Lithium transport through sputter deposited lithium cobalt dioxide thin film electrode

Lithium transport through lithium cobalt dioxide thin film electrode prepar ed by rf-magnetron sputtering was investigated in 1M solution of LiClO4 in propylene carbonate using cyclic voltammetry, galvanostatic intermittent ti tration technique (GITT) and potentiostatic current transient technique. Th e cathodic and anodic current transients exhibited the non-Fickian behaviou r of lithium transport when the applied potential steps encountered potenti al plateaus near 3.91 VLi/Li+, determined from GITT. It is suggested that t he occurrence of this abnormal behaviour during lithium intercalation and d eintercalation is accompanied by a 'diffusion-controlled' alpha/beta phase transformation and 'cell-impedance-controlled' phase transformation, respec tively. Lithium transport through the electrode comprising two phases of al pha and beta has been theoretically considered by a numerical analysis of t he phase transformation.