Ionic Liquid Applications As Electrolyte For Zinc Air Battery

Zinc-air batteries have become high-energy,low-cost,green,and safe,This become an important type of energy storage battery.However,their electrolytes have defects such as water evaporation,reaction with CO2 present in the air,and precipitation to block electrode holes,which restricts their development.To overcome this drawback,Ionic Liquid has become vibrant because research hotspot field of electrolytes because of its vital characteristics of low vapor pressure and high stability.In this paper,a series of electrolytes based on ionic liquids have been developed and their battery performance as zinc-air battery electrolytes has been studied.The main research contents is as follows:(1)Four low-viscosity ionic liquids[Emim]SCN,[Bmim]SCN,[Emim]DCA,and[Emim]Ac were synthesized and used as electrolytes for zinc-air batteries,and their physical and electrochemical properties were measured.The results shows that when the temperature rises,its viscosity decreases continuously,and the conductivity increases accordingly.Among them,[Emim]DCA has the best conductivity performance,and its viscosity,conductivity and temperature,which comply with the description,rule of the Arrhenius formula.The pure ionic liquid electrolyte has a positive correlation between the amount of dissolved oxygen and pressure,[Emim]DCA and[Emim]Ac,has the highest absorption of oxygen.These four pure ionic liquids have been used as battery electrolytes.The order of charge and discharge performance at the time is[Emim]DCA>[Emim]SCN>[Emim]Ac>[Bmim]SCN,and the battery cycles when[Emim]DCA and[Emim]SCN are used as the electrolyte are the largest and close,reaching 180 times or more.(2)The physical and electrochemical properties of ZnAc+[Emim]DCA and ZnSO4+[Emim]DCA binary electrolyte systems were experimentally studied.The results show that as the metal salt content increases,the density and viscosity of the binary system both increase,and the electrical conductivity and the amount of dissolved oxygen gradually decreases.The relationship between the viscosity of the binary system and the content of the metal salt conforms to the fitting result of the Jones-Dole equation.In addition,when the metal salt concentration in the binary system is the same,the conductivity of the electrolyte of the ZnSO4/[Emim]DCA binary system the rate is relatively higher.In addition to the pure ionic liquid electrolyte,the electrochemical performance of the binary system electrolyte is better.When the concentration of both metal salts is 0.1 mol/L,the battery of the ZnSO4/[Emim]DCA binary component electrolyte.The charge and discharge performance is relatively better,and when the concentration of ZnSO4 is 0.2 mol/L,the charge and discharge and the cycle performance of the zinc-air battery are optimal.The charge and discharge voltages are 1.8 and 0.92 V,and the cycle is more than 323 times.(3)The physical and electrochemical properties of two ternary system electrolyte[Emim]DCA+ZnSO4+H2O,[Emim]DCA+ZnSO4+ diethylene glycol methyl ether were studied experimentally.The results show that water can effectively increase the conductivity of the electrolyte system.When the water concentration is 0.1 M,the conductivity of the system reaches the highest value,which is 93.1mS/cm.The addition of diethylene glycol methyl ether slightly reduced the conductivity of the electrolyte system.In addition,the full concentration conductivity of the water/ionic liquid system conforms to the fitting result of the Castel-Amis formula;When the ternary electrolyte system contains 0.3 mol/L H2O,its absorption of oxygen is the highest;in addition,relative to the binary electrolyte system,the use of additives improves the electrochemical performance of the electrolyte.While 0.6 mol/L H2O+0.2 mol/L ZnSO4+[Emim]DCA is used as the electrolyte.the battery charge and discharge performance and the cycle number are also relatively high.The research results show that the electrochemical performance of the electrolyte is ranked as ternary system>binary system>unary system.When 0.6 mol/L H2O+0.2 mol/L ZnSO4+[Emim]DCA is used as the electrolyte,the performance is the best,and the battery is charged and discharged The voltages are 1.98 and 1.22 V respectively,and the cycle number is more than 300 times.