High energy density Zn-ion hybrid capacitor using non-aqueous electrolytes

Abstract

Intensive research in the field of supercapacitors has been fuelled by the need for high efficiency energy storage systems. The concept of hybrid capacitor aims to close the gap between batteries and electrical double-layer capacitors in terms of improving the energy density. The purpose of the study was to find out if Zn-ion hybrid capacitors have the necessary characteristics and properties to be alternative future energy storage technology. Different combinations of acetonitrile and propylene carbonate solvents, together with Zn(TFSI)2, Zn(BF4)2 and Zn(OTf)2 salts were tested. Zn and carbon cloth electrode were studied using different physical characterization methods. Electrochemical performance for assembled test cells was measured and compared using cyclic voltammetry, electrochemical impedance spectroscopy, constant current charge/discharge methods and Ragone plots. Acetonitrile-based systems exhibited promising electrochemical results.