A new family of rechargeable batteries based on halide ions shuttling

Abstract Anion insertion electrochemistry is a new frontier that leads to exciting applicable technologies including anion-based rechargeable batteries. Herein, we demonstrate a family of room temperature anion-type “rocking-chair” batteries by employing halide ions (F−, Cl− or Br−) intercalated CoNi layered double hydroxide (LDH) and metal lithium as electrochemical couples, ionic liquid as electrolyte. Reversible shuttles of anions can be realized in all these three systems and the anion batteries show high capacity (maximum capacity of 338 mAh g−1) and acceptable cycling stability (above 100 mAh g−1 after 50 cycles). A topological transformation energy storage mechanism of reversible anions intercalation/de-intercalation accompanied by oxidation/reduction of intralayer metals is revealed, by using bromide ions battery as a model. The proof-of-concept for LDH materials as cathodes of anion-type rechargeable batteries fills the void in the anion inserted materials innovation landscape, and allows their potential application in next-generation energy storage systems, owing to their variability in chemical composition, high structural stability, and low cost.