Abstract: Using 1,5-pentanediol（PD）and polyethylene glycol（PEG）as co-solvent to improve the electrochemical performance of 13 m（m=mol salt/kg solvent）Li OAc as aqueous lithium-ion batteries electrolytes obtains low-cost fluorine-free aqueous mixed solvent lithium acetate electrolytes.The activity of water molecules in the electrolyte was characterized by infrared absorption and Roman scattering spectroscopy.The results show that in the mixed solvent electrolytes the activity of water molecules is inhibited.Electrochemical tests show that the electrolytes have the widest electrochemical stability window of 3.10 V when the electrolyte composition is 2 m Li OAc-PD₀.₅PEG₀.₅,which makes the negative electrode Li₄Ti₅O₁₂reversibly charge and discharge.Li₄Ti₅O₁₂//Li Mn₂O₄full cell with 2 m Li OAc-PD₀.₅PEG₀.₅tests show an initial platform voltage of 2.3 V and specific energy of 0.0616 k Wh/kg,which obtains higher capacity and cycle stability than 13 m LiOAc electrolytes.