Comprehensive examination of the electrochemistry of indium in the molten LiCl-KCl eutectic

The reduction processes on glassy carbon electrode in molten LiCl-KCl eutec tic containing InCl3 was studied by cyclic voltammetry, chronopotentiometry , convolution voltammetry and numerical simulation of the experimental volt ammograms. The cathodic discharge of indium ions to form metallic indium wa s shown to take place by a consecutive two-step electrochemical reaction. T his process is identified as: In3+ + 2e double left right arrow In+ (revers ible) and In+ + e double left right arrow In-0 (quasi-reversible). The diff usion coefficients of both In3+ and In+ were found equal to 4 x 10(-5) cm(2 ) s(-1) at 440 degrees C, the exchange current density for the In3+/In+ cou ple equal to 0.01 A cm(-2), the rate constant for the In+/In-0 was found to be in the order of 0.001 cm s(-1) and the amount of indium metal needed to cover the electrode surface was found to be 5 x 10(-7) mol cm(-2). (C) 199 8 Elsevier Science Ltd. All rights reserved.