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The replacement of the combustion-engine by sustainable electric or hybrid vehicles, may effectively limit environmental issues such as the global warming greenhouse-gas emission and pollution [1-2]. Lithium-ion battery represents the most promising candidate due to its high energy density, conventionally of about 180 Wh kg-1 that may assure a driving range of 150 km by single charge, i.e. acceptable value, however far from that granted by the conventional combustion engine vehicles. The lithium oxygen system, can theoretically allow to obtain an energy density of 1000 Wh kg-1, i.e. a value that may increase the driving range by single charge [3]. The applicability of the lithium air batteries is limited by several drawbacks, such as the poor electrolyte stability, the short cycle life and the low energy efficiency due to high charge-discharge polarization [4]. A deep knowledge of the lithium-oxygen reaction mechanism [5] and the identification of a stable electrolyte [6] play important role fundamental in allowing the practical application of the system. Furthermore, the safety concerns associated to the reactivity of the lithium metal anode are still hindering the application of the lithium-oxygen battery [7]. We report a Li/O2 cell exploiting an ionic liquid(IL)-based, N-Methyl-N-Butyl-Pyrrolidinium Bis-(trifluoromethanesulfonyl)-Imide Lithium bis-(trifluormethanesulfonyl)-imide, Pyr14TFSI-LiTFSI electrolyte. The use of non-flammable IL-based electrolyte stable up to a 300-400 °C resulted in an improved safety level of the battery [8]. In addition, the ionic-liquid electrolyte allows a fast kinetics of the lithium oxygen electrochemical process, thus lead to an high energy efficiency. The results here obtained, and reported in summary in the figure evidence low cell polarization, most likely due to the reduced particle size of the discharged products [9]. The replacement of the reactive lithium metal by an alternative, safe anode material may be required to further enhance the lithium oxygen cell characteristics [10]. Herein, we employed an alternative, nanostructured tin-carbon composite instead of lithium metal, in lithium ion-oxygen cell characterized in terms of electrochemical properties, focusing particular attention to the study of the oxygen cross-over process. [1] B. Scrosati, J. Hassoun, Y.-K. Sun, Ener. Environ. Sci., 4, 3287 (2011). [2] P. Myounggu, S. Heeyoung, L. Hyungbok, L. Junesoo, C. Jaephil, Adv. Energy Mater., 2, 780 (2012). [3] P. G. Bruce, S. A. Freunberger, L. J. Hardwick, J.-M. Tarascon, Nat. Mater. 11, 19, (2012). [4] Y.-C. Lu, B. M. Gallant, D. G. Kwabi, J. R. Harding, R. R. Mitchell, M. S. Whittingham, Y. Shao-Horn, Energy Environ. Sci., 6, 750, (2013). [5] M. Leskes, N.E. Drewett, L. J. Hardwick, P. G. Bruce, G. R. Goward, C. P. Grey, Angew. Chem. Int. Ed. 51, 8560, (2012). [6] H.-G. Jung, J. Hassoun, J.-B. Park, Y.-K. Sun, B. Scrosati, Nat. Chem. 4, 579, (2012). [7] J.-L. Shui, J.S. Okasinski, P. Kenesei, H.A. Dobbs, D. Zhao, J.D. Almer, D.-J. Liu, Nat. Commun., 4, 2255, (2013). [8] S. Randstrom, G. B. Appetecchi, C. Lagergren, A. Moreno, S. Passerini, Electrochim. Acta 53, 1837, (2007). [9] G.A. Elia, J. Hassoun, W.-J. Kwak, Y.-K. Sun, B. Scrosati, F. Mueller, D. Bresser, S. Passerini, P. Oberhumer, N. Tsiouvaras, J. Reiter, (2014) Nano Lett., 14, 6572, (2014). [10] J. Hassoun, H.-G. Jung, D.-J. Lee, J.-B. Park, K. Amine, Y.-K. Sun, B. Scrosati Nano Lett., 12, 5775, (2012) Figure 1

Batteries based on alkali-ions, such as lithium, sodium and potassium are considered the energy storage systems of choice for the next generation applications, such as electrified mobility and supply for renewable energy storage [1]. These systems are, in principle, light, efficient and potentially capable to meet several of the targets characterizing the emerging markets [2]. However, the use of the alkali-metal anode is definitely hindered by severe safety issues, including extreme reactivity with the electrolyte, eventual dendrite formation and cell short-circuit, leading to possible heating, thermal runway and fire [3,4]. Therefore, the severe requirements of the modern society triggered the replacement of the metallic anode by alternative materials characterized by higher safety content, in particular based on carbon [5], alloys [6] and metal oxides [7]. This radical change, partially succeeding in particular for lithium [6], is however still limited to few examples of efficient systems, employed for practical energy storage [1,3], such as Graphite/LCO, Graphite/LFP and Graphite/LNMC. Within this paper we developed a series of lithium-ion and sodium-ion batteries, including metal alloying [8], conversion [9] and graphene [10] anodes, high voltage spinel [11], olivine [12], sulfur [13,14] and oxygen [15] cathodes, and ionic liquid electrolyte [10,16] considered of interest for practical employment as alternative, safe and high energy storage systems for next generation applications. Figure: examples of various sodium and lithium ion cells in which the metal anode has been replaced by alternative materials References [1] D. Larcher, J-M. Tarascon, Nature Chemistry, 2015, 7, 19. [2] J. B. Goodenough, K.-S. Park, JACS, 2013, 135, 116. [3] J.-M. Tarascon, M. Armand, Nature, 2001, 414, 359. [4] V. L. Chevrier, G. Ceder, J. Electrochem. Soc., 2011, 158, 9, A1011. [5] M. Winter, J. O. Besenhard, M. E. Spahr, P. Novak, Adv. Mater., 1998, 10, 725. [6] J. Hassoun, P. Reale, B. Scrosati, J. Mater. Chem, 2007, 17, 3668. [7] J. Cabana, L. Monconduit, D. Larcher, M. R. Palacìn, Adv. Energy Mater., 2010, 22, E170. [8] J. Hassoun, S. Panero, P. Reale, and B. Scrosati, Adv. Mater., 2009, 21, 4808 [9] R. Verrelli, J. Hassoun, A. Farkas, T. Jacob, B. Scrosati, J. Mater. Chem. A, 2013, 1, 15329 [10] J. Hassoun, F. Bonaccorso, M. Agostini, M. Angelucci, M.G. Betti, R. Cingolani, M. Gemmi, C. Mariani, S. Panero, V. Pellegrini, B. Scrosati, Nano Letters, 2014, 14, 4901 [11] R. Verrelli, B. Scrosati, Y.-K. Sun, J. Hassoun, ACS Appl. Mater. Interfaces, 2014, 6, 5206 [12] I. Hasa, J. Hassoun, Y.-K. Sun, B. Scrosati, ChemPhysChem, 2014, 15, 2152 [13] M. Agostini, J. Hassoun, Scientific Reports, 20155, 7591 [14] D.-J. Lee, J.-W. Park, I. Hasa, Y.-K. Sun, B. Scrosati, J. Hassoun, J. Mater. Chem. A, 2013, 1, 5256 [15] G.A. Elia, R. Bernhard, J. Hassoun, RSC Advances, DOI: 10.1039/c4ra17277a [16] D. Di Lecce, S. Brutti, S. Panero, J. Hassoun, Materials Letters, 2015, 139, 329 Figure 1

Electrification has been a major focus of BMW and large efforts have been initiated in order to investigate technologies of high potential to be integrated in future electric vehicles. Metal-air and particularly lithium-air batteries [1] are one of the possible solutions that may substantially enhance the electric drive range. The main challenges in Li-air batteries are related to the stability of the electrolyte and safety of the negative electrode. BMW, together with three scientific teams initiated a project focusing on the use of ionic liquids and alternative anodes as potential components for Li-air batteries. Due to their excellent electrochemical and chemical properties, onium-based ionic liquids [2] were chosen as the first candidates. The presentation will describe the electrochemical behaviour of a Li-air cell comprising such ionic liquid-based electrolytes. The results prove the concept that the chosen ionic liquid may assure the proper lithium-oxygen cell operation and electrochemical stability during cycling. In this presentation work towards system safety improvement will be also shown [3]. In this field, alternatives to the lithium metal anode were investigated. The latter include: i) tin-carbon composite, ii) carbon-coated Zn1-xFexO [4], iii) SiOx-carbon and SiOx-silicon materials. Electrochemical tests have shown reversible behaviour of all materials both in conventional organic electrolytes as well as in electrolytes based on ionic liquids. References: Girishkumar G., McCloskey B., Luntz A.C., Wanson S., Wilcke W.: Lithium-air battery: Promise and Challenges. J. Phys. Chem. Lett., 2010, 1 (14), p. 2193-2203. Armand M., Endres F., MacFarlane D.R., Ohno H., Scrosati B.: Ionic-liquid materials for the Electrochemical Challenges. Nature Mat., 2009, 8 (8), p. 621-629. Hassoun J., Jung H.G., Lee D.J., Park J.B., Amine K., Sun Y.K., Scrosati B.: A Metal-Free, Lithium-Ion Oxygen Battery: A Step Forward to Safety in Lithium-Air Batteries. Nano Letters, 2012, 12, p. 5775-5779. Bresser D., Mueller F., Fiedler M., Krueger S., Kloepsch R., Baither D., Winter M., Paillard E., Passerini S.: Transition-Metal-Doped Zinc Oxide Nanoparticles as a New Lithium-Ion Anode Material. Chemistry of Materials, 2013, 25 (24), p. 4977-4985.

Due to its high energy density, largely exceeding that of conventional lithium-ion batteries,[1–2] the Li/O2 battery is presently considered as a very promising energy storage system. However, the practical development of this battery is still hindered by several issues, such as: 1) the limited cycle number, affecting its life; 2) the high charge–discharge polarization, resulting in low energy efficiency, and 3) the occurrence of side processes due to moisture and carbon dioxide contamination that preventing its use in open air. The choice of solvent and of electrolyte salt is expected to play a key role in influencing the cell behavior. To further investigate this important aspect, in this work we have examined the response of a Li/O2 cell using a tetraethylene glycol dimethyl ether electrolyte solutions, with four different salts, that is, LiPF6, LiClO4, LiCF3SO3, LiN(SO2CF3)2. This comparative study demonstrates that LiCF3SO3 salt is the best choice for assuring low cell polarization [3]. [1] B. Scrosati, J. Hassoun, Y.-K. Sun, Energy Environ. Sci. 2011, 4, 3287 –3295. [2] G. Girishkumar, B. McCloskey, A. C. Luntz, S. Swanson, W. Wilcke, J. Phys. Chem. Lett. 2010, 1, 2193– 2203. [3] Giuseppe Antonio Elia, Jin-Bum Park, Yang-Kook Sun, Bruno Scrosati, Jusef Hassoun, ChemElectroChem, DOI: 10.1002/celc.201300160.