Preparation of Li2S-FeSx composite positive electrode materials and their electrochemical properties with pre-cycling treatments

Tomonari Takeuchi, Hiroyuki Kageyama, Koji Nakanishi, Masahiro Ogawa, Toshiaki Ohta, Atsushi Sakuda, Hikari Sakaebe, Hironori Kobayashi, Zempachi Ogumi

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17 Citations (Scopus)

Abstract

Li2S-FeSx (x = 1, 2) composite positive electrode material, consisted of low-crystalline Li2S, was prepared by the combination process of the thermal heating and the mechanical milling. The electrochemical tests demonstrated that the Li2S-rich composite sample (Li2S : FeS = 4 : 1 mol) cells showed relatively high initial charge capacity (ca. 600 mAh · g-1). The discharge capacity was ca. 330 mAh · g-1 with the normal electrochemical cycling, and it was enlarged to ca. 730 mAh · g-1 after the stepwise pre-cycling treatment. Ex situ XRD measurements showed the improved reversibility of the Li2S peaks for Li extraction/insertion reactions after the stepwise pre-cycling treatment. Also, ex situ S and Fe K-edge XAFS measurements indicated the improved reversibility of the valence states and local structures around S and Fe atoms after the stepwise pre-cycling treatment. Thus, the stepwise precycling treatment was effective for improving the structural reversibility of the Li2S-FeSx composites, particularly with Li2S-rich composition, for Li insertion/extraction reactions, resulting in the improved electrochemical performances of the cells.

Original languageEnglish
Pages (from-to)A1745-A1750
JournalJournal of the Electrochemical Society
Volume162
Issue number9
DOIs
Publication statusPublished - 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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