Aging phenomena and their modelling in aqueous organic redox flow batteries: A review

Abstract

Renewable energy sources and ways to store this energy due to its intermittency are growing exponentially. Redox flow batteries, which allow decoupling energy from power, are a promising way of electrochemical storage of electricity. Vanadium flow batteries, the current technological reference, are giving way to aqueous organic electroactive species, which present the advantages of multiple designs thanks to functionalization, lower cost, non-toxicity, and less supply issues. Their long-term performances are still compromised because of degradations of the electrodes, the membrane, or the organic species. Physical models are a good way to predict redox flow batteries behavior on long time scales and have a better understanding of the phenomena and their impact on the battery. Some degradations of the electrodes, the membrane or side reactions have been modelled, however very few models for organic active species degradations have been proposed yet.This review presents some reported degradations and their consequences for the cell components and organic electrolytes. Different existing models for aqueous organic redox flow batteries are presented, with a focus on Multiphysics models. Degradations’ modelling in aqueous redox flow batteries is discussed, with existing degradations models as well as some proposals for future degradations modelling.