Exploring the Possibility of Aluminum Plating/Stripping from a Non-Corrosive Al(OTF)3-Based Electrolyte

Abstract

Aluminum abundance sources and the high theoretical volumetric capacity of Aluminum metal make Aluminum Batteries (ABs) promising energy storage systems[1]. Moreover, the low cost, sustainability, and low reactivity of Al in the air due to its passivation layer are advantageous in comparison to Li[2]. However, developing appropriate electrolytes for Aluminum batteries is a challenging topic that hinders their practical use[3]. Of particular concern is that the high charge density of the Al cation results in strong Coulombic interaction with the counter anions and solvents, which negatively impacts the solvation behavior of Al salts [4]. A non-corrosive ternary electrolyte, composed of Al(OTF)3/NMA/urea in the molar fraction of 0.05/0.76/0.19 respectively, was tested for Al battery system as an alternative to the common chloroaluminate-based electrolytes to enable Al plating/stripping[5]. Herein, several techniques, such as scanning electron microscope/energy-dispersive X-ray spectroscope (SEM/EDX), operando Optical microscopy examination, electrochemical quartz crystal (EQCM) and Gas chromatography (GC) were used to explore the Al electrodeposition from this electrolyte. Yet, the hydrogen evolution reaction was found to be associated with electrochemical activities observed in this multicomponent electrolyte rather than Al electrodeposition.