Boosting the Anode and Cathode Stability Simultaneously by Interfacial Engineering via Electrolyte Solvation Structure Regulation Toward Practical Aqueous Zn-ion Battery

The application of zinc-ion batteries (ZIBs) is seriously challenged by the poor stability of Zn anode and cathode in aqueous solution, which is closely associated with electrolyte structure and water reactivity. Herein, the stability issues both for the cathode and anode can be simultaneously addressed via tuning the electrolyte solvation structure in hybrid electrolyte with tripropyl phosphate (TPP) as co-solvent. On the Zn anode, a robust poly-inorganic solid electrolyte interphase (SEI) layer comprised of Zn₃(PO₄)₂-ZnS-ZnF₂ species is in situ formed, effectively suppressing parasitic reaction and dendrite evolution. For V₂O₅ cathode, the notorious vanadium dissolution is effectively restricted with improved structure stability achieved. The optimized electrolyte facilitates the reversible redox kinetics both at the cathode and Zn anode. Consequently, Zn||Zn cells display extended cycling lifespans over 3000 h at 1 mA cm⁻², 1 mAh cm⁻². Zn||V₂O₅ full cells deliver a high reversible capacity of 261.8 mAh g⁻¹ and hold retention of 73.6% upon 500 cycles even operated in harsh conditions with thin Zn anode (10 µm) and low negative/positive (N/P) ratio of ≈4.3, which also showcase impressive performance with regard to rate and storage performance, further emphasizing the potential of electrolyte regulation tactics in advancing the commercialization of ZIBs.