A Rechargeable Mg-O2 Battery

The increase in energy consumption and the need to decrease the amount of CO2 emitted in the atmosphere, has pushed the world's leading manufacturers in the automotive field to invest in research aiming to find cleaner energy storage devices. Among them, metal-air batteries has attracted a lot of attention because of their incredibly high energy density. These systems aim to offer in the future a charming alternative to the high-consumption widespread Li-ion batteries in terms of efficiency, energy density, costs, rechargeability, and safety. Different metals can be adopted as anode and, for this project, we decided to employ magnesium in our system. Magnesium batteries, if they will ever truly become a product of commercial interest, will be much smaller than Li batteries, cheaper, and safer, besides ensuring a high energy density. The purpose of the work is to provide some notion on battery basic working principles and to explore different electrolytes, salts and catalysts which could be good candidates for magnesium-oxygen battery system. Different experiments have been carried out to better understand and analyze the evolution of the chemical processes, reduce the polarization gap, and improve efficiency and cycleability. Many combinations have been considered, utilizing as solvents: dimethyl sulfoxide (DMSO), 1,2-dimethoxyethane (DME), tetraethylene glycol dimethyl ether (TEGDME), and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4); and as salts: trifluoromethanesulfonate, bromide, chloride, and nitrate. Moreover, the report will analyze the effect of changes in ratio between the solvents and various salts concentrations, plus the use of several salts mixtures in order to promote magnesium plating and stripping. Finally, cyclic voltammetry experiments have been performed, using MoS2, WS2 and MoxW(1-x)S2 (i.e. different molar ratio) to evaluate their catalytic activity in Mg/O2 batteries.