High-Rate Quinone Cathodes and Nafion Conditioning for Improved Stability in Aqueous Zinc-Ion Batteries.

The growing need for fast and reliable energy delivery in various applications ranging from electric vehicles and portable electronics to grid-scale storage demands high-performance energy storage systems capable of operating at high charge/discharge rates (C-rates). Aqueous zinc-ion batteries (AZIBs) offer a promising alternative to conventional lithium-ion batteries primarily due to their inherent safety, environmental friendliness, low cost, and high theoretical capacity. Quinone-based cathodes, with their fast redox kinetics and high theoretical capacities, are particularly suitable for high-rate applications. However, their practical application in AZIBs is limited by their high solubility in aqueous electrolytes, leading to significant capacity fading and poor long-term cycling stability, especially at elevated C-rates. To address these challenges, this study investigates the use of Nafion membranes as ion-selective barriers to stabilize quinone cathodes and prevent the dissolution of active materials. The study evaluates four quinone-based cathodes─2,3,5,6-tetrachloro-1,4-benzoquinone (TCBQ), 1,4-naphthoquinone (NQ), anthraquinone (AQ), and poly(2-chloro-3,5,6-trisulfide-1,4-benzoquinone) (PCTBQ)─in AZIBs, focusing on the effect of Nafion membrane conditioning in 1 M ZnSO₄ electrolyte. The results demonstrate that optimized Nafion conditioning significantly enhances the stability and performance of quinone cathodes, reducing dissolution, improving cyclability, and maintaining stable capacity retention under high-rate conditions, i.e., 35C. These findings emphasize the importance of membrane conditioning and demonstrate its potential to advance the development of durable, high-rate AZIBs for rapid energy storage applications.