Manipulating alloying reaction to achieve the stable and dendrite-free zinc metal anodes

Zinc metal anode has serious dendrites and corrosion issues in the mild electrolyte, which greatly hinder the commercialization of aqueous zinc-ion batteries. Herein, zinc-amalgam (Zn3Hg) alloy anode has been prepared and displays a unique synergistic zinc plating/stripping and alloying/dealloying reaction mechanism. The ultrafast zinc ions diffusion in Zn3Hg and the alloying reaction of Zn3Hg with Zn ions effectively suppress the dendrites growth and skillfully address corrosion issues. Consequently, the Zn3Hg anode expresses long cycle life of 2000 h at 1 mA cm−2/1 mAh cm−2 and exhibits the lowest voltage hysteresis of only 8.0 mV that we know so far. Even at 5 mA cm−2/5 mAh cm−2 and 10 mA cm−2/10 mAh cm−2, the Zn3Hg anode also exhibits excellent cycling stability and low voltage hysteresis. Moreover, zinc ion capacitors composed of Zn3Hg anode and active carbon cathode still possess a specific capacity of 61 mAh/g after 5000 cycles at 1 A/g. The Zn3Hg anode enriches the varieties of zinc alloy anodes and provides a new development path for constructing stable and dendrite-free zinc metal anodes.