Potential Posolytes for Aqueous Organic Redox Flow Batteries

Renewable energy plays a crucial role in decarbonizing modern society, but the inherent intermittency of renewable energy sources impedes the integration of renewable energy into power grids. Grid‐scale energy storage technologies and devices are thus needed to balance the mismatch between power supply and demand. Aqueous organic redox flow batteries (AORFBs) have emerged as the most promising type of long‐duration grid‐scale energy storage devices. AORFBs offer advantages, including power and energy decoupling, high safety, low cost, scalable design, and vast electrolyte options. However, the development and practical applications of AORFBs are limited by the properties of posolytes, which currently exhibit relatively low stability, low redox potential, limited structural diversity, and low operational flexibility. Here, the development and molecular design of posolytes for AORFBs are summarized. Key achievements and existing challenges are discussed, followed by perspectives for future research in this field.