In this section
@article{Sun:2026:10.1016/j.jpowsour.2025.238590,
author = {Sun, Y and Brandon, N and Weiss, D and Kucernak, A},
doi = {10.1016/j.jpowsour.2025.238590},
journal = {Journal of Power Sources},
title = {The importance of non-ideality of protons and water in the open circuit potential modelling of redox flow battery aqueous electrolytes},
url = {http://dx.doi.org/10.1016/j.jpowsour.2025.238590},
volume = {661},
year = {2026}
}
TY - JOUR
AB - The non-ideality of electrolytes is commonly neglected in redox flow battery (RFB) modelling work. The neglect of activity coefficients introduces a discrepancy of up to 100 mV between the experimental open circuit potential (OCP) and model predicted reversible Nernstian potential, which propagates into inaccurate state of charge estimation and misinterpretation of thermodynamic efficiency. Due to the complex chemistry and the lack of thermodynamic data, activity coefficients of individual species in highly non-ideal electrolytes are often difficult to determine. In this work, proton and water activity values were calculated using geochemical numerical codes implementing the Pitzer theory, a semi-empirical thermodynamic model that accounts for the non-ideal behavior of ions in electrolyte solutions. The completed Nernst equation with corrected activity values has been elaborated for OCP comparison. An in-operando approach was proposed to measure the proton and water activities of strongly acidic electrolytes. The cell OCP of Hydrogen-Vanadium RFB (H2-V RFB) and Hydrogen-Manganese RFB (H2-Mn RFB) was measured and calculated to assess the electrochemical significance of proton and water non-ideality to the RFB model. With the measured activity data, the error between the experimental and calculated OCP values was reduced from 88-100 mV to 17–50 mV.
AU - Sun,Y
AU - Brandon,N
AU - Weiss,D
AU - Kucernak,A
DO - 10.1016/j.jpowsour.2025.238590
PY - 2026///
SN - 0378-7753
TI - The importance of non-ideality of protons and water in the open circuit potential modelling of redox flow battery aqueous electrolytes
T2 - Journal of Power Sources
UR - http://dx.doi.org/10.1016/j.jpowsour.2025.238590
UR - https://doi.org/10.1016/j.jpowsour.2025.238590
VL - 661
ER -
Prof. Anthony Kucernak
G22B
Molecular Sciences Research Hub (MSRH)
Imperial College London
White City Campus
London
W12 0BZ
United Kingdom
Phone: +44 (0)20 7594 5831
Fax: +44 (0)20 7594 5804
Email: anthony@imperial.ac.uk