Improvement of cycle capability of FeS 2 positive electrode by forming composites with Li 2S for ambient temperature lithium batteries

Tomonari Takeuchi, Hiroyuki Kageyama, Koji Nakanishi, Yasuhiro Inada, Misaki Katayama, Toshiaki Ohta, Hiroshi Senoh, Hikari Sakaebe, Tetsuo Sakai, Kuniaki Tatsumi, Hironori Kobayashi

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45 Citations (Scopus)

Abstract

FeS 2-Li 2S composite positive electrode material, consisted of mainly Li 3Fe 2S 4 and Li 2.33Fe 0.67S 2, was prepared for improving the cycle capability of FeS 2 in rechargeable lithium batteries with liquid electrolytes operated at ambient temperature. The electrochemical tests demonstrated that the FeS 2-Li 2S composite cells showed a relatively higher capacity retention after 15 cycles (ca. 64%) as compared with that of the FeS 2 cells (ca. 26%), though both sample cells showed comparable initial discharge capacities (ca. 740 and 790 mAh·g -1 (4.2 and 4.5 mAh·cm -2), respectively). The improved cycle capability of the FeS 2-Li 2S cells was ascribed particularly to rather unchanged discharge plateau at ca. 2.0 V, which was reported to correspond to the reduction of sulfur. The ex-situ S K-edge X-ray absorption fine structure measurements indicated that the redox reaction of sulfur ions (S 2 2- + 2e - 2S 2-), associated with Li extraction / insertion reactions, was still active after 15 cycles in the FeS 2-Li 2S electrode, while such redox reactions almost disappeared in the FeS 2 electrode. The atomic displacements required in the initial delithiation / lithiation were reduced in the FeS 2-Li 2S composite as compared with FeS 2, which would give rise to the suppression of the structural irreversibility in the following charge / discharge, resulting in the improved cycle capability.

Original languageEnglish
Pages (from-to)A75-A84
JournalJournal of the Electrochemical Society
Volume159
Issue number2
DOIs
Publication statusPublished - 2012
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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