A non-aqueous Li⁺/Cl⁻ dual-ion battery with layered double hydroxide cathode

Dual-ion batteries (DIBs) have unique advantages in energy storage, such as high energy density and low cost. However, most studies on organic DIBs use anions with a large ionic radius (PF₆⁻, TFSI⁻, etc.). Here, we propose a Li⁺/Cl⁻ dual-ion battery (DIB) through using CoFe-Cl layered double hydroxides (LDHs) and non-aqueous LiCl electrolytes, with a mechanism involving anionic insertion into the LDHs cathode and lithium plating/stripping on the anode. Coupled X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques indicate reversible expansion/extraction of (0 0 3) crystal planes of LDHs and valence state changes of Co and Fe, enabling high Cl⁻ storage capacities of 145 mAh/g and 137 mAh/g at 200 mA/g and 1 A/g, respectively. Furthermore, this DIB demonstrates an impressive power density of 1770 W/kg with an energy density of 240 Wh/kg. This work provides a reference for developing high performance DIBs and expands the electrochemical application field of LDHs.