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Molybdenum Disulfide Catalyst for Lithium-Oxygen Batteries

Thursday, 23 June 2016
Riverside Center (Hyatt Regency)

ABSTRACT WITHDRAWN

Molybdenum Disulfide Catalyst for Lithium–Oxygen Batteries

Mohammad Asadi1, Cong Liu2, Patrick Phillips3, Peter Zapol2, Robert F. Klie 3, Larry A. Curtiss2, Amin Salehi-Khojin1

1Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, 60607, USA

2Materials Science Division, Argonne National Laboratory, Argonne, IL, 60439, USA

3Department of Physics, University of Illinois at Chicago, Chicago, IL, 60607, USA

   Lithium–oxygen (Li-O2) batteries have been recognized as an emerging technology for energy storage systems owing to their high theoretical specific energy1-4. In this study, we discovered a system based on molybdenum disulfide (MoS2) nanoflakes and an ionic liquid (IL) that work together as an effective co-catalyst for discharge and charge in a Li-O2 battery.  Cyclic voltammetry results show superior reaction rates for this co-catalyst at lower overpotentials for both oxygen reduction (15 mV) and evolution (20 mV) reactions compared to Au and Pt metal catalysts under identical experimental conditions. This MoS2/IL co-catalyst also performs remarkably well in the Li-O2battery system with 85% round-trip efficiency and reversibility up to 50 cycles.

   Deferential Electrochemical mass spectroscopy (DEMS), X-ray diffraction (XRD), Fourier transform spectroscopy (FT-IR) and Raman experiments were used to elucidate the cell performance.  The results show the fully formation and decomposition of Li2O2 and demonstrate the cell cyclability and stability by the absence of any side products after 50 cycles charge and discharge. Atomic scale characterizations (STEM and EELS experiments) and DFT calculations were used to elucidate the mechanism by which the MoS2 nanoflakes and the ionic liquid electrolyte act together to promote the catalytic properties of the MoS2. The MoS2/IL co-catalyst discovered in this work provides new opportunities for exploiting the unique properties of ionic liquids such as their stability in Li-air batteries as well as activity of MoS2as a cathode material.

 

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