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 TiOSO in acidic solution, the composite electrolyte of 2 m ZnSO+30 mm TiOSO (ZSO/TSO) is configured and its positive contribution to Zn//Zn cells, Zn//Cu cells, and Zn//NHVO batteries are comprehensively investigated by electrochemical tests and theoretical calculations. Based on the theoretical calculations, the introduction of TiOSO contributes to facilitating the desolvation kinetics of Zn ions and guarantees the stable interface reactions of both zinc anode and NHVO cathode. As expected, Zn//Zn cells keep long-term cycling behavior for 3750 h under the test condition of 1 mA cm-1 mAh cm, Zn//Cu cells deliver high Coulombic efficiency of 99.9% for 1000 cycles under the test condition of 5 mA cm-1 mAh cm, and Zn//NHVO batteries maintain reversible specific capacity of 193.8 mAh g after 1700 cycles at 5 A g in ZSO/TSO electrolyte. These satisfactory results manifest that TiOSO additive holds great potential to improve the performances of ZIBs.