Anion-Rich Solvation Structures in High Entropy Aqueous Electrolytes for Supercapacitors with Superior Potential Windows and Rate Capabilities

Abstract

The use of aqueous electrolytes as suitable electrolytes for supercapacitor (SCs) strongly depends on the opening of the operating cell voltage while preserving good rate capabilities so to obtain high energy and power densities over numerous cycles. Electrolyte engineering with anion- and/or solvent-rich solvation structures has been recently explored in batteries of any sort to enhance the interphase stability at high voltages, typically by the formation of a SEI. Less explored has been this approach in SCs to not only extending the range of operational voltage but also balancing the inherently distinct electrochemical stability of cations and anions with carbon electrodes. Herein, we prepared electrolytes composed of two ionic liquids with a common cation (e.g., EMIMTFSI and EMIMBF4) in solvent mixtures of H2O, DMSO and CH3CN. We found that the electrolyte with the richest solvation structure (i.e., with many and diverse anions that surrounded the cation) was the most effective to widening the cell voltage at which the electrolyte is capable to operate (e.g., up to 2.2 V). Interestingly, this extremely-rich solvation structure also exhibited the best transport properties for the different ions that, ultimately, were responsible of an excellent maintainance of the energy density at high power densities.

Supplementary files

Article information

Article type
Paper
Submitted
12 Jun 2025
Accepted
07 Aug 2025
First published
08 Aug 2025
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. A, 2025, Accepted Manuscript

Anion-Rich Solvation Structures in High Entropy Aqueous Electrolytes for Supercapacitors with Superior Potential Windows and Rate Capabilities

L. González-Aguilera, J. M. Vicent-Luna, P. García-Balaguer, S. Calero, R. M. Madero-Castro, E. Raymundo-Piñero, X. Lu, M. L. Ferrer, F. del Monte and M. C. Gutierrez, J. Mater. Chem. A, 2025, Accepted Manuscript , DOI: 10.1039/D5TA04796J

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements