Harnessing Self-Condensing Vinyl Copolymerization for Well-Defined Redox-Active Hyperbranched Polymers Enabled by Flow Chemistry

The increased adoption of renewable power necessitates the development of grid-scale storage solutions, with aqueous redox flow batteries (RFBs) at the forefront. Despite their potential, performance degradation due to crossover typically requires expensive specialty membranes. Previous research has demonstrated the use of cost-effective dialysis membranes, but issues of the solution viscosity and crossover continue to pose challenges. Here we use flow chemistry to create redox-active hyperbranched copolymers (HCPs) with remarkably low dispersity. The distinct reaction dynamics of flow chemistry facilitated the efficient and monomer-independent control over self-condensing vinyl polymerization. This substantially improved the suppression of crossover and enhanced rheology behaviors. RFBs equipped with our redox-active HCPs exhibited exceptional long-term stability, mapping a pathway towards more refined electrolyte design and practical application of polymer-based technologies. Meanwhile, our study underscores the significant advantages and potential of emerging flow chemistry techniques.