Synergistic Interfacial and Bulk Modulation via Mixed Organic Phosphate Additives for Highly Stable Aqueous Zinc-Ion Batteries.

The practical application of aqueous zinc-ion batteries (AZIBs) is severely limited by water-induced issues, such as hydrogen evolution reaction, Zn metal corrosion, and cathode dissolution. To simultaneously stabilize the Zn anode and the NaV3O8 (NVO) cathode, we propose a synergistic strategy based on mixed organic phosphate additives, which integrates triethyl phosphate (TEP) for bulk modulation and tris(2,2,2-trifluoroethyl) phosphate (TFEP) for interfacial regulation. Experimental and computational investigations reveal that the TEP molecules actively participate in the Zn2+ solvation sheath and disrupt the hydrogen-bonding network of water. Meanwhile, the TFEP molecules preferentially adsorb onto the electrode surface and undergo reductive decomposition to construct a robust composite solid electrolyte interphase (SEI). The SEI, consisting of an inorganic-rich inner layer and an organic-rich outer layer, physically isolates the anode from active water and suppresses dendrite growth. Furthermore, the adsorbed TFEP contributes to the formation of a cathode electrolyte interphase (CEI) at the NVO cathode. Consequently, Zn||Zn symmetric cells achieve an extended cycling lifespan over 550 h at 10 mA cm-2 and 10 mAh cm-2, and Zn||NVO full cells exhibit excellent cycling stability with 92.6 % capacity retention after 500 cycles at 1 A g-1. This work provides a synergistic pathway for designing highly stable AZIBs.