An In-Depth Study of Regulable Zincophilic Alloy Matrix toward Stable Zinc Metal Batteries

Introducing 3D hosts is recognized as valid means to low the local current density for alleviating dendrite problems. However, the uncontrollable "top growth" behavior on some 3D hosts is still a serious issue. Although some strategies on the manipulation of Zn2+ ion flux by causing Zn-alloying metals are reported, the covert details during cycles are still ignored. A tuned Cu-Zn alloy interfacial layer on stainless-steel mesh (SS) is proposed here as a fresh tactic. The zincophilic scaffold furnishes nucleation sites and lowers energy barriers for axipetally controllable Zn plating. In-depth study reveals that CuxZny phase generated by variable Cu/Zn ratios preferentially forms into CuZn5 with Zn plating and then converts into metallic Zn in plating cycle, and no decomposition in a given voltage range in stripping process due to a negative Gibbs free energy of formation of zinc alloys. Thus, CuZn5 is the main zincophilic seed in the subsequent cycles, regardless of any CuxZny phases. As a result, the optimized SS in Zn//MnO2 full cell can render 70% retention after 350 cycles, while the bare SS only shows retention of 30%.