Study On High Temperature Performance Of Ionic Liquid Gel Polymer Electrolyte

As one of the world’s most advanced secondary batteries, lithium-ionbattery is widely used in various portable electronic devices, mobilecommunications, aerospace and other fields. Electrolyte is the integral part ofbattery, which has direct impacts on the performance of the battery. Safetyissues caused by abuse of organic electrolyte limit the application scope of thelithium-ion battery. Ionic liquid as electrolyte has features of non-volatile，non-flammability, high conductivity, extended electrochemical steady window andetc, therefore, ionic liquid is expected to lower battery safety risks caused byelectrolyte.This paper focuses on preparation of PP13TFSI/P（VdF-HFP）/LiTFSI andPY14TFSI/P（VdF-HFP）/LiTFSI two ionic liquids and gel polymer electrolytes,various physical and chemical properties at different temperatures are measured.They have superior thermal stability to organic electrolyte, the roomtemperature ionic conductivity of magnitude is close to10-3, the electrochemicalwindow is stable up to5V.Furthermore, the mentioned two ionic liquids and gel polymer electrolytesare applied with electrode LiFePO₄to test the discharge-charge properties atdifferent temperatures. Curves voltammetry cyclics show that the reversibilityof battery is good.0.2C rate has the best battery performance of all aspects, thetemperature has little effect on it. The influence of temperature on batteryperformance of0.5C rate is increased. Battery performance of1C rate is poorerthan0.2C and0.5C, the influence of temperature on which is stronger.And the influence of high temperature to battery is discussed.LiFePO₄is affected by high temparature and water, exhibiting large particle.Alis affected by water and TFSI-at high temparature. Corrosion is obviously seen.A layer of black substance which is speculated to be LiF appreared on Li athigh temperature. Ionic liquids and gel polymer electrolytes has no change.