Tuning ionic liquids properties considering its use as electrolytes in lithium batteries Prof. Roberto Torresi Depto. Química, USP, Brazil rtorresi@iq.usp.br   Lithium-ion batteries are one of the most popular types of batteries, especially for its high charge density and being rechargeable. These batteries are used extensively in portable devices such as cell phones, laptops, digital cameras. Mixtures of aprotic organic solvents and LiPF6 are used in these batteries. However, the flammability of organic solvents and low thermal stability of LiPF6 makes it prohibitive to build lithium-ion batteries using such systems for large devices. Ionic liquids (ILs) have been widely studied due to the unique properties that they display, such as low vapor pressure, non-flammability, thermal stability. The possibility of having an ILs at room temperature,chemically and electrochemical- ly stable has triggered in recent years several papers which discuss the feasibility of using ILs as electrolytes in rechargeable lithium batteries. Thermal properties, ionic conductivity, density, viscosity, diffusion coefficients, Raman spectroscopy and MD simulations revealed that the ionic liquid with LiTFSI has unusual dynamics that depends on the concentration LiTFSI. The decrease in the Walden product indicates changes in the chemical nature of the ion pair formed depending on the LiTFSI concentration. Considering the concentration of all ionic species, the number of transport Li+ is the smallest and the ionic conductivity is governed mainly by the ILs anionic and cationic species. Several way to try to improve Li+ transport will be shown, beginning with different substitution on the organic cation and also by adding an “additive” to the IL. Also, magnesium electrodeposition in different ILs will be discussed. < return