Development of a novel 1-trifluoroacetyl piperidine-based electrolyte for aluminum ion battery

Abstract

The first example of chloroaluminate ionic liquids (ILs) analogues based on amides of fluorinated carboxylic acids, namely 1-trifluoroacetyl piperidine (TFAP), has been described. The possibility of applying of this electrolytes has been experimentally evaluated in the series TFAP/AlCl3; TFAP/LiCl/AlCl3; TFAP/[EMIm]Cl/AlCl3; [EMIm]Cl/AlCl3 for use in an aluminum ion battery. The specific conductivities measured by the method of current interruption and impedance spectroscopy at 30 °C were 0.49, 0.28, 1.37, 20.23 mS cm−1, respectively. The exchange current densities at the two-phase interface aluminium/electrolyte investigated using the impedance spectroscopy method were 0.18, 0.03, 0.42, 1100 μA cm−2, respectively. TFAP-based electrolytes did not crystallize when cooled down to −60 °C, according to DSC data. The presence of the molecular [AlCl3(TFAP)], and the ionic AlCl4−, [AlCl2(TFAP)4]+, and [Al(TFAP)6]3+species is proposed based on the 27Al NMR spectra of the studied new ILs analogues.