Amino-Substituted Azoxybenzenes as Potential Redox-Active Catholyte Materials

Aryl diazenes, particularly azobenzenes (AB), represent a versatile class of compounds with significant historical and practical relevance, ranging from dyes to molecular machines, solar thermal and electrochemical storage. Their oxygen-substituted counterparts, azoxybenzenes (AOB), share structural similarities but have been less explored, especially in energy storage applications. This study investigates the redox properties of AOB, comparing them to AB, and evaluates their potential as redox-active materials for energy storage systems. Through cyclic voltammetry (CV) and spectro-electrochemical analyses, we demonstrate that AOBs exhibit a distinct redox behaviour, influenced by the solvent and electrolyte environment, with a reversible oxidation process. Despite their promising redox characteristics, AOBs suffer from capacity decay during galvanostatic cycling, likely due to the instability of the radical cation intermediate. These findings suggest that while AOBs offer intriguing redox properties, further investigation into stabilization strategies are needed for their application in energy storage.