Exploring non-linearities of carbon-based microsupercapacitors from an equivalent circuit perspective

Abstract

The latest developments of miniature supercapacitors or microsupercapacitors involve the optimization of both energy-storage density and scalability of the manufacturing processes. Due to the reduced size and the compromised performance with material printability or cost, microsupercapacitors might behave non-ideally and non-linearly in real applications. Here we introduce a simple but powerful characterization method based on equivalent circuit analysis to explore the consequences of these imperfections on the charging and discharging properties of microsupercapacitors. Under voltage control, an asymmetric behavior of the voltammetry emerges upon charging and discharging, a part of the storage being hidden from the external circuit. Under current control, the capacitance is dependent on the magnitude and symmetry of applied current. These non-linear effects have to be incorporated into future consideration of any microsupercapacitor circuits.