Energy Storage Technologies Based on Electrochemical Double Layer Capacitors: A Review

Modern design approaches to electric energy storage devices based on nanostructured electrode materials, in particular, electrochemical double layer capacitors (supercapacitors) and their hybrids with Li-ion batteries, are considered. It is shown that hybridization of both positive and negative electrodes and also an electrolyte increases energy density of an electrochemical system, thus, filling the gap between supercapacitors and batteries in terms of specific energy and power, as well as charge rate and the number of charge-discharge cycles.