Electrochemical Energy Storage: Questioning the Popular v/v^1/2 Scan Rate Diagnosis in Cyclic Voltammetry

Abstract

The v/v 1/2 scan rate diagnosis in electrochemical energy storage devices is based on application of the relationship i = k 1 v + k 2 v 1/2 (where k 1 and k 2 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/v 1/2 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.

Understanding Rapid Intercalation Materials One Parameter at a Time

“…Costentin has argued that “pseudocapacitance” is an incorrect notion where such reported box‐like (redox pseudocapacitive) CV curves should be interpreted as EDLC and peak‐like (intercalation pseudocapacitive) curves should be interpreted as normal battery‐like intercalation undergoing slow charge transfer or ohmic drop. [ 60,63 ] That latter interpretation, however, is compatible with the broad definition above for intercalation pseudocapacitance where the question should become whether this behavior is worthy of a special name “intercalation pseudocapacitance.” We thus continue to use the term intercalation pseudocapacitance here. Others have extended the pseudocapacitance definition to be further constrained to examples exhibiting a linear relationship between the applied potential and the state of charge such as RuO 2 (Figure 2a).…”

Bacterial cellulose-derived micro/mesoporous carbon anode materials controlled by poly(methyl methacrylate) for fast sodium ion transport

“…S8a in the ESI †) were obtained. Assuming that the current obeys a power-law relationship with the scan rate as follows: [36][37][38]…”

Dual‐Ion Intercalation and High Volumetric Capacitance in a Two‐Dimensional Non‐Porous Coordination Polymer

“…However, recent work on modelling CVs find that Equation 2 is an oversimplification of experimental currents and is particularly erroneous at high scan rates [43–45] . One approach to address this issue is using multiple step chronoamperometry (MUSCA) to reconstruct CVs, minimize ohmic losses, and allow application of Equation 2 [46] .…”