The Rate-Dependence of Supercapacitor Performance: Quantitative Evaluation Using Peukert’s Constant

Peukert’s law, widely used to model the rate-dependence of battery capacity, is beginning to receive attention in the evaluation of supercapacitors. Here, we demonstrate the use of a simple method of determining Peukert’s constant using impedance spectroscopy in order to analyze the rate-dependence of supercapacitor performance. The relationships between porosity and pseudocapacitance and Peukert’s constant are investigated through the simulation of equivalent circuit models. The utility of Peukert’s constant for the evaluation of the rate-dependence of supercapacitor performance is established through a novel analysis of supercapacitor data available in the literature. The use of a quantitative approach to understanding supercapacitor rate-performance provides additional clarity and insight over the commonly used qualitative approach.