  Discovery of electrocatalytic materials for high-performance energy
conversion and storage applications relies on the adequate characterization of
their intrinsic activity, which is currently hindered by the dearth of a
protocol for consistent and precise determination of double layer capacitance
(CDL). Herein, we propose a seven-step method that aims to determine CDL
reliably by scan rate-dependent cyclic voltammetry. The method considers three
aspects that strongly influence the outcome of the analysis: measurement
settings, data collection, and data processing. To illustrate the proposed
method, two systems were studied: a resistor-capacitor electric circuit and a
glassy carbon disk in an electrochemical cell. With these studies it is
demonstrated that when any of the mentioned aspects of the procedure are
neglected, substantial deviations of the results are observed with
misestimations as large as 61% in the case of the investigated electrochemical
system. Moreover, we propose allometric regression as a more suitable model
than linear regression for the determination of CDL for both the ideal and the
non-ideal systems investigated. We stress the importance of assessing the
accuracy of not only highly specialized electrochemical methods, but also of
those that are well-known and commonly used as it is the case of the
voltammetric methods. The methodology proposed herein is not limited to the
determination of CDL, but can be effectively applied to any other
voltammetry-based analysis that aims to deliver quantitative results.
