Electrochemical Energy Storage: Questioning the Popular v/v1/2 Scan Rate Diagnosis in Cyclic Voltammetry.

The v/v1/2 scan rate diagnosis in electrochemical energy storage devices is based on application of the relationship i = k1v + k2v1/2 (where k1 and k2 are two constants independent of the scan rate v) to the variation of the cyclic voltammetric responses with v. Several examples show that application of this scan rate diagnosis procedure leads to absurd results because the procedure is inappropriate under these conditions. It follows that the best approach is to simply forget about this v/v1/2 scan rate diagnosis, concentrate on the maximum number of experimental observations of the scan rate dependency, and build models able to reproduce these data in each case.