Advancements for aqueous polysulfide-based flow batteries: development and challenge

Abstract

Polysulfide-based redox flow batteries (PSRFBs) have emerged as an innovative solution for large-scale energy storage technology owing to their high energy density and low cost. These advantages position PSRFBs as particularly suitable for grid-scale integration of renewable energy. However, challenges such as sluggish redox kinetics and crossover of polysulfide have impeded their widespread adoption and commercialization. This review aims to provide a comprehensive overview of the working principles, development, and challenges of PSRFBs, focusing on strategies to mitigate crossover and enhance reaction kinetics of polysulfides. Recent advancements in catalytic materials, membrane design, and electrolyte engineering are summarized, highlighting their important roles in improving the electrochemical performance of PSRFBs. Future research directions for PSRFBs are finally suggested to focus on designing ion-exchange membranes with moderate ionic conductivity and ionic selectivity, developing redox mediators or soluble catalysts, tailoring the solvation structure of polysulfides in the anolyte and employing advanced in-situ characterization techniques.