Aluminum Electrodeposition from Chloride-Rich and Chloride-Free Organic Electrolytes

The corrosivity of chloride-based electrolytes is a major shortcoming in the practical realization of rechargeable aluminum batteries. Herein, the effect of Cl – on Al speciation and electrochemistry in tetrahydrofuran (THF) was measured by employing theoretical and experimental approaches for three systems: Al(OTF) 3 /THF, Al(OTF) 3 plus LiCl in THF, and AlCl 3 /THF. The high consistency between measured and computed spectroscopic aspects associated with Al(OTF) 3 /THF electrolyte provided both a rationale for understanding Al complex-ion formation in a Cl – -free environment and an approach for examining the effect of Cl – on Al speciation. Room-temperature Al plating was achieved from dilute solutions ([Al] = 0.1 M) at potentials ≥ 0 V (vs Al/Al 3+ ). Cl – is found to enable facile Al plating and SEM reveals that Al is electrochemically deposited as nanocrystalline grains.