Chronoammetric determination of the lithium transfer rate in carbon electrodes

The diffusion processes, which proceed in an LixC6 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, dE/dx, are determined.