Reverse Dual-Ion Battery by Coupling Adsorption and Conversion Mechanism

As one kind of promising energy storage device, dual-ion batteries (DIBs) have attracted extensive attention because of their high voltage, environmental friendliness, and low cost. However, they generally suffer from low power density resulting from sluggish kinetic of electrolyte anion intercalation. In this work, a new strategy to break through the trade-off of power density and energy density in DIBs is proposed. A vanadium-doped anatase is synthesized by the hydrothermal method and used as the cathode of DIB (employing Li as the anode). During the charging/discharging process, the organic cations in the electrolyte are reversibly adsorbed–desorbed at the cathode; while a conversion reaction of Li/LiCl occurs at the anode. The effective integration of cation adsorption and conversion reaction mechanism results in a large power density of 1532 W kg −1 along with a high energy density of 214 Wh kg −1 at 1 A g −1 . This design concept is universal and has been successfully transplanted to cation/Br − DIB. Therefore, this work provides a novel approach to optimize the energy/power density of DIBs, which is highly desired in constructing high-performance energy storage devices.