An Aluminum–Sulfur Battery with a Fast Kinetic Response

The electrochemical performance of the aluminum‐sulfur (Al‐S) battery has very poor reversibility and a low charge/discharge current density owing to slow kinetic processes determined by an inevitable dissociation reaction from Al 2 Cl 7 − to free Al 3+ . Al 2 Cl 6 Br − was used instead of Al 2 Cl 7 − as the dissociation reaction reagent. A 15‐fold faster reaction rate of Al 2 Cl 6 Br − dissociation than that of Al 2 Cl 7 − was confirmed by density function theory calculations and the Arrhenius equation. This accelerated dissociation reaction was experimentally verified by the increase of exchange current density during Al electro‐deposition. Using Al 2 Cl 6 Br − instead of Al 2 Cl 7 − , a kinetically accelerated Al‐S battery has a sulfur utilization of more than 80 %, with at least four times the sulfur content and five times the current density than that of previous work.