Benzyltriethylammonium Chloride Electrolyte for High‐Performance Al‐Ion Batteries

Abstract Aluminum ion batteries have attached more attention because of inherent advantages such as abundant Al source, low flammability, three‐electron‐redox property and high theoretical capacity. However, many problems exist in the electrolyte system of aluminum ion battery, such as high price, low capacity. We prepare a novel AlCl 3 /Benzyltriethylammonium chloride electrolyte for aluminum ion battery. The battery displays a good performance at high current densities: 102 mA h g −1 at 5 A g −1 with a coulombic efficiency of ∼98% and 91 mA h g −1 at 10 A g −1 after 1500 cycles. It only takes 13 seconds to be fully charged/discharged at the current density of 25 A g −1 . The mechanism of intercalation/de‐intercalation of chloroaluminate anions is confirmed by characterization and we believe AlCl 3 /Benzyltriethylammonium chloride will be a promising electrolyte for aluminum ion batteries.