A Dendrite-Free Zn Anode Co-modified with In and ZnF₂ for Long-Life Zn-Ion Capacitors

Aqueous Zn (zinc) metal batteries have gotten a lot of interest and research because of their great volumetric capacity, low production cost, and high use safety. However, the coulombic efficiency of the Zn metal anode is low due to Zn dendrites formed during the charging and discharging processes of the battery, and the corrosion problem of the Zn anode in the electrolyte also reduces the battery's cycling stability and hinders its practical application. In this paper, InF₃ has been used to decorate the surface of Zn foil, and In (indium) and ZnF₂ coatings have been introduced to the surface of metal Zn simultaneously. After 1400 h of plating and stripping cycles, a symmetrical battery assembled from the modified Zn foil can still maintain a low voltage hysteresis of 30 mV. The Zn-ion capacitor assembled by the InF₃-modified Zn foil (Zn@In&ZnF₂) and activated carbon delivers an energy density of 33.5 Wh kg^-1 and a power density of 1608 W kg^-1 at a current density of 2 A g^-1 and can still maintain almost 100% capacity after 10,000 cycles. This work is helpful to improve the cycling stability and the corrosion problem of aqueous Zn-based batteries.