  Accurate theoretical results for interdigitated array of electrodes (IDAE) in
semi-infinite cells can be found in the literature. However, these results are
not always applicable when using finite cells. In this study, theoretical
expressions for IDAE in a finite geometry cell are presented. At known current
density, transient and steady state concentration profiles were obtained as
well as the response time to a current step. Concerning the diffusion limited
current, a lower bound was derived from the concentration profile and an upper
bound was obtained from the limiting current of the semi-infinite case. The
lower bound, which is valid when Kirchhoff's current law applies to the unit
cell, can be useful to ensure a minimum current level during the design of the
electrochemical cell. Finally, a criterion was developed defining when the
behaviors of finite and semi-infinite cells are comparable. This allows to
obtain higher current levels in finite cells, approaching that of the
semi-infinite case. Examples with simulations were performed in order to
illustrate and validate the theoretical results.
