Li ion diffusion measurements in V2O5 and Li(Co1-xAlx)O-2 thin-film battery cathodes

Thin films of V2O5 and LiCoO2 were deposited by pulsed laser deposition (PL D) and the chemical diffusion coefficients, (D) over tilde were measured by potentiostatic intermittent titration technique (PITT). The PLD-grown V2O5 and LiCoO2 films are electrochemically similar to bulk powders and thin fi lms produced by other techniques. In crystalline V2O5, the maximum and mini mum (D) over tilde were found to be 1.7 x 10(-12) cm(2) s(-1) and 5.8 x 10( -15) cm(2) s(-1) respectively, with a general trend for a to rise in single -phase regions. In amorphous VzQS films, D was initially 5 x 10(-13) cm(2) s(-1) and decreased steadily to 1.2 x 10(-13) cm(2) s(-1) at Li0.4V2O5 The decrease in (D) over tilde then became more gradual with a final value of 5 .52 x 10(-14) cm(2) s(-1) at Li1.5V2O5 The chemical diffusion coefficient o f Li in LiCoO2 films ranged from 1 x 10(-12)-4 x 10(-11) cm(2) s(-1) with a pronounced minimum at Li0.7CoO2 Thin films of LiCo0.5Al0.5O2 also deposite d by PLD exhibited limited cycling capabilities and an upper bound of (D) o ver tilde=9 x 10(-13) cm(2) s(-1). Published by Elsevier Science Ltd.