The article by Tang et al., which was published recently [Electrochim. Acta, Electrochim. Acta 50 (2005) 5581-5587], proposed a novel technique for the determination of diffusion coefficients of intercalated species in host materials. The capacity intermittent titration technique (CITT) is an extension of the ratio of potentiostatic-to-galvanostatic charge (RPG) technique developed initially by the same authors. By the CITT, the Li+ solid-state diffusion coefficient within LiMn2O4 was determined by these authors at different voltages and different galvanostatic-charge currents. In these comments, the ratio of potentiostatic-to-galvanostatic charge is reexamined by taking finite charge-transfer kinetics at the interface and Ohmic drop into consideration. The measurement error of diffusion coefficients evaluated by CITT while using the approximation of infinitely fast charge-transfer kinetics is predicted quantitatively. (c) 2005 Elsevier Ltd. All rights reserved.