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Kwak W.-J.,Hanyang University | Shin H.-J.,Hanyang University | Reiter J.,BMW AG | Tsiouvaras N.,BMW AG | And 5 more authors.
Journal of Materials Chemistry A | Year: 2016

Lithium oxygen batteries are attractive battery systems which can provide high energy density for the next generation. However, even if many research studies have made progress for years, the studies about substitution of Li metal which has inherent limitations in terms of stability and long term cycling properties are terribly deficient. Herein, our group clearly demonstrates the ambiguous unsolved problems of lithium oxygen full-cells using an alternative anode for Li metal by XRD and SEM analysis. The amount of Li source in the alternative anode is limited compared to the quasi-infinite amount of Li source in Li metal. The returning lithium ions during charging form lithium hydroxide which passivates the anode by a side reaction with moisture in the electrolyte and from outside. This report will help to accelerate the development of lithium oxygen full-cells. © 2016 The Royal Society of Chemistry. Source

Elia G.A.,University of Rome La Sapienza | Hassoun J.,University of Rome La Sapienza | Kwak W.-J.,Hanyang University | Sun Y.-K.,Hanyang University | And 10 more authors.
Nano Letters | Year: 2014

A novel lithium-oxygen battery exploiting PYR14TFSI-LiTFSI as ionic liquid-based electrolyte medium is reported. The Li/PYR14TFSI-LiTFSI/O2 battery was fully characterized by electrochemical impedance spectroscopy, capacity-limited cycling, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The results of this extensive study demonstrate that this new Li/O2 cell is characterized by a stable electrode-electrolyte interface and a highly reversible charge-discharge cycling behavior. Most remarkably, the charge process (oxygen oxidation reaction) is characterized by a very low overvoltage, enhancing the energy efficiency to 82%, thus, addressing one of the most critical issues preventing the practical application of lithium-oxygen batteries. © 2014 American Chemical Society. Source

Elia G.A.,University of Rome La Sapienza | Bresser D.,Helmholtz Institute Ulm | Bresser D.,Karlsruhe Institute of Technology | Bresser D.,CEA Grenoble | And 8 more authors.
ACS Applied Materials and Interfaces | Year: 2015

A novel lithium-ion/oxygen battery employing Pyr14TFSI-LiTFSI as the electrolyte and nanostructured LixSn-C as the anode is reported. The remarkable energy content of the oxygen cathode, the replacement of the lithium metal anode by a nanostructured stable lithium-alloying composite, and the concomitant use of nonflammable ionic liquid-based electrolyte result in a new and intrinsically safer energy storage system. The lithium-ion/oxygen battery delivers a stable capacity of 500 mAh g-1 at a working voltage of 2.4 V with a low charge-discharge polarization. However, further characterization of this new system by electrochemical impedance spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy reveals the progressive decrease of the battery working voltage, because of the crossover of oxygen through the electrolyte and its direct reaction with the LixSn-C anode. © 2015 American Chemical Society. Source

Ming J.,Hanyang University | Park J.-B.,Hanyang University | Kim H.-S.,Hanyang University | Yoon C.S.,Hanyang University | And 4 more authors.
Solid State Ionics | Year: 2015

Here we report a low polarization, catalyst-free lithium-oxygen battery using mesoporous carbon electrode. BET analysis, SEM and TEM images evidence that the carbon material has surface area as high as 1500 m2 g-1 and a uniform distribution of nanometric pores. Furthermore, X-ray diffraction analysis and TEM images of the reaction products show that the favourable effect of the mesoporous carbon is due to the formation of amorphous nano-particles of lithium peroxide during the electrochemical process. The results of this study clearly indicate the important role of the carbon matrix in determining a favourable morphology of the lithium-oxygen reaction product that leads to enhanced cell behaviour. © 2015 Elsevier B.V. All rights reserved. Source

Carbone L.,University of Rome La Sapienza | Gobet M.,York College - The City University of New York | Peng J.,York College - The City University of New York | Peng J.,City University of New York | And 4 more authors.
ACS Applied Materials and Interfaces | Year: 2015

Herein, we report the characteristics of electrolytes using various ether-solvents with molecular composition CH3O[CH2CH2O]nCH3, differing by chain length, and LiCF3SO3 as the lithium salt. The electrolytes, considered as suitable media for lithium-sulfur batteries, are characterized in terms of thermal properties (TGA, DSC), lithium ion conductivity, lithium interface stability, cyclic voltammetry, self-diffusion properties of the various components, and lithium transference number measured by NMR. Furthermore, the electrolytes are characterized in lithium cells using a sulfur-carbon composite cathode by galvanostatic charge-discharge tests. The results clearly evidence the influence of the solvent chain length on the species mobility within the electrolytes that directly affects the behavior in lithium sulfur cell. The results may effectively contribute to the progress of an efficient, high-energy lithium-sulfur battery. (Figure Presented). © 2015 American Chemical Society. Source

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