화학공학소재연구정보센터
Journal of Power Sources, Vol.179, No.1, 371-380, 2008
Characterization of solid electrode materials using chronoamperometry: A study of the alkaline gamma-MnO2 electrode
Large voltage step chronoamperometry is shown to be a time-efficient means to examine solid electrode materials compared with conventional electrochemical methods such as linear sweep voltammetry (LSV) and step potential electrochemical spectroscopy (SPECS), all the while providing comparable information concerning the rate capability of a material and its capacity. The applicability of the technique is demonstrated through a study of the alkaline gamma-MnO2 electrode. By sampling the current (and hence the charge) at various times after the chronoamperometric voltage step, the compatibility between chronoamperometry and LSV is disclosed. Furthermore, modelling of the chronoamperometric data using two curves based on a spherical diffusion model representing fast and slow discharge processes are found to be statistically suitable. From this modelling, values of A root D (where A is the electrochemically active surface area and D is the diffusion coefficient) for the two processes are 3.89 x 10(-4) and 0.70 x 10(-4) cm(3) S-1/2 g(-1), respectively, both of which are comparable with A root D data extracted from a SPECS experiment on an identical electrode. (C) 2008 Elsevier B.V. All rights reserved.