Synthesis and Electrochemical Properties of an Aluminum Hexafluorophosphate Electrolyte

Abstract

We report the first synthesis of aluminum hexafluorophosphate (Al(PF<sub>6</sub>)<sub>3</sub>) and its electrochemical properties in dimethyl sulfoxide (DMSO). The single crystal structure of the synthesized Al(PF<sub>6</sub>)<sub>3 </sub>is revealed as Al(PF<sub>6</sub>)<sub>3</sub>·(DMSO)<sub>6</sub>, and 0.25 M Al(PF<sub>6</sub>)<sub>3</sub> in DMSO with high ionic conductivity is obtained. With characterizations including nuclear magnetic resonance spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy, we demonstrate the reversibility of Al deposition-stripping in the electrolyte, which can be improved by triethylaluminium as the electrolyte additive. Finally, the side reaction involving DMSO decomposition to form aluminum oxide during Al deposition is identified by gas chromatography/electron ionization-mass spectrometry.