Chronoammetric Determination of the Lithium Transfer Rate in Carbon Electrodes

The diffusion processes, which proceed in an Li _x C₆ electrode under potentiostatic conditions (when a potential step is applied), are considered. The passive film, which continuously exists on the surface of the electrode, has a pronounced effect on the current–time plot and quantitative diffusion parameters, which are determined chronoammetrically. An analytical solution of the diffusion problem is obtained for small deviations from equilibrium. Experimental current–time plots for thin lithium–carbon electrodes are well described by the theoretical equations; simultaneously, the passive-layer resistance, the diffusion coefficient for lithium in carbon, and the derivative of the electrode potential with respect to its composition, , are determined.