Effect of urea as a chaotropic agent on self-association of organic molecules in aqueous flow batteries - UTU Research Portal

A1 Refereed original research article in a scientific journal

Effect of urea as a chaotropic agent on self-association of organic molecules in aqueous flow batteries

Authors: Shahsavan, Mahsa; Wiberg, Cedrik; Poskela, Aapo; Martinez-Gonzalez, Eduardo; Peljo, Pekka

Publisher: Royal Society of Chemistry

Publication year: 2026

Journal: Physical Chemistry Chemical Physics

ISSN: 1463-9076

eISSN: 1463-9084

DOI: https://doi.org/10.1039/d5cp03782d

Publication's open availability at the time of reporting: Open Access

Publication channel's open availability : Partially Open Access publication channel

Web address : https://pubs.rsc.org/en/content/articlelanding/2026/cp/d5cp03782d

Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/515846404

Self-archived copy's licence: CC BY

Self-archived copy's version: Publisher`s PDF

Abstract

This paper investigates the effect of urea, a widely used denaturing co-solute, on the aggregation of promising candidates for aqueous organic flow batteries, specifically 9,10-anthraquinone-2,7-disulfonic acid (AQDS) and naphthalene diimide derivatives (NDIs). These molecules undergo aggregation through π-π interactions of their aromatic cores. We evaluated how urea influences molecular interactions and electrochemical behavior of these molecules by nuclear magnetic resonance (NMR), cyclic voltammetry (CV), rotating disk electrode (RDE), and flow battery testing. While NMR confirmed that urea effectively disrupts π-π stacking and reduces the concentration-dependent shifts and peak broadening, electrochemical measurements showed that this effect is only partial. These results highlight the difference between molecular-level disruption of aggregation and limited improvements in electrochemical performance.

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Funding information in the publication:
We are grateful for the financial support from the Research Council of Finland (BioFlow project, Grant agreement 343493) and the Jenny and Antti Wihuri Foundation for the homing grant. This work has also partially emanated from the research of P. P. and C. W. supported by the European Research Council (Starting Grant, agreement no. 950038).