Analysis of Charge Storage Behavior in Redox‐electrolyte Based Battery‐like‐systems: A Case Study on Zr‐doped Ceria
Sourav Ghosh, G. Ranga Rao, Tiju Thomas
Abstract
Abstract Redox‐additives are used as a cost‐effective means to improve low‐temperature charge‐storage capacity for aqueous‐supercapacitors. From a technology‐development standpoint, there are challenges associated with a lack of standard techniques to measure the redox‐additive based device‐parameters. This, in turn, yields a relatively poor understanding of the charge‐storage processes, especially in battery‐like supercapacitors. With this as a backdrop, this work undertakes an analysis of Ce 0.9 Zr 0.1 O 2 @Ni‐foam/KOH‐K 3 Fe(CN) 6 electrode/electrolyte system. Here, a method is presented that enables the delineation of the contribution of the effective‐mass of the redox‐additive on the electrode‐surface. This method demonstrates that the effective electrolyte‐mass has a ∼38.5 to ∼15% contribution toward charge‐storage with increasing scan rates (1 to 80 mV s −1 ). The diffusion‐controlled trends are duly analyzed using the well‐established Trasatti analysis; these also serve as a reasonable benchmark for the method reported here. Hence the method is expected to be of use for other hybrid‐supercapacitor systems as well.