UIO‐66/Holey Graphene as a Surface Protective Layer for the Stabilization of Zn‐Metal Anode for High Performance Aqueous Zinc Ion Batteries

The practical use of Zn metal anode for aqueous zinc-ion batteries (AZIBs) still face critical issues of the growth of zinc dendrite, hydrogen evolution reaction (HER), and interfacial side reactions. To address these issues, a hierarchically structured UIO-66/holey graphene (UIO-66/rhG_0.1) composite is rationally designed and synthesized as an artificial protective layer via in situ growth of UIO-66 nanocrystals on holey graphene scaffolds, which is derived from spent lithium-ion battery graphite. The UIO-66/rhG_0.1 synergistically combines of UIO-66 with the porous confinement and hG with holey structures, enabling dual regulation of ion flux homogenization and electric field redistribution. As a result, the optimized symmetric cell achieves exceptional cycling stability over 2700 h with an ultralow voltage hysteresis of 44 mV, effectively suppressing the formation of Zn dendrites and HER. When the Zn@UIO-66/rhG_0.1 is paired with an NaV₃O₈ cathode, the full-cell retains a high 62.4% initial capacity (220.8 mAh g^-1) over 500 cycles, outperforming bare Zn anodes (59.4% and 114.5 mAh g^-1).