Electrochemical investigation on kinetics of potassium intercalating
into graphite in KF melt
into graphite in KF melt
(1. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
2. Department of Chemical and Environmental engineering, Jiaozuo University, Jiaozuo 454003, China;
3. Zhengzhou Research Institute of CHALCO, Zhengzhou 450041, China)
2. Department of Chemical and Environmental engineering, Jiaozuo University, Jiaozuo 454003, China;
3. Zhengzhou Research Institute of CHALCO, Zhengzhou 450041, China)
Abstract: The kinetics of potassium intercalating into graphite in molten KF at 1 163 K was investigated by means of cyclic voltammetry and chronoamperometry. Cyclic voltammetry results indicate that intercalaltion/deintercalation of potassium into/from graphite involve kinetic limitations. The intercalation process of potassium was further confirmed to be governed by both the diffusion of potassium ion in graphite bulk and the phase transition kinetics through the analyses of current-time transient curves with reversible and quasi-reversible equations. The transfer coefficient of the intercalation reaction was calculated to be 0.364 according to the parameters resulting from nonlinear fitting of the current-time transient curves with a quasi-reversible equation. Analysis with scanning electron microscope shows that graphite matrix was severely eroded by intercalation of potassium.
Key words: potassium intercalation; graphite; molten salt; aluminum electrolysis; KF