Electrochemical Study Of Direct Electrolysis Method For Alkali Metals K, Rb And Cs Deposition

Alkali metals, such as K, Rb and Cs are widely used in pharmaceutical, electronicdevices, special material and new energy fields due to their unique physical andchemical properties. Because their chemical properties are too lively, they can’t bereduced from aqueous solution by electrolytic method directly. Molten-salt electrolysisis one of the most important methods to prepare active metals. However, comparedwith aqueous system, the mechanism of molten-salt electrolysis needs further research.The emergence of room temperature ionic liquids provides a possible way to preparealkali metals at mild conditions. Room temperature ionic liquid combines the bothadvantages of aqueous system and molten-salt system, such as wide electrochemicalwindow, high conductivity, environmental friendly, is a promising electrolyte forelectrochemical application. Molten-salt and ionic liquid are used as electrolyte toresearch the electrochemical behavior of alkali metal ion respectively, the mainresearch contents are as follows:（1）1-butyl-3-methylimidazolium tetrafluoroborate （[bmim] BF₄） ionic liquid wasused as electrolyte to prepare potassium by electrolytic method. Its basic properties,like electrochemical window and dissolving capacity for potassium ion were measured.Different experiment conditions, temperature and stiring intensity for instance, wereemployed to test their influences on potassium ion electroplating process.（2）1-butyl-3-methylimidazolium hexafluorophosphate （[bmim] PF₆） ionic liquidwas chosen to research the electrochemical behaviors of rubidium ion. Electrodesmade with different kinds of materials and different experiment conditions, such astemperature and stiring intensity, were employed to test their influences on rubidiumion electroplating process.（3） The electrochemical behavior of cesium ion was studied in CsCl molten-saltsystem and CsCl+LiCl molten-salt system respectively. Different kinds of electrodematerials and electrolytic parameters were used to optimize the electrodepositionprocess.（4） Industrial applications of the two methods discribed above and future researchdirection were discussed.