Analysis of Charge Storage Behavior in Redox‐electrolyte Based Battery‐like‐systems: A Case Study on Zr‐doped Ceria. Issue 5 (3rd February 2020)

• Record Type: Journal Article
• Authors: Ghosh, Sourav; Rao, G. Ranga; Thomas, Tiju
• Is Part Of: ChemistrySelect. Volume 5:Issue 5(2020)
• Page Start: 1628
• Page End: 1639
• Publication Date: 2020-02-03
• Subjects: battery-like supercapacitor -- cerium -- electrode -- electrolyte -- nanoparticles -- redox-additive.; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201904761
• Languages: English
• ISSNs: 2365-6549

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 Ce0.9 Zr0.1 O2 @Ni‐foam/KOH‐K3 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. Abstract : Battery‐like supercapacitor behavior of Ce0.9 Zr0.1 O2 with mixed electrolyte [0.2 M K3 Fe(CN)6 + 2 M KOH] has been studied. An appropriate parametric analysis of the operational windows for the battery‐like system is performed. The electrolytic‐mass contribution goes from 15 to ∼38.5%, with decreasing scan rates. A novel method is reported that allows correlation of device‐performance to the amount of redox‐additive participating at the electrode‐electrolyte interface. The method is benchmarked, making it relevant for analysis of other battery‐like systems.