LAUSR

ABSTRACT Among post Li-ion battery technologies, Al-ion batteries are receiving growing attention due to the high abundance of Al, low cost, ease of handling in an ambient environment, and high theoretical capacities obtained from three-electron redox process. Here, the physicochemical properties of AlCl3 and urea mixtures known as deep eutectic solvents or ionic liquid analogs (ILAs) are investigated by changing the molar ratio of AlCl3/urea in the range of 1.0–1.6. Multinuclear (27Al, 13C, 1H) nuclear magnetic resonance spectroscopy (NMR), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) are used to determine the speciation of ionic moieties, ionic conductivity, and electrochemical stability of this complex system. On the basis of the composition–property results, 1.4 molar ratio of AlCl3/urea was selected as the best composition and was used as the electrolyte in an Al-cell made of Al anode and graphene nanoplatelets (GNP) cathode. The battery delivered a specific capacity of 74 mAh g–1 at 100 mA g–1, and it retained a specific capacity of ∼40 mAh g–1 at a very high current of 1000 mA g–1.