<p>Understanding the mechanisms of charge storage in supercapacitors is crucial for optimizing their performance in advanced energy storage applications. Supercapacitors exhibit a blend of both electric double-layer capacitance (EDLC) and pseudocapacitance, making it essential to differentiate these contributions for material design and device optimization. Among various analytical methods, Dunn’s method, which uses cyclic voltammetry (CV) at varying scan rates, has emerged as a widely employed technique. As it is a relatively straightforward approach for deconvoluting capacitive and diffusion-controlled processes, this review provides a comprehensive overview of Dunn’s method, encompassing its theoretical background, analytical procedure, advantages, limitations, and applications across diverse electrode materials. Furthermore, the comparison of Dunn’s method with other electrochemical characterization techniques such as electrochemical impedance spectroscopy (EIS), galvanostatic charge–discharge (GCD), and Trasatti’s method also underscores future prospects for enhancing its accuracy and applicability. This review aims to serve as a practical guide for researchers looking to employ Dunn’s method in supercapacitor research.</p>