Study of phase changes during 500 full cycles of Li/composite polymer electrolyte/FeS2 battery

E. Strauss*, D. Golodnitsky, E. Peled

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

Abstract

There is a growing demand for the development of high-energy-density lithium batteries for a number of applications including electric vehicles (EV), energy storage and space. The Li/composite polymer electrolyte (CPE)/pyrite battery, which has a high theoretical energy density (about 810 Wh kg-1 based on 2.8e/FeS2), and is made of cheap, non-toxic and green compounds is a good candidate for EV applications. Materials cost is estimated at 50$ kWh-1 five times lower than that of other lithium and lithium-ion batteries. Over 500 100% DOD cycles (at c3 rate) with a capacity fading rate of less than 0.1% per cycle were carried out in a small (1 cm2 area) laboratory prototype cells with 7 μm-thick cathodes. Charge-discharge processes in the Li/LiI-(PEO)n-Al2O3-based CPE/pyrite battery during long-term cycle life have been analyzed with the use of dq/dV curves. These studies furnish insights into the electrochemical behavior of pyrite in polymer electrolyte-systems. Up to seven phases have been identified and found to change during the first 50-100 cycles. These phases do not change much over the subsequent 400 cycles. The major phases have been recently identified by EXAFS and NEXAFS measurements. It was proved that reduction of the ferrous disulfide proceeds as a multi-stage process, first to Li2FeS2 and finally to metallic iron. No evidence of FeS was found. When the battery is charged to 2.25 V, Li2 FeS2 is formed.

Original languageEnglish
Pages (from-to)1519-1525
Number of pages7
JournalElectrochimica Acta
Volume45
Issue number8
DOIs
StatePublished - 3 Jan 2000
EventProceedings of the 1998 6th International Symposium on Polymer Electrolytes (ISPE-6) - Hayama, Jpn
Duration: 1 Nov 19986 Nov 1998

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