Degradation of electrochemical active compounds in aqueous organic redox flow batteries

Aqueous organic redox flow batteries (AORFBs) represent a promising energy storage technology that may enable the gridscale integration of intermittent renewable energy. The watersoluble, redox-active organic species that are utilized to reversibly store electricity are the most critical performancedetermining components in AORFBs. To ensure affordability and competitiveness in practical installations, it is of vital importance to enhance the structural stability and long-term durability of organic electrolytes, ultimately decreasing their levelized cost. Herein, we summarize the proposed decomposition mechanisms for representative organic electrolytes, including quinones, viologens, nitroxide radicals, and ferrocene derivatives. By reviewing the influence of molecular engineering on the side reactions of electrolytes, we intend to provide a better understanding of the decisive factors and inspire further attempts to design structurally robust and cycling-stable electrolytes for AORFB. Finally, we provide possible directions and prospects for future AORFB research.

Automated summary

This paper summarizes the decomposition mechanisms of organic electrolytes in aqueous organic redox flow batteries (AORFBs) and discusses the influence of molecular engineering on the side reactions of electrolytes. It provides inspiration for designing more stable and cycling-stable electrolytes for AORFB and suggests possible directions and prospects for future research.