Abstract: Aqueous zinc-ion batteries (AZIBs) hold promising prospects for large-scale energy storage systems, yet their commercialization is hindered by dendritic growth and water-induced side reactions associated with zinc anodes, especially at high depths of discharge (DOD). Herein, a multifunctional zincophilic additive is developed to promote the planar Zn deposition and construct a stable solid electrolyte interphase (SEI). Disodium malate (DMA) possesses pH-buffering capability that maintains electrolyte pH stability during prolonged cycling, effectively mitigating side reactions. Furthermore, the concentration of DMA significantly influences crystal deposition. An appropriate amount of DMA molecules selectively adsorbs onto the zinc foil, facilitating uniform zinc ion deposition on the (002) crystal plane. In addition, disodium maleate molecules reconfigure the electric double layer (EDL) to reduce free water interaction and promote the in-situ formation of the dense SEI, consisting of inorganic zinc salt and amorphous organic component, on the Zn metal surface. Notably, the dense organic-inorganic hybrid SEI layer persists with remarkable structural integrity even after long cycling. These features enable a highly reversible dendrite-free Zn plating/stripping process and suppress side reactions. As a result, Zn||Zn cells with DMA additives demonstrate extended cycling stability, enduring up to 5000 h at 8.6% DOD. Moreover, DMA-modified Zn anodes achieve an exceptional cycle lifespan of 750 h under 81.9% DOD with a high coulombic efficiency of 99.81% in asymmetric cells. In full-cell configurations, Zn||I₂ cells stably cycle for over 12,000 cycles, retaining 89.77% of their capacity. This electrolyte regulation strategy offers a compelling pathway for the development of aqueous zinc ion batteries.

Key words: Aqueous zinc ion batteries, Zn anode, Solid electrolyte interphase, High depth-of discharge, Plane texture