Regulating Preferred Crystal Plane with Modification of Exposed Grain Boundary Toward Stable Zn Anode

Abstract Aqueous Zn metal batteries (ZMBs) are largely hampered by the poor stability of zinc (Zn) anode in aqueous electrolyte due to uncontrollable deposition behavior and parasitic reactions. Hence, a stable Glu@Zn anode via acid etching is developed that simultaneously exposes (002) plane and modifies exposed grain boundaries. The surface‐preferred (002) plane is achieved by minimizing its surface energy. And the exposed grain boundaries are also modified by decomposition products of acid etching, which can greatly reduce the adverse effects caused by highly active grain boundaries. These features favor Glu@Zn anode by accrediting a long‐term cycle lifespan exceeding 4400 h with a high average coulombic efficiency (CE) of 98.9%. Surprisingly, Glu@Zn anode can run for more than 250 h with 50% Zn utilization. The assembled Glu@Zn//NH 4 V 4 O 10 full batteries deliver a specific capacity of 291.6 mAh g −1 after 400 cycles even at a low current density of 0.5 A g −1 . It can also obtain a stable cycling performance up to 2000 cycles. To further verify its stability, a pouch cell is constructed that can preserve stable 400 cycles with 5 mAh. This study sheds light on surface energy regulation exposing preferred crystal plane to develop highly stable and reversible cycling aqueous ZMBs.