A −60 °C Low‐Temperature Aqueous Lithium Ion‐Bromine Battery with High Power Density Enabled by Electrolyte Design

Abstract Aqueous lithium‐ion batteries are normally limited at low temperatures, because of the consequent low conductivity of electrolytes and the sluggish kinetics of electrode materials. Herein, a high‐performance ultra‐low temperature aqueous lithium ion‐bromine battery (ALBB) realized by a tailored functionalized electrolyte (TFE) consisting of lithium bromide and tetrapropylammonium bromide (TPABr) is reported, which can maintain liquid state with high conductivity (1.89 mS cm ‐1 ) at − 60 ° C. In addition, with the help of excellent bromine‐fixation of TPABr, the high reversible capacity can be provided by the fast redox reaction of Br 2 /Br ‐ couple in the cathode from room temperature (RT) to − 60 ° C. Moreover, 1,4,5,8‐naphthalenetetracarboxylic dianhydride‐derived polyimide anode can deliver excellent low‐temperature capacity retention as well as enhanced rate capability and reversibility at RT in TFE. As a result, the designed TFE can endow ALBB with high energy densities (98, 64, and 32 Wh kg dry ‐1 at RT, − 40, and − 60 ° C, respectively), outstanding power densities (24.6 and 1.2 kW kg dry ‐1 at RT and − 40 ° C, respectively), and superior capacity retentions (94% and 98% after running 1000 cycles at RT and − 40 ° C, respectively). This work demonstrates a novel strategy to widen the temperature range of aqueous batteries.