Ionic Liquid Electrolyte

Room temperature ionic liquids have attracted increasing attentions due to theirexcellent chemical stability, thermal stability and high conductivity. Influence factors ofionic liquid synthesis were investigated with uniform design in this work. Then six ionicliquids (ILs) based on imidazolium cations and maleic/phthalic acid anions weresynthesized according to the best results of the uniform design. Their structures werecharacterized and analyzed by IR. The thermal property, conductivity and electrochemicalstability have been investigated systematically. The thermal properties of ILs wereevaluated by DSC and TG, which indicated these ILs behave good thermal stability. Theconductivities of these ILs were measured at different temperatures. With the temperatureincreasing, the conductivity becomes higher. The conductivities of maleate anion-based arehigher than that of the corresponding phthalate anion-based ILs at a certain temperature.The Vogel-Tammaun-Fulcher (VTF) equation accurately describes the dependence of theconductivity on temperature.Electrolytes based on the synthysized ILs were confected. The conductivities and thesparking voltages of these electrolytes were measured. The results show that the sparkingvoltage values of electrolytes based maleate are higher than which based phalate anions.The sparking voltage values of these electrolytes range from 60V to 95V.The aluminum electrolytic capacitors have been fabricated with these electrolytesbased on ionic liquids. Then the impedance, leakage current, capacitance, loss, the shelflife and the resistance to soldering heat of the capacitors were investigated. The resultsshow that these aluminum electrolytic capacitors utilizing the electrolytes have satisfactorygeneral electric properties, excellent shelf life and high resistance to soldering heat.