Synergistic Interfacial and Structural Modulation via Four‐Pronged Cationic Additives for High‐Stability Aqueous Zinc‐Molybdenum Batteries

Abstract Aqueous Zn‐MoO ₃ batteries are garnering significant attention for high‐performance energy storage systems due to their high theoretical capacity. However, research on this battery system is limited, primarily due to the stability issues associated with severe side reactions of the Zn anode and intrinsic instability of the MoO ₃ cathode. Here, Al ₂ (SO ₄ ) ₃ is introduced into the ZnSO ₄ electrolyte to synergistically stabilize both the anode and cathode. This additive confers four distinct advantages: i) competitive solvation effects that accelerate the dissolution and deposition kinetics of Zn ²⁺ ; ii) in situ construction of a protective layer on the surface of the Zn anode; iii) regulation of the Zn ²⁺ deposition orientation to induce uniform deposition of zinc; and iv) facilitation of the topological transformation of MoO ₃ into Al _x Zn _y H _z MoO ₃ ·nH ₂ O to modify the cathode structure, thereby enabling reversible carrier intercalation into the host material and enhancing cathode stability. As a result, the Zn||Zn battery exhibits an ultra‐long cycling life over 4350 h. Moreover, the assembled Zn||Cu battery achieves an extended cycling life from 196 to 4000 cycles at 4 mA cm ⁻² . The Al _x Zn _y H _z MoO ₃ ·nH ₂ O cathode, following topological transformation, demonstrates significantly enhanced cycling stability, achieving 90.01% capacity retention after 1200 cycles at 5 A g ⁻¹ , compared to only 2.85% without additives.