Promoting Room Temperature Aluminum Deposition Through Rapid Ligand Exchange Complexes

Unlocking room temperature aluminum (Al) electroplating stands as a promising avenue for advancing multivalent energy storage systems and pioneering surface coating methods, pivotal in driving a zero-emission economy. Despite its potential, challenges such as electrolyte-induced parasitic reactions during Al deposition, high flammability risks, suboptimal Coulombic efficiency, and the costliness of organic-based electrolytes have persisted. Addressing these challenges necessitates reducing activation energy and expediting kinetics for the electrochemical reduction of aluminum cations in organic electrolyte solutions. This is pivotal for achieving efficient, reversible room temperature electrodeposition of Al. In our study, we introduce a novel electrolyte material—a highly concentrated aluminum chloride (AlCl₃) solution within weakly coordinating dialkyl-ether and sulfone compounds.^[1] These solvents swiftly form ligand exchange complexes with AlCl₃, enabling rapid Al electrodeposition at a minimal 0.2 V overpotential. Additionally, they effectively suppress the solvent's parasitic reaction, particularly in the low voltage regime. Our research delves into the intricate interactions between solvents and solutes in weakly coordinating environments, shedding light on their influence on electrolyte solution electrochemistry. This foundational understanding is pivotal for future electrolyte design and optimization, benefiting both electroplating and rechargeable batteries.<br/><b>Reference</b><br/>[1] Nguyen, D.T., Murugesan, V., Prabhakaran, V. and Mueller, K.T., Battelle Memorial Institute Inc, 2023. Aluminum-ether-based composition for batteries and ambient temperature aluminum deposition. U.S. Patent Application 18/130,281.