Inorganic Electrolyte Additive Promoting the Interfacial Stability for Durable Zn-Ion Batteries

The development of Zn-ion batteries (ZIBs) is always hindered by the ruleless interface reactions between the solid electrode and liquid electrolyte, and seeking appropriate electrolyte additives is considered as a valid approach to stabilize the electrode/electrolyte interphases for high-performance ZIBs. Benefiting from the unique solubility of TiOSO₄ in acidic solution, the composite electrolyte of 2 m ZnSO₄+30 mm TiOSO₄ (ZSO/TSO) is configured and its positive contribution to Zn//Zn cells, Zn//Cu cells, and Zn//NH₄V₄O₁₀ batteries are comprehensively investigated by electrochemical tests and theoretical calculations. Based on the theoretical calculations, the introduction of TiOSO₄ contributes to facilitating the desolvation kinetics of Zn²⁺ ions and guarantees the stable interface reactions of both zinc anode and NH₄V₄O₁₀ cathode. As expected, Zn//Zn cells keep long-term cycling behavior for 3750 h under the test condition of 1 mA cm^-2-1 mAh cm^-2, Zn//Cu cells deliver high Coulombic efficiency of 99.9% for 1000 cycles under the test condition of 5 mA cm^-2-1 mAh cm^-2, and Zn//NH₄V₄O₁₀ batteries maintain reversible specific capacity of 193.8 mAh g^-1 after 1700 cycles at 5 A g^-1 in ZSO/TSO electrolyte. These satisfactory results manifest that TiOSO₄ additive holds great potential to improve the performances of ZIBs.