Lithium ion chemical diffusion coefficients in (LiMn2O4)-Li-6 thin sputtered films (similar to 2 mu m) were determined by the depth profiles of Li-7 concentration after adopting the potential step in (LiClO4)-Li-7/propylene carbonate solution by using secondary-ion mass spectrometry (SIMS). Lithium chemical diffusion coefficient via bulk (D-bulk) and grain boundary diffusion coefficient normalized with width (dD(gh)) were determined as 1.23 x 10(-15) m(2) s(-1) and 6.55. 10(-20) m(3) s(-1), respectively. (C) 2008 Elsevier B.V. All rights reserved.