition
  • Pseudogap
  • Sodiation
  • Sodium-ion battery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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