Electroanalytical Study of Electrode Processes on Carbon Anode in Lithium Fluoride and Neodymium Fluoride Melt

摘要

The anode processes of carbon electrode in LiF-70%NdF3 melt were studied by electroanalytical techniques, including cyclic voltammetry(CV) and chronoamperometry(CA). Anode gases were analyzed by gas chromatography(GC) on-line during controlled-potential electrolysis. Two anode peaks were observed. The first process starting at 2.0 V vs Li+/Li was corresponded to the discharge of residual oxide ions, with the generation of CO and CO2. The discharge of fluoride ions occurred at the potentials higher than 4.3 V vs Li+/Li, with the generation of a small amount of CF4 and C2F6, accompanied by a sudden drop in current, marking the onset of the anode effect. The second process occurred when the potential exceeded 5.5 V vs Li+/Li, with the generation of a large amount of CF4 and C2F6. When the temperature was changed from 1173 to 1273 K, the current of the second process decreased, leading to a stable anode effect.