Pyrite-based mixtures as composite electrodes for lithium-sulfur batteries

I. Belenkaya, S. Menkin, H. Mazor, T. Mukra, L. Burstein, Yu Rosenberg, A. Gladkich, D. Golodnitsky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Pyrite-based composite materials (Li/S) were prepared by high-energy ball milling of FeS2 with one or more metal sulfides, Li2S, Cu2S, and CuS, in various molar ratios and under different conditions. Prolonged grinding resulted in the formation of mixed compounds rather than single-phase lithiated chalcopyrite. The composite materials were primarily investigated via XPS, XRD, and TOF-SIMS characterization methods, and performance of the materials as composite cathodes was evaluated via analysis of dQ/dV curves. Evidence of main active phases in the materials was found, including, Cu-doped FeS2 (pyrite) and/or nonstoichiometric chalcopyrite (CuxFeyS2 − z). TOF-SIMS measurements exhibited further evidence of formation of partially lithiated pyrite mixtures. Lithium cells comprising mixed pyrite cathodes demonstrate superior electrochemical performance, namely, 98–100% coulombic efficiency and 300–320 mAh g−1 (per gram of active material) after 150 cycles over a voltage range of 1.2–2.8 V at 0.1 C-rate, whereas pristine FeS2/Li cells exhibit only 220 mAh g−1 at similar operating conditions. Lowering of cut-off discharge voltage from 1.2 to 1.0 V of the FeS2/Li cells with FeS2-rich mixed cathodes is accompanied by about 15% capacity enhancement (350–450 mAh g−1 after 200 cycles). The cells with mixed pyrite composite cathodes exhibit an increase in maximum pulse power capability from 5 to 15 W/g and C-rate from 0.3 to 2.5, which points towards higher electrical conductivity of the active material as compared to the pristine pyrite.

Original languageEnglish
Pages (from-to)419-431
Number of pages13
JournalJournal of Solid State Electrochemistry
Issue number2
StatePublished - 12 Feb 2019


  • Cycle life
  • Lithium-sulfur batteries
  • Pyrite-based mixed cathodes


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