ABSTRACT
Since the first patent on supercapacitors in 1957, several studies have been conducted to improve their energy and power densities, charge storage capacity, conductivity, and structural stability. Combining the two main families of supercapacitors: pseudocapacitors and carbon-based electrochemical double-layer capacitors, to produce a hybrid material has been found to show a synergistic enhancement of the physicochemical properties of the two. One example is the most advanced hybrid supercapacitor, which is based on a Li4Ti5O12 working electrode and activated carbon counter electrode and is best coupled with non-aqueous electrolytes to provide high power and energy densities at high voltages. Despite the advances in this field, much effort needs to be focused on hybrid flexible supercapacitors, which have the potential of being integrated into advanced wearable electronic devices, integrated systems, and textile materials.
