title: Insight on the Li2S electrochemical process in a composite configuration electrode.
abstract: A novel, low cost and environmentally sustainable lithium sulfide-carbon composite cathode, suitably prepared by combining polyethylene oxide (PEO), LiCF3SO3and Li2S-C powders is here presented. The cathode is characterized in lithium-metal cell employing a solution of LiCF3SO3salt in dioxolane-dimethylether (DOL-DME) as the electrolyte. Detailed NMR investigation of the diffusion properties of the electrolyte is reported in order to determine its suitability for the proposed cell. The addition of LiNO3to the electrolyte solution allows practical application in a lithium sulfur cell using the Li2S-C-based cathode characterized by a specific capacity of about 500 mAh g-1(as referenced to the Li2S mass). The cell holds its optimal performances for over 70 cycles at C/5 rate, with a steady state efficiency approaching 99%. X-ray diffraction patterns of the cell upon operation suggest the reversibility of the Li2S electrochemical process, while repeated electrochemical impedance spectroscopy (EIS) measurements indicate the suitability of the electrode-electrolyte interface in terms of low and stable cell impedance. Furthermore, the EIS study clarifies the activation process occurring at the Li2S cathode during the first charge process, leading to the decrease of the cell polarization during the following cycles. The data here reported shed light on important aspects to be considered for the efficient application of the Li2S cathode in lithium battery.
authors.affiliation: Sapienza University of Rome, Chemistry Department, Piazzale Aldo Moro, 5, 00185, Rome, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Carbone
authors.affiliation: Sapienza University of Rome, Chemistry Department, Piazzale Aldo Moro, 5, 00185, Rome, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Verrelli
authors.affiliation: Department of Physics & Astronomy, Hunter College of the City University of New York, New York, New York 10065, United States.
authors.forename: Mallory
authors.initials: M
authors.lastname: Gobet
authors.affiliation: Department of Physics & Astronomy, Hunter College of the City University of New York, New York, New York 10065, United States; Ph.D. Program in Chemistry, City University of New York, New York, NY 10016 United States.
authors.forename: Jing
authors.initials: J
authors.lastname: Peng
authors.affiliation: Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, New York 10065, United States.
authors.forename: Matthew
authors.initials: M
authors.lastname: Devany
authors.affiliation: Electtrochimica ed Energia, Rome, Italy (Presently at the Helmholtz Institute, Ulm, Germany).
authors.forename: Bruno
authors.initials: B
authors.lastname: Scrosati
authors.affiliation: Department of Physics & Astronomy, Hunter College of the City University of New York, New York, New York 10065, United States.
authors.forename: Steve
authors.initials: S
authors.lastname: Greenbaum
authors.affiliation: Sapienza University of Rome, Chemistry Department, Piazzale Aldo Moro, 5, 00185, Rome, Italy; Department of Chemical and Pharmaceutical Sciences, Chemistry, University of Ferrara, Via Fossato di Mortara, 17, 44121, Ferrara, Italy.
authors.forename: Jusef
authors.initials: J
authors.lastname: Hassoun
keywords: EIS; Li2S; NMR; lithium battery; lithium-sulfur process