Binder-free Cu-supported Ag nanowires for aqueous rechargeable silver-zinc batteries with ultrahigh areal capacity.

ABSTRACT

As one of the most mature battery systems, the silver-zinc battery holds huge promise in the field of aqueous rechargeable batteries due to superior performance, high safety and environmental friendliness. It is urgent to improve the areal capacity of silver-zinc batteries so far. This study reports a novel Cu-supported Ag Nanowires (Cu@AgNAs1-5 abbreviation of Cu@AgNAs1, Cu@AgNAs2, Cu@AgNAs3, Cu@AgNAs4 and Cu@AgNAs5) as binder-free cathodes for high performance rechargeable aqueous silver-zinc batteries. Cu@AgNAs1-5 are successfully prepared by two steps of electrochemical nanoengineering and mild galvanic replacement between Cu and [Ag(NH3)2]+ chelate ions under green solution. With ultrahigh Ag loading of above 81 mg cm-2, the Cu@AgNAs5 cathode achieves ultrahigh areal capacity of above 36 mAh cm-2 at current density of 10 mA cm-2. Benefiting from synergistic effect of Ag and Cu, multiply twinned structure accompanied by lattice defections (such as lattice distortion, mismatch and dislocation) and heterostructures, the Cu@AgNAs1-5 cathodes achieve excellent Ag utilization and cycling stability. Furthermore, the aqueous rechargeable Cu@AgNAs5-Zn battery demonstrates an excellent areal capacity of 36.80 mAh cm-2 at 10 mA cm-2. This work offers a promising pathway to greatly enhance areal capacity of bimetallic nanostructure-based electrodes and the Cu@AgNAs1-5-Zn batteries are attractive for large-scale energy-storage application.